Journal articles on the topic 'Amendment rates'
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1
Baldock, J. A., C. Creamer, S. Szarvas, J. McGowan, T. Carter, and M. Farrell. "Linking decomposition rates of soil organic amendments to their chemical composition." Soil Research 59, no. 6 (2021): 630. http://dx.doi.org/10.1071/sr20269.
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The stock of organic carbon contained within a soil represents the balance between inputs and losses. Inputs are defined by the ability of vegetation to capture and retain carbon dioxide, effects that management practices have on the proportion of captured carbon that is added to soil and the application organic amendments. The proportion of organic amendment carbon retained is defined by its rate of mineralisation. In this study, the rate of carbon mineralisation from 85 different potential soil organic amendments (composts, manures, plant residues and biosolids) was quantified under controlled environmental conditions over a 547 day incubation period. The composition of each organic amendment was quantified using nuclear magnetic resonance and mid- and near-infrared spectroscopies. Cumulative mineralisation of organic carbon from the amendments was fitted to a two-pool exponential model. Multivariate chemometric algorithms were derived to allow the size of the fast and slow cycling pools of carbon to be predicted from the acquired spectroscopic data. However, the fast and slow decomposition rate constants could not be predicted suggesting that prediction of the residence time of organic amendment carbon in soil would likely require additional information related to soil type, environmental conditions, and management practices in use at the site of application.
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Lutz, Donald S. "Toward a Theory of Constitutional Amendment." American Political Science Review 88, no. 2 (June 1994): 355–70. http://dx.doi.org/10.2307/2944709.
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Constitutional design proceeds under the assumption that institutions have predictable consequences, but modern political science has not pursued the empirical verification of these predicted consequences with much vigor. I shall attempt to link the theoretical premises underlying one important aspect of constitutional design, the amendment process, with the empirical patterns revealed by a systematic, comparative study of constitutions. An examination of all amendments in the 50 American states since 1776 reveals patterns that are then confirmed using data from 32 national constitutions. The interaction of the two key variables affecting amendment rate can be described by an equation that generates predicted amendment rates close to those found in the cross-national empirical analysis. A constitution's length measured in number of words, the difficulty of an amendment process, and the rate of amendment turn out to have interlocking consequences that illuminate principles of constitutional design.
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Worden, Christopher, George Elliott, Bernard Bible, Karl Guillard, and Thomas Morris. "Use of a Food-processing Residual Compost for Salad Green Production on Organic Farms: Soil Response and Crop Yields." HortScience 35, no. 5 (August 2000): 830B—830. http://dx.doi.org/10.21273/hortsci.35.5.830b.
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A composting facility in New Milford, Conn. (NMF), utilizes food-processing residuals, including spent tea leaves, coffee grounds, cocoa shell and cleanings, wastewater treatment sludge from a food ingredients manufacturing plant, and past-expiration processed vegetable products. Materials are composted in aerated, frequently turned windrows under cover. The range of inputs, combined with time constraints on the composting process, has resulted in a variable, immature compost product with a high rate of microbial activity. Users have expressed concern about potential phytotoxicity or nutrient immobilization from using NMF compost. Therefore, research was conducted to determine the influence of cured and uncured NMF compost amendments on potentially sensitive crops with high nutrient requirements. Arugula (Eruca vesicaria) and green bibb lettuce (Lactuca sativa) were grown on two Connecticut organic farm research sites in 1998 and 1999. Both sites have soils classified as coarse loamy over sandy or sandy-skeletal, mixed, mesic, typic, Dystraudepts. Farms differed in the length of time under organic farm management. One farm has been an organic farm since 1988 and consequently has high soil fertility, while the other was a first-year organic farm in 1998, and had relatively low soil fertility. Three amendment types were applied: cured compost, uncured compost, and organic fertilizer (5N-3P2O5-4K2O). Amendment application rates were estimated to provide a comparable range of plant-available nutrients for the amendments and a control without fertilizer. Compost application rates were 3.4, 6.8, 20.2, 35.8, and 71.7 Mg·ha-1 (dry-weight basis) in 1998 and 11.2, 22.4, 44.8, and 89.6 Mg·ha-1 (dry-weight basis) in 1999. Organic fertilizer application rates were 1.34, 2.68, 5.36, 10.72, and 21.44 Mg·ha-1 in 1998 and 1.34, 2.68, 5.38, and 10.72 Mg·ha-1 in 1999. Soil organic matter and nutrients increased with amendment application rate at both locations. Crop yields increased with amendment rate at the new, lower-fertility farm, but yields did not respond to amendments at the older, higher-fertility farm. Yield differences were minor between the uncured and cured compost treatments at both locations. This indicates that either cured or uncured NMF food-processing residual compost can be successfully used as an organic soil amendment for salad green production.
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Duddigan, Sarah, Paul D. Alexander, Liz J. Shaw, Taru Sandén, and Chris D. Collins. "The Tea Bag Index—UK: Using Citizen/Community Science to Investigate Organic Matter Decomposition Rates in Domestic Gardens." Sustainability 12, no. 17 (August 25, 2020): 6895. http://dx.doi.org/10.3390/su12176895.
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Gardening has the potential to influence several ecosystem services, including soil carbon dynamics, and shape progression towards the UN Sustainable Development Goals, (e.g., SDG 13). There are very few citizen/community science projects that have been set up to test an explicit hypothesis. However, citizen/community science allows collection of countrywide observations on ecosystem services in domestic gardens to inform us on the effects of gardening on SDGs. The geographical spread of samples that can be collected by citizen/community science would not be possible with a team of professional science researchers alone. Members of the general public across the UK submitted soil samples and buried standardised litter bags (tea bags) as part of the Tea Bag Index—UK citizen/community science project. Participants returned 511 samples from across the UK from areas in their garden where soil organic amendments were and were not applied. The project examined the effects of application of soil amendments on decomposition rates and stabilisation of litter, and in turn, effects on soil carbon and nitrogen concentrations. This was in response to a call for contributions to a global map of decomposition in the Teatime4Science campaign. Results suggested that application of amendments significantly increased decomposition rate and soil carbon, nitrogen, and carbon: nitrogen ratios within each garden. So much so that amendment application had more influence than geographic location. Furthermore, there were no significant interactions between location and amendment application. We therefore conclude that management in gardens has similar effects on soil carbon and decomposition, regardless of the location of the garden in question. Stabilisation factor was influenced more prominently by location than amendment application. Gardening management decisions can influence a number of SDGs and a citizen/community science project can aid in both the monitoring of SDGs, and involvement of the public in delivery of SDGs.
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Keilhauer, Mary G., Tiffany L. Messer, Aaron R. Mittelstet, Thomas G. Franti, and Jessica Corman. "Nitrate Removal by Floating Treatment Wetlands Amended with Spent Coffee: A Mesocosm-Scale Evaluation." Transactions of the ASABE 62, no. 6 (2019): 1619–30. http://dx.doi.org/10.13031/trans.13431.
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HighlightsA floating treatment wetland design was evaluated for water quality improvements.Nitrate-N removal rates were quantified using spent coffee grounds as a carbon source.Nitrate-N removal rates increased throughout the growing season Abstract. The Midwestern U.S. is vulnerable to eutrophic conditions from high nutrient concentrations. Floating treatment wetlands (FTWs) are an innovative wetland design for nutrient removal from nonpoint sources and provide a unique treatment. The objectives of this project were to quantify nitrate removal in traditional and carbon-amended FTWs planted with Midwestern plant species during the establishment year. Three greenhouse experiments were conducted throughout the growing season using 18 mesocosms. Two vegetation designs were evaluated: rush species ( and ) and diverse species (, , , , , and ). Spent coffee grounds were applied to 9 of the 18 mesocosms as a carbon amendment. Nitrate-N removal increased during the establishment growing season in the FTW systems (Spring: 15.0% to 17.3%, Summer 1: 82.8% to 92.6%, Summer 2: 86.4% to 94.7%). Nitrate-N removal was also impacted by carbon amendments (FTW without amendment: 82.8% to 94.7%, FTW with amendment: 88.4% to 96.1%). Carbon additions were found to enhance denitrifying conditions even in the absence of FTWs (decreased dissolved oxygen, increased available organic carbon). Significant differences in nitrate-N removal were not observed between FTW vegetation designs. This study provides new insight on the impacts of the growing season, plant species, and carbon amendments on FTW nitrate-N removal performance during the establishment year. Keywords: Best management practices, Carbon amendment, Floating treatment wetlands, Nitrogen removal, Spent coffee grounds
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Kumarathilaka, Prasanna, and Meththika Vithanage. "Influence of Gliricidia sepium Biochar on Attenuate Perchlorate-Induced Heavy Metal Release in Serpentine Soil." Journal of Chemistry 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/6180636.
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Perchlorate (ClO4-) is a strong oxidizer, capable of accelerating heavy metal release into regolith/soil. Here, we assessed interactions between ClO4- and serpentine soil to simulate and understand the fate of Ni and Mn and their immobilization with the presence of biochar (BC). A soil incubation study (6 months) was performed using serpentine soil in combination with different ClO4- concentrations (0.25, 0.5, 0.75, and 1 wt.%) and three different amendment rates (1, 2.5, and 5 wt.%) of Gliricidia sepium BC. Bioavailable fraction of Ni and Mn was analyzed using CaCl2 extraction method. An increase of ClO4- concentrations enhanced bioavailability fraction of Ni and Mn. However, BC amendments reduced the bioavailability of Ni and Mn. In comparison, 5% BC amendment significantly immobilized the bioavailability of Ni (68–92%) and Mn (76–93%) compared to other BC amendment rates. Electrostatic attractions and surface diffusion could be postulated for Ni and Mn immobilization by BC. In addition, ClO4- may have adsorbed to BC via hydrogen bonding which may reduce the influence of ClO4- on Ni and Mn mobility. Overall, it is obvious that BC could be utilized as an effective amendment to immobilize Ni and Mn in heavy metal and ClO4- contaminated soil.
