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1.
Ingrid K. Thomsen 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):166-170
Abstract Four rates of straw (0, 4, 8 and 12 t ha?1 yr?1) were incorporated in a field experiment with continuous spring barley. The experiment was conducted on a sandy soil (5.5% clay) and a sandy loam soil (11.2% clay). After eight years, the straw incorporation was combined with catch-crop growing with and without winter application of animal slurry and also spring fertilization with mineral fertilizer (0, 50, 100 or 125 kg N ha?1 yr?1). The combined experiment was conducted for three lyears on the sandy soil and for four years on the sandy loam soil. The effects on barley dry matter yield and N uptake are presented together with the long-term effects of the straw incorporations on crop growth and soil C and N. Grain yield on the sandy loam was unaffected by straw incorporation. On the sandy soil the highest straw application rates reduced grain yield in the unfertilized barley. When the barley received mineral fertilizer at recommended levels (100 kg N ha?1 yr?1), grain yield on this soil was also unaffected by the high straw rates. Including a catch crop had a positive effect on the grain yield of barley on both soils. The total N uptake in grain and straw generally increased with straw application up to 8 t ha?1 yr?1. With the highest straw application rate (12 t ha?1 yr?1), the total N uptake decreased but still exceeded N uptake in barley grown with straw removal. The barley accumulated higher amounts of N when a catch crop was included. The total N uptake in the barley was significantly higher after animal slurry application. The extra N uptake, however, was much lower than the amounts of N applied with the slurry. Incorporation of straw had only a small influence on N uptake after slurry application. The straw, therefore, was not able to store the applied N during winter. In the two four-year periods before the combined experiment, grain yield on the sandy loam was generally negatively affected by straw incorporations. In the second period, N uptake began to show a positive effect of the straw. On the sandy soil, grain yield and N uptake during the whole period were generally positively affected by the straw incorporations except for the highest straw rate (12 t ha?1 yr?1). The sandy loam soil showed higher increases in C and N content after the repeated straw incorporations and catch-crop growing than the sandy soil. When application of animal slurry was combined with the catch crop, no further increases in soil C and N were found relative to soil where a catch crop was grown without slurry application. Large amounts of the N applied with the slurry may therefore have been lost by denitrification or nitrate leaching. 相似文献
2.
The effects of an intercrop catch crop (Italian ryegrass) on (i) the amounts and concentrations of nitrate leached during the autumn and winter intercrop period, and (ii) the following crop, were examined in a lysimeter experiment and compared with that from a bare fallow treatment. The catch crop was grown in a winter wheat/maize rotation, after harvest of the wheat, and incorporated into the soil before sowing the maize. A calcium and potassium nitrate fertilizer labelled with 15N (200 kg N ha?1; 9.35 atom per cent excess) was applied to the winter wheat in spring. Total N uptake by the winter wheat was 154 kg ha?1 and the recovery of fertilizer-derived N (labelled with 15N) was 60%. The catch crop (grown without further addition of N) yielded 3.8t ha?1 herbage dry matter, containing 43 kg N ha?1, of which 4.1 % was derived from the 15N-labelled fertilizer. Two-hundred kg unlabelled N ha?1 was applied to the maize crop. During the intercrop period the nitrate concentration in water draining from the bare fallow lysimeters reached 68 mg N1?1, with an average of 40 mg N1?1. With the catch crop, it declined rapidly, from 41 mg N I?1 to 0.25 mg N I?1, at the end of ryegrass growth. Over this period, 110 kg N ha?1 was leached under bare fallow, compared with 40 kg N ha?1 under the catch crop. 15N-labelled nitrate was detected in the first drainage water collected in autumn, 5 months after the spring application. The quantity of fertilizer-N that was leached during this winter period was greater under bare fallow (18.7% of applied N) than when a catch crop was grown (7.1 %). In both treatments, labelled fertilizer-N contributed about 34% of the total N lost during this period. With the ryegrass catch crop incorporated at the time of seedbed preparation in spring, the subsequent maize grain-yield was lowered by an average of 13%. Total N-uptake by the maize sown following bare fallow was 224 kg N ha?1, compared with 180 kg ha?1 with prior incorporation of ryegrass; the corresponding values for uptake of residual labelled N were 3% (bare fallow) and 2% (ryegrass) of the initial application. Following the maize harvest, where ryegrass was incorporated, 22.7% of the previous year's labelled fertilizer addition was present in an organic form on the top 30 cm of lysimeter soil. This compares with 15.7% for the bare fallow intercropping treatment. Tracer analyses showed overall recoveries of labelled N of 91.7% for the winter wheat/ ryegrass/maize rotation and 97% for the winter wheat/bare fallow/maize rotation. The study clearly demonstrated the ecological importance of a catch crop in reducing N-leaching as well as its efficient use of fertilizer in the plant-soil system from this particular rotation. However, the fate of the organic N in the ploughed-down catch crop is uncertain and problems were encountered in establishing the next crop of maize. 相似文献
3.
