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Feland, Calli. "Nitrogen Fertilizer Types and Application Timing on Hard Red Spring Wheat Productivity and Grain Protein". Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/29209.
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The balance of improving hard red spring wheat (Triticum aestivum L. emend Thell) yield while maintaining grain protein concentration continues to be a challenge in agriculture. The objective of the field research was to evaluate N fertilizer types, additives, rates, and application timing to find N management strategies that improved the efficiency of the applied N with regards to both grain protein and yield. Another aspect of this study was to determine if ground-based active sensor data can predict grain yield and/or protein content. Fertilizer treatments consisted of 2 application timings, 3 sources of N, 3 rates of N, and 2 additive types. Spring applications improved grain protein and yield compared to fall applications. Polymer coated urea shows promise in improving grain protein over urea alone. However, profitability is dependent on environmental factors that may influence N availability, as well as prices at the time that the grain is marketed.Minnesota Wheat and Promotion Council
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Mezainis, Valdis Edgars 1947. "Nitrogen fertilizer and water application rate interactions in trickle irrigated cotton". Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/191097.
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The yield, fruiting habits, plant nitrogen uptake, dry matter production, and boll and fiber properties were studied in relation to nitrogen fertilizer and water application rate interactions in trickle-irrigated cotton. Nitrogen applications did not significantly increase yields because of high initial soil nitrogen and nitrogen added with the irrigation water. Significant yield differences did exist between the 60% consumption use (CU) irrigation level and the 90% and 120% CU irrigation levels. The 60% CU level resulted in appreciable plant water stress and appreciably lower yields. Nitrogen additions significantly increased seasonal plant petiole NO₃-N values as well as the number of flowers produced during the growing season. Increased water application rate lengthened the periods of peak flowering and peak boll production but had no effect on petiole NO₃-N. Increased water application rate did not significantly increase boll production, but an increasing trend of increased boll production with increasing water application rates was evident. Nitrogen applications did not significantly increase boll production, but percent boll set for the control treatment was higher. Both nitrogen additions and increased water application rates increased plant nitrogen uptake, which ranged from 163 kg N/ha to 242 kg N/ha for the water levels and 188 kg N/ha to 220 kg N/ha for the nitrogen treatments. Increased water application rates significantly increased dry matter production during the growing season. Nitrogen and water application rates affected only a few boll and fiber properties. Average boll size was increased significantly with increasing water application rates. This partially accounted for the higher yield observed at the higher irrigation levels.
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Woldetsadik, Kebede. "Shallot (Allium cepa var. ascolonicum) responses to plant nutrients and soil moisture in a sub-humid tropical climate /". Alnarp : Dept. of Crop Science, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/a367.pdf.
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Shiflett, Melinda Cole. "Criteria signaling reapplication of controlled-release fertilizer for maximum growth of Ilex crenata Thunb. 'Helleri'". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09122009-040325/.
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Kang, Choongkwan. "Evaluation of economic and water quality effects for variable rate application of nitrogen fertilizer /". free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9821346.
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Fava, Erica. "The effects of the level and timing of nitrogen fertilizer application on red pepper production in Québec /". Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20819.
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The use of plastic mulches in producing red bell pepper (Capsicum annuum L.) is relatively new to Quebec and management techniques need to be further developed in terms of nitrogen (N) fertilization as well as insect and disease control. A research project was undertaken in the 1995 and 1996 growing seasons to compare peppers grown on black and on silver mulches, and fertigated using either the conventional method (weekly N-fertigated) or N-fertigated using diagnostic chlorophyll meter readings. Both fertigation treatments resulted in similar yields, although those fertilized according to the chlorophyll meter received 28 to 42 kg N/ha less than the weekly fertilized treatments. The chlorophyll meter was able to detect N deficiencies. Alate aphid populations were significantly reduced by mulches, especially by the silver mulch in both years. However, apterous aphid populations were increased by mulches, most markedly by the black mulch. No significant effect of mulch or N was found on tarnished plant bug or European corn borer populations, or on the percentage of fruit with sunscald or viral symptoms.
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MOHAMED, IBRAHIM ELBASHIR. "EFFECTS OF PRE-PLANT APPLICATION OF NITROGEN FERTILIZER ON SYMBIOTIC NITROGEN FIXATION AND YIELD OF COWPEAS (VIGNA UNGUICULATA (L.) WALP.)". Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187957.
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The responses of two cowpea (Vigna unguiculata (L.) Walp.) cultivars inoculated with granular inoculum (a mixture of rhizobia) at different levels of applied nitrogen were evaluated. California Blackeye 5 (Ca5) and Knuckle Purple Hull (KPH) cowpeas were examined under field conditions for percent nodulation, nodule number, and nodule mass per plant, and nitrogenase activity at various times during the 1983 and 1984 growing seasons. Data were also obtained for shoot and root dry weights, seed yield, and protein content. Significant differences between inoculated and uninoculated plots were found at all nitrogen treatments for both cultivars with respect to nodulation percentage, nodule number, nodule mass, and nitrogenase activity. An inverse trend linear and quadratic was noted between nitrogen increments and nodulation (nodule number and nodule mass) of Ca5 and KPH cowpeas. High N (168 kg N ha('-1)) was more inhibitory to nodulation than low (28 kg N ha('-1)) N applied. Nitrogenase activity of both cultivars was significantly stimulated with low and inhibited by high levels of ammonium nitrate. Effects of nitrogen treatments on nodulation and nitrogenase activity were influenced by the stage of growth and cowpea cultivar. At the pod-fill stage, higher nodule numbers and nitrogenase activity were recorded for Ca5 as compared to KPH cowpeas. Morphological differences, with Ca5 plants being erect with few vines, whereas KPH plants were semi-erect and bushy, were observed between inoculated and uninoculated plants of Ca5 and KPH cowpeas at all levels of applied nitrogen. Dry weights of vegetative components of both cultivars were significantly improved when low (28 kg N ha('-1)) rather than high (168 kg N ha('-1)) nitrogen was added. Inoculation significantly increased seed yield of Ca5 cowpeas. When conditions were favorable seed yield of inoculated Ca5 exceeded that of inoculated KPH in all comparisons within the same increments of applied N. Seed yield of both cultivars was adversely affected when high levels of nitrogen were applied. Seed, leaf, petiole, and stem protein content were significantly higher with respect to inoculated than uninoculated plots. However, nitrogen fertilizers tended to decrease protein content of the measured parameters for Ca5 and KPH cowpeas.
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Jakkula, Vijay S. "Synthesis of zeolites and their application as soil amendments to increase crop yield and potentially act as controlled release fertilizers". Thesis, University of Wolverhampton, 2005. http://hdl.handle.net/2436/93299.
