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1.
Abstract

Cultivars of triticale, wheat, and rye were grown with different N‐fertilizer rates and sampled at various maturity stages in 1975 to 1977. ‘6TA 131’ triticale, ‘Arthur’ wheat, and ‘Abruzzi’ rye were used as checks. Increasing N fertilizer rates increased dry matter and N accumulation in the above‐ground plant parts. However, after flowering losses of dry matter and N from the plants increased with N fertilizer rates. Triticale and rye generally absorbed more N from the soil than wheat. Triticale and wheat straw had higher P concentrations than rye. The head/straw concentration ratios were: triticale and rye>wheat for P, wheat>triticale and rye for K while Ca and Mg ratios were triticale>wheat>rye.  相似文献   

2.
Pot experiments were conducted to evaluate the effects of basic slag (6 to 18 t/ha), lime (CaCO3: 3 to 9 t/ha), lime (3 t/ha) plus MnO2 (100 mg/kg), and leaching (1.8 L/kg soils) on the growth, yield, and nutrition of rice plants grown on two saline-acid sulfate soils. The Sulfic Fluvaquent (Chakaria series) and Typic Sulfaquent (Badarkhali series) respectively showed low pH (4, 4.3); high electrical conductivity (16.2, 14.2 mS/cm), sodium adsorption ratio (13.6, 12.8), and water soluble SO42? (4.6, 4.9 cmol/kg). The growth and yield response of rice to the treatments were found better in Chakaria than in Badarkhali soil. The leaching treatment was found to be the best to produce the maximum straw, and grain yield (869% increase over the control) and the highest dose of basic slag (18 t/ha) was ranked second (728%) in Badarkhali soil. But in Chakaria soil, the best response (928%) was determined with the highest dose of lime (6 t/ha) followed by the leaching (900%) treatment. The additional application of Mn02 (100 mg/kg) with lime (3 t/ha) significantly increased the straw and grain yields of rice by 42–47% compared with the lime 3 t/ha in both the soils. Similar effects were observed for N, P, and K concentrations in plant straw at maturity. Leaching, basic slag, and lime treatments exerted significant decrease of the Fe, Mn, Zn, and S concentrations in plants, increase of soil solution pH and optimization of some element concentrations in the plants and soil solutions.  相似文献   

3.
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   

4.
Abstract

An experiment was conducted in 2004–2007 at the University of Podlasie Zawady Experimental Station (52°06′N, 22°50′E), Siedlce, Poland, to examine the effect of either post-harvest residues or residues and straw of spring triticale (Triticale), field pea (Pisum sativum L.) and their mixtures containing the following proportions of both components: 75+25, 50+50, 25+75% on the subsequent crop of winter wheat (Triticum aestivum L.). A field experiment was designed as split-blocks with three replicates. Residue mass, straw mass as well as N, P, K, Ca and Mg amounts were determined in the residues and straw. The residue amount of spring triticale was the greatest. N, Ca and Mg amounts in the residues of spring triticale/field pea mixtures were similar or higher whereas P and K amounts were similar or lower compared with spring triticale residues. Spring triticale straw contained less N, P, Ca and Mg than the straw of either field pea or spring triticale/field pea mixtures. Grain yield, yield components, N content and N uptake in the grain of winter wheat following field pea and spring triticale/field pea mixtures were significantly higher compared with winter wheat following spring triticale. Increasing proportions of field pea in mixtures with spring triticale cultivated as previous crops significantly increased winter wheat grain yields as well as N content and uptake. The residues of the previous crops combined with the straw significantly increased winter wheat grain yield, number of ears per m2, number of grains in an ear, thousand-grain weight and N content and uptake. The highest winter wheat grain yield and N uptake were determined following an application of residues and straw of field pea and 25+75% spring triticale/field pea mixture. The grain of winter wheat after field pea had the greatest N content.  相似文献   

5.
Abstract

Triticales (X Triticosecale, Wittmack), 6TA 131, 6TA 298 and 6TA 298 and 6TA 385, Arthur wheat (Triticum aestivum L.), and Abruzzi rye (Secale cereale L.) were grown in a soil treated with 0, 50, 100, and 200 ppm N. The objective of this study was to determine the influence of N rate on dry matter yields, N uptake, and N utilization efficiency.