Cultivation of grassland presents a high risk of nitrate leaching. This study aimed to determine if leaching could be reduced by growing spring barley (Hordeum vulgare L.) as a green crop for silage with undersown Italian ryegrass (Lolium multiflorum Lam.) compared with barley grown to maturity with or without an undersown conventional catch crop of perennial ryegrass (Lolium perenne L.). All treatments received 0, 60 or 120 kg of ammonium‐N ha?1 in cattle slurry. In spring 2003, two grass‐clover fields (3 and 5 years old, respectively, with different management histories) were ploughed. The effects of the treatments on yield and nitrate leaching were determined in the first year, while the residual effects of the treatments were determined in the second year in a crop of spring barley/perennial ryegrass. Nitrate leaching was estimated in selected treatments using soil water samples from ceramic cups. The experiment showed that compared with treatments without catch crop, green barley/Italian ryegrass reduced leaching by 163–320 kg N ha?1, corresponding to 95–99%, and the perennial ryegrass reduced leaching to between 34 and 86 kg N ha?1, corresponding to a reduction of 80 and 66%. Also, in the second growing season, leaching following catch crops was reduced compared with the bare soil treatment. It was concluded that the green barley/Italian ryegrass offers advantages not only for the environment but also for farmers, for whom it provides a fodder high in roughage and avoids the difficulties with clover fatigue increasingly experienced by Danish farmers. 相似文献
4.
Nitrogen conserving potential of successive ryegrass catch crops in continuous spring barley 总被引：3，自引：0，他引：3
Abstract. The nitrogen (N) conserving effects of Italian ryegrass ( Lolium multiflorum L.) undersown as a nitrate catch crop in spring barley ( Hordeum vulgare L.) were evaluated over a ten-year period in outdoor lysimeters (1.5 m deep, diam. 1 m) with sandy loam soil. Spring barley grown every year received 11.0 or 16.5 g N m−2 before planting or was kept unfertilized. The N was given either as calcium ammonium nitrate or as ammoniacal N in pig slurry. From 1985 to 1989, ryegrass was undersown in the barley in half of the lysimeters while barley was grown alone in the remaining lysimeters. The grass sward was left uncut after barley harvest and incorporated in late winter/early spring. From 1990 to 1994 all lysimeters were in barley only.
Barley dry matter yields and crop N offtakes were not affected by the presence of undersown ryegrass, although grain yields appeared to be slightly reduced. After termination of ryegrass growing, N offtake in barley (grain+straw) was higher in lysimeters in which catch crops had been grown previously.
The loss of nitrate by leaching increased with N addition rate. Regardless of N dressing, ryegrass catch crops halved the total nitrate loss during 1985–1989, corresponding to a mean annual reduction in nitrate leaching of 2.0–3.5 g N m−2 . From 1990 to 1994, lysimeters previously undersown with ryegrass lost more nitrate than lysimeters with no history of ryegrass. The extra loss of nitrate accounted for 30% of the N retained by ryegrass catch crops during 1985–1989.
It is concluded that a substantial proportion of the N saved from leaching by ryegrass catch crops is readily mineralized and available for crop offtake as well as leaching as nitrate. To maximize benefits from ryegrass catch crops, the cropping system must be adjusted to exploit the extra N mineralization derived from the turnover of N incorporated in ryegrass biomass. 相似文献
Barley dry matter yields and crop N offtakes were not affected by the presence of undersown ryegrass, although grain yields appeared to be slightly reduced. After termination of ryegrass growing, N offtake in barley (grain+straw) was higher in lysimeters in which catch crops had been grown previously.
The loss of nitrate by leaching increased with N addition rate. Regardless of N dressing, ryegrass catch crops halved the total nitrate loss during 1985–1989, corresponding to a mean annual reduction in nitrate leaching of 2.0–3.5 g N m
It is concluded that a substantial proportion of the N saved from leaching by ryegrass catch crops is readily mineralized and available for crop offtake as well as leaching as nitrate. To maximize benefits from ryegrass catch crops, the cropping system must be adjusted to exploit the extra N mineralization derived from the turnover of N incorporated in ryegrass biomass. 相似文献
5.