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Zeolites have been used in agriculture since the 1960s, due to the effectiveness of these crystalline microporous solids as soil amendments for plant growth, their cation exchange capacity (CEC) and slow-release fertilizer properties. Most work on slow-release fertilizers has focused on natural Clinoptilolite, Phillipsite and Chabazite. The aim of this study was to synthesize zeolites, study their effectiveness as soil amendments and their ability to act as controlled release fertilizers to decrease nitrate leaching. Nitrate pollution of groundwater is a major agro-environmental concern. The zeolites Phillipsite and Linde-type F were synthesized from aluminosilicate gels; ion exchanged to introduce ammonium and characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Thermo-gravimetric analysis (TGA) and Scanning electron microscopy (SEM) techniques, both before and after ion exchange. Ammoniumexchanged Phillipsites (natural and synthetic), ammonium-exchanged synthetic Linde-type F (the zeolite having highest affinity towards ammonium) and ammonium exchanged Phillipsites (high crystalline and high aluminium) were compared with conventional NPK fertilizer.Three glasshouse experiments were performed to study the effects of zeolite-amended soils on maize growth. Ion exchanged synthetic and natural Phillipsites were first used as soil amendments (w/w 2, 4, 8% zeolite to soil). Synthetic Phillipsite, at 2% loading, resulted in the most significant improvement in both plant growth and phased ammonium release. The synthetic ammonium-exchanged zeolites Phillipsite and Linde-type F (at w/w 1, 2, 4%) were then compared; synthetic Phillipsite, at 2% loading, again resulted in the most significant plant growth response with an increase (≥15%) in shoot dry weight and a decrease (≥30%) in nitrate leaching. Experiments using unexchanged synthetic Phillipsite (at w/w 2%), but with added NPK fertilizer, showed increased plant growth and decreased nitrate leaching, compared with parallel experiments containing unexchanged synthetic Linde-type F (at w/w 2%) and a conventional fertilizer amended soil. This revealed the beneficial effect of Phillipsite for soil amendment, even without ion exchange to the ammonium form. To study the physico-chemical properties affecting the release of ammonium from the Phillipsite framework; high crystalline/low aluminium and low crystalline/high aluminium forms were synthesized and ion exchanged. Both forms were introduced as soil amendments (at w/w 1 and 2%) and experiments showed that the lower zeolite crystallinity decreased cation exchange and therefore decreased nitrate leaching. Experimental results from the glasshouse experiments and cation exchange capacity (CEC) experiments suggest that synthetic Phillipsite, at lower loadings (1 and 2% w/w zeolite to soil) have most potential as soil amendments for both plant growth and controlled-release applications. This conclusion is supported by soil leachate and shoots dry weight analysis. Furthermore, Phillipsite, synthesized in a low crystalline and low ammonium form, may be an even better soil amendment for controlled release of ammonium, which will thereby further decrease nitrate pollution.
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Hans, Ralston Ronald. "Initial growth responses to controlled release fertilizer application at establishment of commercial forestry species in South Africa". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85609.
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Thesis (MScFor)--Stellenbosch University, 2013.ENGLISH ABSTRACT: In South Africa fertilizer applications at establishment is a common practice in the forestry industry. Recommendations are based on past research with conventional sources (CV) and as a result there have only been slight improvements in additional plantation production over recent years. The objective of this study was to investigate initial stand responses in terms of leaf are index (LAI), foliar nutrient content, biomass index (BI) and volume growth to the application of controlled release fertilizers (CRF) at re-establishment. Nitrogen (N), phosphorus (P) and potassium (K) were applied in a three way factorial combination to Pinus radiata at planting on a site in the Western Cape. The design was replicated five times across the study area. N (CRF) and P (CV) were applied in a two way factorial combination at planting to two Eucalyptus grandis x urophylla hybrids and Eucalyptus dunnii across three sites, one ex-agricultural and two re-establishment sites, on the Zululand coastal plain and the Midlands region. The design was replicated nine times on each study site. Harvesting residues were burnt on the eucalypt sites prior to establishment and may have had an impact on the responses found. An outbreak of Fusarium circinatum on the P. radiata site resulted in unexpected and extremely variable responses. An attempt to quantify the effect of the disease had limited success. The mean BI of the control treatment reached 25. The best CV and CRF treatments yielded improvements of 42 % and 83 % in BI over the control respectively, with only the CRF treatment difference being significant. Foliar analysis results revealed marginal to deficient concentrations of P and Mg being alleviated by the treatments in question. On the KZN Zululand sites there was a marked response of the hybrids to N with P having an additive effect on volume growth, LAI and foliar N content. Application of 120 g N and 20 g P per tree on the ex-agriculture site produced a volume of 8 m3 ha-1 at one year of age, a significant increase of 118 % and 80 % over the control and best CV treatment respectively. Application of 80 g N and 20 g P per tree, on the re-establishment site, yielded a volume of 24.6 m3 ha-1 at one year which equates to a significant 39 % and insignificant 7 % additional volume at one year over the control and best CV treatment respectively. A non-significant suppressive effect was found with 20 g CV P application only. At the KZN Midlands site, the major early response in height were to P application. Applications of 20 g CV P per tree, resulted in a mean height of 162.6 cm at seven months of age, a significant 28 % higher than the control. There was no significant effect of 80 g CRF N and 20 g CV P per tree respectively. CRF N applications up to 120 g per tree provide additional growth over recommended CV applications on coastal Zululand sites with low organic carbon (OC) content. On the KZN Midlands site with higher OC and clay content, early responses were limited to P fertilization only regardless of the fertilizer source.
AFRIKAANSE OPSOMMING: Dit is algemene praktyk in die Suid Afrikaanse bosbou industrie om kunsmis tydens aanplanting toe te dien. Hierdie aanbeveling is gebasseer op navorsing resultate met konvensionele bronne (CV), gevolglik was slegs ‘n klein toename in bykomende plantasie produksie gemeet die afgelope paar jaar. Die doelwit tydens hierdie studie is om die aanvanklike reaksie van die bome in terme van blaar oppervlak indeks (LAI), blaar-voedingstof inhoud, biomassa indeks (BI) en volume op die toediening van beheerde vrylating kunsmis (CRF) tydens aanplanting vas te stel. Stikstof (N), fosfor (P) en kalium (K) is in drie-ledige kombinasie aan Pinus radiata op ’n plantasie in die Weskaap toegedien. Die ontwerp is vyf keer in die studiegebied herhaal. N en P is in twee-ledige kombinasie aan twee Eucalyptus grandis x urophylla hibriede en Eucalyptus dunnii op drie groeiplekke, een eks-landbou en twee eks-bosbou, op die Zoeloeland kusvlakte en in die Natalse Middellande toegedien. Die ontwerp is nege keer in elke studiegebied herhaal. Oesreste is voor aanplanting op die Eucalyptus groeiplekke verbrand. Die voorkoms van Fusarium circinatum op die P. radiata groeiplek het onverwagte en hoogs uiteenlopende reaksies tot gevolg gehad. ’n Poging om die effek van die siekte te kwantifiseer, was slegs gedeeltelik suksesvol. Die gemiddelde BI van die kontrole behandeling, was 25. Die beste CV en CRF behandeling het onderskeidelik 42 % en 83 % hoër BI as die kontrole groep gehad, waarvan slegs die CRF behandeling beduidend was. Blaarontleding het gewys dat daar marginale of ontoereikende konsentrasies van P en Mg was. In Zoeloeland het die Eucalyptus hibriede ’n beduidende reaksie op N en P getoon met meer volume groei, LAI en N inhoud. Die toediening van 120 g N en 20 g P per boom op die eks-landbou groeiplek het ’n volume van 8 m3 ha-1 op eenjarige ouderdom tot gevolg gehad. Dis beduidend beter met 118 % en 80 % onderskeidelik vir die kontrole en beste CV behandeling. Die toediening van 80 g N en 20 g P per boom op die hervestigde eks-bosbou groeiplek, het ’n volume van 24.6 m3 ha-1 op eenjarige ouderdom tot gevolg gehad. Dit is 39 % beduidend en 7 % onbeduidend addisionele volume op eenjarige ouderdom vir onderskeidelik die kontrole groep en beste CV behandeling. ’n Onbeduidende depressie effek is met die alleen toediening van 20 g CV P gevind. In die Natalse Middellande groeiplek het die toediening van P ‘n vroeë reaksie in hoogte groei veroorsaak. Die toediening van 20 g CV P per boom, het ’n gemiddelde hoogte van 162.6 cm op die ouderdom van sewe maande tot gevolg gehad. Dit is 28 % beduidend hoër as die kontrole. Die toediening van 80 g CRF N en 20 g CV P per boom was onbeduidend. Toedienings van CRF N tot en met 120 g per boom het in die kusgebiede van Zoeloeland met ‘n lae organiese koolstof (OC) inhoud, groter groei as die aanbevole CV toedienings gehad. Die Middellande groeiplek met ’n hoër OC en klei inhoud, was die vroeë reaksie alleenlik beperk tot P bemesting.
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Mpabanga, Nkosi. "The effect of phosphorus fertilizer application on growth, biomass and nutritive value of Pigeon pea (Cajanus cajan (L.) Millsp.) varieties in Alice, South Africa". Thesis, University of Fort Hare, 2017. http://hdl.handle.net/10353/6180.
