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1
GANESHAMURTHY, A. N. „Soil changes following long-term cultivation of pulses“. Journal of Agricultural Science 147, Nr. 6 (23.06.2009): 699–706. http://dx.doi.org/10.1017/s0021859609990104.
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SUMMARYStudies were conducted on Entisols to understand the effects of continuous pulse cultivation on soil chemical, physical and biological properties by comparing with continuous non-pulse crops and uncultivated soils. Soils of a Typic Ustochrept, developed from the same parent material, from 16-year-old pulse cultivation fields, non-pulse crop fields and uncultivated fallow fields in a location with uniform topography were analysed using a polyphasic approach combining traditional soil physical and chemical analysis, culture-dependent and independent microbiological analysis and enzymatic analysis. Among the soil physical properties, only soil aggregate stability and soil compaction showed significant improvement in soils under pulses than non-pulse crops. Compared to uncultivated fallows, the soil pH after pulse cultivation was about 1 unit lower while non-pulse crop cultivation reduced it by 0·36. The chemical and biological variables that contribute most to the discrimination of the pulses effect and non-pulse crops effect on soil quality are organic carbon (C), microbial biomass C, nitrogen (N) and biomass ninhydrin-N, and secondary variables related to N cycle:nitrate (NO3–N), organic and total soluble N. The enzyme activities were significantly higher in soils after pulse cultivation than after non-pulse crops or uncultivated fallow. The soil quality of pulse cultivation fields seems to be markedly different to that of non-pulse crop fields and uncultivated fallows in terms of all the variables studied.
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CHANG, C., T. G. SOMMERFELDT, T. ENTZ und D. R. STALKER. „LONG-TERM SOIL MOISTURE STATUS IN SOUTHERN ALBERTA“. Canadian Journal of Soil Science 70, Nr. 2 (01.05.1990): 125–36. http://dx.doi.org/10.4141/cjss90-015.
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Nineteen years of soil moisture content data at Lethbridge and two locations near Turin (Turin 1 and Turin 2) in southern Alberta were examined to evaluate the efficiency of follow for conserving moisture, and to calculate the long-term mean amount of water recharge during growing and nongrowing seasons under a fallow-cereal, 2-yr rotation and a continuous cropping system. Soil samples were taken annually from 1969 to 1987 to a depth of 120 cm in 30-cm intervals in the spring (early May) and fall (late September). A method for testing differences of means between nonstandard data using localized uncertainty associated with sliding polynomial smoothing was used to test for differences in the soil moisture contents due to cultural practices. The available soil moisture content of the soil to 120-cm depth was at least 50% of available water-holding capacity (AWHC) of the profile for the fallow treatment at Lethbridge and Turin 2, and, except in some years, at Turin 1. At seeding time, there was an average of 69 mm more available water (AW) in the fallow field than in the continuous cropping field at Lethbridge and 30, 35 and 27 mm more AW in the fallow field than in the fresh stubble field of a fallow-cereal, 2-yr rotation for Lethbridge, Turin 1 and Turin 2, respectively. The overall mean precipitation conserved as soil moisture for the fallow-cereal rotation practice was 23, 29 and 23% for Lethbridge, Turin 1 and Turin 2, respectively. The significantly higher soil water content at the 90- to 120-cm depth for the fallow field than for other fields during various periods of time indicates that the soil water recharge from precipitation might be deeper in the fallow field than in continuous cropping and fresh stubble of fallow-cereal rotation fields. The deeper soil water recharge could increase the available soil moisture for crop production and it could also contribute to ground water recharge. Key words: Soil water, available water content, continuous cropping, summerfallow
3
Wang, G., J. Jin, X. Chen, J. Liu, X. Liu und S. J. Herbert. „Biomass and catabolic diversity of microbial communities with long-term restoration, bare fallow and cropping history in Chinese Mollisols“. Plant, Soil and Environment 53, No. 4 (07.01.2008): 177–85. http://dx.doi.org/10.17221/2313-pse.
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Microbial biomass and community catabolic diversities at three depths (0−10 cm, 20−30 cm, and 40−50 cm) in Chinese Mollisols as influenced by long-term managements of natural restoration, cropping and bare fallow were investigated. Microbial biomass was estimated from chloroform fumigation-extraction and substrate-induced respiration (SIR), and catabolic diversity was determined by using Biolog® EcoPlate. Experimental results showed that microbial biomass significantly declined with soil depth in the treatments of restoration and cropping, and not in the treatment of bare fallow, where the microbial biomass had a positive relationship with the total soil C content. The inspections into the catabolic capability of the microbial community at the same soil depth showed that the treatment of natural restoration had a relatively stronger metabolic ability than the cropping and bare fallow treatments. Shannon”s diversity index, substrate richness and substrate evenness calculated from the Biolog data were higher in the treatments of natural restoration and cropping than the bare fallow treatment with the same soil depth, and with the highest values in the top soil. Principal component analysis indicated that the catabolic profiles not only varied with the soil depth in each treatment, but also differed in the three treatments within the same soil depth. The catabolic profiles of the three treatments were similar to each other in the soil depth of 0−10 cm and distinctly different in the soil depths of 20−30 cm and 40−50 cm. These results suggest that it was microbial biomass rather than community function that was influenced by the different soil management in the topsoil (0−10 cm); in the relative depths, the soil microbial community function was more easily influenced than microbial biomass.
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Selles, F., und R. P. Zentner. „Spring wheat yield trends in long-term fertility trials“. Canadian Journal of Plant Science 73, Nr. 1 (01.01.1993): 83–92. http://dx.doi.org/10.4141/cjps93-011.
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Results from a 16-yr fertility study conducted on fallow and stubble throughout southwestern Saskatchewan were used to assess the effects of technology adoption on spring wheat (Triticum aestivum L.) yields and the influence of available N on the yield effect of these new technologies. The magnitude of the residual trend (after the effect of growing-season precipitation was removed) was considered to reflect the yield increases attributable solely to the newly adopted technologies. Of the independent variables monitored, May and July precipitation and total available water on fallow plots were affected by time. Yields of wheat grown on stubble and fallow increased by an average 48 and 64 kg ha−1 yr−1, respectively. Of this annual yield increase, 52% on stubble and 78% on fallow were attributed to the adoption of new production technologies, with the remainder being explained by the trends observed in May and July precipitation. Nitrogen availability was an important factor in determining the magnitude of the trend due to technology adoption. The technology trend increased linearly from about 10 kg ha−1 yr−1, at the lowest available N levels, to about 65 kg ha−1 yr−1 when 98 kg N ha−1 was available; there were no further yield increases above this level of N. These results demonstrate that the full benefits of adopting new production technologies and more productive cultivars may not be achieved unless other growth-limiting factors, such as N availability, are removed. Further, this study demonstrates that researchers conducting long-term studies must be aware of possible time trends that may alter or obscure effects of treatments, thus making detrending procedures a basic requirement of data analyses in these types of studies. Key words: Spring wheat, yields, N fertilizer, available nitrogen, available water, trends
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Johnston, Adrian M., Francis J. Larney und C. Wayne Lindwall. „Spring Wheat and Barley Response to Long-Term Fallow Management“. Journal of Production Agriculture 8, Nr. 2 (April 1995): 264–68. http://dx.doi.org/10.2134/jpa1995.0264.
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Guenet, Bertrand, Sabrina Juarez, Gérard Bardoux, Valérie Pouteau, Nathalie Cheviron, Christelle Marrauld, Luc Abbadie und Claire Chenu. „Metabolic capacities of microorganisms from a long-term bare fallow“. Applied Soil Ecology 51 (November 2011): 87–93. http://dx.doi.org/10.1016/j.apsoil.2011.07.006.
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ZENTNER, R. P., und C. A. CAMPBELL. „FIRST 18 YEARS OF A LONG-TERM CROP ROTATION STUDY IN SOUTHWESTERN SASKATCHEWAN – YIELDS, GRAIN PROTEIN, AND ECONOMIC PERFORMANCE“. Canadian Journal of Plant Science 68, Nr. 1 (01.01.1988): 1–21. http://dx.doi.org/10.4141/cjps88-001.