《Communications in Soil Science and Plant Analysis》2012,43(12):1525-1539
Swine lagoon sludge is commonly applied to soil as a source of nitrogen (N) for crop production but the fate of applied N not recovered from the soil by the receiver crop has received little attention. The objectives of this study were to (1) assess the yield and N accumulation responses of corn (Zea mays L.) and wheat (Triticum aestivum) to different levels of N applied as swine lagoon sludge, (2) quantify recovery of residual N accumulation by the second and third crops after sludge application, and (3) evaluate the effect of different sludge N rates on nitrate (NO3-N) concentrations in the soil. Sludge N trials were conducted with wheat on two swine farms and with corn on one swine farm in the coastal plain of North Carolina. Agronomic optimum N rates for wheat grown at two locations was 360 kg total sludge N ha?1 and the optimum N rate for corn at one location was 327 kg total sludge N ha?1. Residual N recovered by subsequent wheat and corn crops following the corn crop that received lagoon sludge was 3 and 12 kg N ha?1, respectively, on a whole-plant basis and 2 and 10 kg N ha?1, respectively, on a grain basis at the agronomic optimum N rate for corn (327 kg sludge N ha?1). From the 327 kg ha?1 of sludge N applied to corn, 249 kg N ha?1 were not recovered after harvest of three crops for grain. Accumulation in recalcitrant soil organic N pools, ammonia (NH3) volatilization during sludge application, return of N in stover/straw to the soil, and leaching of NO3 from the root zone probably account for much of the nonutilized N. At the agronomic sludge N rate for corn (327 kg N ha?1), downward movement of NO3-N through the soil was similar to that for the 168 kg N ha?1 urea ammonium nitrate (UAN) treatment. Thus, potential N pollution of groundwater by land application of lagoon sludge would not exceed that caused by UAN application. 相似文献
6.
J. Evans N. A. Fettell G. E. O'Connor D. J. Carpenter P. M. Chalk 《Biology and Fertility of Soils》1997,24(1):87-95
The effects of soil incorporation with cereal straw (nil, 2.5, 5 and 10 t straw ha?1) and direct drilling on the proportion and amount of pea N derived from biological N fixation were investigated in three field experiments. Fixed N was determined by15N dilution using barley as a reference plant. The three sites were on acidic, red clay-loams in the cropping zone of southeastern Australia. Seasonal plant available soil N, as determined by the N accumulated in barley, was 31, 56 and 158 kg N ha?1, for the three sites. Incorporated straw reduced soil nitrate at sowing by 10–50 kg N ha?1 (0–30 cm), and 5 or 10 t straw ha?1 reduced barley uptake of N by 10–38 kg N ha?1. However, reducing plant available soil N was generally ineffective for increasing the N fixed by pea. Fixed N increased only at the site with the least plant-available N, and only one-third of the increase could be attributed to lower soil N uptake by pea. There was no evidence that direct drilling pea increased fixed N by decreasing crop uptake of soil N. It is proposed that a lower requirement for soil N by pea as compared to barley, and availability of mineral N beneath the soil layer treated with straw, minimise the effectiveness of straw incorporation for increasing the N fixed by pea. 相似文献
7.
A long-term field experiment (1984–2011), was conducted on a Calcic Haploxeralf from semi-arid central Spain to evaluate the combined effect of three treatments: farmyard manure (FYM), straw and control without organic amendments (WOA) and five increasing rates of mineral N on: (1) some energetic parameters of crop production, and (2) the effect of the different treatments on soil organic carbon (SOC) and total N stocks. Crop rotation included spring barley, wheat and sorghum. The energy balance variables considered were net energy produced (energy output minus energy input), the energy output/input ratio and energy productivity (crop yield per unit energy input). Results showed small differences between treatments. Total energy inputs varied from 9.86 GJ ha?1 year?1 (WOA) to 11.14 GJ ha?1 year?1 in the FYM system. For the three crops, total energy inputs increased with increasing rates of mineral N. Energy output was slightly lower in the WOA (33.40 GJ ha?1 year?1) than in the two organic systems (37.34 and 34.96 GJ ha?1 year?1 for FYM and straw respectively). Net energy followed a similar trend. At the end of the 27-year period, the stocks of SOC and total N had increased noticeably in the soil profile (0–30 cm) as a result of application of the two organic amendments. Most important SOC changes occurred in the FYM plots, with mean increases in the 0–10 cm depth, amounting an average of 9.9 Mg C ha?1 (667 kg C ha?1 year?1). Increases in N stocks in the top layer were similar under FYM and straw and ranged from 0.94 to 1.55 Mg N ha?1. By contrast, simultaneous addition of increasing rates of mineral N showed no significant effect on SOC and total N storage. 相似文献
8.