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Low soil fertility has been identified to be among the major causes of low pasture quantity and quality. Scarcity of high quality forage mainly during the dry season threatens animal productivity in some areas of South Africa, thus the need for identifying livestock feed alternatives. Pigeon pea is a woody legume that has continually been an important shrub in agroforestry and can provide protein-rich livestock feed during times of shortage. Soil fertility to support the production of pigeon pea can be enhanced by application of fertilisers. Therefore, this study was carried out firstly, to determine the effect of phosphorus fertiliser on the growth performance and biomass production of three pigeon pea varieties, and secondly, to investigate the influence of phosphorus application on the nutrient and anti-nutrient content of three pigeon pea varieties. The field experiment was done at the University of Fort Hare research farm in Alice, South Africa. The factors investigated were three pigeon pea varieties namely Chitedze 1, Chitedze 2 and CIMMYT 1 and three phosphorus fertiliser application rates of 0, 40 and 60 kg P/ha. The study was a 3× 3 factorial experiment set up in a randomised complete block design and was replicated three times. The growth performance attributes evaluated in this study include the number of branches, plant height and root collar diameter. Root collar diameter was not significantly (p>0.05) different among the pigeon pea varieties and phosphorus levels. Likewise, the application of phosphorus was not significant (p>0.05) on plant height and the number of branches of all the varieties. However, when P level was varied, there were significant differences among the varieties, and so were the interaction (p<0.05) between variety and phosphorus on plant height and the number of branches. There was no significant (p>0.05) difference among the phosphorus levels on the fresh leaf yield of Chitedze 1 and Chitedze 2, but phosphorus application at 40 kg P/ha increased the fresh leaf yield of CIMMYT 1. Phosphorus application at 60 kg P/ha increased (p<0.05) the dry matter content of Chitedze 1 and Chitedze 2. Furthermore, the results of the trial show that the application of 40 kg P/ha and 60 kg P/ha increased (p<0.05) the dry matter yield of the varieties CIMMYT 1 and Chitedze 2, respectively. The effects of phosphorus application on the nutrient composition of the three pigeon pea varieties varied. The composition of hemicellulose of all the varieties was significantly (p<0.05) increased by the application of 40 kg P/ha. Conversely, the concentration of crude protein, phosphorus, copper and iron, and the calcium to phosphorus ratio of all the pigeon pea varieties was not significantly (p>0.05) affected by phosphorus application and there was no interactive effect of variety and phosphorus. The proximate compositions of fat, total non-structural carbohydrates, ash, neutral detergent fibre, acid detergent fibre, cellulose, neutral detergent insoluble nitrogen, acid detergent insoluble nitrogen of the pigeon pea varieties varied significantly (p<0.05) at different phosphorus application levels. There was an interactive (p<0.05) effect of variety and the level of phosphorus on the concentration of calcium (Ca), potassium (K), magnesium (Mg), sodium, zinc, manganese, and the K/(Ca+Mg) ratio. The digestible dry matter, dry matter intake and the relative feed value were significantly (p<0.05) different among the pigeon pea varieties at varying phosphorus levels. The anti-nutrient composition of Chitedze 2 was not significantly (p>0.05) affected by phosphorus application but the concentration of phenols and saponins of Chitedze 1 was significantly (p<0.05) increased when 60 kg P/ha was applied, but these anti-nutrients were reduced (p<0.05) for CIMMYT 1 at 60 kg P/ha. It can be concluded that phosphorus application influences the biomass production and chemical composition while the optimum phosphorus level vary among the pigeon pea varieties.
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Nurmakhanova, Mira. "Essays on fall fertilizer application". [Ames, Iowa : Iowa State University], 2008.
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Stroehlein, Jack, Karen Kebler i Paul Forrest. "Response of Guar to Fertilizer Applications". College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/200554.
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Fertilizer studies were carried out with guar in the field and greenhouse over two seasons. Response to N was found in terms of plant growth and bean yield. With very low available soil P, fertilizer P increased the P concentration in guar plants but not bean yields. Zinc increased yields in the greenhouse only on the soil with the lowest available Zn.
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Rose, Terry. "Deep-placed phosphate fertiliser improves phosphorus uptake and seed yield of canola (Brassica napus L.) in a Mediterranean-type climate". University of Western Australia. Dept. of Soil Science and Plant Nutrition, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0237.
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In Mediterranean-type climates, topsoil frequently dries out during spring. Problems associated with reduced nutrient (P, K) availability in dry topsoil may be overcome by placing fertilisers deeper in the soil, where the soil is more likely to remain moist for longer periods as opposed to conventional fertiliser placement. Deep-P placement has resulted in significant yield improvements for lupin crops in Mediterranean environments because lupin crops generally require soil P supply during spring (throughout the flowering stage); in contrast, wheat yields have seldom improved with deep P placement, presumably because plants have accumulated sufficient P prior to spring (grain filling stage) for maximum grain yields. The P and K accumulation patterns of canola had not been investigated, and therefore any potential yield benefits of deep placed fertilisers were unknown. This study aimed to define the P and K demands of canola throughout the growing season, and assess the viability of deep placement of fertiliser in matching soil P and K supply to crop demand. The study further investigated the impact of deep placement of P fertiliser on root growth and distribution throughout the soil profile. Initial glasshouse studies compared the P and K accumulation patterns of several canola cultivars with wheat, and found that the P and K demand of canola continued until later into the season than wheat, but there was little difference in the P and K accumulation patterns of the various canola cultivars. Further experiments in sand culture determined that regardless of the level of K supply, canola plants had accumulated sufficient K for maximum seed yields by early flowering. Under high P supply, canola plants had accumulated enough P for maximum seed yields by early flowering, but when P supply during vegetative growth was just adequate, plants required a continual P supply until mid silique-filling to attain maximum yields. Because plants had accumulated sufficient K for maximum seed yields by early flowering (therefore topsoil drying in spring was unlikely to affect yields), further field experiments examined only deep placement of P fertiliser to improve P uptake and yields.
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Ahmed, Sabah Kedar. "Yield, dry matter production, and nitrogen uptake of drip irrigated cotton". Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/191143.
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The study consisted of two experiments conducted over two growing seasons. Urea ammonium nitrate was used as a source of N at rates of 50, 75, 100 and 150% of levels estimated to be ideal for maximum yield of cotton (Gossvpium hirsutum L.). The nitrogen fertilizer was applied through a drip irrigation system. The yield of seed cotton, flowering pattern, boll set, plant N uptake, and dry matter production were studied in relation to four N fertilizer rates and two plant populations in the 1984 study. Yield of seed cotton, plant N uptake and dry matter production were studied in relation to four N rates, three seeding rates, and three cotton cultivars in the 1985 study. Petiole nitrate patterns were studied both seasons. The effect of N applications on seed cotton yield was dependent upon the initial soil N and the yield possibility. In this study the lower rate of N appeared to be sufficient for the yields obtained. Thinning resulted in reduction of the total number of flowers and significantly decreased yield, but percent boll set was not affected. Nitrogen additions significantly increased plant N uptake and dry matter production as well as petiole NO₃-N levels during the growing season. The N need of cotton under drip irrigation was determined throughout the growing season by using petiole analysis. The levels of petiole NO₃-N for N sufficiency and deficiency which are accepted under furrow irrigation cotton were shown to be applicable for drip irrigated cotton. Yield of DPL-775 and DPL-90 cotton cultivars was significantly higher than that for DPL-41 cotton cultivar in 1985.
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Mohamed, Abdellatif Abdellatif 1956. "Response of cotton to N and water applied via a trickle irrigation system : growth, yield, and nutrient uptake". Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/191128.