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The effects of rotation length, crop sequence, and N and P fertilizers on yield, grain quality, and economic performance of 10 crop rotations in an ongoing experiment conducted on a Brown Chernozemic silty loam soil at Swift Current, Saskatchewan are discussed after the first 18 yr. When N and P fertilizers were applied based on soil tests, yields of wheat grown on fallow were similar for the 2-yr and 3-yr wheat rotations (1905 kg ha−1). Yields of wheat grown on N- and P-fertilized stubble were also similar whether grown in 3-yr or continuous rotations (1379 kg ha−1). Stubble wheat yields were unaffected by the preceding crop, except when following flax in a continuous-type rotation where it was suppressed due to moisture competition from weeds. Fertilizer N had no affect on yields of wheat grown on fallow because little N was required or applied; but yields of wheat grown on stubble were increased 7% when grown in a 3-yr rotation and 17% when grown continuously. Application of P fertilizer increased fallow and stubble wheat yields by 11–12%. In contrast to seeded area yields, total wheat production was lowest for the fallow-wheat rotation (949 kg ha−1 yr−1), intermediate for fallow-wheat-wheat (1105 kg ha−1 yr−1), and highest for wheat grown continuously (1354 kg ha−1 yr−1). Protein concentrations in wheat grown on fallow were similar in the 2-yr and 3-yr wheat rotations and were generally higher than that found in wheat grown on stubble, except when wheat was grown on flax stubble. Fallow-wheat was the most profitable rotation when wheat prices were below $130.00 t−1. At wheat prices between $130.00 and $160.00 t−1, the fallow-wheat and fallow-wheat-wheat rotations provided the highest and about equal net return; between wheat prices of $160.00 and $275.00 t−1, fallow-wheat-wheat provided the highest net return while continuous wheat provided the highest net return for wheat prices above $275.00 t−1. The cost of producing wheat was lowest for fallow-wheat ($88.00 t−1), intermediate for fallow-wheat-wheat ($94.00 t−1), and highest for continuous wheat ($138.00 t−1). Income variability and risk of financial loss decreased as the proportion of fallow in the rotation increased.Key words: Crop rotations, protein, fertilizer effects, net returns, costs, income variability
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Barré, P., T. Eglin, B. T. Christensen, P. Ciais, S. Houot, T. Kätterer, F. van Oort et al. „Quantifying and isolating stable soil organic carbon using long-term bare fallow experiments“. Biogeosciences 7, Nr. 11 (26.11.2010): 3839–50. http://dx.doi.org/10.5194/bg-7-3839-2010.
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Abstract. The stability of soil organic matter (SOM) is a major source of uncertainty in predicting atmospheric CO2 concentration during the 21st century. Isolating the stable soil carbon (C) from other, more labile, C fractions in soil is of prime importance for calibrating soil C simulation models, and gaining insights into the mechanisms that lead to soil C stability. Long-term experiments with continuous bare fallow (vegetation-free) treatments in which the decay of soil C is monitored for decades after all inputs of C have stopped, provide a unique opportunity to assess the quantity of stable soil C. We analyzed data from six bare fallow experiments of long-duration (>30 yrs), covering a range of soil types and climate conditions, and sited at Askov (Denmark), Grignon and Versailles (France), Kursk (Russia), Rothamsted (UK), and Ultuna (Sweden). A conceptual three pool model dividing soil C into a labile pool (turnover time of a several years), an intermediate pool (turnover time of a several decades) and a stable pool (turnover time of a several centuries or more) fits well with the long term C decline observed in the bare fallow soils. The estimate of stable C ranged from 2.7 g C kg−1 at Rothamsted to 6.8 g C kg−1 at Grignon. The uncertainty associated with estimates of the stable pool was large due to the short duration of the fallow treatments relative to the turnover time of stable soil C. At Versailles, where there is least uncertainty associated with the determination of a stable pool, the soil contains predominantly stable C after 80 years of continuous bare fallow. Such a site represents a unique research platform for characterization of the nature of stable SOM and its vulnerability to global change.
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Hannah, MC, und GJ O'Leary. „Wheat yield response to rainfall in a long-term multi-rotation experiment in the Victorian Wimmera“. Australian Journal of Experimental Agriculture 35, Nr. 7 (1995): 951. http://dx.doi.org/10.1071/ea9950951.
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Seventy-six years of wheat yield data from a long-term rotation experiment at Dooen in the Victorian Wimmera were analysed to describe the response of wheat yield to seasonal rainfall, crop sequence, and time. Wheat yields from 7 different 1- to 4-course rotations involving wheat, barley, oat, field pea, grass pasture and fallow were compared as a function of growing-season (May-November) rainfall. The field layout had no within-year replication, but each phase of each rotation was represented once in each year. An approximate quadratic response of wheat yield to both current year and previous year May-November rainfall was observed for each rotation. Previous year May-November rainfall boosted wheat yields grown on fallow, but decreased the yield of wheat grown on field pea or wheat stubble. Highest wheat yields followed fallow preceded by pasture, high yields followed fallow preceded by a cereal, moderate yields followed field pea, and low yields occurred for continuous wheat. Long-term trends in wheat yields adjusted for rainfall depended on crop sequence and fluctuated more in the non-fallow, 3-course rotations. Over the 76 years, average yield declined in all rotations except the continuous wheat, which was always low, but there was evidence that yield of all continuous cropped rotations had increased during the last 2 decades.
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Beke, G. J., H. H. Janzen und T. Entz. „Salinity and nutrient distribution in soil profiles of long-term crop rotations“. Canadian Journal of Soil Science 74, Nr. 2 (01.05.1994): 229–34. http://dx.doi.org/10.4141/cjss94-031.
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The effect of cropping systems on salt and nutrient movement in soil has been studied mainly at relatively short-term (< 20 yr) experimental sites or at commercial sites without documented history. This study investigated the impact of two similar, unfertilized, long-term crop rotation experiments, differing in duration and experimental design, on soil EC (salinity), sodium adsorption ratio (SAR), nitrate-N, and extractable-P distributions in semi-arid southern Alberta. The experiments, established in 1911 and 1951 at the Lethbridge Research Station on moderately well drained soils, included continuous spring wheat (Triticum aestivum L.) fallow-wheat-wheat and fallow-wheat cropping sequences. Regardless of length of experiment or cropping sequence, the salinity and SAR values increased with soil depth. Leaching of salts had occurred to a minimum depth of 150 cm, depending on the nature of the parent material and soil-drainage volumes. Within the 90- to 150-cm depth, most salt leaching had taken place under the fallow-wheat rotation and least under the continuous-wheat cropping sequence. Downward movement of nitrate-N generally peaked in the lower root zone, regardless of cropping system or duration of the experiment. Deep leaching of nitrate-N had occurred in the fallow-wheat soil. Movement of extractable P was restricted to the 0- to 30-cm depth. Significant deep leaching of salts had taken place over the 35-yr period of the 1951 experiment whereas the longer, 75-yr period of the 1911 experiment was required to cause significant deep leaching of nitrate-N and of extractable P movement in the 0- to 30-cm depth. Key words: Dryland crop rotations, summerfallow, semi-arid region, soil salinity, soil nitrate and phosphate
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Šimon, T. „Characterisation of soil organic matter in long-term fallow experiment with respect to the soil hydrophobicity and wettability“. Soil and Water Research 2, No. 3 (07.01.2008): 96–103. http://dx.doi.org/10.17221/2105-swr.
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Soil organic matter under different tillage and fertilisation systems of long-term fallow experiment established in 1958 in Prague was characterised in period of 1972–2004. This experiment consists of seven variants (control (no tillage, no manuring); farmyard manure compost (FYM); 2FYM; mineral fertilisation (NPK); 2NPK; reduced tillage (RT), and conventional tillage (CT)). In 1989, regular manuring and tillage were terminated and since then the plots have been maintained bare. Organic carbon content (C<sub>ox</sub>) was analysed and the hydrophobic (A) and hydrophilic (B) functional groups were determined using Fourier-transform infrared (FTIR) spectroscopy. Hydrophobicity index (HI) and soil wettability (A/B ratio) were assessed in the experimental variants. A high significant positive correlation (r = 0.976; P < 0.05) was found, between hydrophobic functional groups (Band A) and C<sub>ox</sub>, hydrophilic functional groups (Band B) did not correlate with C<sub>ox</sub>. Soil wettability tended to decrease after the organic manuring was finished with the result that the values of A/B ratio were significantly different according to the farmyard manure doses applied. On the contrary, HI responded to organic manuring termination later on and no significant differences were found between different farmyard manure doses. In the variants without any fertilisation, a continual decrease in both soil wettability and hydrophobicity during the selected time period was found; the degradation process is going on in these variants.
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JANZEN, H. H. „EFFECT OF FERTILIZER ON SOIL PRODUCTIVITY IN LONG-TERM SPRING WHEAT ROTATIONS“. Canadian Journal of Soil Science 67, Nr. 1 (01.02.1987): 165–74. http://dx.doi.org/10.4141/cjss87-014.