Liina Talgre Enn Lauringson Hugo Roostalu Alar Astover Viacheslav Eremeev Are Selge 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(1):70-76
Abstract A field experiment was conducted in 2004–2006 to investigate the effect of green manure treatments on the yield of oats and spring barley. In the experiment, different green manure crops with undersowing and pure sowing were compared for amounts of N, C, and organic matter driven into soil and their effect on cereal yield. The spring barley field had a total of 41.7–62.4 kg N ha?1 and 1.75–2.81 Mg C ha?1 added to the soil with straw, weed, and roots, depending on the level of fertilisation; with red clover, and both common and hybrid lucerne undersowing, with barley straw and roots, the values were 3.45–3.96 Mg C ha?1 and 139.9–184.9 kg N ha?1. Pure sowings of these three leguminous green manure crops had total applications of 3.37–4.14 Mg C ha?1 and 219.7–236.8 kg N ha?1. The mixed and pure sowing of bird's-foot trefoil provided considerably less nitrogen and carbon to the soil with the biomass than with the other leguminous crops. Application of biomass with a high C/N ratio reduced the yield of the succeeding spring cereals. Of the green manures, the most effective were red clover and both common and hybrid lucerne, either as undersowing or as pure sowing. Undersowings with barley significantly increased the N supply for the succeeding crop without yield loss of the main crop compared with the unfertilised variant. Compared with ploughing-in of green manure in autumn, spring ploughing gave a 0.2–0.57 Mg ha?1 larger grain yield. 相似文献
9.
《Communications in Soil Science and Plant Analysis》2012,43(7):912-924
A field experiment was conducted for 3 years during 2006–2009 in India to study the effects of plant nutrient recycling through crop residue management, green manuring, and fertility levels on yield attributes, crop productivity, nutrient uptake, and biofertility indicators of soil health in a rice–wheat cropping system. The study revealed that soil microbial biomass carbon (SMBC) and carbon dioxide (CO2) evolution were significantly greatest under crop residue incorporation (CRI) + Sesbania green manuring (SGM) treatment and were found at levels of 364 μg g?1 soil and 1.75 μg g?1 soil h?1, respectively; these were increased significantly by recycling of organic residues. Activities of dehydrogenase and phosphatase enzymes increased significantly after 3 years, with maximum activity under CRI + SGM treatment. The CRI with or without SGM significantly influenced the plant height, number of tillers m?2, number of grains panicle?1 or ear?1, and 1000-grain weight. Mean yield data of rice and wheat revealed that CRI or crop residue burning (CRB) resulted in slightly greater yield over crop residue removal (CRR) treatment. The CRI + SGM treatment again observed significantly greatest grain yields of 7.54 and 5.84 t ha?1 and straw yields of 8.42 and 6.36 t ha?1 in rice and wheat, respectively, over other crop residue management treatments. Total nitrogen (N), phosphorus (P) and potassium (K) uptake in rice–wheat system was greatest with amounts of 206.7, 37.2, and 205.6 kg ha?1, respectively, in CRI + SGM treatment. Fertility levels significantly influenced the rice and wheat yield with greatest grain yields of 6.66 and 5.68 t ha?1 and straw yields of 7.94 and 5.89 t ha?1 in rice and wheat, respectively, with the application of 150% of recommended NPK. Total NPK uptake in rice–wheat system also increased significantly with increase in fertility levels with greatest magnitude by supplying 150% of recommended NPK. Overall, nutrient recycling through incorporation of crop residues and Sesbania green manuring along with inorganics greatly improved the crop productivity, nutrient uptake, and biofertility indicators of soil health with substantial influence on SMBC, CO2 evolution, and dehydrogenase and phosphatase enzyme activities. This indicates that crop residue management along with Sesbania green manuring practice could be a better option for nutrient recycling to sustain the crop productivity and soil health in intensive rice–wheat cropping system in India as well as in similar global agroecological situations, especially in China, Pakistan, and Bangladesh. 相似文献
10.