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The crop growth rate (CGR); the relative growth rate (RGR); seed yield; plant uptake of N, P, K, Ca, Mg, Fe, and Na; and the water use efficiency (WUE) were studied in relation to N fertilizer and water application rate interactions in trickle-irrigated cotton. Increasing water application rate significantly increased CGR, but no significant differences were detected among the RGR values at the various water levels. Nitrogen fertilizer additions significantly increased the CGR. Nitrogen and water applications significantly increased seed yield, however, the effect of the interaction between N and water was not significant. Water levels had a positive significant effect on the cotton reproductive growth. Increased N and water significantly increased total N-uptake by cotton plants. Nitrogen additions significantly increased N% of leaves, burrs and seed. However, N% of stem was significantly reduced with high N applications. Total uptake of P, K, Ca, and Mg significantly increased with the increased application of N and water. Addition of 1.2 consumptive use (Cu) irrigation rate significantly increased P% in cotton stems, however, K% in stem was reduced. The irrigation rate of 0.9 CU and 1.2 CU significantly increased Mg% in both leaves and stems. Nitrogen application rates of 224 and 336 kg N/ha significantly decreased Mg% in leaves and stems. Increasing the irrigation rate from 0.9 CU to 1.2(1.3) CU reduced the WUE by cotton plants. However, WUE appeared to increase as N fertilizer increased up to 33 kg N/ha with water level of 0.9 CU.
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Woodward, Timothy Ryan. "Evaluation of Urea Ammonium-Nitrate Fertilizer Application Methods". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76800.
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Increased nitrogen (N) costs and environmental concerns have created a need to reevaluate current sidedress N application recommendations for corn. Injection of Urea Ammonium-Nitrate (UAN) may reduce N-loss via ammonia (NH?) volatilization compared to current surface application methods. This study evaluated injection and surface-banding application techniques of UAN in two ways: (1) by conducting a laboratory experiment where NH?-N loss was measured from UAN applied by both techniques across varying residue covers; and (2) by performing a field study where the application methods were compared by their effect on corn grain yield, ear leaf tissue N content, and stalk nitrate (NO3). The laboratory system used to compare the NH?-N loss from the UAN application methods was evaluated and found to be capable of providing rapid, accurate, and precise measurements of N loss throughout a range of N rates and conditions. In the laboratory study, injection of UAN reduced NH?-N losses to <1% of applied N. Surface-banding of UAN resulted in NH?-N losses between 15.3 and 32.5% of applied N. Results from the field study suggest that differences between application methods were commonly seen in ear leaf tissue N, where injection of UAN was often found to increase tissue N compared to surface-banding. Also, injection of UAN reduced the optimal N rate by 25 kg N ha?? compared to surface-banding. The results suggest that injection of UAN reduces the potential of NH?-N losses and is a practice worth considering in developing an efficient N fertilizer program.Master of Science
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Gardner, B. R., i T. C. Tucker. "Effect of Phosphorus Fertilizer Application on Cotton Yields". College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/204087.
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Stroehlein, J. L., W. C. Hofmann, S. K. Ahmed i Cathy Creekmore. "Response of Surface Drip Irrigated Cotton to Fertilizer Application". College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219761.
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The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.Fertilizer nitrogen rates and the addition of phosphorus, potassium and zinc were studied in a drip irrigated field at Eloy. Response to nitrogen was found with the optimum rate being about 170 lbs/acre although higher rates tended to increase yields. Significant response to P and K were not found, but there appeared to be a response to zinc. Yields were below desired levels because of problems with obtaining a good stand and infestations of cotton rust and root rot.
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Zhang, Feng 1962. "Effects of N formulation, application rate, and application time on corn yield and quality in eastern Canada". Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61039.
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An experiment was conducted to investigate the effects of N formulation, application rate, and application time on corn yield and quality under Eastern Canadian conditions, to evaluate the hypothesis that application of N will increase corn grain yield and protein concentration without decreasing the total energy content. Three N formulations, each with the rates of 90, or 180 kg ha$ sp{-1}$ were applied at different times. The results indicated that the grain yield increased with increasing N fertilizer rate and with increasing numbers of N application times. N application significantly increased grain protein concentration, on both a per kernel and a dry matter basis, and protein yield. Such as, N application increased the averaged protein concentration, on a dry matter basis, of corn grain by about 8.40% as compared to the control. The protein concentration was not affected by the number of N application times before the plants were 90 cm high. Neither lipid nor non-structural carbohydrate concentration, on both a per kernel and a dry matter basis, were significantly affected by N application in most of the location-years. In addition Near infrared reflectance (NIR) was used to determine the lipid concentration in the aerial corn tissue at different growth stages. The correlation coefficients between the standard analytical method and the NIR method of lipid concentration were all above 0.95, and were significant at 0.01 level.
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FULTON, JOHN PATRICK. "A SPATIAL MODEL FOR EVALUATING VARIABLE-RATE FERTILIZER APPLICATION ACCURACY". UKnowledge, 2003. http://uknowledge.uky.edu/gradschool_diss/248.
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The popularity of variable-rate technology (VRT) has grown. However, the limitations and errors ofthis technology are generally unknown. Therefore, a spatial data model was developed to generate "asapplied"surfaces to advance precision agricultural (PA) practices. A test methodology based on ASAEStandard S341.2 was developed to perform uniform-rate (UR) and variable-rate (VR) tests to characterizedistribution patterns testing four VRT granular applicators (two spinner spreaders and two pneumaticapplicators). Single-pass UR patterns exhibited consistent shapes for three of the applicators with patternsshifts observed for the fourth applicator. Simulated overlap analysis showed that three of the applicatorsperformed satisfactorily with most CVs less than 20% while one applicator performed poorly (CVs andgt;25%). The spinner spreaders over-applied at the margins but the pneumatic applicators under-appliedsuggesting a required adjustment to the effective swath spacing. Therefore, it is recommended that CVsaccompany overlap pattern plots to ensure proper calibration of VRT application.Quantification of the rate response characteristics for the various applicators illustrated varying delayand transition times. Only one applicator demonstrated consistent delay and transition times. A sigmoidalfunction was used to model the rate response for applicators. One applicator exhibited a linear responseduring a decreasing rate change. Rate changes were quicker for the two newer VR control systemssignifying advancement in hydraulic control valve technology. This research illustrates the need forstandard testing protocols for VRT systems to help guide VRT software developers, equipmentmanufacturers, and users.The spatial data model uses GIS functionality to merge applicator descriptive patterns with a spatialfield application file (FAF) to generate an 'as-applied' surface representing the actual distribution ofgranular fertilizer. Field data was collected and used to validate the "as-applied" spatial model.Comparisons between the actual and predicted application rates for several fields were madedemonstrating good correlations for one applicator (several R2 andgt; 0.70), moderate success for anotherapplicator (0.60 andlt; R2 andlt; 0.66), and poor relationships for the third applicator (R2 andlt; 0.49). A comparison ofthe actual application rates to the prescription maps generated R2 values between 0.16 and 0.81demonstrating inconsistent VRT applicator performance. Thus, "as-applied" surfaces provide a means toproperly evaluate VRT while enhancing researchers' ability to compare VR management approaches.
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Hulm, Sharon C. "Fertilizer nitrogen transformations following urea application to an afforested ecosystem". Thesis, University of Aberdeen, 1987. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU010535.
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Fertilizer nitrogen transformations in two Sitka spruce stands in northeast Scotland were studied using 15N-labelled (2.5 atom % 15N) urea at a rate equivalent to 160 kg N ha-1. The use of urea fertilizer resulted in accelerated growth of the tree crowns, and higher concentrations of total N in foliage, twigs and new wood. There was no fertilizer effect observed for bark. Despite a positive growth response by the trees to fertilizer N, only an estimated 17% of applied-N was utilized by the tree biomass. Application of urea-N resulted in a reduction in the leaching of inorganic N and certain cations (particularly Ca 2+). Gaseous losses of N were elevated following urea application, but estimated losses of fertilizer N via NH3 volatilization and denitrification were negligible. Data from both sites indicated a retention of volatilized NH3 in the tree canopy which was returned to the soil in throughfall. Urea application to the forest floor resulted in elevated pH of the LFH for a period of about 100 days. Urea application also led to a flush of acetic acid extractable PO4-P in the LFH. The addition of urea also resulted in increased counts of bacteria in the LFH. Data indicacted that elevated NO3- concentrations in the LFH may have been due to bacterial nitrification. Little effect of fertilizer N was observed for mineral soil, with a retention of the bulk of fertilizer N in the LFH.