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Surface soil samples taken from two long-term crop rotations at Lethbridge, Alberta were used to assess the influence of fertilizer N and P on total and mineralizable concentrations of organic C and N in a Dark Brown Chernozemic soil. Rotations sampled were continuous wheat and fallow-wheat-wheat initiated in 1912. In 1967 and 1972, N fertilizer and P fertilizer treatments, respectively, were superimposed over the rotation treatments (which had received no previous fertilizer) to produce a factorial of two N rates (0 and 45 kg N ha−1) by two P rates (0 and 20 kg P ha−1). After 18 yr of application, N fertilizers increased organic C content in both rotations by approximately 14% over that observed in soil receiving no N fertilizer. Organic N contents, similarly, were increased by 15 and 11% in the continuous wheat and fallow-wheat-wheat rotations, respectively. As well, N fertilization increased relative N mineralization potential by 22% in the continuous wheat rotation and by 44% in the fallow-wheat-wheat rotation. Phosphorus fertilization had no significant influence on either total or mineralizable C and N concentrations. Soil pH (measured in dilute CaCl2) was reduced, on average, from 7.2 to 6.9 by 18 annual N applications. These results demonstrate that N fertilization can make significant contributions to the replenishment of organic matter in soil and to the maintenance of indigenous soil N fertility. Key words: Organic matter, nitrogen, carbon, mineralizable nitrogen, mineralizable carbon, pH
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McKenzie, R. H., J. W. B. Stewart, J. F. Dormaar und G. B. Schaalje. „Long-term crop rotation and fertilizer effects on phosphorus transformations: I. In a Chernozemic soil“. Canadian Journal of Soil Science 72, Nr. 4 (01.11.1992): 569–79. http://dx.doi.org/10.4141/cjss92-047.
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The objective of this study was to determine effects of different cropping systems and nitrogen (N) and phosphorus (P) fertilizers on soil P fractions and transformations in long-term rotation plots on a Chernozemic soil at Lethbridge, Alberta. Continuous wheat, wheat-wheat-fallow, and wheat-fallow crop rotations and fertilizer application significantly affected the amount and distribution of phosphorus among labile and stable inorganic (Pi) and organic (Po) forms as determined by a sequential fractionation procedure. Without N and P fertilizer, the proportion of total soil P in more labile forms that were sequentially extractable with an anion exchange resin (resin-Pi), sodium bicarbonate (bicarb-Pi and Po) and sodium hydroxide (NaOH-Pi and Po) were reduced to a greater extent in continuous wheat than in wheat-wheat-fallow and wheat-fallow rotations. The addition of P fertilizer significantly increased total P and all Pi fractions, with the greatest change in more labile Pi forms (resin, bicarb and NaOH), but had no effect on labile Po forms. In contrast, N fertilizer addition increased the proportion of P in labile Po fractions in all rotations, and decreased the proportion of P in labile Pi forms. The combination of fertilizer N and P generally increased both Pi and Po labile forms. The continuous wheat rotation, coupled with N and P fertilizer inputs, had the most positive effect on P cycling and transformations. Key words: Soil P transformations, Chernozemic soils, P bioavailability, sequential extraction
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Smith, E. G., R. E. Blackshaw, C. W. Lindwall, F. J. Larney und T. L. Peters. „Economics of reduced tillage fallow-crop systems in the Dark Brown soil zone of Alberta“. Canadian Journal of Soil Science 76, Nr. 3 (01.08.1996): 411–16. http://dx.doi.org/10.4141/cjss96-049.
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The use of conservation tillage management in fallow cropping systems reduces soil erosion and improves soil quality. The economic benefits of these alternate tillage methods are less certain. This study examined the economic returns from reduced tillage methods on fallow using yield and input data from two experiments at the Agriculture and Agri-Food Canada Research Centre at Lethbridge, Alberta. One experiment was long-term study initiated in 1955 with eight treatments, the second was a 5-yr study with 15 treatments. Results from the 5-yr study indicated no difference in net returns between conventional and reduced tillage fallow systems. In contras, the long-term study net returns were highest for tilled systems and lowest for herbicide-only systems. The long-term study had a build-up of weeds that are difficult to control with herbicides alone. The resulting lower average yield and higher herbicide costs of the herbicide-only treatments in the long-term study accounted for most of the contrasting results between the two experiments. An economic evaluation of tillage practices requires the entire system to be evaluated, not just the tillage component. Key words: Economics, tillage, reduced tillage, conservation practices, weed control
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JANZEN, H. H. „SOIL ORGANIC MATTER CHARACTERISTICS AFTER LONG-TERM CROPPING TO VARIOUS SPRING WHEAT ROTATIONS“. Canadian Journal of Soil Science 67, Nr. 4 (01.11.1987): 845–56. http://dx.doi.org/10.4141/cjss87-081.
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Soil from a long-term crop rotation study conducted at Lethbridge, Alberta was analyzed to determine the influence of various spring wheat rotations with and without perennial forages on total and mineralizable soil organic matter contents. Crop rotations considered included: continuous wheat (W), fallow-wheat (FW), fallow-wheat-wheat (FWW), and fallow-wheat-wheat-forage-forage-forage (FWWAAA) in which the forage was a mixture of alfalfa and crested wheat grass. The organic C and N contents of soil after 33 yr of cropping were highest in treatments W and FWWAAA, and decreased with increasing frequency of fallow in the rotation. The inclusion of the perennial forage in the rotation did not increase organic C and N levels above those observed in the continuous wheat treatment (W). Differences in levels of mineralizable organic matter among treatments, as measured in laboratory incubations, were much greater than differences in total organic matter content among treatments. In the surface soil layer (0–15 cm), N mineralization was significantly higher in treatment W than in treatments FWW and FWWAAA, and was more than twice that observed in treatment FW. In the subsurface soil layer (15–30 cm), N mineralization was greatest in treatment FWWAAA when sampled just after the plowdown of forage. Effects of crop rotation on C mineralization were similar to those observed for N. Levels of mineralized organic matter were closely related to levels of "light fraction" material (specific gravity < 1.59 g cm−3), which is believed to consist primarily of incompletely decomposed organic matter of plant origin. Differences in amounts of mineralizable organic matter among treatments were attributed to varying frequencies and patterns of crop residue additions. The pronounced effects of crop rotation on the distribution of organic matter among labile and humified organic matter will have a strong impact on soil fertility and may need to be taken into consideration in the development of fertilizer recommendations. It was concluded that inclusion of perennial forages in spring wheat rotations for the purpose of enhancing soil fertility and organic matter levels was not justified under semiarid conditions. Key words: Carbon, nitrogen, mineralization
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Zakharchenko, A. V., O. A. Pasko und I. B. Sorokin. „The Dynamics of the Reduction of Arable Land Areas According to their Long-term Monitoring in the Tomsk Region“. Ecology and Industry of Russia 25, Nr. 7 (20.07.2021): 54–59. http://dx.doi.org/10.18412/1816-0395-2021-7-54-59.
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The results of agroecological monitoring of arable and fallow lands are considered. It has been established that the content of humus and mobile phosphorus in the soils of the fallow, as well as the value of the salt pH, is lower than on arable land; mobile potassium is higher. This may be due to the migration of deposited potassium from the lower soil horizons into the humus horizon and its release from the absorbed state during the decomposition of organic matter. It was revealed that in fallow soils, the content of mobile phosphorus in the range of 150–600 mg/kg directly correlates with the value of salt pH (4–6 pH units), while this dependence is not observed on arable land.
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Tatzber, Michael, Michael Stemmer, Heide Spiegel, Christian Katzlberger, Franz Zehetner, Georg Haberhauer, Elena Garcia-Garcia und Martin H. Gerzabek. „Spectroscopic behaviour of 14C-labeled humic acids in a long-term field experiment with three cropping systems“. Soil Research 47, Nr. 5 (2009): 459. http://dx.doi.org/10.1071/sr08231.
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The stabilisation of 14C-labelled farmyard manure was investigated under different cropping systems (crop rotation, monoculture, and bare fallow) in a long-term field experiment established in 1967. Solid-state 13C-NMR of bulk soils yielded a gradient of increasing aromatic properties in the order: straw manure–crop rotation < straw manure–monoculture < straw and farmyard manure–bare fallow. The opposite trend was observed for O-alkyl groups. The farmyard manure–bare fallow treatment was used to investigate changes of humic acids (HAs) with time. The FT-IR bands of aromatics, carbonyl groups, and a band of methyls and benzene rings increased over the 36 years of the experiment, whereas 2 amide bands and a band of sulfone and/or ester groups decreased. Fluorescence spectroscopy verified the increase in aromatic properties with age. Consequently, during soil organic matter stabilisation, HAs showed increasing properties of carbonyl and aromatic groups, whereas amidic groups decreased. The dynamic character of HAs, as shown by 14C, was also reflected by distinct spectroscopic changes over the period of investigation.
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Barré, P., T. Eglin, B. T. Christensen, P. Ciais, S. Houot, T. Kätterer, F. van Oort et al. „Long-term bare fallow experiments offer new opportunities for the quantification and the study of stable carbon in soil“. Biogeosciences Discussions 7, Nr. 3 (23.06.2010): 4887–917. http://dx.doi.org/10.5194/bgd-7-4887-2010.