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Little, Neith G., Charles L. Mohler, Quirine M. Ketterings, and Antonio DiTommaso. "Effects of Organic Nutrient Amendments on Weed and Crop Growth." Weed Science 63, no. 3 (September 2015): 710–22. http://dx.doi.org/10.1614/ws-d-14-00151.1.
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Sufficient fertility is important for crop growth and yield but supplying a balanced amount of N, P, and K with compost and manure is a challenge and nutrient imbalances can benefit weeds more than crops. The goal of this study was to compare the aboveground growth responses of common northeastern U.S. crops and weeds to addition of composted poultry manure (CPM). A secondary goal was to test whether the observed growth responses to CPM could be attributed to the three macronutrients—N, P, and K—supplied in the CPM. Two field experiments were conducted over 2 yr. Species grown were corn, lettuce, kale, Powell amaranth, common lambsquarters, giant foxtail, and velvetleaf. Plants were grown in soil amended with CPM or single-nutrient organic N, P, and K fertility amendments. Single-nutrient P treatments with bone char did not adequately mimic P supply from CPM. In both years, biomass of all weeds studied increased with CPM amendment rate. Powell amaranth was the most responsive to CPM addition, increasing 1,775 and 159% from the control to the highest CPM rate in 2010 and 2011, respectively. Corn biomass increased by 22% with CPM rate in 2010 but did not increase with CPM rate in 2011. Lettuce biomass increased with CPM amendment rate (175% in 2010 and 109% in 2011), but due to the increased weed biomass at high CPM amendment rates, good weed control will be necessary to maintain this yield benefit. The increase in growth of Powell amaranth, common lambsquarters, and giant foxtail with CPM amendment was not due to N or K, and may have been influenced by P or another factor in the CPM. Velvetleaf was the only species that exhibited increased biomass with N addition (as blood meal), similarly to the increase with added CPM, suggesting the velvetleaf growth response to CPM was due to N in the CPM. The results show that nutrient ratios should be considered when applying organic amendments, because application rates of organic amendments that meet the crop's needs for one nutrient may oversupply other nutrients. Overfertilization will not benefit crop yield, but the results of this study show that high organic fertility application rates are likely to increase weed growth.
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McCray, J. Mabry, Shangning Ji, and Leslie E. Baucum. "Sugarcane Yield Response to Furrow-Applied Organic Amendments on Sand Soils." International Journal of Agronomy 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/426387.
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Organic amendments have been shown to increase sugarcane yield on sand soils in Florida. These soils have very low water and nutrient-holding capacities because of the low content of organic matter, silt, and clay. Because of high costs associated with broadcast application, this field study was conducted to determine sugarcane yield response to furrow application of two organic amendments on sand soils. One experiment compared broadcast application (226 m3 ha−1) of mill mud and yard waste compost, furrow application (14, 28, and 56 m3 ha−1) of these materials, and no amendment. Another experiment compared furrow applications (28 and 56 m3 ha−1) of mill mud and yard waste compost with no amendment. There were significant yield (t sucrose ha−1) responses to broadcast and furrow-applied mill mud but responses to furrow applications were not consistent across sites. There were no significant yield responses to yard waste compost suggesting that higher rates or repeated applications of this amendment will be required to achieve results comparable to mill mud. Results also suggest that enhancing water and nutrient availability in the entire volume of the root zone with broadcast incorporation of organic amendments is the more effective approach for low organic matter sands.
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Essien, OE. "Effect Of Varying Rates Of Organic Amendments On Porosity And Infiltration Rate Of Sandy Loam Soil." Journal of Agriculture and Environment 12 (February 5, 2013): 51–58. http://dx.doi.org/10.3126/aej.v12i0.7563.
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Infiltration rate and porosity of sandy loam soil amended separately with goatyard manure (GYM) and poultry waste at 30, 50 and 70 tonnes/hectare each were investigated and the results were statistically analyzed using SPSS ver 17 package. Infiltration rates under GYM amendment and poultry waste amendment showed significant difference (p?0.01), indicating that the variation of infiltration under GYM amendment was superior to the use of poultry waste. Infiltration rates under poultry waste amendment and those of the control soil correlated perfectly (r= 0.99, p?0 .01). The application of 70t/ha of GYM indicated no superior short-term effect on soil’s infiltration rate than its lower amendment rates. The constant infiltration rate of amended soil under 30T/ha of GYM was reduced to 1.60cm/min below the 2.28cm/min for its GYM counterpart and 1.69cm/min for the control soil; and is recommended for optimum irrigation water conservation in sandy loam soil. The change in porosity was less under GYM amendment than under poultry waste amendment. The Journal of Agriculture and Environment Vol:12, Jun.2011, Page 51-58 DOI: http://dx.doi.org/10.3126/aej.v12i0.7563
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Gaulke, Linda S., Charles L. Henry, and Sally L. Brown. "Nitrogen fixation and growth response of Alnus rubra amended with low and high metal content biosolids." Scientia Agricola 63, no. 4 (August 2006): 351–60. http://dx.doi.org/10.1590/s0103-90162006000400006.
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Forest application of biosolids offers a potential environmentally friendly alternative to landfilling. This two-year investigation was designed to analyze the effects of elevated soil metal concentration resulting from the land application of biosolids on the symbiotic, nitrogen (N) fixing relationship between Alnus rubra Bong. (red alder) and Frankia. High metal biosolids and a modern-day composted biosolid applied at high loading rates of 250, 500, and 1000 Mg ha-1, were used to represent a worst-case scenario for metal contamination. The high metal biosolids were obtained before the current regulations were formulated and had been lagooned prior to use in this study. Total cadmium (Cd), lead (Pb) and zinc (Zn) in the high metal biosolids were 45, 958, and 2623 mg kg-1 respectively. These metal concentrations are above current regulatory limits in the US. The compost was made using biosolids that are currently produced and had Cd, Pb and Zn of 0.8, 20 and 160 mg kg-1 respectively. Trees were harvested and analyzed for rate of N fixation (as measured by acetylene reduction activity), biomass, and foliar metals. Soils were analyzed for available N, total carbon and N, pH and total Cd, Pb and Zn. Rates of N fixation were not affected by soil amendment. In year 2, shoot biomass of trees grown in both the compost and high metal amendments were higher than the control. Shoot biomass increased with increasing amount of compost amendments, but decreased with increasing amount of high metal amendments. There was no relationship between soil metal concentration and plant biomass. Foliar Cd and Pb were below detection for all trees and foliar Zn increased with increasing amount of both compost and high metal amendment, with concentrations of 249 mg kg-1 for trees grown in the compost amendment and 279 mg kg-1 for the high metal amendment. The results from this study indicate that the growth of A. rubra benefited from both types of biosolids used in the study and that the Alnus/Frankia relationship was not negatively impacted by metal concentrations resulting from the high metal biosolids amendments.
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Sidhu, J. K., M. J. Stout, D. C. Blouin, and L. E. Datnoff. "Effect of silicon soil amendment on performance of sugarcane borer,Diatraea saccharalis(Lepidoptera:Crambidae) on rice." Bulletin of Entomological Research 103, no. 6 (July 5, 2013): 656–64. http://dx.doi.org/10.1017/s0007485313000369.
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AbstractThe sugarcane borer,Diatraea saccharalis(F.), is a pest of graminaceous crops in the southern USA, including sugarcane, maize, and rice. This study was conducted to investigate the effect of silicon (Si) soil amendments on performance of sugarcane borer,D. saccharalis, on two rice cultivars, Cocodrie and XL723. There was a significant increase in the Si content of rice plants supplemented with calcium silicate as compared to non-treated plants. Soil Si amendment led to lower relative growth rates (RGRs) and reduced boring success of sugarcane borer larvae. Effects of soil Si amendments on borer success and RGR appeared to be more pronounced in ‘Cocodrie’, the cultivar relatively susceptible to borers, than in the moderately resistant cultivar, XL723. Soil Si amendment may contribute to the management ofD. saccharalisthrough reduced feeding injury and increased exposure to adverse environmental conditions and natural enemies arising from reduced boring success.
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Pettygrove, Dennis R., and Denny V. Naylor. "Metribuzin Degradation Kinetics in Organically Amended Soil." Weed Science 33, no. 2 (March 1985): 267–70. http://dx.doi.org/10.1017/s0043174500082230.
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The rates of degradation of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] were determined in an untreated Portneuf silt loam, in soil with added organic amendments, and in soil previously treated with metribuzin. While first-order rate kinetics generally described the degradation of the metribuzin in the soil, a quadratic expression was superior. Organic amendments were found to inhibit or accelerate the rate of breakdown of metribuzin depending upon the kind of amendment. Neither a lag phase nor an enrichment was observed from prior treatment with metribuzin.
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Awal, Ripendra, Almoutaz El Hassan, Farhat Abbas, Ali Fares, Haimanote K. Bayabil, Ram L. Ray, and Selamawit Woldesenbet. "Patterns of Nutrient Dynamics within and below the Rootzone of Collard Greens Grown under Different Organic Amendment Types and Rates." Sustainability 13, no. 12 (June 17, 2021): 6857. http://dx.doi.org/10.3390/su13126857.