The dry matter and N uptake increased while the N utilization efficiency decreased with increasing N fertilizer applied to the soil for all the cultivars. At high N rate, rye had higher dry matter and N uptake than the triticales and wheat; no consistent differences were obtained between triticale and wheat. However, rye and triticale tended to be more efficient in utilizing absorbed N than wheat at the lower N rates.  相似文献   

6.
Abstract

Field studies were conducted to determine the influence of ammonia fertilization on cotton grown in conservation tillage systems. The studies were located on a Decatur silt loam (Rhodic Paleudult) in the Limestone Valley and a Norfolk sandy loam (Typic Paleudult) in the Coastal Plain of Alabama. Winter annual legumes, crimson clover (Trifolium incarnatum L. at the Norfolk site) and hairy vetch (Vicia villosa Roth at the Decatur site) were established as whole plots along with a winter fallow area. Sources of fertilizer differing widely in their NH4+‐N contents were used for split plot treatments applied at time of cotton (Gossypium hirsutum L.) planting. Fertilizer treatments included calcium nitrate, ammonium nitrate, urea, urea with dicyandiamide, and a no N check. The cotton was planted with a strip‐till conservation planter. Nitrogen production by winter legumes was adequate to meet N requirements for cotton on the Decatur silt loam (67 kg N/ha) but not at the Norfolk sandy loam site (101 kg N/ha). Cotton populations were 24% higher in fallow than legume whole plots. Differences in plant growth and N concentrations were highly variable and treatment trends were not found. Seed cotton yields were 4% higher in fallow than legume plots. Maximum populations and yields were achieved with ammonium nitrate in fallow area and urea in legume areas.  相似文献   

7.
This study determined whether the application of nitrogen (N) and phosphorus (P) could ameliorate salt‐induced reduction in wheat production. Saline irrigation water (0.5, 4.0, 8.2, and 12.5 dS/m) and N and P fertilizers (150 kg N/ha and 37.5 kg P2O5/ha) were applied to wheat (Triticum aestivum L. ‘Saka 92') grown on a calcareous soil in a greenhouse experiment. Plants received equal amounts of each fertilizer, but the time and frequency of application differed. All salinity levels reduced straw and grain yields, leaf soluble proteins, nitrate (NO3) content, actual and potential nitrate reductase activity (NRA), and grain protein content. The delay in pollen meiotic cell division increased with salinity. Under saline conditions, applying N and P fertilizers at the end of the grain filling stage improved yield and metabolic performance of the plants compared to other fertilizer treatments.  相似文献   

8.
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   

9.
Abstract. The residual value of mineral N fertilizer applied in the spring was investigated in a field experiment where four cereals (winter wheat, winter barley, spring barley and spring oats) had been grown at reduced (0.7N), normal (1N) or high (1.3N) N fertilizer rates for 20 to 28 years. The effect of previous N fertilizer dressing was tested in two succeeding years by replacing the original N rate with five test N rates ranging from 0 to 240 kg N ha?1 for winter cereals and 0 to 200 kg N ha?1 for spring cereals. In the first test year, winter wheat grown on plots previously supplied with the high rate of mineral fertilizer (202 kg N ha?1 yr?1) yielded more grain and straw and had a higher total N uptake than wheat on plots previously supplied with the normal (174 kg N ha?1 yr?1) or reduced (124 kg N ha?1 yr?1) rate. The grain yield response and N uptake was not significantly affected by the N supply in the test year. The winter wheat grown in the second test year was unaffected by the previous N supply. Grain and straw yield response and total N uptake for spring barley, winter barley and oats, were almost identical irrespective of the previous N rate. After 20 to 28 years there were no significant differences in soil C and N (0 to 20 cm) between soil receiving three rates of N fertilizer. Soil from differently fertilized oat plots showed no significant differences in N mineralizing capacity. Nitrate leaching losses from the soils at the three N rates were estimated and the N balances for the 20 to 28 years experimental period calculated. The data indicated a reduction in overall loss of 189 to 466 kg N ha?1 at the normal and high N rates compared with the reduced N rate. We conclude that the N supplying capacity and soil organic matter content of this fertile sandy loam soil under continuous cereal cropping with straw removal was not significantly affected by differences in N fertilizer residues.  相似文献   