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Abstract. The stability of soil carbon is a major source of uncertainty for the prediction of atmospheric CO2 concentration during the 21st century. Isolating experimentally the stable soil carbon from other, more vulnerable, pools is of prime importance for calibrating soil C models, and gaining insights on the mechanisms leading to soil organic carbon (SOC) stability. Long-term bare fallow experiments, in which the decay of SOC is monitored for decades after inputs from plant material have stopped, represent a unique opportunity to assess the stable organic carbon. We synthesized data from 6 bare fallow experiments of long-duration, covering a range of soil types and climate conditions, at Askov (Denmark), Grignon and Versailles (France), Kursk (Russia), Rothamsted (UK), and Ultuna (Sweden). The conceptual model of SOC being divided into three pools with increasing turnover times, a labile pool (~ years), an intermediate pool (~ decades) and a stable pool (~ several centuries or more) fits well with the long term SOC decays observed in bare fallow soils. The modeled stable pool estimates ranged from 2.7 gC kg−1 at Rothamsted to 6.8 gC kg−1 at Grignon. The uncertainty over the identification of the stable pool is large due to the short length of the fallow records relative to the time scales involved in the decay of soil C. At Versailles, where there is least uncertainty associated with the determination of a stable pool, the soil contains predominantly stable C after 80 years of continuous bare fallow. Such a site represents a unique research platform for future experimentation addressing the characteristics of stable SOC and its vulnerability to global change.
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Barroso, Patricia, José A. Barasona, Pelayo Acevedo, Pablo Palencia, Francisco Carro, Juan José Negro, María José Torres, Christian Gortázar, Ramón C. Soriguer und Joaquín Vicente. „Long-Term Determinants of Tuberculosis in the Ungulate Host Community of Doñana National Park“. Pathogens 9, Nr. 6 (05.06.2020): 445. http://dx.doi.org/10.3390/pathogens9060445.
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Animal tuberculosis (TB) is endemic in wild boar (Sus scrofa), red deer (Cervus elaphus), fallow deer (Dama dama) and cattle in south and central Spain. In order to clarify the processes that operate in the medium and long-term, we studied TB at the wildlife–livestock interface in Doñana National Park for 14 years (2006–2018) in relation to host density, stochastic factors (rainfall) and environmental features (e.g., aggregation points such as waterholes). Wild boar showed the highest prevalence of TB (76.7%), followed by red deer (42.5%), fallow deer (14.4%) and cattle (10.7%). We found evidence of relevant epidemiological processes which operate over the long-term and interact with host and community ecology. Interestingly, the effect of high wild boar population density on increased TB rates was mediated by sows, which could determine high incidence in young individuals already in maternal groups. Rainfall significantly determined a higher risk of TB in male red deer, probably mediated by sex-related differences in life history traits that determined more susceptibility and/or exposure in comparison to females. The positive association between the prevalence of TB in fallow deer and cattle may indicate significant interspecies transmission (in either direction) and/or similar exposure to risk factors mediated by ecological overlapping of grazing species. The identification of long-term drivers of TB provided evidence that its control in extensive pastoral systems can only be achieved by targeting all relevant hosts and integrating measures related to all the factors involved, such as: population abundance and the aggregation of wild and domestic ungulates, environmental exposure to mycobacteria, cattle testing and culling campaigns and adjustments of appropriate densities.
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Jones, M. J., und M. Singh. „Yields of crop dry matter and nitrogen in long-term barley rotation trials at two sites in northern Syria“. Journal of Agricultural Science 124, Nr. 3 (Juni 1995): 389–402. http://dx.doi.org/10.1017/s0021859600073354.
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SUMMARYTrials were established at two sites in 1982 to compare six 2-course rotations, in which barley alternated with feed legumes (pure or mixed with barley), fallow or barley, in partial factorial combination with different N and P fertilizer regimes. This paper summarizes data from the second to the seventh cropping seasons.Barley yielded most after fallow and more after legumes than after barley; but, on the basis of total dry matter production over both courses, barley-legume rotations outyielded barley-fallow and barley-barley rotations. In terms of net nitrogen offtake, which may be taken as a rough measure of feed value, barley-legumes surpassed the other rotations by c. 100% at both sites, whether the comparison was made on values obtained from plots with or without added fertilizer. Of the legumes, Lathyrus sativus was slightly more productive than Vicia saliva, and this carried over into the rotational yield of both dry matter and nitrogen. Rotations involving pure legumes were slightly more productive than those involving legume/barley mixtures.Yields of all crops and rotations varied greatly from year to year depending on rainfall. Those of the barley-fallow rotation were much less variable than those of the barley-barley rotation at the wetter site (323±103 mm), with the barley-legume rotation intermediate; but variability was much greater at the drier site (250±79 mm), with much less difference between rotations. Nevertheless, fertilizer use and rotations including legumes gave a significant yield advantage under the driest conditions.
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Abu, S. T. „Evaluating long-term impact of land use on selected soil physical quality indicators“. Soil Research 51, Nr. 6 (2013): 471. http://dx.doi.org/10.1071/sr12360.
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This paper presents findings of comparative evaluation of selected soil physical quality (SPQ) indicators, obtained from fields subjected to: >50 years of cultivation of three perennial pasture grasses (i) Digitaria smutsii (DS), (ii) Brachiaria decumbens (BD), and (iii) Andropogon gayanus (AG); (iv) >50 years of continuous cultivation (CC) of cereals–legumes; and (v) >20 years of natural fallow (NF). The study was aimed at identifying the land-use system having optimal values for SPQ. Fields under CC had the highest bulk density, and the lowest total porosity (PORt) and macroporosity (PORp), field capacity (FC), and available water capacity (AWC). Perennial pasture grasses fields had significantly higher organic carbon, PORt, FC, AWC, and saturated hydraulic conductivity, and, hence, had better SPQ than CC fields and, in some instances, NF fields. The usefulness of ratios FC/PORt = 0.66 and ACt/PORt = 0.34 as additional indicators for assessing soil response to land-use systems was not proven in this study, and therefore, further studies should be conducted on the subject matter. Pasture grasses improved SPQ values relative to continuous cereal–legume cropping and fallow. The SPQ under CC and NF fields might be best improved by applying organic matter.
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Kozlova, L. M., E. N. Noskova und F. A. Popov. „Improvement of crop rotations aimed at increasing their efficiency and conserving soil fertility in conditions of biological intensification“. Agricultural Science Euro-North-East 20, Nr. 5 (21.10.2019): 467–77. http://dx.doi.org/10.30766/2072-9081.2019.20.5.467-477.
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The long-term research conducted in 2002-2017 in a long stationary experiment on studying different types of field crop rotations under conditions of the Kirov region showed that on sod-podzolic soils the loss of humus could be lowered using agro technical methods. The most critical of them include the reduction of a portion of bare fallow, transition to sown and green-manure fallow, expanded use of perennial legume and grain-legume crops and intercrop sowings. In eight-field crop rotations when using such means of a biologization as plowing of the root-stubble residues, aboveground mass of green-manure crops in fallow fields and intercrop sowings, the supply of organic substance was within 17.24-83.03 t/ha. By mineral-ization of this substance 7.64-11.51 t of humus were produced. In a crop rotation with bare fallow there is a negative balance of humus of -0.06 t/ha. The positive balance is obtained when using sown, green-manure fallows, intercrop sowings (two-three fields), and introduction of up to 25% perennial legumes to the structure of crop rotations. The formation of 0.96-1.44 t/ha of humus in the arable layer provides positive balance of 0.20-0.72 t/ha. The increase of the part of grain crops up to 62.5-75.0% in the structure of crop rotations resulted in rise of their efficiency up to 4.74-4.79 thousand fodder units. It was 0.27-0.32 thousand fodder units higher than in the control crop rotation with bare fallow. Dependence of productivity of agricultural crops on humus content was insignificantly negative (r = -0.16). The efficiency of the studied crop rotations depended considerably on the amount of productive moisture in the soil in a phase of ear formation of grain crops (r = -0.78) and on biological activity of the soil (r = -0.80).
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Probert, ME, BA Keating, JP Thompson und WJ Parton. „Modelling water, nitrogen, and crop yield for a long-term fallow management experiment“. Australian Journal of Experimental Agriculture 35, Nr. 7 (1995): 941. http://dx.doi.org/10.1071/ea9950941.
