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1.
Jehan Bakht Mohammad Shafi Mohammad Tariq Jan Zahir Shah 《Soil & Tillage Research》2009,104(2):233-240
Management of N is the key for sustainable and profitable wheat production in a low N soil. We report results of irrigated crop rotation experiment, conducted in the North West Frontier Province (NWFP), Pakistan, during 1999–2002 to evaluate effects of residue retention, fertilizer N application and mung bean (Vigna radiata) on crop and N yields of wheat and soil organic fertility in a mung bean–wheat sequence. Treatments were (a) crop residue retained (+residue) or (b) removed (−residue), (c) 120 kg N ha−1 applied to wheat, (d) 160 kg N ha−1 to maize or (e) no nitrogen applied. The cropping system was rotation of wheat with maize or wheat with mung bean. The experiment was laid out in a spit plot design. Postharvest incorporation of crop residues significantly (p < 0.05) increased the grain and straw yields of wheat during both years. On average, crop residues incorporation increased the wheat grain yield by 1.31 times and straw yield by 1.39 times. The wheat crop also responded strongly to the previous legume (mung bean) in terms of enhanced grain yield by 2.09 times and straw yield by 2.16 times over the previous cereal (maize) treatment. Application of fertilizer N to previous maize exerted strong carry over effect on grain (1.32 times) and straw yield (1.38 times) of the following wheat. Application of N fertilizer to current wheat produced on average 1.59 times more grain and 1.77 times more straw yield over the 0 N kg ha−1 treatment. The N uptake in wheat grain and straw was increased 1.31 and 1.64 times by residues treatment, 2.08 and 2.49 times by mung bean and 1.71 and 1.86 times by fertilizer N applied to wheat, respectively. The soil mineral N was increased 1.23 times by residues, 1.34 times by mung bean and 2.49 times by the application of fertilizer N to wheat. Similarly, the soil organic C was increased 1.04-fold by residues, 1.08 times by mung bean and 1.00 times by the application of fertilizer N. We concluded that retention of residues, application of fertilizer N and involvement of legumes in crop rotation greatly improves the N economy of the cropping system and enhances crop productivity in low N soils. 相似文献
2.
In the dry savannas of west and central Africa, where low soil fertility is major constraint to maize production, the development of tropical maize genotypes with high and stable yield under low-nitrogen condition is very important, since access to these improved genotypes may be the only affordable alternative to many small scale farmers.
Field trials were conducted at Samaru (Typic Haplustalfs) to investigate the response of low-N tolerant maize cultivars to nitrogen (N) fertilizer. Nitrogen application rates were 0, 30, 60, 90 kg N ha−1 and four maize cultivars (Low-N pool C2, ACR 8328 BN C7, Super Oba II and TZR-SR). Maize leaf area index, intercepted radiation, leaf area and stover weights were increased due to nitrogen application at flowering. For most of the parameters, 60 kg N ha−1 appeared to have the significantly high values. However, there was no significant difference between application rates of 60 and 90 kg N ha−1 in stem weight, stover weight, grain yield and shelling percent at harvest. Genotypic variation observed in the maize agronomic traits were not significant except in leaf weight and grain yield. The amount of nitrogen taken by maize increased with increase in fertilizer rates. Application of 30 and 90 kg N ha−1 to soil increased the maize grain N concentration and total N uptake. About 45.3 kg ha−1 and 8.8 g N kg−1 nitrogen uptake was obtained in maize shoot and grain, respectively, at the application of 90 kg N ha−1. Low-N pool C2 genotype had the highest grain N concentration and shoot uptake significantly higher than TZB-SR. Nitrogen fertilizer applied accounted for 97% variation in soil nitrate. There existed a positive and significant correlation between maize grain yield and leaf nitrogen uptake (r = 0.33, P < 0.01). Averagely, nitrogen fertilizer applied accounted for 86% variations in maize grain yield. 相似文献
3.
In earlier crop rotation studies in which grain sorghum (Sorghum bicolor (L.) Moench) followed winter wheat (Triticum aestivum L.) after a 10- to 11-month fallow period during which the wheat residues were managed by different tillage methods, sorghum yields increased in response to increases in soil water content at sorghum planting time. Similar results were obtained when residues were placed on the surface at the start of the fallow period. The soil water contents at planting time were positively correlated with amounts of wheat residue maintained on the soil surface during fallow.