10.
Abstract. Three successive crops of winter wheat were grown on a sandy loam to test the residual effect of long‐term annual incorporation of spring barley straw at rates of 0, 4, 8 and 12 t ha?1, and ryegrass catch crops with or without additions of pig slurry. Soil receiving 4, 8 and 12 t ha?1 of straw annually for 18 years contained 12, 21 and 30% more carbon (C), respectively, than soil with straw removal, and soil C and nitrogen (N) contents increased linearly with straw rate. The soil retained 14% of the straw C and 37% of the straw N. Ryegrass catch‐cropping for 10 years also increased soil C and N concentrations, whereas the effect of pig slurry was insignificant. Grain yield in the first wheat crop showed an average dry matter (DM) increase of 0.7 t ha?1 after treatment with 8 and 12 t straw ha?1. In the two subsequent wheat crops, grain yield increased by 0.2–0.3 t DM ha?1 after 8 and 12 t straw ha?1. No grain yield increases were found after 4 t straw ha?1 in any of the three years. Previous ryegrass catch crops increased yields of wheat grain, but effects in the third wheat crop were significant only where ryegrass had been combined with pig slurry. Straw incorporation increased the N offtake in the first wheat crop. In the second crop, only 8 and 12 t straw ha?1 improved wheat N offtake, while the N offtake in the third wheat crop was unaffected. Ryegrass catch crops increased N offtake in the first and second wheat crop. Again, a positive effect in the third crop was seen only when ryegrass was combined with slurry. Long‐term, annual incorporation of straw and ryegrass catch crops provided a clear and relatively persistent increase in soil organic matter levels, whereas the positive effects on the yield of subsequent wheat crops were modest and transient.  相似文献   

11.
Abstract

We studied the effects of liming on dry matter production, nutrient composition, and grain yields of wheat in field experiments conducted on two soil types at three locations during the 1976–77 and 1977–78 growing seasons. Lime sources were commercial agricultural lime, finely divided stack dust, and dolomitic limestone (which contained 10.6% Mg). Lime applied at 2,800 kg/ha in the 1976–77 and 10,750 kg/ha in the 1977–78 experiments provided Mg from the dolomite at rates of 300 and 1,140 kg/ha, respectively.

Soil pH was significantly increased by liming, but Mg saturation percentages were significantly greater only at the 1,140 kg/ha rate. Forage dry matter and grain yields were not increased by lime applied at the lower rate, but significant increases were found in dry‐matter production in the late fall and spring samplings of the 1977–78 experiment. Those increases in plant growth and dry matter production were probably due to reductions in the soluble Mn and Al concentrations in the soil. Forage N and P concentrations were generally not influenced by liming. Potassium concentrations in forage from the limed plots were usually equal to or greater than those in forage from unlimed plots. Calcitic limestone sources generally increased forage Ca concentrations, but liming with dolomite more often than not depressed Ca concentrations below levels found in the check plots. Dolomite, when applied at the 1,140 kg/ha rate, effectively increased the forage Mg concentration, although the concentration exceeded 0.2% only during the early growth stages. Liming generally showed no significant reduction in the tetany potential of the wheat forage as predicted by the equivalent ratio K/(Ca + Mg).  相似文献   

12.
Adverse effects on crop yield or quality have been reported in sewage‐sludge treated soils at soil total metal concentrations below those of the current EU directives. A field trial was set up in Belgium (2002–2004) to assess crop response to the application of sewage sludge below these soil thresholds but with sludge metal concentrations either above (high‐metal) or below (low‐metal) sludge metal limits. Two lime‐stabilized and two raw, dewatered sludges were applied annually at rates of 10, 25 and 50 t dry matter (dm) ha?1 for 3 years with four rates of N‐fertilizer as a reference. Final soil metal concentrations increased to maximums of 1.6 mg Cd kg?1 and 225 mg Zn kg?1 through sludge applications. Maize yield was marginally affected by treatments in year 1, whereas wheat and barley grain yields in subsequent years increased up to threefold with increasing sludge or fertilizer rates and were mainly explained by grain‐N. However, the grain yield of winter wheat in year 2 was reduced by about 14% in lime‐stabilized high‐metal sludge treatments compared with wheat receiving N‐fertilizer at equivalent grain‐N. Wheat grain and straw analysis showed no nutrient deficiencies but Zn concentrations in grain and straw were greater than in N‐fertilizer and lime‐stabilized, low‐metal sludge treatments, suggesting Zn toxicity. Sludge properties other than Cd concentration (e.g. electrical conductivity) affected crop Cd in the first year (maize), whereas significant correlations between Cd application and wheat grain Cd were found in the second year. Wheat grain Cd concentrations reached the international trade guideline of 0.1 mg Cd kg?1 fresh weight in the plots amended with lime‐treated, high‐metal sludge even though soil Cd remained below EU limits. In the third year, barley grain Cd remained largely below EU limits. We discuss the possibility that sludge properties rather than soil total metal concentrations are related to effects on crops in the initial years after sludge applications. In none of the 3 years were any adverse effects on crops found for sludge meeting current EU regulations.  相似文献   