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The knowledge about nutrient dynamics in the soil is pivotal for sustainable agriculture. A comprehensive research trial can retort unanswered questions. Dynamics of nutrients sourced from organic amendment types (chicken manure, dairy manure, and MilorganiteTM) applied at different rates (0, 168, 336, 672 kg total N/ha) were monitored within and below the rootzone of collard greens cultivated on a sandy loam soil in Prairie View, TX, USA. Macro- and micronutrients (e.g., TN: total nitrogen, P: phosphorous, K: potassium, Na: sodium, Ca: calcium, Mg: magnesium, B: boron, Cu: copper, Fe: iron, and Zn: zinc) were analyzed from soil solution samples collected during six sampling periods from within and below the rootzone. As hypothesized, the organic amendment types and rates significantly (p < 0.05 and/or 0.01) affected nutrient dynamics within and below the crop rootzone. Chicken manure released significantly more TN, P, K, Na, Ca, Mg, B, Cu, and Fe than the other two amendments. The application of chicken manure and MilorganiteTM resulted in higher below-the-rootzone leachate concentration of TN, Na, Mg, and Ca than in the leachates of dairy manure. Dairy manure treatments had the lowest concentrations of TN, Ca, and Mg; whereas, MilorganiteTM had the lowest concentrations of P, K, Na, B, and Cu in the collected leachates. The higher level of P (i.e., 4% in MilorganiteTM as compared to 2 and 0.5% in chicken and dairy manures, respectively, might have reduced the formation of Vesicular-Arbuscular (VA) mycorrhizae—a fungus with the ability to dissolve the soil P, resulting in slow release of P from MilorganiteTM treatment than from the other two treatments. Patterns of nutrient dynamics varied with rain and irrigation events under the effects of the soil water and time lapse of the amendment applications’ rates and types. All the macronutrients were present within the rootzone and leached below the rootzone, except Na. The dynamic of nutrients was element-specific and was influenced by the amendments’ type and application rate.
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Sloan, R. Crofton, Richard L. Harkess, and William L. Kingery. "Nitrogen and Cotton Gin Waste Enhance Effectiveness of Pine Bark Soil Amendment." HortTechnology 14, no. 2 (January 2004): 212–17. http://dx.doi.org/10.21273/horttech.14.2.0212.
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Urban soils are often not ideal planting sites due to removal of native topsoil or the mixing of topsoil and subsoil at the site. Adding pine bark based soil amendments to a clay soil altered soil bulk density and soil compaction which resulted in improved plant growth. Addition of nitrogen (N) or cotton gin waste to pine bark resulted in improved plant growth compared to pine bark alone. Growth of pansies (Viola × wittrockiana) during the 1999-2000 winter growing season was enhanced by the addition of pine bark plus nitrogen at 3- and 6-inch (7.6- and 15.2-cm) application rates (PBN3 and PBN6) and pine bark plus cotton gin waste at the 6 inch rate (CGW6). Plant size and flower production of vinca (Catharanthus roseus) were reduced by pine bark amendments applied at 3- or 6-inch rates (PB3 or PB6). Crapemyrtle (Lagerstroemia indica) grown in plots amended with 3 or 6 inches of pine bark plus cotton gin waste (CGW3 or CGW6) and pine bark plus nitrogen at 3- or 6-inch rates (PBN3 or PBN6) produced greater shoot growth than other amendment treatments. In some instances PB3 treatments suppressed growth. High levels of N and soluble salts derived from CGW and PBN soil amendments incorporated into the soil probably contributed to the improved plant growth observed in this experiment.
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Nair, Ajay, Mathieu Ngouajio, and John Biernbaum. "Alfalfa-based Organic Amendment in Peat-compost Growing Medium for Organic Tomato Transplant Production." HortScience 46, no. 2 (February 2011): 253–59. http://dx.doi.org/10.21273/hortsci.46.2.253.
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In the last decade, organic production has been the fastest growing segment in U.S. agriculture. With increase in organic acreages there is a strong and growing demand for organically grown transplants. As a result of limited commercial availability of certified vegetable transplants, growers often produce their transplants on-farm. Commercial organic mixes for organic transplant production may not be locally available and are usually expensive. Growers often design their own mixes using compost and other organic amendments. The purpose of this study was to evaluate the incorporation of alfalfa-based amendment in a peat-compost medium for organic tomato transplant production. Growing medium of 2 peat:1 vermiculite:1 compost (by volume) was amended with 0%, 0.6%, 1.2%, 1.8%, or 2.4% weight by weight of alfalfa-based organic amendment and incubated for 0, 1, 2, 3, or 4 weeks. Medium pH and electrical conductivity (EC), seed germination (untreated Solanum Lycopersicon L. ‘Mountain Fresh’ seed), transplant dry weight, height, stem diameter, and SPAD values were measured. Medium pH increased with addition of alfalfa-based amendment but remained within the range of 5.5 to 7.0. Germination percentages were less than 50% in amended medium that was either not incubated or incubated for 4 weeks. Germination was greater than 75% if amended media were incubated for 1, 2, or 3 weeks. Seeds grown in peat-compost without any amendments had the highest germination rates; however, severe nutrient deficiency suppressed seedling growth. Relative to growth in medium with no amendments, plants growing in the amended medium had increased stem diameter, height, leaf chlorophyll content, and plant dry weight (90% to 160% more), provided the amended medium was incubated for at least 1 week. Application rate of 0.6% or 1.2% of alfalfa-based amendment produced transplants with suitable growth characteristics and met commercially acceptable standards for transplanting and handling at a reasonable estimated cost.
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Walker, R. F., and C. D. Huntt. "Production of Containerized Jeffrey Pine Planting Stock for Harsh Sites: Growth and Nutrition as Influenced by Controlled-Release Fertilization." Western Journal of Applied Forestry 15, no. 2 (April 1, 2000): 86–91. http://dx.doi.org/10.1093/wjaf/15.2.86.
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Abstract Low, medium, and high rates of four controlled-release nutrient amendments, Sierra 17-6-10, Sierrablen 18-7-10, High N 24-4-8, and Osmocote 18-6-12, were evaluated for their effect on production of containerized Jeffrey pine (Pinus jeffreyi) planting stock. Peters 20-10-20 water soluble fertilizer treatments and nonfertilized seedlings provided for comparisons of amendment formulation effects on growth and nutrition. In general, growth increased with increasing amendment application rates regardless offormulation. Seedlings fertilized with Peters 20-10-20 had the greatest shoot growth, although those that received Sierra 17-6-10 or High N 24-4-8 were only marginally smaller. The Sierra formulation proved most effective in the stimulation of root growth. Shoot/root ratios rose with amendment application rates, although all treatments produced proportional shoot and root mass. Fertilized seedlings had higher foliar N, P, and S concentrations, while K, Ca, Mg, Mn, and B concentrations were higher in nonfertilized seedlings. It is likely that N, P, and S nutrition contributed heavily to the variation in shoot and root growth among treatments. The aridity of the western Great Basin and eastern Sierra Nevada renders the regeneration of forests and woodlands difficult, but with careful selection of formulation and application rate, controlled-release fertilization may facilitate the production of container stock with the large caliper and balanced shoot and root growth necessary for successful field establishment on the harsh sites of this region. West. J. Appl. For. 15(2):86-91.
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Duddigan, Sarah, Paul D. Alexander, Liz J. Shaw, and Chris D. Collins. "Effects of Repeated Application of Organic Soil Amendments on Horticultural Soil Physicochemical Properties, Nitrogen Budget and Yield." Horticulturae 7, no. 10 (October 7, 2021): 371. http://dx.doi.org/10.3390/horticulturae7100371.
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Application of organic amendments to soil is commonplace in domestic gardening. However, a vast array of materials could be labelled as ‘compost’ by retailers and suppliers. We investigated six different amendments currently used, or available for use, in horticulture: composted bark, composted bracken, spent mushroom compost, composted horse manure, garden waste compost (at two different application rates), and peat. Using a controlled field experiment, we examined the physicochemical differences between the amendments, the subsequent effects on soil characteristics, and resultant yield and biometrics of Lavatera trimiestris. Amended soils resulted in a significantly different multivariate soil environment and N budget when compared to the unamended control. However, the effect on yield and plant biometrics (number of flowers, plant height, etc.) depended on the amendment used. Application of garden compost resulted in up to a five-fold increase in yield. However, there was no significant difference in yields in soils amended with composted bark or peat, when compared to the unamended control. This has implications, as there is increasing pressure to remove peat from products available to domestic gardeners. The variability in the different amendments investigated in our research, in addition to the variable effects on plant growth parameters, suggests that repeated use of a single amendment may not be best practise for gardeners.
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Li, Dianpeng, Jianqin Zhou, Yuxin Zhang, Tao Sun, Shuqing An, and Hongtao Jia. "Effects of Amendments on Physicochemical Properties and Respiration Rate of Soil from the Arid Region of Northwest China." Sustainability 13, no. 10 (May 11, 2021): 5332. http://dx.doi.org/10.3390/su13105332.
