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1.
Nitrogen penetration and persistence in soil under uncovered and covered farmyard manure heaps
After deposition of cattle manure for 308 days neither the total nitrogen nor the nitrate but onlv the ammonia content in the soil (0–70 cm) was significantly increased. During a 258 days period from autumn to spring the observed microbial oxidation of penetrated ammonia to nitrate was tardy and by no means quantitative. So leaching of nitrate was hardly to be detected during the whole period. In the soil layer 40–70 cm a maximum of 1.6 g NO3-N/m2 was measured, which was in an equivalent range with the amounts detected by large scale investigations in agricultural soils at the same season. Therefore the manure heaps in question did not lead to an uncommon increase of nitrate in soil. The protection of the heaps against precipitation simply brought about small and only a few times significant reductions in soil Nmin content.  相似文献   

2.
Results of yield formation at ecological oriented winter wheat cultivation on Calcic Chernozem soil in arid areas
The influence were examined in field experiments of wheater elements (air temperature, precipitation), nitrogen fertilization, sowing rate and irrigation on the yield and yield formation of winter wheat stands. The average level of yields amounts to 81.3 dt/ha (76…93.8 dt/ha). Limiting factor for yields is the availability of water in the soil. In humide seasons 9…12 % higher yields were obtained then in dry seasons. Without nitrogen fertilization yields of winter wheat are lower by 18 % than with nitrogen fertilization. At very high level of N fertilization only vegetative biomass increases, and the water use efficiency decreases.
Increase in plants/m2 caused a rise of vegetative biomass and of ears/m2, kernels per ear strongly decreased in the same time. At winter wheat cultivation in low input farming systems without nitrogen fertilization high yields will be obtained with 320…370 plants/m2 and 15,000 kernels/m2. Nitrogen uptake from the soil amounts to 180 kgN/ha. Because of great amounts of inorganic in the soil (70…200 kgN/ha) sufficient nitrogen is available until heading of the wheat plants. The nitrogen supply of wheat plants in later stages of development is influenced by wheater conditions.  相似文献   

3.
NO3 dynamics in the soil, yield formation and N uptake of winter wheat as influenced by dosage and distribution effects of N-fertilizer application
In a 4 year series of field trials carried out with 9 regimes of nitrogen fertilizer application at two trial sites with rather shallow top soil layers but large deviations in soil characteristics, grain yield varied between 50 dt/ ha and 120 dt/ha with nitrogen doses from 0–170 kg N/ha. Soil nitrogen supply for wheat grain formation on unfertilized plots reached 80 kg N/ha/year within the narrow range of 75–95 kg N/ha in different years at both sites which amounts to 1.5 % and 0.5 % of the highly different N-content of the trial sites.
The most successful nitrogen application regimes are characterized by modest fertilizer doses in early spring and the delay of supplemental fertilizer doses until growth stage EC 32. They resulted into modest NO) soil content from EC 29 to EC 32 and/or a noticable decrease of soil NO3 content during growth stage EC 30–32, which seems to be responsible for the development of only modest stand densities and reduced straw yield, while the delayed supplementation with nitrogen fertilizer overcompensated these effects mainly by increased grain numbers/ear and a remarkable improvement of harvest index.
The contribution of soil borne nitrogen to kernel yield formation started to decrease with even low dosages of supplemental nitrogen fertilization with the exception of the highest yielding season 1987/88. Top levels of grain yield have been regularly obtained with supplemental nitrogen fertilizer dosages about 40 kg N/ha below grain yield nitrogen extraction if they were added within favorable application regimes.  相似文献   

4.
Two barley crops, one fertilized with 120 kg N ha−1 (B120) and the other without nitrogen fertilization (BO), were cultivated for the second year on the same plot. In 1981 the growth and nitrogen content of the whole plant, above- and below-ground parts were measured by sampling every second week. Production was calculated as the difference between annual maximum and minimum amounts of biomass found above- and below-ground. Nitrogen uptake was estimated as the sum of the peak amounts of nitrogen present in the roots and shoots. The amount and concentration of nitrogen in partly decomposed plant debris in the soil was estimated simultaneously with the biomass.
Total net production in B120 was 1004 g m−2 of which the roots constituted 16%. The unfertilized barley produced 558 g m−2 of which 23% were produced below-ground. The maximum amount of living roots found in B120 was 160 g ash-free dry mass m−2 and 128 g m−2 in BO.
In the fertilized treatment 15 g N m−2 (21% in roots) was taken up by the plant, compared to 5.8 g N m−2 (28% in roots) in the unfertilized crop.  相似文献   