13.
Genotypic variation and mycorrhiza play an important role in plant uptake of phosphorus (P). A pot experiment was conducted with three cereals, wheat (Triticum aestivum L. cv. PBW-34), rye (Secale cereale L. cv. R-308), and triticale (Triticale octoploide L. cv. DT-46), a hybrid of wheat and rye, to examine the genetic variation in the degree of arbuscular-mycorrhizal (AM) infection and its inheritability from parents (wheat and rye) to their progeny (triticale). The soil used for pot culture was low in available P (7.8 mg P kg?1soil). Inoculation with AM fungi showed a significant increase in extent of root colonization for all three cereals (average 70%) compared with their performance without AM (average 19.1%). However, among the three cereals, this increase was significantly greater in rye than in the other two crops, while wheat and triticale did not differ significantly. Mycorrhizal infection resulted in 1.6, 1.7, and 1.8-fold increases in shoot, root, and total plant dry matter, respectively, compared with the un-inoculated treatment. Among the three cereals, rye recorded maximum shoot, root, and total plant dry mass and P content with AM inoculation. The P uptake by wheat, rye, and triticale was 10%, 64%, and 35%, respectively, higher with rather than without mycorrhizal infection. Rye was most responsive to AM inoculation, with mycorrhizal dependency of 193%; here again, triticale followed wheat, with similar mycorrhizal dependency. Rye showed an increase in P utilization efficiency (PUE) without AM inoculation while the PUE of triticale was intermediate between wheat and rye. High efficiency of AM symbiosis in terms of P uptake exists in rye and most of these traits in triticale seem to be inherited from wheat rather than rye.  相似文献   

14.
Effects of varied irrigation and zinc (Zn) fertilization (0, 7, 14, 21 kg Zn ha‐1 as ZnSO47.H2O) on grain yield and concentration and content of Zn were studied in two bread wheat (Triticum aestivum), two durum wheat (Triticum durum), two barley (Hordeum vulgare), two triticale (xTriticosecale Wittmark), one rye (Secale cereale), and one oat (Avena sativa) cultivars grown in a Zn‐deficient soil (DTPA‐extractable Zn: 0.09 mg kg‐1) under rainfed and irrigated field conditions. Only minor or no yield reduction occurred in rye as a result of Zn deficiency. The highest reduction in plant growth and grain yield due to Zn deficiency was observed in durum wheats, followed by oat, barley, bread wheat and triticale. These decreases in yield due to Zn deficiency became more pronounced under rainfed conditions. Although highly significant differences in grain yield were found between treatments with and without Zn, no significant difference was obtained between the Zn doses applied (7–21 kg ha‐1), indicating that 7 kg Zn ha‐1 would be sufficient to overcome Zn deficiency. Increasing doses of Zn application resulted in significant increases in concentration and content of Zn in shoot and grain. The sensitivity of various cereals to Zn deficiency was different and closely related to Zn content in the shoot but not to Zn amount per unit dry weight. Irrigation was effective in increasing both shoot Zn content and Zn efficiency of cultivars. The results demonstrate the existence of a large genotypic variation in Zn efficiency among and within cereals and suggest that plants become more sensitive to Zn deficiency under rainfed than irrigated conditions.  相似文献   