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In arid regions, decreased soil fertility has adversely affected agricultural sustainability. The effects of different amendments in alleviating these issues and increasing soil fertility remain unclear. Herein, a two-year field experiment was conducted to evaluate the properties of grey desert soil and soil respiration (SR) dynamics under six different treatment groups: biochar (BC), leonardite (LD), anionic polyacrylamide (PAM−), cationic polyacrylamide (PAM+) powder, anionic polyacrylamide solution in water (PAM−W), and control (CK). We observed that the BC and LD amendments significantly altered soil pH, organic matter, available nitrogen, available phosphorus, cation exchange capacity, and SR. PAM amendment increased the SR as compared to the control, except in autumn, but PAM did not affect the soil properties. SR under different amendments showed strong seasonal patterns, the highest and lowest SR rates were observed in June and January, respectively. Amendments and seasonal dynamics significantly affected SR, but no interaction was observed between these factors. Temporal variation of SR was substantially influenced by soil temperature at 15 cm of soil depth. Temperature sensitivity of SR (Q10) increased with soil depth and decreased with amendment addition. SR was significantly affected by soil temperature, moisture, air temperature, and their interactions. The outcomes of this study suggested that the BC and LD amendments improved soil fertility and negated the net carbon accumulation by increasing the SR and Q10 in arid agriculture soil.
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Pu, X. Z., G. J. Zhang, P. P. Zhang, Y. J. Liu, and W. F. Zhang. "Effects of straw management, inorganic fertiliser, and manure amendment on soil microbial properties, nutrient availability, and root growth in a drip-irrigated cotton field." Crop and Pasture Science 67, no. 12 (2016): 1297. http://dx.doi.org/10.1071/cp16230.
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Organic amendments not only improve soil conditions but also affect belowground biological processes. This study used a split plot design to investigate the effects of cotton straw management, inorganic fertiliser, and manure amendment on (i) soil nutrient content, (ii) soil microbial properties, and (iii) cotton root growth in a drip-irrigated cotton field. Straw return significantly increased soil inorganic nitrogen (N), N transformation rates, organic carbon (C), and urease activity. Straw return, however, had no significant effect on either root growth or activity. Inorganic fertiliser and/or manure amendment significantly increased inorganic N, N transformation rates, organic C, microbial biomass C, urease activity, and invertase activity. Inorganic fertiliser and/or manure also significantly increased fine root growth, triphenyltetrazolium chloride-reducing capacity, and specific root length. Moreover, the inorganic fertiliser plus manure treatment had the greatest soil inorganic N concentrations, N mineralisation rate, total carbon dioxide efflux, C mineralisation rate, soil organic C concentration, microbial biomass C concentration and enzyme activity, as well as root biomass, fine root : coarse root ratio, root triphenyltetrazolium chloride-reducing capacity and specific root length. Straw return to inorganically fertilised soil increased inorganic N concentrations by 11%, net N mineralisation rate by 59%, net nitrification by 59%, gross nitrification by 14%, denitrification by 39%, and urease activity by 25% compared with inorganic fertiliser alone. Taken together, the results indicated that straw return and manure application significantly promoted soil microbial activity and soil N transformation in the presence of inorganic fertiliser. The manure amendment enabled the crop to develop a more extensive root system, primarily by increasing the number of fine roots. Thus, organic amendments may improve the acquisition efficiency of inorganic fertiliser in drip-irrigated cotton fields.
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Russo, Vincent M. "Biological Amendment, Fertilizer Rate, and Irrigation Frequency for Organic Bell Pepper Transplant Production." HortScience 41, no. 6 (October 2006): 1402–7. http://dx.doi.org/10.21273/hortsci.41.6.1402.
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Use of biological amendments in vegetable transplant production may affect plant development. Rhizosphere bacteria can alter conditions in the root zone and affect plant growth even if root tissue is not colonized. Arbuscular mycorrhizae (AM) affect plant development through symbiotic relations. Abiotic factors may mediate effects of biotic amendments. Organically certified potting medium was inoculated with a mix of Sinorhizobium sp. bacteria or a mix of AM fungi. Controls consisted of no amendment. Bell pepper, Capsicum annuum L., cv. Jupiter, seed were sown in the medium and irrigated either twice a day for 3 minutes per application or three times a day for 2 minutes per application. Seedlings were treated with 8, 16, 24, or 32 mL·L–1 of an organically certified liquid fertilizer beginning 3 weeks after sowing. Use of bacteria improved plant height and dry weight. Interactions of bacteria and fertilizer rate or irrigation regime affected plant height or dry weight. When irrigated twice a day, plants were tallest when provided 16 mL·L–1 fertilizer, and heaviest when provided 24 mL·L–1 fertilizer. When irrigated three times a day, plants were taller at the lower rates of fertilizer and heaviest at the highest rate of fertilizer. Use of AM had little effect on plant height and dry weight. Most of the responses when AM was the amendment were the result of fertilizer rate and irrigation regime. When irrigated twice a day, AM-treated plants were tallest and heaviest when provided at least 24 mL·L–1 fertilizer. Regardless of biological amendment, plant heights were correlated with plant dry weights over fertilizer rates and irrigation regime. Use of Sinorhizobium sp. appeared to provide a benefit to the development of bell pepper transplants.
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Schefe, C. R., A. F. Patti, T. S. Clune, and W. R. Jackson. "Organic amendment addition enhances phosphate fertiliser uptake and wheat growth in an acid soil." Soil Research 46, no. 8 (2008): 686. http://dx.doi.org/10.1071/sr08035.
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The effect of 2 organic amendments (lignite and compost) on wheat growth and phosphate fertiliser efficiency (triple superphosphate, TSP; di-ammonium phosphate, DAP) in an acid soil was investigated in a glasshouse experiment. Organic amendments were incorporated into the top 40 mm of soil at rates resulting in a 1% and 2.5% increase in soil C, and fertilisers were banded within the seed row at rates equivalent to 5, 10, and 25 kg P/ha. When no P was applied, addition of both organic amendments increased shoot height, with greatest growth recorded in the compost-amended treatments. Addition of organic amendments and P fertiliser resulted in additive effects, with increased shoot height, tiller number, and shoot dry matter (DM) in both the lignite- and compost-amended soils with fertiliser addition. The addition of 1% C resulted in plant growth equal to that measured at a higher rate of addition (2.5% C), resulting in a higher relative efficiency of application. Tissue P uptake was significantly increased when soil amendment was combined with 25 kg P/ha DAP addition. Significant differences in nutrient uptake were also measured for other important plant nutrients. As the addition of organic amendments resulted in increased DM compared with untreated soil per unit of P fertiliser applied, it is feasible that this growth response may translate into increased yield. However, further study is required to define the agronomic and economic feasibility of broad-scale application of such amendments for production gains.
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Schnackenberg, Ashley, Géraldine Bidar, Valérie Bert, Patrice Cannavo, Sébastien Détriché, Francis Douay, René Guenon, et al. "Effects of Inorganic and Organic Amendments on the Predicted Bioavailability of As, Cd, Pb and Zn in Kitchen Garden Soils." Advances in Environmental and Engineering Research 3, no. 1 (November 11, 2021): 1. http://dx.doi.org/10.21926/aeer.2201004.
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Moderately contaminated garden soils can benefit from gentle remediation options such as soil amendments, which improve soil functions and agronomic potentialities while decreasing environmental and human risk. This study aimed to analyze the effects of doses of various common soil amendments generally applied by gardeners on the predicted bioavailability (i.e., extractability) of metal(loid)s (i.e., As, Cd, Pb, and Zn) in contaminated kitchen garden soils. Fourteen different amendment mixes (i.e., a green waste compost with two degrees of maturity used alone and in combination with zeolite, three organic fertilizers, two calcareous amendments, two natural siliceous or alumino-silicate amendments, and one potting soil) were tested on three different garden soils with diverse sources of contamination and physico-chemical characteristics. Chemically extractable metal(loid)s were analyzed using 0.05 M EDTA extraction and 1 M NH4NO3 extraction. In one soil sample, potting soil showed significant potential to reduce the availability of As, as analyzed by both extractants. This amendment also effectively reduced the Pb extractability in the geogenic-contaminated soil, as did other high-organic matter amendments such as various application rates of composts. Zeolite and zeolite-compost mixes demonstrated success on various metal(loid)s and therefore could be a promising emerging amendment mix. Other efficient amendments include crushed horn, which effectively reduced available Zn in all soils, as well as available Pb. The application of bone meal similarly reduced the extractable As, Pb, and Zn in various soils. The two applications of limes were effective against Cd, As, Pb, and Zn in the different soils studied. This study provided evidence that it is possible to reduce the extractability and thus the environmental availability of the metal(loid)s applied with available and affordable amendments. The results depended on the physico-chemical soil parameters and metal(loid)s considered. There is no single solution, which implies that tests must be carried out before any implementation activities on the kitchen gardens.
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Mohiuddin, Muhammad, Zahid Hussain, Asim Abbasi, Jawad Ali, Muhammad Irshad, Muhammad Atiq Ur Rehman Tariq, Anum Intisar, Aiman Hina, Qamar Uz Zaman, and Anne Wai Man Ng. "Sawdust Amendment in Agricultural and Pasture Soils Can Reduce Iodine Losses." Sustainability 14, no. 20 (October 20, 2022): 13620. http://dx.doi.org/10.3390/su142013620.