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Two models that differ markedly in how they represent the crop-soil system have been used to simulate soil processes and crop production in the long-term experiment at Hermitage Research Station, Warwick, Queensland. The experiment was designed to examine the effects of tillage, stubble management, and nitrogen (N) fertiliser on the productivity of a winter cereal-summer fallow cropping system. it commenced in 1968 and the treatments have been maintained until the present. CENTURY operates on a monthly time step, considers all soil N transformations to occur in a single soil layer, and has a very simple crop growth routine that does not deal with crop phenology. APSIM provides a framework whereby a model of a cropping system is configured from component modules, which operate on a daily time step. For simulating the Hermitage experiment, modules to represent the dynamics of soil-water, N, surface residues, and growth of a wheat crop were used. The water and N modules deal with a multi-layered soil, whilst the wheat module develops leaf area, intercepts light, and accumulates and partitions dry matter in response to weather, soil-water, and N. Both models were specified to simulate the whole experimental period (1969-92) as a continuous run. The ability of these models to simulate grain yields, soil-water and drainage, nitrate-N, and soil organic matter were examined. Both models predict, in agreement with the observed data, that for this continuous cereal cropping system there has been a decline in soil organic matter for all the treatments and a reduction through time in the capacity of the soil to mineralise and accumulate nitrate during the fallows. CENTURY performed better than APSIM in predicting the relative yields of the N treatments but was less satisfactory than APSIM for absolute grain yield, soil-water, and drainage. Yield predictions with APSIM were sensitive to carry-over errors in the water balance from one season to the next, so that in some seasons large errors occurred in the predicted relative yields. Both models reproduced the observations well enough to indicate their suitability for providing useful insights into the behaviour of cropping systems where the focus is on depletion of soil fertility.
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Parton, William J., und P. E. Rasmussen. „Long-Term Effects of Crop Management in Wheat-Fallow: II. CENTURY Model Simulations“. Soil Science Society of America Journal 58, Nr. 2 (März 1994): 530–36. http://dx.doi.org/10.2136/sssaj1994.03615995005800020040x.
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Latta, Jo, und Garry J. O’Leary. „Long-term comparison of rotation and fallow tillage systems of wheat in Australia“. Field Crops Research 83, Nr. 2 (August 2003): 173–90. http://dx.doi.org/10.1016/s0378-4290(03)00073-x.
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DERRY, D., R. VORONEY und J. BRICENO. „Long-term effects of short-fallow on soil phosphorus pools in Costa Rica“. Agriculture, Ecosystems & Environment 110, Nr. 1-2 (01.10.2005): 91–103. http://dx.doi.org/10.1016/j.agee.2005.05.006.
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Wang, W. J., R. C. Dalal und P. W. Moody. „Soil carbon sequestration and density distribution in a Vertosol under different farming practices“. Soil Research 42, Nr. 8 (2004): 875. http://dx.doi.org/10.1071/sr04023.
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Abstract Agricultural soils play an important role in the global carbon (C) cycling and can act as a significant C sink if managed properly. The long-term (33 years) effects of no till (NT) v. conventional till (CT), stubble retention (SR) v. stubble burning (SB), and N fertiliser application (NF) v. nil N fertilisation (N0) on soil organic C sequestration, and their seasonal variations during the fallow period, were studied in a winter cereal–summer fallow cropping system under semi-arid subtropical climate in Queensland, Australia. The function of different density fractions of soil organic C in determining total organic C (TOC) dynamics and sequestration was investigated. Significant effect of NT, SR, or NF on soil organic C level was observed only in the top 10 cm soil and when they were practiced together, with the TOC contents being 1.1 to 3.4 t/ha higher under NT + NF + SR than under other treatments. There were significant seasonal fluctuations in TOC contents at different stages of the fallow period, and the lowest levels of TOC and treatment effects were observed in the late fallow period. Density fractionation of soil organic C showed that light fraction C (<1.6 g/cm3) declined rapidly during the fallow period and did not accumulate substantially in soil. TOC dynamics, either as a consequence of seasonal variations or as a long-term response to different farming practices, were predominantly controlled by the changes in the heavy fraction C (>1.6 g/cm3).
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Curtin, D., P. M. Fraser und M. H. Beare. „Loss of soil organic matter following cultivation of long-term pasture: effects on major exchangeable cations and cation exchange capacity“. Soil Research 53, Nr. 4 (2015): 377. http://dx.doi.org/10.1071/sr14173.
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Cultivation of grassland is known to lead to the depletion of soil organic matter (SOM), but the effect on the size and composition of the exchangeable cation suite has not been documented. We measured cation exchange capacity (CEC) and exchangeable cations (calcium, Ca; magnesium, Mg; potassium, K; sodium, Na), as well as soil carbon (C) and nitrogen (N) (0–7.5, 7.5–15, and 15–25 cm), 8 years after conversion of long-term ryegrass–white clover pasture (grazed by sheep) to annual crop production. The trial was near Lincoln, Canterbury, New Zealand. The trial included three tillage treatments: crops established using intensive cultivation (mouldboard ploughing), minimum tillage (shallow cultivation, ~10 cm), or no-tillage. The 8-year rotation was barley, wheat, pea, barley, pea, barley, barley, barley. A sheep-grazed pasture was maintained as an experimental control. The experiment also included a permanent fallow treatment (maintained plant-free using herbicides; not cultivated). After 8 years under arable cropping, soil C stocks (0–25 cm) were 10 t ha–1 less, on average, than under pasture. The vertical distribution of soil organic matter (SOM) was affected by tillage type, but the total amount of organic matter in the top 25 cm did not differ (P > 0.05) among the tillage treatments. Under permanent fallow (C loss of 13 t ha–1 relative to pasture), total exchangeable cation (Ca + Mg + K +Na) equivalents declined by 47 kmolc ha–1, a 20% decrease compared with pasture. Loss of exchange capacity resulted in the selective release of cations with lower affinity for SOM (K, Na, Mg). Smaller losses of exchangeable cations were recorded under the arable cropping rotation (average 31 kmolc ha–1), with no differences among tillage treatments. Effective CEC (at field pH) decreased under permanent fallow and cultivated treatments because of: (1) depletion of SOM (direct effect); and (2) soil acidification, which eliminated some of the remaining exchange sites (indirect effect). Acidification in the permanent fallow can be attributed to the N mineralisation process, whereas in the cropped systems, excess cation removal in harvested straw and grain accounted for about half of the measured acidification. There was evidence that the organic matter lost under arable cropping and fallow had lower CEC than SOM as a whole.
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Bremer, E., H. H. Janzen und E. de Jong. „SHORT COMMUNICATION: Difficulties in using 137Cs to measure erosion in stubble-mulched soil“. Canadian Journal of Soil Science 75, Nr. 3 (01.08.1995): 357–59. http://dx.doi.org/10.4141/cjss95-051.
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Soil erosion may be difficult to quantify from redistribution of 137Cs at sites where stubble-mulch techniques were adopted prior to 137Cs deposition, because appreciable 137Cs may have been transported before it was mixed into the soil Ap layer. We present evidence that this occurred in two long-term cropping experiments in southern Alberta. Key words: Cesium-137, tillage, long-term crop rotations, fallow
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Kovalevskaya, N. P., N. E. Zavyalova, D. Yu Sharavin und D. S. Fomin. „Biological activity of sod-podzolic soils in the long term experiment with different agrotechnical methods“. Rossiiskaia selskokhoziaistvennaia nauka, Nr. 3 (24.06.2019): 38–41. http://dx.doi.org/10.31857/s2500-26272019338-41.
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The effect of long-term application of grain-fallow-plow crop rotation with various legume densities, permanent cultivation of winter rye and barley, continuous bare fallow on the ecological and physiological state of the microbial community of sod-podzolic heavy loam soil was investigated. Biological activity indexes of soil microbiocenoses such as potential intensity of СО2 emission, microbial biomass gross respiration rate, metabolic coefficient, nitrogen fixation were assessed. It has been shown that the best humus state of soil and significant increase in the total nitrogen content provides the introduction of organic fertilizer (manure) in the “Crop rotation of 28,6% of legumes”. The ratio of the microbial biomass in sod-podzolic heavy loam soil organic matter varies from 1,50 to 3,24%. Application of mineral fertilizers leads to insignificant decrease in the carbon content of microbial biomass and raising of labile organic carbon. The decrease of metabolic activity in microbial communities has been determined in all variants of long-term study regardless of agrotechnical techniques. It has been established that permanent intensive cultivation of crops either with or without crop rotation leads to stability interference of the Cis-Urals soil microbiocenosis.
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KOLAWOLE, G. O., G. TIAN und H. TIJANI-ENIOLA. „EFFECTS OF FALLOW DURATION ON SOIL PHOSPHORUS FRACTIONS AND CROP P UPTAKE UNDER NATURAL REGROWTH AND PLANTED PUERARIA PHASEOLOIDES FALLOW SYSTEMS IN SOUTHWESTERN NIGERIA“. Experimental Agriculture 41, Nr. 1 (Januar 2005): 51–68. http://dx.doi.org/10.1017/s0014479704002327.