5.
Influence of long-time Nitrogen-fertilizing on yield response of agricultural crops and mineralized Nitrogen in soil
In the years 1979–1986 a fertilizer trial with increasing Nitrogen amount was performed in order to prove the Nmin-method according to S charpf and W ehrmann . The Nmin-method regards the mineralized N in soil (Nmin) for optimizing the N-fertilizer amount at the begin of vegetation, could be confirmed. The optimal N-rate (including Nmin) was for winter wheat and winter barley 120 kg/ha, winter rye 100 kg/ha and sugar beet 200 kg/ha. For cereals additional N-rates were given at the end of tillering 20 kg/ha N and at ear emergency 60 kg/ha N. For the optimal N-fertilizing system we found a positive N-balance (input-output) in a range of 10–25 kg/ha. The influence of N-fertilizing on the mineralized N-amount in soil was very small comparing to influence of weather, soil type or crops. Only at one location a little increase of Nmin (10–15 kg/ha) could be observed after a positive N-balance (50 kg/ha).  相似文献   

6.
Field studies were conducted during the winter seasons of 1995–96 and 1996–97 at the Agricultural Farm of Aligarh Muslim University, Aligarh, India on mustard ( Brassica juncea L. Czern & Coss., var. Alankar) under non-irrigated conditions, to evaluate the effect of foliar spray of 200 p.p.m. ethrel (2-chloroethyl phosphonic acid) at flowering growth stage along with basal 0, 40, 80 or 120 kg N ha−1 on net photosynthetic rate (PN), stomatal conductance (CS), stomatal resistance (RS), leaf K content, relative water content (RWC), leaf area index (LAI) and total dry matter (TDM) production monitored at 20 days after spray application, and plant N content, seed N content, nitrogen harvest index (NHI), nitrogen yield merit (NYM), pods plant−1, 1000 seed weight, seed yield, biological yield, harvest index (HI), seed yield merit (SYM) and merit of genotype (MOG) at harvest. Results indicated that, at 0 or 40 kg N ha−1, ethrel did not produce any significance effect, but at basal 80 kg N ha−1, ethrel affected the parameters favourably with the exception of 1000 seed weight, HI, seed N and NHI. Ethrel-sprayed plants utilized N from the soil more effectively and showed increased NYM. Yield attributes, seed yield and merit of genotype (in terms of NYM and SYM) were also enhanced. Ethrel spray enhanced seed yield under water stress conditions mainly by increasing K uptake and retaining higher RWC, thereby decreasing RS and increasing LAI, PN and TDM production.  相似文献   

7.
To determine a suitable nitrogen fertilizer application rate, an experiment was conducted using Jinza 34, Liaoza 27, Jinsi 2, Jinnuo 3, and Fenjiuliang 1 with six nitrogen (N) fertilization levels, including 0 (N0), 75 (N75), 150 (N150), 225 (N225), 300 (N300), and 450 kg hm-2 (N450). The effects of long-term nitrogen fertilization with different levels on sorghum grain yield, nitrogen use characteristics and soil nitrate nitrogen distribution were investigated. The grain yield, grain number and N accumulation of sorghum increased initially and then tended to be stabile with the increase of nitrogen fertilizer application. Among them, the maximum increase of sorghum under N75 treatment compared with that under N0 treatment was 23.68%, 48.05%, and 51.86%, respectively. With the increase of nitrogen fertilizer application, the grain starch content decreased, while the grain starch yield increased firstly and then decreased. Nitrogen apparent recovery rate, nitrogen fertilizer agronomic efficiency and nitrogen use efficiency which were accumulated for five years were reduced significantly with the increase of nitrogen fertilizer application. Compared with the N150 treatment, nitrogen use efficiency accumulated for five years under N75 treatment, which was 63.01%, was increased by 76.91%. When nitrogen fertilizer application was beyond 225 kg hm-2, after four to five years later, nitrate nitrogen residue was increased rapidly in the 60-200 cm soil layer year by year, NO3--N accumulation peaks distributed in the 0-200 cm soil layer and the risk of nitrate nitrogen leaching was increased. In view of the yield, starch yield, nitrogen utilization and environmental benefit, the reasonable nitrogen fertilizer application for sorghum was between 75 kg hm-2 and 150 kg hm-2.  相似文献   