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Iodine loss is common in the soil of hilly regions due to higher precipitation rates and steeper slopes. Iodine deficiency in soil reduces iodine’s bioavailability to fruits and vegetables and consequently may contribute to health complications. However, the iodine retention of soils after the addition of selected organic and inorganic amendments has not been studied. Therefore, a study was carried out to investigate iodine loss during surface runoff. For this purpose, a soil amendment (namely, sawdust, charcoal, wood ash, lime or gypsum) was applied separately to pasture and agricultural soils under natural rainfall conditions. The soil was fertigated with iodine in the form of potassium iodide (KI) at the rate of 200 ppm. Surface runoff was related to soil properties. Results showed that iodine content in surface runoff was linearly related with soil pH (R2 = 0.89, p < 0.05) and inversely related with soil organic carbon (R2 = −0.76, p < 0.05). Soils amended with sawdust had significantly reduced iodine content in runoff. A higher amount of iodine was lost via surface runoff from soil after inorganic amendment. Soil amendments were varied for iodine retention in soil in the order of sawdust > charcoal > wood ash > lime > gypsum. The study results indicated that organic amendments, especially sawdust, improved soil properties and increased the iodine retention capacity of soils.
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Smith, Karen, Peter May, and Robert White. "Above and Belowground Growth of Corymbia maculata in a Constructed Soil: The Effect of Profile Design and Organic Amendment." Arboriculture & Urban Forestry 36, no. 1 (January 1, 2010): 11–17. http://dx.doi.org/10.48044/jauf.2010.002.
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Spotted gum (Corymbia maculata (Hook.) K.D. Hill & L.A.S. Johnson), a common street tree in southern Australian cities, was used to assess growth responses to variations in profile design and organic amendment of constructed soils. Aboveground growth responses were total stem dry weight and foliar nutrient content. The belowground response was root length density. Soil profiles were constructed of sand, amended with either coir fiber, composted biosolids or composted green waste, at rates of 0, 5, 10 or 20% by volume. The profiles were either layered, with a 150 mm (6 in) organic-amended surface layer, or uniform, with amendment of the entire profile. A single fertilizer treatment was applied to all profiles. Shoot dry weight was only affected by organic matter type with the greatest growth in sand amended with composted biosolids. Foliage P and K content were affected by amendment but foliage N was not. Profile design affected root length density and distribution. Trees in uniform profiles had greater root length density, and a more uniform distribution of roots, especially with compost amendments. Above- and belowground growth increases are thought to be due to increased nutrient status resulting from organic matter mineralization.
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Xiao, Meng, Guangming Liu, Shengguo Jiang, Xuewei Guan, Jinlin Chen, Rongjiang Yao, and Xiuping Wang. "Bio-Organic Fertilizer Combined with Different Amendments Improves Nutrient Enhancement and Salt Leaching in Saline Soil: A Soil Column Experiment." Water 14, no. 24 (December 14, 2022): 4084. http://dx.doi.org/10.3390/w14244084.
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Salt-affected soils frequently experience leaching and desalination issues, which severely restrict plant growth and water uptake. Hence, in this experiment, four treatments including CG (no amendments addition); OF (organic fertilizer addition); OH (organic fertilizer and Hekang amendment addition); and OB (organic fertilizer and fulvic acid addition) were designed to examine the effect of organic amendment on soil chemical properties, water and salt transport, and soil desalination laws of coastal saline soil. The results showed that the addition of organic amendments significantly reduced soil pH (8.47–8.52) and salt content (2.06–2.34 g kg−1), while increasing soil organic matter content, available phosphorus, and available potassium. OH treatment has a higher available phosphorus content than other treatments. OH and OB treatments elevated the soil desalination ratio (32.95% and 32.12%, respectively) by raising the leaching volume and leaching rate. Organic amendments significantly promoted Na+ (4.5–32%) and SO42− (12–27%) leaching compared to CG. Organic treatments, particularly OB treatment, not only increased the content of soil organic matter and available nutrients but also promoted salt ion leaching, improved soil permeability and increased soil desalination and water leaching rates. Our results may provide a theoretical basis for revealing the desalination law of coastal saline soil.
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Dormaar, J. F., C. W. Lindwall, and G. C. Kozub. "Role of continuous wheat and amendments in ameliorating an artificially eroded Dark Brown Chernozemic soil under dryland conditions." Canadian Journal of Soil Science 77, no. 2 (May 1, 1997): 271–79. http://dx.doi.org/10.4141/s96-071.
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Complete loss of topsoil resulting from erosion or other causes generally results in reduced crop yield. To determine, under dryland conditions, the effect of loss of various amounts of soil and of various amendment practices suitable for use under a cereal production program on soil properties and crop yields, a field was artificially eroded during cut and fill of land-levelling in 1957. Continuous cropping to barley for 7 yr was followed by a wheat-fallow rotation for 22 yr. A continuous wheat experiment was conducted from 1987 to 1991 to determine the effects of five fertility amendments on restoring the productivity to soil from which 10–20 cm and 46+ cm of soil had been removed. In 1990, a below-average precipitation year, after 33 yr and 23 crops, yields from the unfertilized 46+ cm eroded field were only 44% of the yields from the uneroded field. However, with the increased precipitation in 1991 this value was 66%. A one-time topsoil amendment was beneficial in the earlier stages of the experiment, but lost its effect as cultivation mixed it into the "subsoil" over time. Plot treatments with annual applications of manure and high rates of fertilizer generally out-yielded the yields of the check plots of the uneroded treatment. Amendment with straw + fertilizer was not very effective. Soil, once lost, is non-renewable without amendments within the working lifetime of the producer. Key words: Soil erosion, manure, commercial fertilizer, topsoil soil, productivity
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Zayani, K., H. Bousnina, A. Mhiri, R. Hartmann, and H. Cherif. "Evaporation in layered soils under different rates of clay amendment." Agricultural Water Management 30, no. 2 (April 1996): 143–54. http://dx.doi.org/10.1016/0378-3774(95)01217-6.
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Oueriemmi, Houda, Petra Kidd, Carmen Trasar-Cepeda, Beatriz Rodríguez-Garrido, Rahma Zoghlami, Kaouther Ardhaoui, Ángeles Prieto-Fernández, and Mohamed Moussa. "Evaluation of Composted Organic Wastes and Farmyard Manure for Improving Fertility of Poor Sandy Soils in Arid Regions." Agriculture 11, no. 5 (May 4, 2021): 415. http://dx.doi.org/10.3390/agriculture11050415.
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Farmyard manure, an amendment traditionally used for improving the fertility of sandy soils in arid climates, is becoming scarce and expensive. Its shortage makes it necessary to evaluate, at field scale, the suitability and medium-term performance of other cheap, highly available substitutes. A field trial was established to analyze the effects of a single application of three organic residues on barley yield and nutrient uptake and selected soil properties after two consecutive harvests. Municipal solid waste compost (MSWC), sewage sludge compost (SSC) and farmyard manure (FYM) were tested at rates of 0, 20, 40 and 60 t ha−1. Adding all three organic amendments increased organic matter, cation exchange capacity and available P, Ca, Mg and K in the soil, the grain yield (up to 51%), and the barley plants’ nutrient contents. After the second harvest, a positive residual effect of the amendment was observed in plant yield (up to 77%) and nutrient contents. MSWC and SSC induced slight increases on the extractable fractions (BCR protocol) of Co, Cu and Ni, relative to the unamended soil. The results demonstrate the positive immediate and residual effect of the amendments evaluated as fertilizers for agricultural purposes.
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Basiri Jahromi, Nastaran, Amy Fulcher, Forbes Walker, and James Altland. "Optimizing Substrate Available Water and Coir Amendment Rate in Pine Bark Substrates." Water 12, no. 2 (January 29, 2020): 362. http://dx.doi.org/10.3390/w12020362.
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Water resources can be used more efficiently by including sustainable substrate components like coir that increase water-holding capacity. The first objective of this study was to evaluate the impact of coir amendment rate on plant available water and plant gas exchange, with the goal of optimizing substrate available water and determining the optimum coir amendment rate in a greenhouse environment. The second objective was to establish the optimum method of determining plant available water using either plant gas exchange parameters or substrate physical properties. Greenhouse experiments were conducted with Hydrangea paniculata ‘Jane’ (Little Lime® hardy hydrangea) potted with one of five different coir rates (0%, 10%, 25%, 40% and 65%) mixed with pine bark on a volume basis. Plant gas exchange parameters and substrate water content were measured daily over a range of increasingly drier substrate moisture contents. Actual photosynthetic rates increased with increasing coir amendment rate and were highest with 65% coir amendment. Amending pine bark with coir increased the water storage capacity, plant available water, and plant gas exchange parameters. Results suggest that 65% coir amendment rate was the optimum amendment rate among those tested in a greenhouse environment and plant photosynthetic rate was the better method of determining plant available water.
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Landorfa-Svalbe, Zaiga, Māra Vikmane, and Gederts Ievinsh. "Vermicompost Amendment in Soil Affects Growth and Physiology of Zea mays Plants and Decreases Pb Accumulation in Tissues." Agriculture 12, no. 12 (December 7, 2022): 2098. http://dx.doi.org/10.3390/agriculture12122098.
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Minimization of the possible harmful effects of soil pollution on agricultural production and food safety are the major challenges in modern agriculture. There is great scientific interest in the detailed understanding of the physiology of lead uptake and toxicity in Zea mays, together with the search for approaches to minimizing Pb accumulation in tissues. The aim of the present study was to explore the possibility of reducing Pb accumulation in Z. mays plants cultivated in Pb-contaminated soil, by means of vermicompost amendment. Z. mays plants were cultivated at three soil vermicompost amendment rates (10, 20, and 30%), with the addition of 1000 mg L−1 of Pb in the form of Pb(NO3)2 or an equivalent amount of nitrogen in the form of NH4NO3. Additional nitrogen had a significant stimulatory effect on plant growth and physiology, but only for control plants, and at a low vermicompost amendment rate. Independently, Pb had an insignificant negative effect on plant growth and biomass partitioning, but significantly negatively affected the mineral nutrition of Z. mays plants. At a 10 and 20% soil vermicompost amendment rate, the Pb concentration in plant leaves and roots decreased by 65%, while plant biomass increased four to five times in comparison to soil-grown control plants, together with accelerated flowering. It was concluded that vermicompost is one of the most promising soil amendments for reducing heavy metal uptake and accumulation in crop plants, while also being an efficient organic fertilizer.