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Silvertooth, J. C., G. W. Thacker, J. E. Malcuit, T. A. Doerge i S. H. Husman. "Upland and Pima Cotton Response to Banded Fertilizer Applications, 1990". College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/208629.
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Two field experiments were established in Arizona in 1990 to evaluate the effects of banded phosphorus (P) fertilizer on cotton. Experiments involved both Upland (Gossvpium ltirsutum, L.) and American Pima (Q. barbadense L.). Banded applications of P fertilizerwere made with placement of the concentrated band of fertilizer 6 in. below and 3-6 in. to the side of the zone of seed placement. The P₂O₅ was supplied from 10-34-0. Rates of applied P ranged from 0 to 160 lb P₂O₅ /acre. In one experiment, treatments consisting of 5 to 10 lbs. Zn/acre were included in all possible combinations with the P₂O₅ treatments. In all cases, treatments in the field were arranged in a randomized complete block design with four replications. Plant measurements for plant height, flower numbers per unit area, number of mainstem nodes, and nodes to the first fruiting branch were initiated by the fifth true leaf stage to evaluate plant response in terms of growth and development. Plant tissue samples were also taken at several stages of growth from each experiment throughout the growing season. Tissue samples consisted of petioles from the uppermost fully - developed leaves. Petioles were analyzed for extractable PO₄-P. Lint yield measurements also were taken. No statistically significant differences (P ≤ 0.05) were found among any treatments for any of the plant growth parameters. The same was true with regard to petiole PO₄-P levels measured. No significant differences were detected among Upland or Pima cotton lint yields in response to the applications of P fertilizers.
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Bhogal, Anne. "Effect of long-term nitrogen applications on nitrogen cycling under continuous wheat". Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294731.
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Gildow, Marie C. "Evaluating Fertilizer Application Practices to Reduce Phosphorus Discharge from the Maumee River". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437400849.
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Sunderlage, Brent. "LATE APPLICATION NITROGEN ON CORN IN SOUTHERN ILLINOIS AND SOIL PROPERTIES AFFECTING AMMONIA VOLATILIZATION FROM UREA FERTILIZER". OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2154.
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AN ABSTRACT OF THE THESIS OF BRENT C. SUNDERLAGE, for the Master of Science degree in Plant, Soil, and Agricultural Systems, presented on March 8, 2017, at Southern Illinois University Carbondale. TITLE: LATE APPLICATION NITROGEN ON CORN IN SOUTHERN ILLINOIS AND SOIL PROPERTIES AFFECTING AMMONIA VOLATILIZATION FROM UREA FERTILIZER MAJOR PROFESSOR: Dr. Rachel L. Cook In corn (Zea mays L.) production systems, typical nitrogen fertilization occurs either before planting or after crop emergence, as late as the V6 stage. Since the majority of nitrogen uptake does not occur until V10 through R1, delaying nitrogen fertilization until V10 may reduce potential for early season soil N transformations and losses, while sustaining crop yields. A two-year study, conducted across three southern Illinois locations, evaluated the effects of various late sidedress nitrogen applications and enhanced efficiency fertilizers on corn yield and residual mineral soil N. The various nitrogen treatments compared: rates from 0-224 kg N ha-1; sources of urea and 32% UAN, with and without urease inhibitors 0.09% N-(n-butyl) thiophosphoric triamide (NBPT) as Agrotain® Ultra (AT) and 0.06% NBPT + 0.02% N-(n-propyl) thiophosphoric triamide (NPPT) as Limus® (L), and polymer-coated urea (ESN®); application timings at planting, V6, V10, and VT; placement either dribble applied, broadcasted, or injected. Across sites and years, late (V10) nitrogen split applications generally resulted in corn yields greater than or equal to the same total nitrogen rate applied at planting. Most late N treatment differences varied between sites and years, but 56 kg N ha-1 as broadcasted UAN at planting with 112 kg N ha-1 as broadcasted urea, either with or without AT or L at V10 were on average highest yielding treatments among sites in both years, with 16% greater yield than 168 kg N ha-1 as broadcasted UAN at planting. Urease inhibitors did not enhance yield in most instances, likely due to sufficient incorporating rainfall shortly after application. The effects of urease inhibitors used with late-application nitrogen on corn yield and actual ammonia volatilization remained ambiguous. Residual soil mineral nitrogen concentrations between 0-30 cm after harvest in the late nitrogen treatments did not elicit water quality concerns. Furthermore, ammonia volatilization from surface applied urea is controlled by many interrelated soil properties as well as environmental conditions. However, conclusions about the influence of soil properties on ammonia volatilization differ according to geographies and are not well established across a wide range of soil types. A laboratory soil incubation experiment measured the effects of soil properties on ammonia volatilization over 7 days from surface-applied urea and the efficacy of three urease inhibitors: Agrotain® Ultra (AT) as 0.09% NBPT, Limus® (L) as 0.06% NBPT + 0.02% NPPT, and NutriSphere-N® (NS) 30% calcium salt of maleic-itaconic copolymer among 83 soil surface samples from across the United States with a wide range of soil properties. The soil properties evaluated were: total exchange capacity, 1:1 CaCl2 pH, organic matter, buffering capacity, clay content, and urease activity. In Urea (R2 = 0.69) and Urea + NS (R2 = 0.62) models, total exchange capacity, clay, and buffering capacity significantly reduced ammonia volatilization, and organic matter significantly increased ammonia volatilization, while 1:1 CaCl2 pH and urease activity were non-significant. Clay, organic matter, and buffering capacity were correlated to total exchange capacity. Total exchange capacity was the strongest predictor and best consolidated variable to predict N loss of urea. In Urea + AT (R2 = 0.54) and Urea + L (R2 = 0.67) models, ammonia volatilization was significantly reduced at lower 1:1 CaCl2 pH and total exchange capacity, and all other soil properties were non-significant. The NBPT in Urea + AT and Urea + L likely decayed more rapidly under acidic soil conditions, resulting reduced NBPT efficacy and greater N loss at lower pH. Urea + AT and Urea + L reduced volatilization significantly by 18.2 percentage points compared to Urea or Urea + NS, and there were no significant differences between Urea + AT and Urea + L (α = 0.05). On average, NutriSphere-N® did not reduce volatilization.
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Stovall, Jeremy Patrick. "Growth and Physiological Responses to Fertilizer Application in Clonal Loblolly Pine". Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/38684.
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More than 20 million clonal loblolly pines have been planted throughout the southeastern United States. Fertilizer has been applied to more than 6.5 million hectares of plantations to alleviate deficiencies of nitrogen and phosphorus that limit growth. Because cloning loblolly pine in large numbers has only become possible in the last decade, it is unknown how clones may respond differently to fertilizer application. Growth, growth efficiency, and biomass partitioning responses to fertilizer application were investigated among 25 clones planted in the Virginia Piedmont. Closely related clones varied in their fertilizer stem volume responses, but not enough to be statistically significant (p = 0.11). Clones varied in growth efficiency and partitioning to individual tissues, but clone-by-fertilizer interactions were not observed. Clonal variability was observed in root morphology, and maximum rooting depth showed a significant clone-by-fertilizer interaction.
Clones with rapid growth rates can be selected with a range of other desirable traits. Short-term (i.e. weeks) responses to fertilization are often inconsistent with long-term (i.e. years) responses, but are critical to understanding growth responses. We investigated carbon allocation in two full-sibling clones of loblolly pine under two levels of fertilizer application over four months in a greenhouse. Using monthly harvests of some trees and ecophysiological measurements throughout, we determined carbon allocation on a monthly scale. In response to fertilizer application, both clones reduced allocation belowground and increased allocation to foliage to some extent, increasing whole-canopy photosynthetic capacity. However, these changes in allocation were ephemeral. By the end of the experiment, root-shoot ratios were no longer significantly affected by fertilizer application. Clones had allocation patterns distinct from one another, with one allocating more belowground and the other allocating more to stem mass. While their overall growth responses to fertilizer application were similar, the physiological mechanisms that resulted in these responses were different between clones.
Results of the two studies indicate that while fertilizer responses may not need to be included when testing clones for deployment, knowledge of the fertilizer responses of widely-deployed clones would offer forest managers opportunities to apply clone-specific precision-silvicultural systems to optimize growth rates and manage for a range of products.