A laboratory study was conducted at the Indian Agricultural Research Institute, New Delhi on a sandy clay loam soil of pH 7.9 and organic C content of 0.34% to study the effect of incorporating Sesbania or Vigna legume residues or wheat straw at 15 and 30t ha?1 on temporal variation in ammoniacal and nitrate‐N in soil under submergence and well drained conditions. Under submergence most mineral N was present as ammoniacal‐N, while under well drained conditions it was present as Nitrate‐N. The content of ammoniacal N in soil was the highest after 30 days of incubation and declined thereafter under submergence. On the other hand under well drained conditions the mineral‐N (mostly nitrate) content in soil at 30 DAI was very little and showed increases only later, reaching the highest level at 90 DAI. Application of wheat straw specially at 301 ha?1 level resulted in immobilization of native soil‐N. These results show that rice which is grown under submergence can be transplanted soon after incorporation of legume residues, but for wheat or other crops which are grown under well drained condition a time interval of 30 days or more needs to be provided before sowing the crop. 相似文献
11.
Ground 15N-labelled legume material (Medicago littoralis) was mixed with topsoils in confined microplots in the field, and allowed to decompose for 7 and 5 months in successive years (1979, 1980) before sowing wheat. The soil cropped in 1979 (and containing 15N-labelled wheat roots and legume residues) was cropped again in 1980.The results support evidence that ungrazed legume residues, incorporated in amounts commonly found in southern Australian wheat growing regions, contribute only a little to soil available N and to crop N uptake, even in the first year of their decomposition. Thus mature first crops of wheat, although varying greatly in dry matter yield (2.9-fold) and total N uptake (2.4-fold), took up only 27.8 and 20.2% of the legume N applied at 48.4 kg ha?1, these corresponding to 6.1 and 10.8% of the N of the wheat crops. The availability of N from medic residues to a second wheat crop declines to <5% of input. For both first and second wheat crops, uptake of N from legume residues was approximately proportional to legume N input over the range 24.2 to 96.8 kg ha ?1.The proportional contributions of medic N to soil inorganic N, N released in mineralization tests, and to wheat crop N, differed between seasons and soils, but for a given crop did not significantly differ between tillering, flowering and maturity. In both years, grain accounted for 52–65% of the total 15N of first crops, roots for < 5–6%. In neither year did the amounts of N or 15N in the tops change significantly between flowering and maturity, despite a gain in tops dry matter in 1979; by contrast N and 15N of roots decreased significantly during ripening in both years. Wheat plants at tillering contained about 75% of the N and 15N taken up at flowering. The amounts of legume-derived 15N in mature first wheat crops were equivalent to 82–88% of the amounts of inorganic 15N in the soil profiles at sowing. Wheat straw added at the rate of 2.5 t ha?1, 2 months before sowing, decreased the uptake of N (15%) and 15N (18%) by wheat in a nitrogen responsive season. 相似文献
12.
Prakash Chandra Srivastava Uzma Ilias Ansari Satya Pratap Pachauri Arvind Kumar Tyagi 《Journal of plant nutrition》2016,39(3):348-364
Apparent utilization of zinc (Zn) and potassium (K) fertilizers was examined in rice (Oryza sativa L.)-wheat (Triticum aestivum L.) using combinations of no K; soil applied K levels and no Zn; soil and foliar applied Zn. Application of 33.2 kg K ha?1 in rice and 24.9 kg K ha?1 in wheat along with foliar spray of 2 kg Zn ha?1 at 30 and 60 days gave the highest mean grain yields. Foliar application of zinc increased Zn concentration in flag leaves, grain, and straw of rice and wheat and K concentration in flag leaves of rice and straw of wheat significantly. Potassium application increased Zn concentration in rice grain and straw and K concentration in wheat straw significantly. Zinc and K increased the uptake of each other in grain; straw and total uptake by both crops significantly. Zinc fertilizer enhanced the utilization of soil K. Potassium fertilizer enhanced the utilization of applied Zn. 相似文献
13.