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Eid, Ebrahem M., Ahmed F. El-Bebany, Mostafa A. Taher, Sulaiman A. Alrumman, Tarek M. Galal, Kamal H. Shaltout, Nasser A. Sewelam, and Mohamed T. Ahmed. "Heavy Metal Bioaccumulation, Growth Characteristics, and Yield of Pisum sativum L. Grown in Agricultural Soil-Sewage Sludge Mixtures." Plants 9, no. 10 (October 1, 2020): 1300. http://dx.doi.org/10.3390/plants9101300.
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The application of sewage sludge (SS) in agriculture is an alternative disposal method for wastewater recycling and soil fertilization. This study evaluated heavy metal bioaccumulation, growth, and yield of Pisum sativum (pea) grown in agricultural soil amended with SS at rates of 0, 10, 20, 30, and 40 g/kg. The results show that root, shoot, pod length, biomass, and number of leaves and pods increased with SS amendments of 10 and 20 g/kg, while rates declined at 30 and 40 g/kg. SS had greater salinity and organic content than the soil. Heavy metals in the postharvest soil samples increased for all SS application rates except Fe and Mo. The significant increase in Cd content started at the lowest amendment rate 10 g/kg; for Co, Mn, and Pb, the significant increase was detected at the highest amendment rate (40 g/kg). Generally, all heavy metals increased significantly in portions of P. sativum except Cd in the shoot. At an amendment rate of 10 g/kg, Co in the shoot and root, Cr in the fruit, Cu in the root, Fe in the fruit, Mn in the shoot and fruit, Mo in the fruit, Pb in the shoot, and Zn in the fruit were elevated significantly. In contrast, the concentrations of Cd in the fruit, Cr in the root, Cu in the shoot, Fe in the shoot and root, Ni in the fruit and root, Pb in the fruit and root, and Zn in the root significantly increased only at the highest rate of 40 g/kg. The highest regression R2 was 0.927 for Mn in pods and the lowest was 0.154 for Cd in shoots. Bioaccumulation and translocation factors were > 1 for Mo and the bioaccumulation of Pb was >1. SS could be used for pea fertilization but only at rates below 20 g/kg to avoid environmental and health hazards.
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Reeder, R. K., R. L. Darnell, and T. A. Obreza. "Blueberry Production in a High-density, Evergreen System." HortScience 30, no. 4 (July 1995): 800E—800. http://dx.doi.org/10.21273/hortsci.30.4.800e.
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Blueberry plants fertilized at 3-week intervals with nitrogen (N) throughout the year and protected from freezing temperatures avoid dormancy and produce an off-season “winter” crop. Southwestern Florida offers a climate where this production system can be implemented without undue fear of freezes. `Sharpblue', `Gulfcoast', and `Warmabe' southern highbush blueberry cultivars have been planted at high density (10,000 plants/ha) to determine the feasibility of successfully establishing an evergreen production system for blueberry. Three rates of N fertilization (84, 168, and 252 kg·ha–1) and the use of peat or municipal solid waste (MSW) compost as soil amendments are being evaluated in this study. Initial data on plant growth indicate that, during the first 9 months of the planting, 168 kg N/ha will produce plants similar in height, but with significantly less volume, to those receiving 252 kg N/ha. MSW compost appears to be a beneficial soil amendment for blueberry establishment despite an increase in soil pH associated with the compost amendment.
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Ortlip-Sommers, Sarah. "Living Freely Behind Bars: Reframing the Due Process Rights of Transgender Prisoners." Columbia Journal of Gender and Law 40, no. 3 (August 6, 2021): 355–407. http://dx.doi.org/10.52214/cjgl.v40i3.8599.
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Federal constitutional jurisprudence, as it stands today, provides insufficient protections for transgender individuals who are incarcerated. Transgender prisoners face high rates of physical and sexual assault, harassment, and other mistreatment by state and federal prison officials and individuals incarcerated with them. Commonly pursued avenues for relief—namely the Eighth Amendment, the Equal Protection Clause of the Fourteenth Amendment, and the right to privacy—present hurdles in the form of too-hard-to-meet legal standards, and they perpetuate harmful stereotypes and cultural norms that should occupy no place in modern constitutional law. This Note proposes that, instead of relying on these inadequate constitutional claims to vindicate their rights, transgender prisoners and their advocates should consider litigating under the Due Process Clause of the Fifth and Fourteenth Amendments, articulating a right to live freely in accordance with one’s gender identity. Recognition of such a right would enable plaintiffs to utilize more favorable substantive due process legal standards and eschew perpetuating outdated notions of gender within the law.
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Nyambo, Patrick, Thembalethu Taeni, Cornelius Chiduza, and Tesfay Araya. "Effects of Maize Residue Biochar Amendments on Soil Properties and Soil Loss on Acidic Hutton Soil." Agronomy 8, no. 11 (November 10, 2018): 256. http://dx.doi.org/10.3390/agronomy8110256.
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Soil acidification is a serious challenge and a major cause of declining soil and crop productivity in the Eastern parts of South Africa (SA). An incubation experiment investigated effects of different maize residue biochar rates on selected soil properties and soil loss in acidic Hutton soils. Biochar amendment rates were 0%, 2.5%, 5%, 7.5%, and 10% (soil weight) laid as a completely randomized design. Soil sampling was done on a 20-day interval for 140 days to give a 5 × 7 factorial experiment. Rainfall simulation was conducted at 60, 100 and 140 days after incubation to quantify soil loss. Relative to the control biochar amendments significantly improved soil physicochemical properties. After 140 days, biochar increased soil pH by between 0.34 to 1.51 points, soil organic carbon (SOC) by 2.2% to 2.34%, and microbial activity (MBC) by 496 to 1615 mg kg−1 compared to control. Soil aggregation (MWD) changes varied from 0.58 mm to 0.70 mm for the duration of the trial. Soil loss significantly decreased by 27% to 70% under biochar amendment compared to control. This indicates that maize residue biochar application has the potential to improve the soil properties and reduce soil loss in the degraded acidic Hutton soil.
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Bai, Yanchao, Wengang Zuo, Yiyun Yan, Chuanhui Gu, Yongxiang Guan, Lijuan Mei, Weijie Xue, Yuhua Shan, and Ke Feng. "Sewage Sludge Amendment Combined with Green Manuring to a Coastal Mudflat Salt-Soil in Eastern China: Effects on Soil Physicochemical Properties and Maize Yield." International Journal of Agronomy 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/8526598.
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Sewage sludge and green manure have become widely used organic amendments to croplands in many regions of the world. However, the amending effect of the combination of sewage sludge with green manuring in reclaimed coastal mudflat salt-soil has been unclear yet. This paper was one of earlier studies to investigate and evaluate the effects of sewage sludge amendment combined with green manuring on selected soil physicochemical properties of the mudflat soil in a rain-fed agroecosystem. The mudflat salt-soil was amended by one-time input of sewage sludge at the rates of 0, 30, 75, 150, and 300 t ha−1. After green manuring for three consecutive seasons, maize (Zea maysL.) was planted in 2013 and 2014. The results showed that SSA combined with green manuring decreased bulk density, pH, salinity, and exchangeable sodium percentage of the topsoil (0–20 cm soil layer) and increased aggregate stability, cation exchange capacity, and N and P concentration of the topsoil. As a result, the maize yield increased with the increase of SSA rates. Sewage sludge combined with green manuring can be applied in coastal mudflat salt-soil amendment, which provides an innovative way to create arable land resources and safe disposal of sewage sludge.
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Anderson, Kelsey, Philip A. Moore, Jerry Martin, and Amanda J. Ashworth. "Evaluation of a Novel Poultry Litter Amendment on Greenhouse Gas Emissions." Atmosphere 12, no. 5 (April 28, 2021): 563. http://dx.doi.org/10.3390/atmos12050563.
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Gaseous emissions from poultry litter causes production problems for producers as well as the environment, by contributing to climate change and reducing air quality. Novel methods of reducing ammonia (NH3) and greenhouse gas (GHG) emissions in poultry facilities are needed. As such, our research evaluated GHG emissions over a 42 d period. Three separate flocks of 1000 broilers were used for this study. The first flock was used only to produce litter needed for the experiment. The second and third flocks were allocated to 20 pens in a randomized block design with four replicated of five treatments. The management practices studied included an unamended control; a conventional practice of incorporating aluminum sulfate (referred to as alum) at 98 kg/100 m2); a novel litter amendment made from alum mud, bauxite, and sulfuric acid (alum mud litter amendment, AMLA) applied at different rates (49 and 98 kg/100 m2) and methods (surface applied or incorporated). Nitrous oxide emissions were low for all treatments in flocks 2 and 3 (0.40 and 0.37 mg m2 hr−1, respectively). The formation of caked litter (due to excessive moisture) during day 35 and 42 caused high variability in CH4 and CO2 emissions. Alum mud litter amendment and alum did not significantly affect GHGs emissions from litter, regardless of the amendment rate or application method. In fact, litter amendments such as alum and AMLA typically lower GHG emissions from poultry facilities by reducing ventilation requirements to maintain air quality in cooler months due to lower NH3 levels, resulting in less propane use and concomitant reductions in CO2 emissions.