Ph. D.
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Clark, Lee J., i Bryant R. Gardner. "Effect of Nitrogen Fertilizer Application on Cotton Yields, Safford Agricultural Center". College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219792.
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The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.A soil depleted of nitrogen by cropping with Sudan grass and removing all the residues was planted to Upland (DP 90) and Pima (S-6) cotton. Nitrogen was added in the form of urea at three different stages of plant growth, applying a total of 0, 50 or 100 pounds of nitrogen. The yield of lint from DP 90 was increased where nitrogen was added; however, there were no differences in yield with the timing nor total amount of nitrogen added. In the case of S-6, fertilizer nitrogen did not increase yield.
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Keene, Thomas Clarkson. "SWITCHGRASS YIELD AND QUALITY WITH MULTIPLE FERTILIZER APPLICATIONS AND HARVEST DATES". UKnowledge, 2014. http://uknowledge.uky.edu/pss_etds/42.
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Switchgrass (Panicum virgatum L.) is an important native warm-season grass for biomass and forage production in the U.S. This research determined the effect of fertilizer type (conventional, manure, and biosolids) and rate on switchgrass biomass yield and forage quality. Fertilizers were added at 0, 33, 67, 100, and 134 kg N ha-1 on established stands of ‘Kanlow’ switchgrass in three northeastern Kentucky counties. Soils across sites ranged from recently cleared forestland (low pH, P, and K) to productive cropland (high pH, P and K). Stands were sampled for forage nutritive value in June, simulating a hay harvest. Nutritive value and biomass yield were sampled in November and March. Results showed a harvest date effect for mean crude protein (CP) of 8.31% in June and 1.16% November and March. There was also a harvest effect for biomass with a mean yield of all harvests of 16.6 MT ha-1 but a N response at only one site. In conclusion, this study suggested that switchgrass may produce adequate nutritive value for dry beef cows in June and fertilizer type and rate may have a limited effect on biomass yields.
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Wagner, Nicole Catherine. "Wheat yield prediction modeling for localized optimization of fertilizer and herbicide application". Diss., Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/wagner/WagnerN0805.pdf.
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Nelson, J. M., i G. L. Hart. "The Response of Lesquerella to Nitrogen Fertilizer Rate and Time of Application". College of Agriculture, University of Arizona (Tucson, AZ), 1996. http://hdl.handle.net/10150/202423.
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Lesquerella is a plant that grows in the wild in southwestern U.S. and produces seeds containing hydroxy fatty acids similar to those in castor beans. Research has indicated that lesquerella has potential as a crop plant for Arizona. An important step in the commercialization of this plant for Arizona farms is the development of an efficient agronomic production system. Research to determine the effect of nitrogen (N) rates and timing of N applications on lesquerella production was conducted at the Maricopa Agricultural Center in the 1993 -94 and 1995 -96 seasons. Nitrogen application rates of 0 to 108 and 0 to 162 lbs. N /acre were evaluated in 1993 -94 and 1995 -96 tests, respectively. Seed yields as high as 1780 lbs. /acre were obtained in the 1995 -96 test using a conventional combine for harvest. In both tests, lesquerella biomass production and seed yields increased as the N rate was increased. In 1995 -96, a split application of N in March and April resulted in higher seed yields than a single application in March. Seed oil content decreased in both tests as the N rate was increased. In 1995 -96, seed oil content decreased 12% as the N rate was increased from 0 to 162 lbs. N /acre. The N application rate had no effect on 1000 -seed weight.
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Campbell, Allan J. "Design and evaluation of liquid swine manure injectors for potato nutrient placement". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0025/NQ50124.pdf.
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Norton, E. R., L. J. Clark i H. Borrego. "Evaluation of Variable Rate Fertilizer Applications in an Arizona Cotton Production System". College of Agriculture, University of Arizona (Tucson, AZ), 2005. http://hdl.handle.net/10150/198174.
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A project was initiated in the 2004 cotton (Gossypium hirsutum) growing season in an effort to accomplish two major objectives. The first was to continue with phosphorus (P) fertilization evaluations that have taken place in the Upper Gila River Valley for the past four seasons by continuing to document the effects of P fertilization on crop yield and fiber quality. The second objective was to investigate the feasibility of utilizing a Global Positioning Systems (GPS) and Geographic Information Systems (GIS) technology for making variable rate (VR) applications of P fertilizers based upon yield data from the previous cropping season. Yield maps from a cotton picker mounted yield monitoring system were collected from the 2003 growing season and used to develop prescription applications of P fertilizers in the 2004 season. The project was established with four treatments including a control (Treatment 1 - 0 P fertilizer applied); a VR application treatment (Treatment 2 - received 52 lbs P/acre on average); a high Uniform Rate (UR) application (Treatment 3 - 75 lbs P/acre); and a low UR application (Treatment 4 - 45 lbs P/acre). These treatments were arranged in a randomized complete block design with four replications. The size of each experimental unit was 0.7 acres. Lint yield results indicated a positive response to applied P fertilizers with treatments 2, 3, and 4 producing significantly higher yields than the control. Lint yield was not significantly affected by fertilizer application technique. Yield differences among the treatments receiving P fertilizer were minimal, particularly among treatments 2 and 3. However, it is important to note that the amount of P fertilizer used in treatment 2 was reduced by 27% with the use of the VR application technique. This produces an approximate $7/acre savings to the grower. This project will be continued in the 2005 growing season and will be expanded to investigate VR application technology in nitrogen (N) fertilization also.
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Garcia, Teijeiro Rosalia. "Effect of slow release nitrogen fertilizer application on soil quality-soil microbial population /". Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1324374171&sid=9&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Horner, Emily Renee. "THE EFFECT OF NITROGEN APPLICATION TIMING ON PLANT AVAILABLE PHOSPHORUS". The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1211932436.
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Deizman, Marcia McCutchan. "A computer simulation model for investigating the effect of land application of sludge on runoff water quality". Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44629.
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CREAMS-NT, a modified version of the field-scale model for Chemicals, Runoff, and Erosion from Agricultural Management Systems (CREAMS) model, was developed to simulate the nitrogen (N) transformations and subsequent nutrient transport processes which occur in the soil following organic waste applications. CREAMS-NT accounts for nutrient addition through fertilization and rainfall and losses of N by volatilization, denitrification, plant uptake, leaching, and overland flow. Data required by CREAMS-NT includes runoff volume, sediment yield, percolation, and soil environmental conditions which is generated by the hydrologic and erosion components of the original CREAMS model. The mineralization, nitrification, denitrification, ar1d volatilization processes are simulated using firstâ order knetic equations adjusted for the effects of soil environmental conditions including temperature, moisture, pH, soil/sludge contact, and soil cation exchange capacity. Prior to a runoff event, soil ammnonium-N (NH4 â N) is partitioned between adsorbed and desorbed phases. CREAMS-NT predicts the transport of organic-N, NH4 â N, and sediment=bound phosphorus (P3b) in runoff using enrichment ratios. The transport of soluble nutrients, nitrate-N (NO3 â N), NH4 â N, and soluble P (PTF), is estimated using extraction coefficients.Master of Science
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Schoeman, Stephanus P. (Stephanus Philippus). "Physiological measurements of daily daylight fertigated citrus trees". Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/53000.