Unground 15N-labelled medic material (Medicago littoralis) was mixed with topsoils at 3 field sites in South Australia, allowed to decompose for about 8 months before sowing wheat, and then for a further 7 months until crop maturity. The site locations were chosen to permit comparisons of recoveries and distribution of 15N in soils (organic N and inorganic N to 90 cm depth) and wheat (grain, straw and roots to 20 cm depth) in areas where rainfall (and wheat yields) differed greatly. Soils differed also in their texture and organic matter contents. Recoveries of applied 15N in wheat plus soil were 93.1% from a sandy loam (Caliph) and 92.3% from a sandy soil (Roseworthy) despite differences in rainfall and extent of leaching of the 15NO3? formed from the decomposing medic residues. From a heavy clay soil (Northfield), which received the highest rainfall, the 15N recovery was 87.7%. The loss of 15N at this site was not due to leaching, as judged by 15NO3? distribution in the soil profile at seeding and crop maturity.Wheat plants took up only 10.9–17.3% of the 15N added as legume material. Percentage uptakes of 15N were not related to grain yields. The proportions of wheat N derived from decomposing medic residues were 9.2% at Caliph (input medic, N, 38 kg N ha?1), 10.5% at Roseworthy (input medic N, 57 kg N ha?1), and only 4.6% at Northfield (input medic N, 57 kg N ha?1). Most (51–70%) of the 15N recovered in wheat was accounted for in the grain. Inorganic 15N in the soil profiles was depleted during the cropping phase, and at wheat harvest represented from 0.6 to 3.1% only of 15N inputs. The major 15N pool was soil organic 15N accounting for 71.9–77.7% of 15N inputs.We conclude that, in the context of N supply from decomposing medic tissues to wheat crops, the main value of the legume is long-term, i.e. in maintaining soil organic N concentrations to ensure adequate delivery of N to future cereal crops.The N of the wheat was not uniformly labelled, root N being generally of the highest atom% enrichmensts, and straw N of the lowest. Nevertheless, at the Roseworthy site, the enrichments of wheat N were similar to those of NO3? N in the profile at seeding, indicating that the proportions of 14N and 15N in the inorganic N pool did not change appreciably during the cropping period. By assuming equilibrium at this site, we calculate that during 15 months decomposition the soil plus legume delivered about 189 kg N ha?1, of which 93.2 kg ha?1 (49.3%) was taken up by the wheat, 37.2 kg ha?1 (19.7%) was immobilized or remained as fine root residues, and 17.3 kg ha?1 (9.2%) remained as inorganic N in the soil profile; 41.7 kg ha?1 (22.1%) was unaccounted for in the soil-plant system, and was probably lost via inorganic N. Thus about 6.5 kg inorganic N ha?1 was supplied by the soil plus medic residues per 100 kg dry matter ha?1 removed as wheat grain. 相似文献
14.
A long-term field experiment was conducted for 8 years on a Vertisol in central India to assess quantitatively the direct and residual N effects of soybean inoculation with Bradyrhizobium and wheat inoculation with Azotobacter in a soybean–wheat rotation. After cultivation of soybean each year, its aerial residues were removed before growing wheat in the same plots using four N levels (120, 90, 60 and 30 kg ha?1) and Azotobacter inoculation. Inoculation of soybean increased grain yield by 10.1% (180 kg ha?1), but the increase in wheat yields with inoculation was only marginal (5.6%; 278 kg ha?1). There was always a positive balance of soil N after soybean harvest; an average of +28 kg N ha?1 yr?1 in control (nodulated by native rhizobia) plots compared with +41 kg N ha?1 yr?1 in Rhizobium-inoculated plots. Residual and direct effects of Rhizobium and Azotobacter inoculants caused a fertilizer N credit of 30 kg ha?1 in wheat. Application of fertilizers or microbial inoculation favoured the proliferation of rhizobia in crop rhizosphere due to better plant growth. Additional N uptake by inoculation was 14.9 kg N ha?1 by soybean and 20.9 kg N ha?1 by wheat crop, and a gain of +38.0 kg N ha?1 yr?1 to the 0–15 cm soil layer was measured after harvest of wheat. So, total N contribution to crops and soil due to the inoculants was 73.8 kg N ha?1 yr?1 after one soybean–wheat rotation. There was a total N benefit of 13.8 kg N ha?1 yr?1 to the soil due to regular long-term use of microbial inoculants in soybean–wheat rotation. 相似文献
15.