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Shrestha, Utsala, Mary E. Dee, Bonnie H. Ownley, and David M. Butler. "Anaerobic Soil Disinfestation Reduces Germination and Affects Colonization of Sclerotium rolfsii Sclerotia." Phytopathology® 108, no. 3 (March 2018): 342–51. http://dx.doi.org/10.1094/phyto-04-17-0152-r.
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Growth chamber and field studies were conducted with organic amendment mixtures of carbon (C) and nitrogen (N) at C:N ratios 10:1, 20:1, 30:1, and 40:1 and amendment rates of C at 2, 4, 6, and 8 mg/g of soil (C:N ratio 30:1) to evaluate anaerobic soil disinfestation (ASD) effects on germination and colonization of Sclerotium rolfsii. In the growth chamber, sclerotial germination was reduced in all ASD treatments regardless of C:N ratio (0.6 to 8.5% germination) or amendment rate (7.5 to 46%) as compared with nonamended controls (21 to 36% and 61 to 96%, respectively). ASD treatment increased Trichoderma spp. colonization of sclerotia, with consistently higher colonization in ASD treatments with amendment rates of C at 2 or 4 mg/g of soil (>87% colonization) compared with nonamended controls (<50% colonization). In the 2014 field study, sclerotial germination was reduced by 24 to 30% in ASD treatments when compared with the nonamended control. Sclerotial colonization by Trichoderma spp. was predominant; however, other potential mycoparasites (i.e., Aspergillus spp., Fusarium spp., zygomycetes, and other fungi) were present in the field study. Amendment C:N ratios in the range of 10:1 to 40:1 were equally effective in reducing sclerotial germination and enhancing colonization by potentially beneficial mycoparasites of sclerotia.
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Rojas, Jaime Aguilar, Amalesh Dhar, and M. Anne Naeth. "Urban Naturalization for Green Spaces Using Soil Tillage, Herbicide Application, Compost Amendment and Native Vegetation." Land 10, no. 8 (August 15, 2021): 854. http://dx.doi.org/10.3390/land10080854.
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Naturalization is a new and promising ecological approach to green space development for urban environments, although knowledge is sparse on techniques to implement it. We evaluated naturalization of eight native trees and shrubs, with site preparation (tillage, herbicide) and soil amendment (compost rates) treatment combinations at six sites in the city of Edmonton, Alberta, Canada. Soil texture improved with all compost rates, and acidity, electrical conductivity and total carbon increased, especially with 100% compost. Soil nutrients generally increased with compost then declined within a year. Plant species with highest potential for use in urban green spaces were Picea glauca, Symphoricarpos albus and Rosa acicularis. Herbicide was the most influential site preparation treatment, positively increasing survival and growth of planted woody species, while negatively lowering non-native species cover and increasing noxious weed cover. Soil amendment with compost influenced cover not species richness, with high compost amendment reducing vegetation cover across sites, and increasing individual plant size. This study suggests amendment of soil with compost and appropriate site preparation can positively influence naturalization of these woody species for urban green spaces.
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Li, Dong, Lei Chen, Xiao Na Song, and Guo Cheng Liu. "Improving Maize Growth by Biochar and Biochar-Based Amendment in Light Sierozem in Ningxia." Applied Mechanics and Materials 707 (December 2014): 251–54. http://dx.doi.org/10.4028/www.scientific.net/amm.707.251.
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Biochar has been applied in soil amelioration due to its multiple agricultural and environmental benefits. Biochar sample (BC) and biochar-based amendment (AD) were added into a poor quality soil (light sierozem) collected from Ningxia Hui Autonomous Region at the rates of 0%, 1.5%, 3% and 5% (w/w), respectively. Maize (Zea mays) was chosen as a test plant, and the effect of BC and AD on its growth was investigated. The results indicated that the maize biomass increased by 44.4-96.2% and 113.8-187.3% in the soils amended with BC and AD, respectively. Therefore, BC and AD may be used as the poor quality soil amendments.
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Summers, KJ, BH O'Connor, and DR Fox. "Radiological consequences of amending soils with bauxite residue gypsum mixtures." Soil Research 31, no. 4 (1993): 533. http://dx.doi.org/10.1071/sr9930533.
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This paper reports on the gamma (�) radiation flux from sandy soils of the Swan Coastal Plain treated with bauxite residue/gypsum at various application rates and assesses the radiological significance of soil amendment in relation to currently accepted standards. Amendment rates of up to 2000 t ha-1 of bauxite residue were used. There is a linear increase of incremental � dose with increasing rate of residue. The 1 mSv limit for incremental � dose exposure for the general public is reached for 100% occupancy at an amendment rate of 1500 t ha-1 of bauxite residue. The gamma rate of approximately 0.15 �Gy h-1 is similar to that for soils of much of the area between Bunbury and Capel in the south-west of Western Australia and is significantly lower than levels for Minninup beach where there are deposits of mineral sands.
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Renshaw, Andrew A., and Edwin W. Gould. "Comparison of Disagreement and Amendment Rates by Tissue Type and Diagnosis." American Journal of Clinical Pathology 126, no. 5 (November 2006): 736–39. http://dx.doi.org/10.1309/dh4u0kt6qb01kr55.
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Sun, Haiguo, Francis J. Larney, and Murray S. Bullock. "Soil amendments and water-stable aggregation of a desurfaced Dark Brown Chernozem." Canadian Journal of Soil Science 75, no. 3 (August 1, 1995): 319–25. http://dx.doi.org/10.4141/cjss95-046.
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Aggregate stability, which influences soil resistance to wind and water erosion, can be improved by the application of organic amendments. In spring 1992, a desurfaced Dark Brown Chernozem in southern Alberta was amended with six animal manures, four crop residues and two rates of phosphate fertilizer, to determine their efficacy in restoring soil productivity. Eroded check (no amendment) and topsoil check (no desurfacing) treatments were left for comparison. One year later, wet aggregate stability at five levels of aggregate pre-wetting was determined. Aggregate stabilities of crop residue-amended soils were significantly higher (P < 0.01) than those of soils treated with animal manures or fertilizer/checks at all wetness levels. Significant (P < 0.01) quadratic response and plateau relationships between aggregate stability and soil water content showed that there was a threshold moisture content for maximum stability. With the onset of rainfall, aggregates on the crop residue-amended treatments would reach maximum stability sooner than those on the fertilizer/check treatments, thereby decreasing the potential for water erosion. Stability of air-dry aggregates showed weak positive relationships with organic and inorganic C. Amendment of eroded soils with crop residues is likely more effective in limiting erosion than amendment with animal manures or chemical fertilizers, at least in the first year after incorporation. Key words: Soil erosion, aggregate stability, animal manure, crop residue
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Williams, David G., and R. Alan Black. "Effects of nutrient amendment and environment on growth and gas exchange for introduced Penniseturn setaceum in Hawaii." Canadian Journal of Botany 74, no. 2 (February 1, 1996): 268–75. http://dx.doi.org/10.1139/b96-032.
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We examined the effects of a balanced soil nutrient amendment on photosynthesis, growth, and reproduction for the alien grass Penniseturn setaceum across an altitudinal gradient on the island of Hawaii. Nutrient amendment of plants enhanced aboveground growth, height, and numbers of reproductive tillers and inflorescences similarly across the altitudinal gradient. Nutrient amendment increased aboveground biomass 22 to 25% but had little effect on predawn water potential, leaf nitrogen concentration, or photosynthesis. Leaf nitrogen concentrations declined with altitude (22 ± 0.5 mg/g N at the coastal site; 16 ± 0.1 mg/g N at the subalpine site) and partially compensated for decreases in specific leaf area with altitude. Plants at the subalpine site had high dark respiration rates, low CO2 saturated photosynthetic rates, and low photosynthetic nitrogen use efficiencies compared with plants at lower altitudes. Chilling temperatures or high respiratory rates may limit net carbon uptake and growth for plants at higher altitude relative to plants at lower altitude. Seasonal patterns of net photosynthesis, stomatal conductance, and water potential suggest that drought colimited carbon uptake and growth at the low altitude site. Success of Penniseturn in Hawaii may stem, in part, from its ability to respond morphologically to compensate for heterogeneous nutrient and water availability across different habitats. Keywords: altitude, Hawaii, nutrient amendment, photosynthesis, Penniseturn setaceum, resource limitation.
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Song, Xue Ying, Ru Jing Liang, Yu Shuang Li, Xin Xin Li, and Xiao Jun Hu. "Composting Study of Petroleum Contaminated Soil." Advanced Materials Research 864-867 (December 2013): 67–70. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.67.
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Composting has been shown to be an effective bioremediation technique for the treatment of hydrocarbon-contaminated soil. In this research, the major objective of this research was to find the appropriate mix ratio of organic amendments for enhancing the degradation of petroleum hydrocarbons during diesel oil contaminated soil composting. The spent mushroom was added as an amendment for supplementing organic matter for composting of contaminated soil. The volumn ratios of contaminated soil to organic amendments were 1:1, 1.5:1 and 2:1. Target contaminant of this research was diesel oil, which was spiked at 16240 mg/kg sample on a dry weight basis. The degradation of diesel oil was significantly enhanced by the addition of these organic amendments relative to straight soil control. Degradation rates of total petroleum hydrocarbons (TPH) were the greatest at the ratio of 1:1 of contaminated soil to organic amendments on the volumn ratio. The abiotic loss of TPH was only about 6.83% of initial TPH.