The studies also suggested that sorghum responded positively to growing season precipitation when increasing of residue remained on the soil during the growing season. The objective of this study was to evaluate this response to growing season precipitation through statistical analyses of data from five earlier tillage and residue placement studies. Regression analyses of data from the studies showed that sorghum grain yields increased with increasing amounts of surface residues at planting time. Differences in response of grain yield to precipitation were greatest in the vegetative period. For the period, grain yields increased 0.014 Mg ha−1 per mm of precipitation when residue amounts ranged from 0 to 0.4 Mg ha−1 per mm of precipitation when residue amounts ranged from 0 to 0.4 Mg ha−1, and 0.027 Mg ha−1 per mm of precipitation when residue amounts were 3.2 Mg ha−1.
Differences in response to rainfall in the heading and grain filling period were lower or negligible. High responses for the vegetative period were attributed to the residues which increased infiltration and reduced evaporation before canopy development. Lower responses during heading and lack of responses during grain filling were attributed to: (1) canopy development, which minimized the effect of residues on imfiltration and evaporation; (2) soil cracking, which resulted in similar infiltration with all treatments; and (3) residue decomposition, which minimized differences among residue amounts on the soil with different treatments. 相似文献
4.
Soil compaction has been recognized as a problem limiting crop production, especially in the Southern Coastal Plain of the USA. Development of tillage and residue management systems is needed to alleviate soil compaction problems in these soils. Fertilizer nitrogen (N) management is also an important factor in these management systems. In 1988, a study was initiated with a wide-frame (6.3 m) vehicle to determine the interactive effects of traffic, deep tillage, and surface residue management on the fate of fertilizer N applied to corn (Zea mays L.) grown on a Norfork loamy sand (fine-loamy, siliceous, Thermic, Typic Kandiudults). Corn was planted into a winter cover crop of ‘Tibbee’ crimson clover (Trifolium incarnatum L.). Treatments included: traffic (conventional equipment or no traffic); deep tillage (no deep tillage, annual in-row subsoiling, or one-time only complete disruption); residue management (no surface tillage or disk and field cultivation). The one-time only complete disruption was accomplished by subsoiling at a depth of 43 cm on 25 cm centers in spring 1988. In 1990–1991, fertilizer applications were made as 15N-depleted NH4NO3 to microplots inside each treatment plot. The 1990 and 1991 data are reported here. In 1990 an extreme drought resulted in an average grain yield of 1.8 Mg grain ha−1, whereas abundant rainfall in 1991 resulted in 9.4 Mg grain ha−1. Deep tillage increased corn dry matter production in both years. In 1991, grain yields indicated that corn was susceptible to recompaction of soil owing to traffic when residues were incorporated with surface tillage. In the dry year, plant N uptake was increased 27% with deep tillage and decreased 10% with traffic. In the wet year, a surface tillage × deep tillage × traffic interaction was observed for total N uptake, fertilizer N uptake, and total fertilizer N recovery in the plant-soil system. When combined with traffic, plant N uptake was reduced with the highest intensity tillage treatment (135 kg N ha−1) because of rootrestricting soil compaction, and with the lowest intensity tillage treatment (129 kg N ha−1) because of increased N losses. In these soils, leaving residues on the soil surface can reduce the detrimental effect of traffic on corn production, but if no surface tillage is performed, deep tillage is needed. 相似文献
5.
氮肥施用对冬小麦籽粒产量和氮素表观损失的影响 总被引：16，自引：0，他引：16
Excessive nitrogen （N） fertilizer application to winter wheat is a common problem on the North China Plain. To determine the optimum fertilizer N rate for winter wheat production while minimizing N losses, field experiments were conducted for two growing seasons at eight sites, in Huimin County, Shandong Province, from 2001 to 2003. The optimum N rate for maximum grain yield was inversely related to the initial soil mineral N content （Nmin） in the top 90 cm of the soil profile before sowing. There was no yield response to the applied N at the three sites with high initial soil mineral N levels （average 212 kg N ha^-1）. The average optimum N rate was 96 kg N ha^-1 for the five sites with low initial soil Nmin （average 155 kg N ha^-1） before sowing. Residual nitrate N in the top 90 cm of the soil profile after harvest increased with increasing fertilizer N application rate. The apparent N losses during the wheat-growing season also increased with increasing N application rate. The average apparent N losses with the optimum N rates were less than 15 kg N ha^-1, whereas the farmers＇ conventional N application rate resulted in losses of more than 100 kg N ha^-1. Therefore, optimizing N use for winter wheat considerably reduced N losses to the environment without compromising crop yields. 相似文献
6.