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Soil phosphorus fractions, maize and cassava P uptakes in natural regrowth fallow and Pueraria phaseoloides fallow systems, as affected by the duration (1–3 years) of fallow, were assessed in 1998 and 1999 in a long-term fallow management trial, established in 1989 at the International Institute of Tropical Agriculture, Ibadan, Nigeria. After one and three years fallow respectively, the mean P accumulation in fallow vegetation was 4.2 and 9.4 kg ha−1 in 1998, and 8.9 and 12.1 kg ha−1 in 1999 for natural fallow. For Pueraria, the corresponding values were 6.3 and 7.4 kg ha−1 in 1998 and 6.1 and 13.5 kg ha−1 in 1999. The positive effects of fallow lengths on dry matter and P accumulation were not as pronounced under Pueraria. Continuous cropping reduced soil pH and depleted Olsen P more than crop-fallow rotations under both fallow systems. An increase in fallow duration enhanced the availability of resin P, NaHCO3-, and NaOH- extractable P fractions, especially under natural fallow. Continuous cropping in a natural fallow system resulted in lower resin inorganic P (Pi) and NaHCO3-extractable inorganic and organic P (Po) fractions, and higher refractory P fractions (concentrated HCl-extractable Pi and Po and residual P) as compared to crop-fallow rotations. Although continuous cropping in the Pueraria system resulted in higher refractory P fractions than the crop-fallow rotations, the effects of fallow length on P fractions were not consistent or pronounced. Maize and cassava P uptakes increased with fallow duration. Phosphorous in maize grain was positively correlated with fallow vegetation P accumulation. Total P uptake by maize was positively but weakly correlated with NaHCO3-Po, Olsen P and fallow vegetation P accumulation.
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B.R., Iniyalakshimi, Shanmugasundaram R, Avudainayagam S., Jagadeeshwaran R., Paul Sebastian S. und Thangavel P. „Assessment of Land Cover changes on long-term treated industrial effluent irrigation using Remote sensing and GIS techniques“. Journal of Applied and Natural Science 11, Nr. 4 (10.12.2019): 791–95. http://dx.doi.org/10.31018/jans.v11i4.1833.
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A study was under taken to identify and map the changes in land use and land cover over a period of (1992 to 2017) 25 years in an area irrigating with treated industrial waste water using remote sensing and GIS technologies. Four LANDSAT TM and ETM+ images of 1992, 1999, 2006 and 2017 with a spatial resolution 30mx30m were used to determine the temporal land cover changes. Consequently, ground truth confirmation was done in the study area. Supervised classification was carried out in ArcGIS to identify the LULC classes. The study area was classified into four major classes; Water bodies, Settlements, Vegetation and Fallow lands. The study revealed that fallow lands was decreased by 99.8%, vegetation was found to be increased by 90.2% and settlement area was found to increase by 65.7 % over the period of 15 years. Livelihood increased with increased socio-economic status of the people.
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Chen, Yong, Gary Marek, Thomas Marek, Jerry Moorhead, Kevin Heflin, David Brauer, Prasanna Gowda und Raghavan Srinivasan. „Assessment of Alternative Agricultural Land Use Options for Extending the Availability of the Ogallala Aquifer in the Northern High Plains of Texas“. Hydrology 5, Nr. 4 (26.09.2018): 53. http://dx.doi.org/10.3390/hydrology5040053.
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The Ogallala Aquifer has experienced a continuous decline in water levels due to decades of irrigation pumping with minimal recharge. Corn is one of the major irrigated crops in the semi-arid Northern High Plains (NHP) of Texas. Selection of less water-intensive crops may provide opportunities for groundwater conservation. Modeling the long-term hydrologic impacts of alternative crops can be a time-saving and cost-effective alternative to field-based experiments. A newly developed management allowed depletion (MAD) irrigation scheduling algorithm for Soil and Water Assessment Tool (SWAT) was used in this study. The impacts of irrigated farming, dryland farming, and continuous fallow on water conservation were evaluated. Results indicated that simulated irrigation, evapotranspiration, and crop yield were representative of the measured data. Approximately 19%, 21%, and 32% reductions in annual groundwater uses were associated with irrigated soybean, sunflower, and sorghum, respectively, as compared to irrigated corn. On average, annual soil water depletion was more than 52 mm for dryland farming scenarios. In contrast, only 18 mm of soil water was lost to evaporation annually, for the long-term continuous fallow simulation. The fallow scenario also showed 31 mm of percolation for aquifer recharge.
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Allen, Brett L., Joseph L. Pikul, Jed T. Waddell und Verlan L. Cochran. „Long-Term Lentil Green-Manure Replacement for Fallow in the Semiarid Northern Great Plains“. Agronomy Journal 103, Nr. 4 (Juli 2011): 1292–98. http://dx.doi.org/10.2134/agronj2010.0410.
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Lyon, Drew J., Walter W. Stroup und Randall E. Brown. „Crop production and soil water storage in long-term winter wheat–fallow tillage experiments“. Soil and Tillage Research 49, Nr. 1-2 (November 1998): 19–27. http://dx.doi.org/10.1016/s0167-1987(98)00151-2.
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Mielke, L. N., und W. W. Wilhelm. „Comparisons of soil physical characteristics in long-term tillage winter wheat–fallow tillage experiments“. Soil and Tillage Research 49, Nr. 1-2 (November 1998): 29–35. http://dx.doi.org/10.1016/s0167-1987(98)00152-4.
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Drijber, R. A., J. W. Doran, A. M. Parkhurst und D. J. Lyon. „Changes in soil microbial community structure with tillage under long-term wheat-fallow management“. Soil Biology and Biochemistry 32, Nr. 10 (September 2000): 1419–30. http://dx.doi.org/10.1016/s0038-0717(00)00060-2.
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MCELLIGOTT, ALAN G., KATE P. O’NEILL und THOMAS J. HAYDEN. „Cumulative long-term investment in vocalization and mating success of fallow bucks,Dama dama“. Animal Behaviour 57, Nr. 5 (Mai 1999): 1159–67. http://dx.doi.org/10.1006/anbe.1999.1076.
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Smiley, Richard W., Stephen Machado, Karl E. L. Rhinhart, Catherine L. Reardon und Stewart B. Wuest. „Rapid Quantification of Soilborne Pathogen Communities in Wheat-Based Long-Term Field Experiments“. Plant Disease 100, Nr. 8 (August 2016): 1692–708. http://dx.doi.org/10.1094/pdis-09-15-1020-re.
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Rainfed experiments operated continuously for up to 84 years in semiarid eastern Oregon are among the oldest agronomic trials in North America. Disease incidence and severity had been quantified visually but quantification of inoculum density had not been attempted. Natural inoculum of 17 fungal and nematode pathogens were quantified for each of 2 years on eight trials using DNA extracts from soil. Crop type, tillage, rotation, soil fertility, year, and their interactions had large effects on the pathogens. Fusarium culmorum and Pratylenchus thornei were more dominant than F. pseudograminearum and P. neglectus where spring crops were grown, and the opposite species dominances occurred where winter wheat was the only crop. Bipolaris sorokiniana and Phoma pinodella were restricted to the presence of spring cereals and pulse crops, respectively. Helgardia spp. occurred in winter wheat-fallow rotations but not in annual winter wheat. Gaeumannomyces graminis var. tritici was more prevalent in cultivated than noncultivated soils and the opposite generally occurred for Rhizoctonia solani AG-8. Densities of Pythium spp. clade F were high but were also influenced by treatments. Significant treatment effects and interactions were more prevalent in two long-standing (>50-year) annually cropped experiments (29%) than two long-standing 2-year wheat-fallow rotations (14%). Associations among pathogens occurred mostly in an 84-year-old annual cereals experiment. This survey provided guidance for research on dynamics of root-infecting pathogens of rainfed field crops and identified two pathogens (Drechslera tritici-repentis and P. pinodella) not previously identified at the location.
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Whish, J. P. M., L. Price und P. A. Castor. „Do spring cover crops rob water and so reduce wheat yields in the northern grain zone of eastern Australia?“ Crop and Pasture Science 60, Nr. 6 (2009): 517. http://dx.doi.org/10.1071/cp08397.
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During the 14-month-long fallow that arises when moving from summer to winter crops, stubble breakdown can denude the soil surface and leave it vulnerable to erosion. Cover crops of millet have been proposed as a solution, but this then raises the question, how often is there sufficient water in the system to grow a cover crop without reducing the soil water reserves to the point of prejudicing the following wheat crop? An on-farm research approach was used to compare the traditional long fallow (TF) with a millet fallow (MF) in a total of 31 commercial paddocks over 3 years. Each treatment was simulated using the simulation-modelling framework (APSIM) to investigate the outcomes over a longer timeframe and to determine how often a millet fallow could be successfully included within the farming system. The on-farm trials showed that early-sown millet cover crops removed before December had no effect on wheat yield, but this was not true of millet cover crops that were allowed to grow through to maturity. Long-term simulations estimated that a spring cover crop of millet would adversely affect wheat yields in only 2% of years if planted early and removed after 50% cover had been achieved.