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Wolff, Xenia. "EFFECTS OF SOIL pH, WATERING RATE, AND SOIL ANENDMENTS ON THE PRODUCTIVITY OF GREENHOUSE-GROWN CHAYOTE (SECHIUM EDULE)." HortScience 25, no. 9 (September 1990): 1064c—1064. http://dx.doi.org/10.21273/hortsci.25.9.1064c.
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Chayote (Sechium edule Swartz) is a minor vegetable crop gaining in popularity in the U.S., but with only scant cultural information on it available. The soil pH and water requirements-and the effects of various soil amendments on plant productivity were detemined in three separate greenhouse pot studies. Chayote plants were grown in either one of eight soil pH levels (5.0 to 6.5), were watered at one of three rates (1.3, 2.5, or 5.0 cm per week), or were planted in one of 16 soil amendment treatments (Oliver silt loam soil or a 1 soil: 1 peat moss (v/v) mix amended with inorganic N-P-K fertilizer, 25 or 50 kg cow or rabbit manure/ha, or 12.5 or 25 kg chicken manure/ha). Data on date of germination, plant height, single and total leaf areas, total plant and separate plant part fresh and dry weights, and presence of flowers were collected. Greatest plant productivity was achieved with a soil pH range of 5.6 to 6.5, a watering rate of 2.5 cm per week, and with several of the soil amendment treatments.
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Azeem, Muhammad, Lauren Hale, Jonathan Montgomery, David Crowley, and Milton E. McGiffen. "Biochar and compost effects on soil microbial communities and nitrogen induced respiration in turfgrass soils." PLOS ONE 15, no. 11 (November 30, 2020): e0242209. http://dx.doi.org/10.1371/journal.pone.0242209.
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We examined the effect of a labile soil amendment, compost, and recalcitrant biochar on soil microbial community structure, diversity, and activity during turfgrass establishment. Two application rates of biochar (B1 at 12.5 t ha-1and B2 at 25 t ha-1), a 5 centimeter (cm) green waste compost treatment (CM) in top soil, a treatment with 12.5 t ha-1 biochar and 5 cm compost (B1+CM), and an unamended control (CK) treatment were prepared and seeded with tall fescue. Overall, results of phospholipid fatty acid analysis (PLFA) profiling and Illumina high-throughput sequencing of 16S rRNA genes amplified from soil DNA revealed significant shifts in microbial community structures in the compost amended soils whereas in biochar amended soils communities were more similar to the control, unamended soil. Similarly, increases in enzymatic rates (6–56%) and nitrogen-induced respiration (94%) were all largest in compost amended soils, with biochar amended soils exhibiting similar patterns to the control soils. Both biochar and compost amendments impacted microbial community structures and functions, but compost amendment, whether applied alone or co-applied with biochar, exhibited the strongest shifts in the microbial community metrics examined. Our results suggest application of compost to soils in need of microbiome change (reclamation projects) or biochar when the microbiome is functioning and long-term goals such as carbon sequestration are more desirable.
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Feng, Weiying, Jiayue Gao, Rui Cen, Fang Yang, Zhongqi He, Jin Wu, Qingfeng Miao, and Haiqing Liao. "Effects of Polyacrylamide-Based Super Absorbent Polymer and Corn Straw Biochar on the Arid and Semi-Arid Salinized Soil." Agriculture 10, no. 11 (November 3, 2020): 519. http://dx.doi.org/10.3390/agriculture10110519.
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Green approaches are much more appreciable during the present scenario. Soil amendments are frequently applied for improving water use efficiency, reducing soil salinity in arid and semi-arid areas, controlling the secondary salinization of cultivated soils, and increasing the carbon sequestration capacity of soils. Thus, lab soil column simulation experiments and field experiments were carried out to evaluate these functions of two separate amendments, polyacrylamide-based super absorbent polymer (SAP) and corn straw biochar at different application rates. The simulation experiments showed that both SAP and biochar inhibited the accumulation of soil salinity, with a reduced rate of 9.7–26.3% and 13.5–37.2%, respectively, dependent on the amendment application rates. The field experiments found different salt inhibition effects of the two amendments with growth stages of maize. Soil salinization was inhibited in the pre-germination and early jointing stages by SAP, but throughout the whole growth period by biochar. Both soil amendments reduced soil electrical conductivity, and biochar increased the soil contents of Ca2+, Mg2+, and K+. Our observations demonstrated that application of biochar and SAP played important roles in increasing soil fertility and inhibiting soil salt accumulation. It provided an effective method to potentially mitigate the environmental crisis and promote sustainable development in agriculture.
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Azarenko, Anita N., Annie Chozinski, Sarah F. McDonald*, Thomas A. Forge, and Timothy Righetti. "Alternative Orchard Floor Management Practices for Improving Soil Quality and Optimizing Nitrogen Uptake Efficiency." HortScience 39, no. 4 (July 2004): 841C—841. http://dx.doi.org/10.21273/hortsci.39.4.841c.
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Information about the use of alternative management practices (AOFMP) in perennial systems to manage soil biota and influence the uptake of nutrients is limited. The objectives of this study are to evaluate AOFMP on soil quality, focussing on soil biology, and on nitrogen uptake efficiency. Research plots are located in Lewis-Brown Farm (LB), Corvallis, OR (`Fuji' apple trees) and Mid-Columbia Ag. Research & Extension Cent. (HR), Hood River, OR (`Red Delicious' apple trees). Main plot treatments were weed control methods: herbicide or cultivation. Sub plot treatments were soil amendments: no amendment, bark mulch (BM), compost, and green vetch/barley mulch (VB). A split-plot completely randomized design with 3 replications was used. Depleted NH3 SO4 was applied to single-tree replicates at bud break in 2001, 2002, and 2003. Compost amended plots contained more fungivorous nematodes than other treatments, although this difference was not significant at LB. At both sites there was a significant interaction between main and sub plot treatments in the number of bacterivores. At LB, the interaction between main and sub plot treatments affected the number of enrichment opportunists and the F-ratio was affected by amendment. At HR, the structural index was also affected by amendment. Compost resulted in the most diverse populations. Soil respiration rates in compost and BM plots were consistently higher than in unamended and VB treated plots. Soil P, pH, and organic matter content were increased by compost amendment and bulk density was decreased. At HR mid-season leaves, fruit, and first year growth from compost treated plots contained the least nitrogen derived from fertilizer, followed by bark mulch. The highest nitrogen derived from fertilizer was in unamended plots.
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Baptiste, Aman Jean, Memel Jean Didier, Kouassi Kouadio Daniel, and Otchoumou Atcho. "Fiche technique de l’impact de l’amendement du substrat en poudre de coquille d’œuf de poule sur la reproduction de Archachatina marginata (Swainson, 1821)." European Scientific Journal, ESJ 14, no. 33 (November 30, 2018): 239. http://dx.doi.org/10.19044/esj.2018.v14n33p239.
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This study consists in looking for an improvement of Archachatina margina reproductions performances by amendment of the breeding substrates. As a result, five types of substrate were prepared by soil amendment at different rates (0%, 10%, 20%, 30% et 40%) with chicken egg shell powder. On these substrates, snails were raised from spat stage until they were laid. Reproductive parameters such as: age of first laying, the number of annual laying per animal, the number of eggs per laying on the different substrates were recorded. Overall, snail laying performances improved with increasing rate of substrate amendment. However, beyond a rate of 20%, the weight of eggs laid began to decline. The chicken egg shell powder is suitable for the amendment of the breeding substrate of snails Archachatina marginata in view of an improvement in their reproductive performance. The rate of amendment recommended to this effect is 20%.
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van der Merwe, Roelof du Toit, Neill Jurgens Goosen, and Robert William McClelland Pott. "Macroalgal-Derived Alginate Soil Amendments for Water Retention, Nutrient Release Rate Reduction, and Soil pH Control." Gels 8, no. 9 (August 29, 2022): 548. http://dx.doi.org/10.3390/gels8090548.
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There is a need to develop sustainably sourced products that can address the needs for improved water retention in soils, slow the release rate of fertilizers (to prevent leaching and downstream eutrophication), and control soil pH for use in agriculture. This article investigates the use of industrial kelp solid waste extracted alginate (IW) slurries to produce soil amendment beads, potentially improving soil water retention, acting as slow-release fertilizers (SRFs), and combined with limestone controls soil pH levels. Alginate extracted from the IW was determined to have a lower guluronic (G) to mannuronic (M) acid ratio than pure laboratory-grade (LG) alginate (0.36 vs. 0.53). Hydrogels produced from the IW alginate achieved significantly higher equilibrium swelling ratios (1 wt% IW = 1.80) than LG hydrogels with similar concentrations (1 wt% LG = 0.61). Hydrogel beads were impregnated with ammonium nitrate and potassium chloride to produce potential SRFs. The release rates of K+ and NO3− nutrients from the produced SRFs into deionised water were decreased by one order of magnitude compared to pure salts. The nutrient release rates of the IW-based SRFs were shown to be similar to SRFs produced from LG alginate. Hydrogel beads were impregnated with limestone, and it was determined that the alginate-based hydrogels could significantly decrease the nutrient release rate. Using industrial kelp solid waste extracted alginate slurries shows potential for soil amendments production. This report emphasises, for the first time, the use of a crude alginate product in soil amendment formation. Further, it demonstrates slower release rates and soil pH control.