In irrigated grain-growing soils on Canada's prairies, straw management can affect nitrogen (N) fertility and long-term soil organic matter reserves. We conducted a 2-year field experiment in southern Alberta, on a Dark Brown Chernozemic Lethbridge loam (Typic Boroll), to determine the effects of straw removal, tillage, and fertilizer timing on crop uptake of soil and fertilizer N. During the study (1991 and 1992), the crop was oat (Avena sativa L.) and wheat (Triticum aestivum L.), respectively, in an experiment that had been in a wheat-wheat-oat-wheat rotation since 1986. Five straw-tillage treatments were: straw-fall plow, straw-pring plow, no straw-fall plow, no straw-spring plow and no straw-direct seeding. Fertilizer N was applied in fall or spring. Ammonium nitrate (5 at.% 15N) was added at 100 kg N ha−1 in fall 1990 or spring 1991. For oat (1991), plant N derived from soil was higher under fall plow than under spring plow, higher with tillage than direct seeding, and unaffected by straw removal. The plant N derived from fertilizer was not affected by straw removal in fall plow treatments, but under spring plow, it was higher with straw removal. The plant N derived from fertilizer showed a significant straw-tillage × fertilizer timing interaction; with fall incorporated straw, plant N derived from fertilizer was 44.0 kg N ha−1 for spring-applied, and 30.6 kg N ha−1 for fall-applied N, but in other straw-tillage treatments there was no effect of fertilizer timing. Cumulative fertilizer N recovery (plant + soil) over the 2 years averaged 64.2%, and was unaffected by straw-tillage treatment. Fertilizer N recovery, however, was less with fall-applied N (61.3%) than spring applied N (66.8%). At mid-season, fall plow treatments had higher soil inorganic N and inorganic N derived from fertilizer than spring plow treatments, apparently because of less immobilization. The fall plow treatments also retained higher inorganic N after harvest. Straw removal and fertilizer timing did not influence soil inorganic N and soil inorganic N derived from fertilizer. N removal in straw (16 kg N ha−1 yr−1) could deplete soil N in the long-term. Long-term effects of tillage timing on soil N will depend on the relative amount of N lost by leaching with fall plowing and that lost by denitrification under spring plowing. With direct seeding, crop yield and uptake of soil N was less, and N losses by denitrification could be greater. Application of N in spring, rather than fall, should enhance crop N uptake, reducing N losses and enhancing long-term soil organic N. 相似文献
7.
Influence of wheat residue management on irrigated corn grain production in a reduced tillage system
Management of wheat (Triticum aestivum L.) residues for corn (Zea mays L.) planting is an important issue in southern parts of Iran where these two irrigated crops are consecutively grown. Concerns have been raised in recent years over the burning of the crop residues by farmers in these areas. A 2-year (2001–2002) field experiment was conducted as a randomized complete block design with three replications. The treatments consisted of irrigated corn planted, after burning wheat residues followed by conventional tillage (CT), after residue removal followed by CT, after soil incorporation of 0, 25, 50, 75, and 100% of residue followed by chisel plow, disk harrow, and row crop planter equipped with row cleaner. The CT operations consisted of mollboard plowing followed by two times disk harrowing. Treatments had significant effects on corn grain yield, biological yield, and leaf area index. The highest grain yield (15.73 t ha−1) and grains per ear (709.3) were obtained when 25–50% of wheat residues were soil incorporated and the seeds were sown with planter equipped with row cleaner in both years as compared with conventional tillage practices. It is recommended that complete residue removal or burning should be avoided; hence for successful corn production after wheat, residue management techniques that reduce residue level in the row area should be implemented. 相似文献
8.
Wheat (Triticum aestivum L.) yield and quality is influenced by management of the previous crop but is highly dependent on current year management. The objective of this study was to evaluate the response of winter wheat seeded in two tillage systems [conventional tillage (CT) and no-till (NT)] to four N rates applied to a previous cotton (Gossypium hirsutum L.) crop (0, 67, 134, and 202 kg ha−1). The experiment with wheat was conducted on a Dothan sandy loam (fine, loamy siliceous, thermic Plinthic Kandiudults) at the University of Florida North Florida Research and Education Center near Quincy, FL from 1995 to 1997. For most plant characteristics, there was a tillage x N x year interaction. Greater plant emergence (79.4 vs. 65.3%) and grain N (23.5 vs. 21.5 g kg−1), and lower grain moisture (139 vs. 142 g kg−1) were obtained under NT than CT, respectively, in one out of two years. Nitrogen applied to a previous cotton crop increased wheat grain yields, plant height and seed number under NT in 1995–1996 and CT in 1996–1997, head density under NT in both years, harvest index under CT in 1996–1997, and grain N concentration in 1995–1996 and 1996–1997 due to residual plant and soil N. With every 1 kg N applied to a previous cotton crop, wheat grain yields increased by 5.38 kg ha−1 under NT, whereas grain yield under CT was not influenced by N application to cotton in 1995–1996. In 1996–1997, grain yields increased by 4.96 and 4.23 kg ha−1 for wheat grown in NT and CT, respectively. Generally, wheat seeded in NT following cotton did not decrease stand or yields compared to CT and wheat grain yields and grain N content increased with N fertilization of the previous crop. However, we would have to apply about 134 kg N ha−1 to a previous cotton crop to maximize wheat production under NT and CT. 相似文献
9.