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Thesis (MScAgric)--University of Stellenbosch, 2002.ENGLISH ABSTRACT: Daily daylight fertigation regimes (involvinq drip fertigation, on a daily basis, during the daylight hours) are becoming widely used in the South African citrus industry in the endeavor to enhance tree productivity. Such regimes could provide sensitive nutrient and moisture management, reducing plant stress in general as well as the response time to root-directed cultural activities. There is a need to evaluate the efficacy of daily daylight fertigation systems relative to conventional irrigation systems. Standard horticultural evaluation of orchard management practices is very time consuming. We opted for physiological studies comparing plant stress levels, in an attempt to quantify plant performance under each system. Citrus trees under daily daylight fertigation and conventional micro-jet and drip-irrigated regimes were monitored to establish plant stress levels as indicated by sap flow, xylem water potential, stomatal conductance and chlorophyll a fluorescence. Plants under a daily daylight fertigation regime are believed to have good soil water conditions in their rooting volume, and therefore experience negligible baseline levels of stress. The trees do, however, experience midday depression in stomatal conductance, to a lesser degree, but not unlike trees under conventional regimes. It appears as if a larger rooting volume of microjet irrigation regimes enhances recovery from the midday depression. It is recommended that producers optimise productivity during the moming hours, by early irrigation, so that plants can function optimally, whilst environmental conditions are most favourable for high physiological activity. We also assessed the effect of withholding water from trees adapted to a daily daylight fertigation regime to evaluate the risk involved with short-term water deficits in trees adapted to this regime, as well as the usefulness of physiological techniques for identifying water stress. Stomatal conductance and xylem water potential indicated water stress sooner than the other physiological parameters. Citrus trees seem to be relatively insensitive to water deficit stress as measured by sap flow and chlorophyll a fluorescence. Sap flow is buffered by tree capacitance, and although mediated via stomatal conductance, atmospheric conditions and not the soil water content primarily determine it. As daily fertigation is applied to trees under DOF regimes, they exhibit more optimal levels of xylem water potential and stomatal conductance, compared to trees from which water is withheld. Although alleviating it to a degree, daily irrigation did not mitigate the midday depression in these values. Seen over a season, even small enhancements of stomatal conductance (and with it photosynthesis and possibly, growth) and xylem water potential, could incrementally produce higher yields.
AFRIKAANSE OPSOMMING: In die strewe na verhoogde boomproduktiwiteit, word daaglikse sproeibemesting (deur 'n drupbesproeiingsstelsel toegedien tydens die dagligure) al meer algemeen in die Suid Afrikaanse sitrusbedryf gebruik. Hierdie praktyk verminder algemene plantstres deur baie spesifieke voedingsen vogbeheer, en verkort ook die plant se reaksietyd op wortelgerigte bewerkingsaktiwiteite. Dit is nodig om die relatiewe voordeel van daaglikse sproeibemesting teenoor konvensionele besproeiingssisteme te evalueer. Huidige tuinboukundige evaluering van boord-bestuurspraktyke is baie tydrowend. In 'n poging om plantreaksie onder verskillende praktyke te beskryf, het ons besluit om die plantstresvlakke met fisiologiese metodes te vergelyk. Sitrusbome onder daaglikse sproeibemesting, en konvensionele mikro- en drupbesproeiing, is onderskeidelik gemonitor om die plant se stresvlakke vas te stel, soos aangedui deur sapvloei, xileem-waterpotensiaal, stomatale geleiding en chlorofil a f1uoresensie. Die plante onder daaglikse sproeibemesting ondervind lae viakkke van waterstremming, waarskynlik weens hoë grondvogtigheid in die wortelsone. Die bome ondervind wel, soos dié onder konvensionele besproeiing, middagdepressie in stomatale geleiding, hoewel tot 'n mindere mate. Dit blyk asof die groter wortelvolume van mikrospuit besproeide bome die herstel na middagdepressie bespoedig. Produsente word aangeraai om die oggendure optimaal te gebruik deur vroeg te besproei sodat plantproduktiwiteit hoog is terwyl die omgewingsfaktore op hul gunstigste is en wanneer die hoogste fisiologiese aktiwiteit voorkom. Ons het ook die effek van wateronthouding gemeet op die bome wat aangepas is vir daaglikse sproeibemesting. Sodoende is die risiko verbonde aan 'n korttermyn watertekort op hierdie bome ge-evalueer, asook die bruikbaarheid van fisiologiese tegnieke om waterstremming in sitrus te identifiseer. Stomatale geleiding en xileem-waterpotensiaal het waterstremming vroëer aangedui as die ander fisiologiese parameters. Sitrusbome blyk redelik onsensitief te wees teenoor droogtestremming soos gemeet deur sapvloei en chlorofil a fluoresensie. Sapvloei word gebuffer deur boom-kapasitansie, en alhoewel sapvloei gereguleer word deur stomatale geleiding, is dit die atmosferiese toestande (hoofsaaklik dampdruk verskil) wat dit primêr beïnvloed, en nie die grond-water inhoud nie. Omdat bome daagliks sproeibemes word, het hulle meer optimale vlakke van xileemwaterpotensiaal en stomatale geleiding in vergelyking met bome waarvan water weerhou is. Alhoewel daaglikse sproeibemesting die middagdepressie verlaag het, is dit nie daardeur opgelos nie. Oor die typerk van 'n seisoen kan selfs minimale verhogings in stomatale geleiding (en daarmeesaam fotosintese en moontlik groei) en xileem-waterpotensiaal, hoër opbrengste tot gevolg hê.
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Tejos, Dante Pinochet. "The residual effect of applications of phosphate fertilizer measured by the Olsen method". Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308579.
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Palumbo, John C. "Compatibility of Fertilizer and Neonicotinoid Soil Applications for Whitefly Control in Spring Cantaloupes". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/214963.
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Studies were conducted in the spring of 2001 and 2002 to evaluate the interaction between starter and side dress fertilizer mixes with neonicotinoid insecticides and their performance against whiteflies in spring cantaloupes in Yuma, AZ. No incompatibility was observed between the fertilizers and the Admire and Platinum mixtures applied at planting and side dress, and both insecticides provided comparable control of whitefly populations regardless of fertilizer used. However, based on our experience in 2001, we suggest that growers use a dilute mixture with the final applied volume to avoid any potential "clumping" problems in the mix tank. In some cases the addition of the DuneUp® starter fertilizer appeared to improve plant growth, but was probably more due to the unique mixture of NPK rather than the combination with the insecticides. Based on the results of these studies growers should not hesitate to apply either Admire or Platinum with starter and side dress fertilizers in melon crops.
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Colley, Richard T. III. "Development of a Machine Vision System for Mass Flow Sensing and High-Resolution Mapping of Granular Fertilizer Application". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543564969065918.
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Weggler-Beaton, Karin M. "The beneficial and detrimental effects of sewage sludge applications in South Australia". Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phw4113.pdf.
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Torr, Leigh Christine. "Applications of dairy wastewater as a fertilizer to agricultural land : an environmental management perspective". Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1641.
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Thesis (MSc (Geography and Environmental Studies))--University of Stellenbosch, 2009.As with any form of intensive agriculture, there are potential environmental impacts associated with the management and housing of livestock on dairy farms. Within the field of dairy farming, particular focus falls to the issue of environmental degradation of water resources, as this form of pollution is currently a major environmental issue around the world. Conventional agricultural practices involving the application of chemical fertilizers to land and crops are causing environmental problems as a result of poor management practices. Dairy wastewater and manures could however be a valuable resource for agricultural producers in the form of an alternate fertilizer for their crops. Waste application as a fertilizer is more environmentally friendly than chemical fertilizers, and could drastically reduce costs for farmers, whilst alleviating storage and management problems often associated with farmyard manures (FYM). The application of organic wastes, notably livestock manures, to land has historically been important for maintaining soil fertility on farms in terms of nutrient status and organic matter levels, as well as helping to reduce soil erosion and improve waterholding capacity. The research sought to investigate the environmental and economical feasibility of using dairy wastewater and manures as an alternative form of fertilizer within agriculture in South Africa.
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Gouveia, Aline Mendes de Sousa 1985. "Adubação potássica na produção e qualidade pós-colheita do rabanete /". Botucatu, 2016. http://hdl.handle.net/11449/136239.