15.
Crop response to fertilization and liming was investigated in field and pot trials on sandy loam Dystric Albeluvisols (pH 4.2–4.3). Treatments in the field trial were: 1, no fertilizer; 2, PK; 3, NK; 4, NP; 5, NPK; 6, lime; 7, lime+PK; 8, lime+NK; 9, lime+NP; 10, lime+NPK. In the pot trial, they were: 1, no fertilizer; 2, N; 3, P; 4, K; 5, NP; 6, NK; 7, PK; and 8, NPK applied to unlimed and limed soils. All treatments were in four replicates. Crops sensitive to soil acidity (winter wheat, fodder beet, spring barley and clover-timothy ley) and the less acid-sensitive winter rye, potatoes, oats and lupins and oats mixture were sown in the field trial. In the pot trial, the acid-sensitive spring barley and red clover, and the less acid-sensitive oats and lupin-oats served as the test crops. Combined application of fertilizers (NPK) increased yields of crops sensitive to soil acidity in plots receiving lime by 23%, and those of crops less sensitive to soil acidity by 18% in comparison to crops grown on unlimed soils. The results of pot experiments corroborated the field results. When N was applied alone, crop yields were always higher than those recorded for P or K treatments on both the unlimed and limed treatments. N application proved to be a prerequisite for high crop yields in the soils investigated. Thus, the efficiency of P and K fertilizers increased in the order NK<NP<NPK, with the effects being accentuated more in the limed than in the unlimed treatments. The results demonstrated the importance of multi-nutrient (NPK) fertilization in combination with liming for enhancement of high crop productivity in the unlimed soil investigated. N applied alone in combination with liming produced relatively good yields; hence, where resources are limited for the purchase of P and K fertilizers, applying N and lime can be a viable option in the short term.  相似文献   

16.
Abstract: Crop residues that are left on the soil surface to serve as mulch can diminish the soybean response to surface application of lime under no‐till management by ameliorating soil chemical and physical attributes and the plant nutrition. A field experiment was performed in the period from 2000 through 2003 in Paraná State, Brazil, on a clayey‐sandy Rhodic Hapludox. Soil chemical attributes and soybean [Glycine max (L.) Merrill] nutrition, grain yield, and quality were evaluated after surface application of lime and covering with crop residues of black oat (Avena strigosa Schreb) and corn (Zea mays L.) under a no‐till system. Dolomitic lime was surface applied at the rates of 0, 2.5, 5.0, and 7.5 t ha?1 on the main plots, and three treatments with vegetable covering were applied on the subplots: (i) without covering, (ii) with covering of corn straw, and (iii) with covering of corn straw and black oat residue (oat–corn–oat). After 30 months, surface‐applied lime increased soil pH and the exchangeable calcium (Ca2+) and magnesium (Mg2+) levels down to a 10‐cm depth, independent of the vegetable covering treatments. The black oat and corn residues on the soil surface increased the soil exchangeable K+ level at the 5‐ to 10‐cm depth. Liming increased leaf potassium (K) content and phosphorus (P) content in the soybean grain and reduced leaf zinc (Zn) content and manganese (Mn) content in the soybean leaf and grain. There was no effect of liming on soybean grain, oil, or protein yields, independent of the vegetable residues kept on the soil surface. The treatment with black oat covering and corn straw increased leaf N content, P content in the leaf and grain, and the contents of K, Mg, copper (Cu), and Zn in the soybean grain. It also increased soybean grain and protein yields. The corn straw left at the surface after harvesting was very important to the performance of the no‐till soybean.  相似文献   

17.
施氮水平对黄土旱塬区小麦产量和土壤有机碳、氮的影响   总被引：13，自引：4，他引：9  
施用氮肥是雨养农业区提高作物产量和土壤有机碳（SOC）、氮[TSN（Total soil N）]含量的重要养分管理措施。利用长期田间试验（1984～2007）,定量评价了常规耕作条件下5个施氮水平N 0（N0）、45（N45）、90（N90）、135（N135）和180（N180）kg/hm2处理下,小麦子粒产量、SOC、TSN和氮肥利用效率的变化。研究了施氮水平对黄土旱塬区旱地小麦产量、SOC和TSN积累的影响。结果表明,1984～2007年期间,N0、N45、N90、N135和N180处理小麦产量的平均值依次为1.2、2.4、2.9、3.2和3.4 t/hm2;N0处理的小麦产量随试验年限而降低,年降低幅度达67 kg/hm2（P0.001）;但增施氮肥后降低趋势得到显著控制,当施氮水平提高到N 90 kg/hm2时,产量随年限呈现出缓慢升高的趋势。随着施氮水平的提高,地上部氮肥利用率由40%（N45处理）降低到28%（N180）。不同施氮水平条件下,SOC含量随年限呈缓慢升高趋势。23年后（2007年）,N0、N45、N90、N135和N180处理下,0—20 cm土层SOC储量依次为16.9、18.2、18.7、19.0和19.1 t/hm2;TSN储量依次为2.03、2.16 、2.24 、2.34和2.37 t/hm2。施氮水平与产量呈显著的抛物线关系（R2＝0.993）。产量与SOC存在着极显著的线性相关关系（R2=0.997）。增施N 1 kg/hm2,小麦产量可提高29 kg/hm2,SOC提高1.2 kg/hm2,TSN提高0.13 kg/hm2。根茬还田量的增加是导致黄土旱塬区SOC和TSN提高的主要因素。  相似文献   