An 8-yr (1998–2005) field experiment was conducted on a Gray Luvisol (Boralf) soil near Star City, Saskatchewan, Canada, to determine the effects of tillage (no-tillage – NT and conventional tillage – CT), straw management (straw retained – R and straw not retained – NR) and N fertilizer (0, 40, 80 and 120 kg N ha−1, except no N to pea (Pisum sativum L.) phase of the rotation) on seed and straw yield, mass of N and C in crop, organic C and N, inorganic N and aggregation in soil, and nitrous oxide (N2O) emissions for a second 4-yr rotation cycle (2002–2005). The plots were seeded to barley (Hordeum vulgare L.) in 2002, pea in 2003, wheat (Triticum aestivum L.) in 2004 and canola (Brassica napus L.) in 2005. Seed, straw and chaff yield, root mass, and mass of N and C in crop increased with increasing N rate for barley in 2002, wheat in 2004 and canola in 2005. No-till produced greater seed (by 51%), straw (23%) and chaff (13%) yield of barley than CT in 2002, but seed yield for wheat in 2004, and seed and straw yield for canola in 2005 were greater under CT than NT. Straw retention increased seed (by 62%), straw (by 43%) and chaff (by 12%) yield, and root mass (by 11%) compared to straw removal for barley in 2002, wheat in 2004, and seed and straw yield for pea in 2003. No-till resulted in greater mass of N in seed, and mass of C in seed, straw, chaff and root than CT for barley in 2002, but mass of N and C were greater under CT than NT for wheat in 2004 and for canola in 2005 in many cases. Straw retention had greater mass of N and C in seed, straw, chaff and root in most cases compared to straw removal for barley in 2002, pea in 2003 and wheat in 2004. Soil moisture content in spring was higher under NT than CT and with R than NR in the 0–15 cm depth, with the highest moisture content in the NT + R treatment in many cases. After eight crop seasons, tillage and straw management had no effect on total organic C (TOC) and N (TON) in the 0–15 cm soil, but light fraction organic C (LFOC) and N (LFON), respectively, were greater by 1.275 Mg C ha−1 and 0.031 Mg N ha−1 with R than NR, and also greater by 0.563 Mg C ha−1 and 0.044 Mg N ha−1 under NT than CT. There was no effect of tillage, straw and N fertilization on the NH4-N in soil in most cases, but R treatment had higher NO3-N concentration in the 0–15 cm soil than NR. The NO3-N concentration in the 0–15, 15–30 and 30–60 cm soil layers increased (though small) with increasing N rate. The R treatment had 6.7% lower proportion of fine (<0.83 mm diameter) and 8.6% greater proportion of large (>38.0 mm) dry aggregates, and 4.5 mm larger mean weight diameter (MWD) compared to NR treatment. This suggests a lower potential for soil erosion when crop residues are retained. There was no beneficial effect of elimination of tillage on soil aggregation. The amount of N lost as N2O was higher from N-fertilized (580 g N ha−1) than from zero-N (155 g N ha−1) plots, and also higher in CT (398 g N ha−1) than NT (340 g N ha−1) in some cases. In conclusion, retaining crop residues along with no-tillage improved some soil properties and may also be better for the environment and the sustainability of high crop production. Nitrogen fertilization improved crop production and some soil quality attributes, but also increased the potential for NO3-N leaching and N2O-N emissions, especially when applied in excess of crop requirements. 相似文献
10.