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Lanzanova, Mastrângello Enívar, Flávio Luiz Foletto Eltz, Rodrigo da Silveira Nicoloso, Elemar Antonino Cassol, Ildegardis Bertol, Telmo Jorge Carneiro Amado und Vitor Cauduro Girardello. „Residual effect of soil tillage on water erosion from a Typic Paleudalf under long-term no-tillage and cropping systems“. Revista Brasileira de Ciência do Solo 37, Nr. 6 (Dezember 2013): 1689–98. http://dx.doi.org/10.1590/s0100-06832013000600025.
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Soil erosion is one of the chief causes of agricultural land degradation. Practices of conservation agriculture, such as no-tillage and cover crops, are the key strategies of soil erosion control. In a long-term experiment on a Typic Paleudalf, we evaluated the temporal changes of soil loss and water runoff rates promoted by the transition from conventional to no-tillage systems in the treatments: bare soil (BS); grassland (GL); winter fallow (WF); intercrop maize and velvet bean (M+VB); intercrop maize and jack bean (M+JB); forage radish as winter cover crop (FR); and winter cover crop consortium ryegrass - common vetch (RG+CV). Intensive soil tillage induced higher soil losses and water runoff rates; these effects persisted for up to three years after the adoption of no-tillage. The planting of cover crops resulted in a faster decrease of soil and water loss rates in the first years after conversion from conventional to no-tillage than to winter fallow. The association of no-tillage with cover crops promoted progressive soil stabilization; after three years, soil losses were similar and water runoff was lower than from grassland soil. In the treatments of cropping systems with cover crops, soil losses were reduced by 99.7 and 66.7 %, compared to bare soil and winter fallow, while the water losses were reduced by 96.8 and 71.8 % in relation to the same treatments, respectively.
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Lester, David W., Colin J. Birch und Chris W. Dowling. „Fertiliser N and P applications on two Vertosols in north-eastern Australia. 1. Comparative grain yield responses for two different cultivation ages“. Australian Journal of Agricultural Research 59, Nr. 3 (2008): 247. http://dx.doi.org/10.1071/ar07169.
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Nitrogen (N) and phosphorus (P) are the 2 most limiting nutrients for grain production within the northern grains region of Australia. The response to fertiliser N and P inputs is influenced partly by the age of cultivation for cropping, following a land use change from native pasture. There are few studies that have assessed the effects of both N and P fertiliser inputs on grain yield and soil fertility in the long term on soils with contrasting ages of cultivation with fertility levels that are running down v. those already at the new equilibrium. Two long-term N × P experiments were established in the northern grains region: one in 1985 on an old (>40 years) cultivation soil on the Darling Downs, Qld; the second in 1996 on relatively new (10 years) cultivation on the north-west plains of NSW. Both experiments consisted of fertiliser N rates from nil to 120 kg N/ha.crop in factorial combination with fertiliser P from nil to 20 kg P/ha.crop. Opportunity cropping is practiced at both sites, with winter and summer cereals and legumes sown. On the old cultivation soil, fertiliser N responses were large and consistent for short-fallow crops, while long fallowing reduced the size and frequency of N response. Short-fallow sorghum in particular has responded up to the highest rate of fertiliser N (120 kg N/ha.crop). Average yield increase with fertiliser N compared with nil for 5 short-fallow sorghum crops was 1440, 2650, and 3010 kg/ha for the 40, 80, and 120 kg N/ha, respectively. Average agronomic efficiency of N for these crops was 36, 33, and 25 kg grain/kg fertiliser N applied. This contrasts with relatively new cultivation soil, where fertiliser N response was generally limited to the first 30 kg N/ha applied during periods of high cropping intensity. Response to P input was consistent for crop species, VAM sensitivity, and starting soil test P level. At both the old and new cultivation sites, generally all winter cereals responded to a 10 kg P/ha application, and more than half of long-fallow sorghum crops from both sites had increased grain yield with P application. At the old cultivation site, average yield gain for 10 kg P/ha.crop treatment was 480 kg/ha for all winter cereal sowings, and 180 kg/ha for long-fallow sorghum. Short-fallow sorghum did not show yield response to P treatment.
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Barroso, Patricia, Ignacio García-Bocanegra, Pelayo Acevedo, Pablo Palencia, Francisco Carro, Saúl Jiménez-Ruiz, Sonia Almería, Jitender P. Dubey, David Cano-Terriza und Joaquín Vicente. „Long-Term Determinants of the Seroprevalence of Toxoplasma gondii in a Wild Ungulate Community“. Animals 10, Nr. 12 (09.12.2020): 2349. http://dx.doi.org/10.3390/ani10122349.
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Toxoplasma gondii is an obligate intracellular protozoan which infects warm-blooded vertebrates, including humans, worldwide. In the present study, the epidemiology of T. gondii was studied in the wild ungulate host community (wild boar, red deer, and fallow deer) of Doñana National Park (DNP, south-western Spain) for 13 years (2005–2018). We assessed several variables which potentially operate in the medium and long-term (environmental features, population, and stochastic factors). Overall, the wild ungulate host community of DNP had high seroprevalence values of T. gondii (STG; % ± confidence interval (CI) 95%; wild boar (Sus scrofa) 39 ± 3.3, n = 698; red deer (Cervus elaphus) 30.7 ± 4.4, n = 423; fallow deer (Dama dama) 29.7 ± 4.2, n = 452). The complex interplay of hosts and ecological/epidemiological niches, together with the optimal climatic conditions for the survival of oocysts that converge in this area may favor the spread of the parasite in its host community. The temporal evolution of STG oscillated considerably, mostly in deer species. The relationships shown by statistical models indicated that several factors determined species patterns. Concomitance of effects among species, indicated that relevant drivers of risk operated at the community level. Our focus, addressing factors operating at broad temporal scale, allows showing their impacts on the epidemiology of T. gondii and its trends. This approach is key to understanding the epidemiology and ecology to T. gondii infection in wild host communities in a context where the decline in seroprevalence leads to loss of immunity in humans.
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Littleboy, M., DM Freebairn, GL Hammer und DM Silburn. „Impact of soil erosion on production in cropping systems .II. Simulation of production and erosion risks for a wheat cropping system“. Soil Research 30, Nr. 5 (1992): 775. http://dx.doi.org/10.1071/sr9920775.
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Maintenance of productive soil base by minimizing soil erosion is vital to long-term crop production. In this study, a modelling approach is used to estimate effects of soil erosion on productivity for a wheat cropping system at three locations in northeast Australia, Emerald, Dalby and Gunnedah. Predictions of erosion, runoff and yield decline due to erosion for variations in initial soil depth, slope and fallow management strategy are presented. Rates of yield decline were highest at Emerald due to summer dominance of rainfall resulting in higher runoff during summer fallow periods. On average, soil depth decreased by 0.35 cm year-1 at Emerald, 0.25 cm year-1 at Dalby and 0.1 cm year-1 at Gunnedah for a 5.0% slope, 100 cm initial soil depth and a disc/chisel fallow management strategy. Rates of soil removal and subsequent yield decline were higher for shallower soils, steeper slopes and if management practices provided less stubble cover during the fallow. The productivity half-life concept shows that the productive life of the soil was less than 100 years for some soil depth, climate, slope and management combinations. For other combinations, significant yield decline was predicted after 100 years of cropping. The quantification of erosion-productivity relationships allows us to identify regions of higher risk, to estimate the utility of management options, and provide a basis for focusing research and development of management strategies to preserve long-term production.
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Turpin, J. E., J. P. Thompson, B. J. Bridge und D. Orange. „Water and bromide movement in a Vertosol under four fallow management systems“. Soil Research 37, Nr. 1 (1999): 75. http://dx.doi.org/10.1071/s97108.
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Recent work on the Hermitage long-term fallow management found increased rates of anion movement under zero tillage systems compared with conventional tillage. Four separate experiments have been used to determine relative rates of water movement through different fallow management treatments on the Hermitage long-term fallow management trial and the causes of any differences. Photography of the aggregation patterns at the depth of tillage (approx. 15 cm) showed that conventional tillage combined with stubble burning has led to the formation of large massive peds up to 20 cm across below the tillage layer, whereas zero-tillage with stubble retention has maintained much smaller aggregates in this zone. Measurements of hydraulic conductivity at 15 cm under both dry and moist conditions indicated that, when the soil is dry and cracked, all tillage treatments have similar conductivities, but when the soil swells and cracks close, zero tillage–stubble retention maintains a greater volume of large pores and thereby greater conductivity. This effect was further demonstrated when a bromide tracer solution was applied to a relatively wet soil by ring infiltrometer, where only 15% of the solution moved below 15 cm in conventional tillage–stubble burning compared with 26% and 38% in zero tillage{stubble retention. In the final experiment, which followed the movement of surface applied bromide over a 6-month fallow, there were no significant differences in rates of leaching between management treatments.