18.
Abstract

The effects of liming (7 500 kg CaCO3/ha) and rate of urea application (0,50,100, and 200 kg N/ha) and its placement at the surface or at 5 cm depth on grain yield and nutrient uptake by corn grown on an acidic tropical soil (Fluventic Eutropept) were studied. Liming significantly increased grain yield, N uptake, and P and K uptake although Ca and Mg uptake, generally, were unaffected. Sub‐surface application of urea increased N uptake only. Yield response to applied N was observed up to 50 kg N/ha when limed but at all rates in the absence of liming. It therefore, reduced the fertilizer N requirement for optimum grain yield. Liming the acidic soil also reduced exchangeable Al but increased nitrification rate and available P in the soil profile (at least up to 0.6 m depth).  相似文献   

19.
Nitrogen balances, i.e. the difference between N 2 fixation inputs and N in harvested products (outputs), and rotational benefits of chickpea ( Cicer arietinum) on soil organic fertility and wheat ( Triticum aestivum) yields were quantified for rain-fed systems in the northern Punjab, Pakistan. The experiments were conducted during 1995–2000 at three sites. The four treatments were continuous wheat (0 N), continuous wheat (+N), chickpea-wheat (0 N) and chickpea-wheat (+N). The +N fertiliser rate was 100 kg N ha -1 applied to the wheat. Grain yields of the wheat with 0 N varied in the range 1.0–3.0 t ha -1, compared with 2.0–3.2 t ha -1 for the N-fertilised wheat. Chickpea grain yields were in the range 0.6–2.0 t ha -1. Chickpea N 2 fixation was assessed using the natural 15N abundance method. Percentage of chickpea N derived from N 2 fixation (%Ndfa) estimates were 58% (Mandra), 65% (Taxila) and 86% (Islamabad). The overall mean %Ndfa was 78%. Crop N fixed by the chickpea varied between sites (87–186 kg N ha -1) and essentially reflected crop biomass. The overall mean N balance for chickpea (crop N fixed minus N removed in grain and above-ground residues) was +28 kg N ha -1. Wheat grain yields responded to chickpea (19–73% increase for the three sites), to fertiliser N (99–136% increase) and to the combination of chickpea and fertiliser N (106–145% increase). Chickpea in the rotation increased soil organic C by 30% and soil N by 38%, relative to the continuous wheat with 0 N. These experiments indicated that chickpea could have a positive N balance, even when shoot residues were removed, and confirmed the rotational benefits of chickpea for improving soil organic fertility and yield of a following wheat crop.  相似文献   

20.
在山西石灰性褐土一年一作条件下,通过16年的田间定位试验,研究了长期施钾和秸秆还田对小麦产量和土壤钾素平衡的影响。结果表明,只施用氮、磷肥,冬小麦年平均产量5.5 t/hm2,土壤钾素养分严重亏缺,年平均亏缺104.3 kg/hm2,与试验前的初始值比较,土壤速效钾和缓效钾含量分别下降23.6%和14.3%。在施用氮、磷肥的基础上每年施用钾肥(K2O 150 kg/hm2),平均增产10.2%以上;小麦秸秆还田平均增产6.6%以上,二者配合平均增产17.6%,年平均吸钾量提高32.0 kg/hm2。与试验初始值比较,土壤速效钾、缓效钾分别提高38.6%和11.0%。在施用氮、磷肥的基础上,长期施用钾肥和秸秆还田在显著增加冬小麦的经济产量、生物产量和吸钾量的同时,也减少年度间因气候因素等影响引起的产量变异,提高年度间产量和植物吸钾量的稳定性。  相似文献   

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