Tillage, nitrogen and crop residue effects on crop yield, nutrient uptake, soil quality, and greenhouse gas emissions 总被引：4，自引：0，他引：4
Management practices that simultaneously improve soil properties and yield are crucial to sustain high crop production and minimize detrimental impact on the environment. The objective of this study was to determine the influence of tillage and crop residue management on crop yield, N uptake and C removal in crop, soil organic C and N, inorganic N and aggregation, and nitrous oxide (N2O) emissions on a Gray Luvisol (Boralf) soil near Star City, Saskatchewan, Canada. The 4-year (1998–2001) field experiment was conducted with two tillage systems: no tillage (NT), and conventional tillage (CT); two levels of straw: straw retained (S), and straw removed (NS); and four rates of fertilizer N: 0, 40, 80, and 120 kg N ha−1, except no N to pea phase of the rotation. The plots were seeded to barley (Hordeum vulgare L.) in 1998, pea (Pisum sativum L.) in 1999, wheat (Triticum aestivum L.) in 2000 and canola (Brassica napus L.) in 2001. Tillage and straw treatments generally had no effect on crop yield during the first three years. But in 2001, NT produced 55, 32, and 20% greater canola seed, straw and chaff than CT, respectively, whereas straw retention increased seed and straw yield by 33 and 19% compared to straw removal. Seed, straw and chaff yield of canola increased with N rate up to 40 kg N ha−1, and root mass (0–15 cm depth) with N rate to 80 kg N ha−1. Amount of N uptake and C removed in wheat and canola generally increased with N rate, but tillage and straw management had no consistent effect. After four crop seasons, total organic C (TOC) and N (TN), light fraction organic matter (LFOM), C (LFC), and N (LFN) were generally greater with S than NS treatments. Tillage did not affect TOC and TN in soil, but LFOM, LFC, and LFN were greater or tended to be greater under NT than CT. There was no effect of tillage, straw and N fertilization on NH4-N in soil, but CT and S tended to have higher NO3-N concentration in 0–15 cm soil than NT and NS, respectively. Concentration of NO3-N increased substantially with N rate ≥80 kg ha−1. The NT + S treatment had the lowest proportion (34%) of wind-erodible (<0.83 mm diameter) aggregates and greatest proportion (37%) of larger (>12.7 mm) dry aggregates, compared to highest (50%) and lowest (18%) proportion of corresponding aggregates in CT + NS, indicating less potential for soil erosion when tillage was omitted and crop residues were retained. Amount of N lost as N2O was higher from N-fertilized than from zero-N plots, and it was substantially higher from N-applied CT plots than from N-applied NT plots. Retaining crop residues along with no-tillage improved soil properties and may also be better for the environment. 相似文献
11.
Crop responses to annual compaction treatments (applied to whole plots) and management treatments to ameliorate compacted soil were determined in a field experiment on a Vertisol. Initially, all treatments except a control were compacted with a 10 Mg axle load on wet soil (26% gravimetric water content compared with a plastic limit of 22%). Annually applied axle loads of 10 and 6 Mg on wet soil (25–32% soil water) tended to reduce seedling emergence, grain yield (wheat, sorghum and maize), soil water storage and crop water use efficiency (WUE). Annual applications of an axle load of 6 Mg on dry soil (<22% soil water) had little effect on crop performance. Mean reductions in the yield of five crops (three wheat, one sorghum and one maize) in comparison with the uncompacted control were 23% or 0.79 Mg ha−1 (10 Mg on wet soil), 13% or 0.44 Mg ha−1 (6 Mg on wet soil) and 1% or 0.03 Mg ha−1 (6 Mg on dry soil). Maize grown in the fifth year of treatment application was most affected by compaction of wet soil, its WUE being reduced from 14.3 to 9.7 kg ha−1 mm−1 in response to an axle load of 10 Mg. Reduced WUE was associated with delayed soil water extraction at depth. A 3-year pasture ley was the most successful amelioration treatment. A wheat and a maize crop grown after the ley outyielded the control by 0.33 and 0.90 Mg ha−1, respectively. So the pasture not only ameliorated the initial compaction damage, with respect to crop performance, but resulted in improvements in two subsequent crops. 相似文献
12.
M. Nyborg E. D. Solberg R. C. Izaurralde S. S. Malhi M. Molina-Ayala 《Soil & Tillage Research》1995,36(3-4):165-174
Long-term influence of N fertilizer, tillage and straw on crop production and soil properties are not well known in central Alberta. Field experiments were established in autumn 1979, on a Black Chernozemic soil and on a Gray Luvisolic soil in north-central Alberta to determine the long-term effect of tillage, straw and N fertilizer on yield and N uptake of barley (Hordeum vulgare L.). Fertilizer N was applied annually at 56 kg ha−1. The 11 year averages of barley yields and N uptake under zero tillage were lower than under conventional tillage. Retention rather than removal of straw tended to reduce barley yield for the initial 6 years and 2 year at Site 1 and Site 2, respectively. A simple mathematical model of average annual plant N uptake and grain yield could account for most of the variation in the data observed at both sites (R2 = 0.907; P < 0.01). Final values of soil N, calculated using a mass balance approach, agree closely with values measured at the end of the eleventh year. Conventional tillage and zero tillage, with addition of fertilizer N and retention of straw, were the only treatments with apparent but small net addition of N to soil at Site 1 (40 kg ha−1 and 117 kg ha−1, respectively). At Site 2, only the zero tillage treatment with addition of fertilizer and retention of straw gained soil N (29 kg ha−1). In conclusion, soil ecosystems functioning in subhumid environments with slight to moderate heat limitations such as those in central Alberta can adapt, within a few years, to zero tillage practices with full retention of straw. 相似文献
13.