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Kozak, Małgorzata, und Rafał Pudełko. „Impact Assessment of the Long-Term Fallowed Land on Agricultural Soils and the Possibility of Their Return to Agriculture“. Agriculture 11, Nr. 2 (11.02.2021): 148. http://dx.doi.org/10.3390/agriculture11020148.
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Agricultural land abandonment is a process observed in most European countries. In Poland and other countries of Central and Eastern Europe, it was initiated with the political transformation of the 1990s. Currently, in Poland, it concerns over 2 million ha of arable land. Such a large acreage constitutes a resource of land that can be directly restored to agricultural production or perform environmental functions. A new concept for management of fallow/abandoned areas is to start producing biomass for the bioeconomy purposes. Production of perennial crops, especially on poorer soils, requires an appropriate assessment of soil conditions. Therefore, it has become crucial to answer the question: What is the real impact of the fallowing process on soil, and is it possible to return it to production at all? For this purpose, on the selected fallowed land that met the marginality criteria defined under the project, physicochemical tests of soil properties were carried out, and subsequently, the results were compared with those of the neighboring agricultural land and with the soil valuation of the fallow land, which was conducted during its past agricultural use. The work was mainly aimed at analyzing the impact of long-term fallowing on soil pH, carbon sequestration and nutrient content, e.g., phosphorus and potassium. The result of the work is a positive assessment of the possibility of restoring fallowed land for agricultural production, including the production of biomass for non-agricultural purposes. Among the studied types of fallow plots, the fields where goldenrod (Solidago L.—invasive species) appeared were indicated as the areas most affected by soil degradation.
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Zentner, R. P., C. A. Campbell, V. O. Biederbeck, F. Selles, R. Lemke, P. G. Jefferson und Y. Gan. „Long-term assessment of management of an annual legume green manure crop for fallow replacement in the Brown soil zone“. Canadian Journal of Plant Science 84, Nr. 1 (01.01.2004): 11–22. http://dx.doi.org/10.4141/p02-188.
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In the Brown soil zone of western Canada summerfallowing (F) is traditionally used to reduce the water deficit associated with cereal production, but frequent use of this practice results in soil degradation and reduces the N-supplying capacity of soils. Some scientists suggest that an annual legume green manure crop (LGM) could be used as a partial-fallow replacement to protect the soil against erosion and increase its N fertility, particularly when combined with a snow-trapping technique to replenish soil water used by the legume. We assessed this possibility by comparing yields, N economy, water use efficiency, and economic returns for hard red spring wheat (W) (Triticum aestivum L.) grown in rotation with Indianhead black lentil (Lens culinaris Medikus) green manure (i.e., LGM-W-W) vs. that obtained in a traditional F-W-W system. Further, we assessed whether a change in manage ment of the LGM crop (i.e., moving to earlier seeding and earlier turn-down) was advantageous to the overall performance of this practice. The study was conducted over 12 yr (1988–99) on a medium-textured Orthic Brown Chernozem at Swift Current, Saskatchewan. Wheat stubble was left tall to trap snow, tillage was kept to a minimum, and the wheat was fertilized based on NO3 soil tests. When we examined results after 6 yr, we concluded that by waiting until full bloom to turn down the legume (usually late July or early August) so as to maximize N2 fixation, soil water was being depleted to the detriment of yields of the following wheat crop. The change in management of the LGM crop since 1993 resulted in wheat yields following LGM equaling those after fallow (due to improved water use efficiency), a gradual and significant increase over time in grain protein and in N yield of aboveground plant biomass of wheat in the LGM-W-W compared to the F-W-W system, plus a gradual decrease in fertilizer N requirements of wheat in the LGM system accompanying an improvement in the N supplying power of the soil. These savings in N fertilizer, together with savings in tillage and herbicide costs for weed control on partial-fallow vs. conventional-fallow areas, and higher revenues from the enhanced grain protein, more than offset the added costs for seed and management of the LGM crop. Thus, our results imply that, if producers seed the LGM in April and turn it down in early July, an annual LGM-cereal rotation is a viable option in the semiarid Canadian prairies; however, one negative consequence of adopting this management strategy is the possibility of enhancing NO3 leaching. Key words: Nitrogen yields, grain protein, green fallow, summerfallow substitute, economic returns, NO3 leaching
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Izaurralde, R. C., Y. Feng, J. A. Robertson, W. B. McGill, N. G. Juma und B. M. Olson. „Long-term influence of cropping systems, tillage methods, and N sources on nitrate leaching“. Canadian Journal of Soil Science 75, Nr. 4 (01.11.1995): 497–505. http://dx.doi.org/10.4141/cjss95-071.
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The extent of nitrate leaching in cultivated soils of Alberta is unknown. We studied how long- and short-term agricultural practices influenced nitrate leaching in a cryoboreal subhumid soil-climate of north-central Alberta. The study used plots from three crop rotation-tillage studies at Breton on an Orthic Gray Luvisol, and from one at Ellerslie on an Orthic Black Chernozem. Soil samples were taken in the fall of 1993 from selected treatments as well as native forest sites in 0.3-m depth increments from 0 to 3.9 m and analyzed for NO3-N. No NO3− were found under native forest vegetation. NO3-N accumulated below 0.9-m depth of agricultural ecosystems cultivated for as long as 64 yr ranged from 0 to 67 kg N ha−1. At Breton, fallow-wheat rotation plots receiving fertilizer N and manure contained eight times more NO3-N below 0.9 m depth than non-fertilized plots. NO3-N levels in an 8-yr legume-based rotation and in continuous-barley plots were similar but greater than in continuous-forage plots. Eighty-seven percent of NO3− found under continuous barley occurred below the root zone compared with only 35% in the 8-yr rotation. At Ellerslie, NO3-N mass was related to fertilizer N and mineralization of soil organic matter. Increased efforts should be directed towards better synchronizing N release from or addition to soils with plant uptake. Evidence of greater nitrate leaching under zero tillage than under conventional warrants further confirmation. Key words: Nitrogen loss, fallow, Hordeum vulgare L., Triticum aestivum L., manure, legumes, synthetic fertilizer
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Perfilyev, N. V., und O. A. Vyushina. „Efficiency of crop rotation under long-term application of basic tillage systems“. Siberian Herald of Agricultural Science 50, Nr. 4 (25.09.2020): 5–12. http://dx.doi.org/10.26898/0370-8799-2020-4-1.
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An assessment is given of the long-term impact of basic tillage systems of various degrees of intensity on the yield and economic efficiency of production in the cultivation of cereals in grainfallow crop rotation. The study was carried out in 2017–2019 in a long-term stationary experiment on dark grey forest heavy loamy soil in Tyumen region. The experiments were carried out during the seventh rotation of the grain-fallow crop rotation: bare fallow – winter rye – spring wheat – spring wheat – spring barley, spread in time and space. In years with high temperatures and good rainfall, close to the average annual rainfall, resource-saving tillage systems with disk harrowing BDT-2.5 by 10-12 cm and stubble-mulch tillage by 12-14 cm with and without fertilizers led to a decrease in winter rye yield by 0.30-0.98 t/ha. Wheat yield against winter rye and barley was close to the variant with the moldboard tillage. There was a decrease in the yield of wheat sown repeatedly without the use of fertilizers by 0.04-0.40 t/ha. When fertilizers were used, the yield was equal to the control. The moldboard tillage without fertilizers was the most effective, with the net income of 14.92 thousand rubles/ha. Combined and surface soil tillage systems were similar in efficiency to the moldboard tillage (inferior by 4.3-6.6%). The most effective cultivation of cereals with the use of fertilizers was by minimum combined tillage with alternating plowing and disk harrowing, with the net income of 17.74 thousand rubles/ha, which was 13.4% higher compared to moldboard plowing. Differentiated, stubble-mulch and combined tillage brought the net income close to the control. In the remaining options studied, the net income was lower than with the moldboard tillage: without fertilizers – by 1.26-2.44 thousand rubles/ha (8.5-16.3%), with the use of fertilizers – by 1.02-1.78 thousand rubles/ha (6.5-9.0%).
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Naumov, Mihail Olegovich, Dmitriy Vladimirovich Bochkarev, Alexander Nikolaevich Nikolskiy, Vladimir Dmitrievich Bochkarev und Svetlana Anatolevna Pismarova. „Efficiency of systemic application of herbicides in the growing of amaranth on protective lands“. Agrarian Scientific Journal, Nr. 7 (15.07.2019): 23–27. http://dx.doi.org/10.28983/asj.y2019i7pp23-27.
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Data of long-term researches of the systematic use of herbicides in the amaranth crops in the development of fallow lands are presented. It has been established that the use of herbicides has a significant effect on reducing the salinity of crops by long-term monocotyledonous weed. The maximum grain yield was after combined application of Tornado 500 (4 l/ha) and Miura (1.2 l/ha). The combined use of herbicides allowed collecting proteins and starch with amaranth grain per unit of area.