Ya-Lin Hu Feng-Ping Wu De-Hui Zeng Scott X. Chang 《Biology and Fertility of Soils》2014,50(8):1291-1299
Application of crop residues and its biochar produced through slow pyrolysis can potentially increase carbon (C) sequestration in agricultural production systems. The impact of crop residue and its biochar addition on greenhouse gas emission rates and the associated changes of soil gross N transformation rates in agricultural soils are poorly understood. We evaluated the effect of wheat straw and its biochar applied to a Black Chernozemic soil planted to barley, two growing seasons or 15 months (at the full-bloom stage of barley in the second growing season) after their field application, on CO2 and N2O emission rates, soil inorganic N and soil gross N transformation rates in a laboratory incubation experiment. Gross N transformation rates were studied using the 15N isotope pool dilution method. The field experiment included four treatments: control, addition of wheat straw (30 t ha?1), addition of biochar pyrolyzed from wheat straw (20 t ha?1), and addition of wheat straw plus its biochar (30 t ha?1 wheat straw + 20 t ha?1 biochar). Fifteen months after their application, wheat straw and its biochar addition increased soil total organic C concentrations (p?=?0.039 and <0.001, respectively) but did not affect soil dissolved organic C, total N and NH4 +-N concentrations, and soil pH. Biochar addition increased soil NO3 ?-N concentrations (p?=?0.004). Soil CO2 and N2O emission rates were increased by 40 (p?p?=?0.03), respectively, after wheat straw addition, but were not affected by biochar application. Straw and its biochar addition did not affect gross and net N mineralization rates or net nitrification rates. However, biochar addition doubled gross nitrification rates relative to the control (p?2 and N2O emissions and enhance soil C sequestration. However, the implications of the increased soil gross nitrification rate and NO3 ?-N in the biochar addition treatment for long-term NO3 ?-N dynamics and N2O emissions need to be further studied. 相似文献
16.
Organic agricultural systems rely on organic amendments to achieve crop fertility requirements, and weed control must be achieved without synthetic herbicides. Our objective was to determine the crop yield and soil quality as affected by a transition from grass to dryland organic agriculture in the Central Great Plains of North America. This study evaluated three beef feedlot compost(BFC)treatments in 2010–2015 following biennial application rates: 0(control), 22.9, and 108.7 t ha~(-1) on two dryland organic cropping systems: a wheat(Triticum aestivum)-fallow(WF) rotation harvested for grain and a triticale(Triticosecale)/pea(Pisum sativum)-fallow(T/P-F) rotation harvested for forage. The triticale + pea biomass responded positively to the 108.7-t ha~(-1) BFC treatment,but not the 22.9-t ha~(-1) BFC treatment. The wheat biomass was not affected by BFC addition, but biomass N content increased.Beef feedlot compost input did not increase wheat grain yields, but had a positive effect on wheat grain Zn content. Soil total C and N contents increased with the rate of 108.7 t ha~(-1) BFC after three applications, but not with 22.9 t ha~(-1) BFC. Soil enzyme activities associated with N and C cycling responded positively to the 108.7-t ha~(-1) BFC treatment. Saturated salts were high in the soil receiving 108.7 t ha~(-1) of BFC, but did not affect crop yields. These results showed that BFC was effective in enhancing forage yields, wheat grain quality, and soil C and N, as well as specific microbial enzymes important for nutrient cycling. However, the large rates of BFC necessary to elicit these positive responses did not increase grain yields, and resulted in an excessive buildup of soil P. 相似文献
17.
《Communications in Soil Science and Plant Analysis》2012,43(22):3483-3505
A field experiment was conducted to evaluate the effects of directly, residually, and cumulatively applied mixed sludge generated by the soft-drink industry on rice and wheat yields, soil fertility, grain heavy-metal uptake, depthwise distribution of micronutrients and heavy-metals after 3 years of application. Crop (rice/wheat) yield (grain/straw) increased significantly with direct sludge application at 10.0 t ha?1 year?1, either alone or jointly with fertilizers, over the absolute control. Interestingly, the effects of sludge application on crop (rice/wheat) yield either applied directly at 10.0 t ha?1 year?1, residually at 30.0 t ha?1 year?1, and/or cumulatively at 15.0 t ha?1 were nonsignificant. Direct sludge application at 5.0/10.0 t ha?1 year?1 resulted in significant increase in heavy-metal uptake over the absolute control. The micronutrient/heavy-metal contents in surface soil were significantly greater with sludge application than those in subsurface layers. The results thus show that sludge application results in significant improvement in yield and soil fertility. 相似文献
18.