R.M. Bhagat 《Soil & Tillage Research》1990,17(3-4):315-326
Field experiments were conducted on a river deposit during 1983–1984 and 1984–1985 in order to study the effect of different soil management practices, such as zero tillage with surface-applied crop residue mulch at a rate of 10 t ha−1 (ZT+M), conventional tillage (CT), CT+ surface-applied crop residue mulch at a rate of 10 t ha−1 (CT + M), CT+crop residue incorporation at a rate of 10 t ha−1 (CT + SI), CT + farmyard manure incorporation at a rate of 10 t ha−1 (CT + FYM), on soil hydro-thermal regime root growth, nutrient uptake and dry matter yield of winter wheat (Triticum aestivum L.). The soils of the site are classified as Entisol, Typic Psammaquent with pH 6.0, cation exchange capacity 10 c mol (p+) per kg in the surface (0–0.3 m) depth. In the CT + M and CT + FYM treatments, higher water retention was observed compared to CI. The minimum soil temperature was also raised by 3°C under CT + M to CT at 0.1-m depth. CT + M and CT + FYM had significantly higher root mass density compared with other treatments at all stages of crop growth. The nitrogen (N) uptake under these two treatments was also significantly higher compared to CT. Under CT+M, plants did not suffer from N stress compared to other treatments. Phosphorus (P) uptake (except at tillering) and potassium (K) uptake under CT+M and CT + FYM were significantly higher than for all the other treatments. Treatments ZT+M and CT+SI behave simply to CT in terms of hydro-thermal regime, root growth, nutrient uptake and dry matter yield. The grain yield under CT+M and CT+FYM during 1983–1984 and 1984–1985 was significantly higher than that under all the other treatments. 相似文献
14.
Long-term fertilization, manure and liming effects on soil organic matter and crop yields 总被引：2，自引：0，他引：2
Yield decline or stagnation and its relationship with soil organic matter fractions in soybean (Glycine max L.)–wheat (Triticum aestivum L.) cropping system under long-term fertilizer use are not well understood. To understand this phenomenon, soil organic matter fractions and soil aggregate size distribution were studied in an Alfisol (Typic Haplustalf) at a long-term experiment at Birsa Agricultural University, Ranchi, India. For 30 years, the following fertilizer treatments were compared with undisturbed fallow plots (without crop and fertilizer management): unfertilized (control), 100% recommended rate of N, NP, NPK, NPK+ farmyard manure (FYM) and NPK + lime. Yield declined with time for soybean in control (30 kg ha−1 yr−1) and NP (21 kg ha−1 yr−1) treatments and for wheat in control (46 kg ha−1 yr−1) and N (25 kg ha−1 yr−1) treatments. However, yield increased with time for NPK + FYM and NPK + lime treatments in wheat. At a depth of 0–15 cm, small macroaggregates (0.25–2 mm) dominated soil (43–61%) followed by microaggregates (0.053–0.25 mm) with 13–28%. Soil microbial biomass carbon (SMBC), nitrogen (SMBN) and acid hydrolysable carbohydrates (HCH) were greater in NPK + FYM and NPK + lime as compared to other treatments. With three decades of cultivation, C and N mineralization were greater in microaggregates than in small macroaggregates and relatively resistant mineral associated organic matter (silt + clay fraction). Particulate organic carbon (POC) and nitrogen (PON) decreased significantly in control, N and NP application over fallow. Results suggest that continuous use of NPK + FYM or NPK + lime would sustain yield in a soybean–wheat system without deteriorating soil quality. 相似文献
15.
土壤地力和长期施肥对潮土区小麦和玉米产量演变趋势的影响 总被引：19，自引：4，他引：15
为潮土区合理施肥管理提供依据,对32个长期定位点、24年（1987～2010）不施肥和化肥配施秸秆（农民常规施肥）处理的小麦和玉米产量及其与土壤地力和施肥量间的关系进行了分析。结果表明:潮土区土壤地力对小麦和玉米产量的平均贡献率分别为51.4%和54.0%,变异系数分别为39.0%和41.2%。不施肥处理小麦和玉米产量每年分别下降4.1 kg/hm2和96.6 kg/hm2;常规施肥处理的小麦和玉米每年分别增产61.5 kg/hm2和26.8 kg/hm2。施化肥量与作物增产量（常规施肥产量－不施肥产量）呈显著正相关。通过通径分析进一步证明,施氮量对小麦产量具有显著直接作用。同时,磷肥对提高小麦和玉米的产量具有重要作用。总之,在农民习惯耕作施肥管理水平下,潮土区不施肥处理的产量下降缓慢（含品种对产量的贡献）,常规施肥区产量表现出缓慢增加的趋势。 相似文献
16.