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Orientador: Regina Marta EvangelistaBanca: Pablo Forlan Vargas
Banca: Eliane Aparecida Benato Rodrigues da Silva
Resumo: O rabanete pode ser cultivado entre o período de safra de outras culturas de ciclo mais longo, sendo uma opção interessante aos pequenos produtores rurais que enxergaram nesta hortaliça uma possibilidade de incremento na rentabilidade das suas áreas. Devido a poucas informações na literatura que mostrem os efeitos do potássio na produção, qualidade e nas características bioquímicas do rabanete, objetivou-se com este trabalho avaliar os efeitos da adubação potássica aplicado em cobertura na produção e qualidade pós-colheita da cultura do rabanete armazenado sob refrigeração. O experimento foi conduzido na Fazenda Experimental da FCA/UNESP, em São Manuel/SP e as avaliações foram realizadas no Departamento de Horticultura da Faculdade de Ciências Agronômicas (FCA/UNESP). O delineamento experimental foi em blocos ao acaso, composto por cinco tratamentos de doses de potássio (K2O) (0; 22,5; 45; 67,5 e 90 kg ha-1) na forma de cloreto de potássio em cobertura, com cinco repetições. Foram avaliadas as características vegetativas da planta, acúmulo de nutrientes na raiz e produtividade. Para as características de qualidade (físico-química e bioquímica) as raízes colhidas foram armazenadas a temperatura de 5 ± 1 °C e UR de 85 ± 5 % durante 28 dias, sendo avaliadas a cada 7 dias, quanto a perda de massa, pH, acidez titulável, sólidos solúveis, açúcares redutores, ácido ascórbico (vitamina C), compostos fenólicos, pigmentos (carotenoides e antocianinas totais) e atividade enzimática (peroxidase). Para as características de produção do rabanete, obtiveram-se respostas lineares significativas em função das doses de potássio aplicadas em cobertura para: altura de plantas, massas da matéria fresca da parte aérea, raiz e total, com incremento de 0,46 cm, 0,61 g, 1,05 g, e 2,02 g por planta para cada 10 kg ha-1 de K2O aplicados, respectivamente. Para produtividade ...
Abstract: The radish is grown in consortium with other longer-cycle crops, but now small farmers have seen in the vegetable, a chance to increase the profitability of their areas. The literature has little information as to potassium's effects on the production, quality and the biochemical Radish characteristics. This study is aimed to evaluate the effects of potassium fertilizer applied in coverage in the production and culture of post-harvest quality radish under refrigeration. The experiment was conducted at the Experimental Farm of FCA/UNESP in San Manuel / SP and the evaluations were carried out in the Department of Horticulture, Faculty of Agricultural Sciences (FCA / UNESP). The experimental design was in randomized blocks, comprising of five treatments of potassium (K2O) (0; 22,5; 45; 67,5 and 90 kg ha-1) in coverage, with five repetitions. We evaluated the vegetative characteristics of the plant, nutrient accumulation in the shoots, roots and productivity. For the quality features, physical chemistry and biochemistry harvested roots were stored at 5 ± 1 °C and RH 85 - 90 % for 28 days were evaluated every 7 days, the mass loss, pH, titratable acidity, soluble solids, reducing sugars, ascorbic acid (vitamin C), phenolic compounds, pigments (carotenoids and anthocyanins) and enzyme activity (peroxidase). For radish production characteristics, we obtained significant responses as a function of potassium doses on coverage for plant height, mass of fresh matter of the aerial part, root and total, an increase of 0,46 cm, 0,61 g, 1,05 g and 2,02 g per plant per 10 kg ha-1 K2O applied, respectively. The decreasing order of macronutrintes accumulated by the root is: K> N> Ca> P> S> Mg. For productivity, there was an increase by 1,05 t ha-1 every 10 kg ha-1 K2O applied and the dose 52,4 kg ha-1 K2O with the highest percentage (97,7 %) in marketable yield. For the physicochemical and biochemical ...
Mestre
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Navarro-Ainza, Jose A. Cristobal. "Fertilizer Nitrogen Recovery and N15 and Bromide Distribution in the Soil Profile as Affected by the Time of Application on an Irrigated Upland Cotton (Gossypium hirsutum L.)". Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194172.
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The first project involved the evaluation of different times of application on the fertilizer nitrogen recovery (FNR) in the soil-plant system in an irrigated upland cotton system, during two seasons. This was accomplished by using the isotopic dilution technique applying the 15N to microplots. No differences were observed in the total plant FNR, seed and stover, soil and the total FNR among the different 15N application times; however, despite no differences were observed in the plant the FNR value ranged from 30-38%, while the seed exhibited the highest FNR with an average over 50% of the 15N recovered in the plant. In the soil, the obtained average FNR value was over 40% while the total FNR (plant + soil) ranged from 70-80%, being reduced as the 15N application time was delayed.The second project was conducted during two seasons to examine the 15N and bromide distribution pattern in the soil profile as a function of the time of application. 15Nitrogen and bromide were applied to the soil at three different times in a cotton growth cycle; after that, soil samples were taken at the end of the cotton cycle to a depth of 1.80 m., and 15N and bromide recoveries were determined. Slightly higher FNR were obtained with the intermediate application time. The higher FNR were detected in the surface layer (0-30 cm) with an average of 40%. Below 30 cm depth, low 15N recoveries were obtained and even lower below the 60 cm soil layer. Bromide recovery behavior was related to the water movement in the soil profile: as the Br- application time was delayed more of the anionic tracer was found in the top of the soil profile, while less Br- was found in the surface soil for the early Br- application time.
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Wetzel, Sharon. "The application of thermophilic anaerobic digestion in the degradation of poultry waste". Thesis, University of Exeter, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391214.
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Radley, Reed Alan. "The effect of foliar applications of sprays made from kelp (macrocystis integrifolia) on growth of phaseolus vulgaris : b possible role of algal phytohormone-like substances". Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29773.
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The effects of two applications of foliar sprays made from kelp (Macrocystis intearifolia Bory) on growth of beans (Phaseolus vulgaris L.) under three moisture regimes were investigated. Date of kelp harvest had little effect on plants grown in water excess or deficit conditions, although means for kelp collected in spring tended to be higher. On soils maintained near field capacity, spray made from kelp collected in July resulted in increases in some bean yield components beyond the effects of kelp collected in spring or fall. The effect of storage of liquefied kelp at room temperature was also investigated and found to be soil moisture dependent. Leaf and root weights of plants grown in field capacity and dry soil respectively were lower for plants treated with kelp aged for 118 days compared to plants treated with kelp stored for longer or shorter durations. In wet soil conditions, the effect of sprays on plant height was reduced by storage of the liquefied kelp. Kelp extracts were fractionated by solvent partition. The butanolic fraction was shown to increase significantly many yield variables under wet soil conditions. This fraction had cytokinin-like activity in two bioassay systems, and contained substances co-eluting with isopentenyl adenine and zeatin in column, thin layer, and gas-liquid chromatography systems. Non-significant increases for some plant yield components resulting from application of unfractionated kelp paralleled these increases. A kelp fraction with undefined constituents increased some yield variables of plants grown in field capacity soil, as did a fraction with auxin and gibberellin-like activities in bioassay. The presence of inhibitors in the kelp was indicated by significantly lower pod yields under dry soil conditions, and a reduction in cytokinin-like bioassay activity when increasing amounts of kelp were assayed. The possibility that phytohormone deficits resulting from root stress are ameliorated by some components of the kelp spray is discussed.Land and Food Systems, Faculty of
Graduate
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Hirono, Yuhei. "Assessment and mitigation of the environmental impacts of nitrogen fertilizer application in green tea fields". Kyoto University, 2018. http://hdl.handle.net/2433/235969.
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Koski, Anthony James. "The effects of timing of nitrogen application on quality, carbohydrate status, root growth, and thatch accumulation in 'Baron' Kentucky bluegrass (Poa pratensis L.) /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487267024996817.
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Sun, Yajie [Verfasser]. "Uranium accumulation in agricultural soils as derived from long-term phosphorus fertilizer applications / Yajie Sun". Bonn : Universitäts- und Landesbibliothek Bonn, 2021. http://d-nb.info/1230878572/34.
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Barcos, Sebastián Raúl. "Efficiency of fall and spring broadcast fertilizer phosphorus application for corn and soybean in no-till". [Ames, Iowa : Iowa State University], 2007.
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Amoo, Taiwo Lookman. "Application of operational research to fertilizer distribution in a developing country : a case study of Nigeria". Thesis, University of Exeter, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317397.
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