This model analysis of catch crop effects on nitrate retention covered three soil texture classes (sand, loamy sand, sandy loam) and three precipitation regimes in a temperate climate representative of northern Europe (annual precipitation 709–1026 mm) for a period of 43 years. Simulations were made with two catch crops (ryegrass and Brassica) with different rooting depths, and soil N effects in the next spring were analysed to 0.25, 0.75 and 2.0 m depth to represent the catch crop effect on following crops with different rooting depths. Nitrate retained without a catch crop was generally located in deeper soil layers. In the low precipitation regime the overall fraction of nitrate retained in the 0–2.0 m soil profile was 0.23 for the sandy soil, 0.69 for the loamy sand and 0.81 for the sandy loam. Ryegrass reduced leaching losses much less efficiently than Brassica, which depleted nitrate in the 0–0.75 m soil layer more completely, but also in the deeper soil layer, which the ryegrass could not reach. A positive N effect (Neff, spring mineral N availability after catch crop compared with bare soil) was found in the 0–0.25 m layer (that is shallow rooting depth of a subsequent main crop) in all three soil texture classes, with on average 10 kg N/ha for ryegrass and 34 kg N/ha for Brassica. Considering the whole soil profile (0–2.0 m deep rooting of next crop), a positive Neff was found in the sand whereas generally a negative Neff was found in the loamy sand and especially the sandy loam. The simulations showed that for shallow‐rooted crops, catch crop Neff values were always positive, whereas Neff for deeper‐rooted crops depended strongly on soil type and annual variations in precipitations. These results are crucial both for farmers crop rotation planning and for design of appropriate catch crop strategies with the aim of protecting the aquatic environment. 相似文献
19.
S. D. Heming 《Soil Use and Management》2007,23(2):162-170
The behaviour of P in a range of English arable soils was examined by plotting the change in resin P in the topsoil (ΔPres) at the end of a 3‐ to 5‐year period, against the P balance over the same period (fertilizer P applied minus offtake in crops, estimated from farmers’ reported yields and straw removal). Based on the assumption that values for offtake per tonne of crop yield used for UK arable crops are valid averages, 20–60% of ΔPres was explained by the balance. Applying excess P fertilizer increased Pres, and reducing P fertilizer use decreased it; typically 3–4 kg P ha?1 was required for each mg L?1ΔPres (6–8 kg ha?1 for each mg L?1 of Olsen P). About half the P balance seems to be resin extractable and this differed little between soil groups, except in cases of very low P (index 0) in which the P buffering was stronger, and on very high P soils (index 4/5) when buffering was less. However, on calcareous soils and red soils, when fertilizer was applied in accord with offtake, Pres fell by up to 4 mg L?1 year?1 (2 mg L?1 yr?1 olsen P) and to prevent this an extra 3–10 kg P ha?1 year?1 fertilizer was required. But on most non‐calcareous soils, replacing offtake maintained Pres, with perhaps slight rises on soils of low clay content or greater organic matter content. In soils under arable rotations, the apparent recovery of P from fertilizer was often around 100%, falling to 85% on Chalk soils and 75% on medium–heavy soils on limestone or Lower Chalk. The fate of the ‘missing’ P needs clarification. The case for corrections to current P fertilizer recommendations in the UK on certain soil types is discussed. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(20):2548-2560
Field experiments (established in autumn 1979, with monoculture barley from 1980 to 1990 and barley/wheat–canola–triticale–pea rotation from 1991 to 2008) were conducted on two contrasting soil types (Gray Luvisol [Typic Haplocryalf] loam soil at Breton; Black Chernozem [Albic Agricryoll] silty clay loam soil at Ellerslie) in north-central Alberta, Canada, to determine the influence of tillage (zero tillage and conventional tillage), straw management (straw removed [SRem] and straw retained [SRet]), and N fertilizer rate (0, 50 and 100 kg N ha?1in SRet, and only 0 kg N ha?1in SRem plots) on seed yield, straw yield, total N uptake in seed + straw (1991–2008), and N balance sheet (1980–2008). The N fertilizer urea was midrow-banded under both tillage systems in the 1991 to 2008 period. There was a considerable increase in seed yield, straw yield, and total N uptake in seed + straw with increasing N rate up to 100 kg N ha?1 under both tillage systems. On the average, conventional tillage produced greater seed yield (by 279 kg ha?1), straw yield (by 252 kg ha?1), and total N uptake in seed + straw (by 6.0 kg N ha?1) than zero tillage, but the differences were greater at Breton than Ellerslie. Compared to straw removal treatment, seed yield, straw yield, and total N uptake in seed + straw tended to be greater with straw retained at the zero-N rate used in the study. The amounts of applied N unaccounted for over the 1980 to 2008 period ranged from 1114 to 1846 kg N ha?1 at Breton and 845 to 1665 kg N ha?1 at Ellerslie, suggesting a great potential for N loss from the soil-plant system through denitrification, and N immobilization from the soil mineral N pool. In conclusion, crop yield and N uptake were lower under zero tillage than conventional, and long-term retention of straw suggests some gradual improvement in soil productivity. 相似文献