Crop establishment is an important yield factor for pearl millet in the Sahel. Therefore, we conducted a series of experiments to determine the effects of seed size, depth and method of planting, millet variety, pre-sowing tillage, and soil fertilization upon seedling emergence, crop establishment, and yield. All experiments were conducted on a sandy Psammentic Paleustalf in Niger.
For all three millet varieties studied, out of a range of sowing depths from 1 to 7 cm, a sowing depth of 3–5 cm resulted in the highest percentage emergence, the highest above-ground biomass, and most secondary roots. High soil temperatures are common during establishment, typical maximum temperatures at a depth of 1 cm exceed 46°C. The adverse effects of wind erosion were least when sowing in hills; establishment, crop stand survival, and yield were better under hill planting than drilling seed.
Pre-sowing tillage increased initial stands and their survival, the latter also depending on fertility. Thus, improved crop yields result from better stand survival and higher yields per hill. Fertilizer application of 17 kg ha−1 P and 40 kg ha−1 of N tripled grain yields. Ridging without prior tillage and plowing increased grain and stover yields two- to three-fold. In combination with fertilizer application, sixfold yield increases were obtained.
If pre-sowing tillage is considered, then, in view of the time limitations, ridging without prior tillage would be preferable to plowing, as it is a much faster operation giving equally good results in terms of crop establishment and yield. 相似文献
17.
Alternative tillage and crop residue management in wheat after rice in sandy loam soils of Indo-Gangetic plains 总被引：2，自引：0，他引：2
A 3-year field study was conducted to evaluate the effect of three tillage practices (conventional, zero and reduced/strip) with two nitrogen levels (120 and 150 kg N ha−1) applied in primary strips and three crop residue management practices (removal, burning and incorporation) in secondary strips in wheat after rice. Reduced tillage resulted in significantly higher overall mean wheat yield (5.10 Mg ha−1) compared to conventional (4.60 Mg ha−1) and zero tillage (4.75 Mg ha−1). Residue incorporation resulted in highest mean yield (5.86 Mg ha−1) during third year. Maximum mean yield (6.1 Mg ha−1) was obtained in reduced tillage followed by conventional tillage (5.8 Mg ha−1) under residue incorporation in third year. The weed dry weight recorded at 30 days after sowing was highest (0.3 Mg ha−1) under zero tillage and lowest under conventional tillage (0.16 Mg ha−1). Among crop residue management practices, the highest dry weight of weeds (0.22 Mg ha−1) was recorded under residue incorporation. The highest infiltration rate (1.50 cm h−1) was recorded in residue incorporation followed by residue burning (1.44 cm h−1) whereas; the lowest (0.75 cm h−1) in zero tillage. Soil bulk density was the highest (1.69 Mg m−3) under zero tillage and the lowest in residue incorporation (1.59 Mg m−3). There were no changes in soil available P and K after each crop sequence in relation to tillage practices during first 2 years. Higher organic carbon (5.1–5.4 g kg−1) was measured under zero tillage compared to other treatments. Residue incorporation increased soil organic carbon and available P while higher available K was monitored in burning treatment during the third year. These results suggest that reduced tillage and in situ incorporation of crop residues at 5 Mg ha−1 along with 150 kg N ha−1 were optimum to achieve higher yield of wheat after rice in sandy loam soils of Indo-Gangetic plains of India. 相似文献
18.
N mineralization and nitrate leaching from vegetable crop residues under field conditions: a model evaluation 总被引：6，自引：0，他引：6
Six different vegetable crop residues were incorporated in the field and N mineralization from the residues and from an unamended plot was followed over 4 months by periodically monitoring mineral N contents of the soil. The crop residues were also fractionated according to a modified Stevenson chemical fractionation. Nitrogen mineralization parameters of the first order kinetic model N(t)=NA(1−e−kt) were derived from the chemical fractionation data. The first order model was used in combination with a model describing the temperature dependence of N mineralization and a simple leaching model to predict N mineralization rates and nitrate redistribution after crop residue incorporation under field conditions. Comparison of predicted and measured mineral N contents in the upper soil layer (0–30 cm) before the start of leaching showed that the model was able to predict N mineralization from both soil organic matter and crop residues under field conditions. From the onset of leaching, mineral N contents were slightly overestimated in the upper layer and underestimated in the lower soil layers. Although the Burns leaching model underestimated the leaching rate, the general pattern of nitrate movement was simulated satisfactorily. Statistical analysis using the variance ratio test yielded small but significant F values, indicating that the model can still be improved. The modelling efficiency was rather high and the coefficient of residual mass very close to zero. Linear regression between measured and simulated nitrate contents over the whole profile (0–120 cm) for all samplings yielded Y=9.6+0.876X (r=0.94***) with all deviations smaller than 25 kg N ha−1. Total N mineralization ranged from 48 kg N ha−1 for the control plot to 136 kg N ha−1 for the plots with cauliflower residues and cumulative leaching losses from 26–66 kg N ha−1, with most of the mineral N left in the 60–120 cm layer. These results show that N losses by leaching in winter can be high when vegetable crop residues are incorporated, even when there is little mineral N in the soil at the time of incorporation. 相似文献
19.
In a region where water is the primary limiting factor of crop production, loss of water from fields by overland flow represents an economic loss to producers. Traditional crop management practices in north-central Oregon have led to crop water loss by overland flow. In 1931, a long-term experiment was begun near Pendleton, Oregon, in a Walla Walla silt loam (coarse-silty, mixed, mesic Typic Haploxeroll—US; Kastanozems—FAO), to examine the influence on soil fertility and crop production by nutrient amendments and crop residue management practices. This experiment provided the opportunity to evaluate the influence of a several traditional farming practices on field hydrology. Tillage in all treatments consisted of moldboard plowing and multiple passes with secondary tillage equipment to smooth the surface for planting and for weed control. The treatments were combinations of nutrient amendments (0.90 kg N ha−1 commercial fertilizer, and 145 kg N ha−1 from manure) and residue management (fall-burn, spring-burn, and no-burn), whose soil organic carbon increased with increasing nutrient amendments. These treatments were in a winter wheat–fallow system and represent a set of past and current cultural practices. Overland flow from these treatments was measured. Lister furrows separated the plots of 12 m×40 m (≈0.05 ha) to prevent overland flow from treatment to treatment and were instrumented with weirs to capture and measure overland flow. To determine if hydrologic differences existed between treatments, we tested the overland flow to precipitation (Q/P) ratio. The Q/P ratio (P<0.15) was greatest within crop year/low soil fertility (0 kg N ha−1, burn) whereas the high fertility (145 kg N ha−1, no-burn) treatment crop year plots Q/P ratios were similar to fallow, standing stubble plots. Most notably, the manure amendment plots in crop, produce significantly less overland flow than the other residue and nutrient management practices, and marginally less overland flow than treatments in stubble. This research demonstrates that overland flow was greater from low fertility and stubble burned treatments. Increased overland flow increases the risk of soil erosion and loss of water to overland flow is potentially a loss of needed soil water for crop growth and production. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(3-4):574-586
Abstract Nitrogen (N) management may be improved by a thorough understanding of the nutrient dynamics during previous‐crop residue decomposition and its impact on fertilizer N fate in the soil–plant system. An experiment was conducted in the Argentine Pampas to evaluate the effect of maize and soybean as previouscrops and plow‐till and no‐till methods on N dynamics and 15N‐labeled fertilizer uptake during a wheat growing season. Maize and soybean residues released N under both tillage treatments, but N release was faster from soybean residues and when residues were buried by tillage. Net immobilization of N on decomposing residues was not detected. A regression model that accounted for 92% of remaining N variability included time, previous crop, and tillage treatment as independent variables. The rapid residue decomposition with N release was attributed to the high temperatures of the agroecosystem. The recovery of 15N‐labeled fertilizer in the wheat crop, soil organic matter, and decomposing residues was not statistically different between previous crop treatments or tillage systems. Crop uptake of fertilizer N averaged 52% across treatments. Forty percent of fertilizer N was removed in grains. Immobilization of labeled N on soil organic matter was substantial, averaging 34% of the 15N‐labeled fertilizer retained, but was very small on decomposing residues, averaging 0.2–3.0%. Fertilizer N not accounted for at harvest in the soil–plant system was 12% and was ascribed to losses. Previous crop or tillage system had no impact on wheat yield, but when soybean was the previous crop, N content of grain and straw+roots increased. Discussion is presented on the potential availability of N retained in wheat straw, roots, and soil organic matter for future crops. 相似文献