8.
Nitrogen (N) fertilizer management for production of bread quality wheat may increase nitrate residues in the soil. To assess soil nitrate levels associated with bread quality wheat ( Triticum aestivum L.) production in Eastern Canada, an experiment was conducted for 2 years at each of two sites in Québec. Four cultivars (Columbus, Katepwa, Max and Hege 155-85), four N levels (0, 60, 120 and 180 kg N ha−1) and two N timings (all at seeding time or 60 % at seeding and 40 % at anthesis) were combined in a factorial arrangement on a Bearbrook clay and a Ste-Rosalie clay. Residual soil NO3-N levels were measured in the 0–20 and 20– 60 cm soil layers. The cultivars used have potential as bread wheats. Cultivar effects on soil nitrate levels existed only in the Ste-Rosalie soil, suggesting that the cultivars used were better adapted to the conditions on the Bearbrook soil. Changes in soil NC3N levels over winter indicated that mineralization had occurred. Calculated balance-sheet values were larger than measured residual NO3-N in the autumn of each year, indicating that NO3-N was lost from the systems, possibly due to denitrification. Potential increases in, and thus potential pollution from, residual soil NO-N existed only at the 180 kg N ha−1 level. Overwinter changes in soil NO3-N levels were proportional to the inverse of the fall NC3N levels. Differences between sites were large for many of the variables measured.  相似文献   

9.
Nitrogen Uptake and Nitrogen Residuals of Winter Oil-Seed Rape and Fallout Rape
The objective of the investigation was a study of the relationship between seed dry-matter production and vegetative dry-matter production in oil-seed rape crops and their dependence on the production conditions. In addition to the relationship between the N-uptake during the vegetation period and the N-residue after harvest was of major interest. Furthermore the potential for N-uptake in fallout rape was measured. Over two vegetation periods factorial field experiments with winter oil-seed rape, cv. Lirabon, different drilling techniques and different nitrogen fertilization levels were tested. Measured traits were: the dry-matter accumulation including root mass and fall-off leaf-material mass, the N-uptake of both the oil-seed crops and the fallout rape stands, and, simultaneously, the soil NO3-N content. Finally the harvest indices and the N-harvest indices were calculated.
Combined with a N-uptake of up to 330 kg N/ha, oil-seed rape crops produced up to 200 dt dry matter/ ha. At seed yield levels of 33dt/ha (d.m.), harvest indices varied from 0.14—0.23 and N-harvest indices varied from 0.30–0.50. As a result of the residue of vegetative plant material at harvest, leaf losses before harvest and the soil NO3-N-contents at harvest up to 275 kg N/ha remained in the field. After the harvest of oil-seed rape, the soil NO3-N-contents were quickly reduced by emerging and growing fallout rape stands. However, following soil-preparation measures in the autumn, a continuous rise in the soil NO3-N-content was observed.  相似文献   

10.
In a 3-year field experiment conducted on a Gleyic Luvisol in Stuttgart-Hohenheim, ten maize cultivars (nine commercial and one experimental hybrid) were compared in their ability to utilize a high soil nitrogen (N) supply. Total N content of the shoots at about silage maturity ranged from 213 to 328 kg N ha−1 (1986), from 177 to 223 kg N ha−1 (1987) and from 185 to 226 kg N ha−1 (1988). In all three experimental years, total shoot N uptake was significantly positively correlated to stover yield, and also to N concentrations in the ears and in the total plant dry matter. In contrast, a negative correlation between ear yields of the cultivars and total N uptake was indicated. Differences between the cultivars in N uptake were reflected in a corresponding soil nitrate depletion. At harvest, residual nitrate-N in the 0–90 cm soil layer ranged from 34–63 kg N ha−1 m 1987 and 32–71 kg N ha−1 in 1988. The results indicate, that growing of cultivars selected for high N uptake-capactiy of the shoots may contribute to an increased utilization of a high soil N supply and thus to a reduction of nitrate leaching.  相似文献   

11.
Two field experiments were conducted during] 994-95 to study the effect of spray of 10−5 M GA3 at 40 days after sowing on mustard ( Brassica juncea (L.) Czern & Coss.) cv. Varuna grown with basally applied 0, 40, 80 and 120 kg N ha−1 (Expt. 1) and 0,15, 30 and 45 kg P ha−1 (Expt. 2) on pod number per plant, seeds per pod, 1000 seed weight, seed yield, biological yield, harvest index and fatty acid composition of oil. No significant difference between water and GA3 spray was found when basally applied nitrogen was 0 or 40 kg N ha−1. N80 proved to be the best for yield characteristics. In another experiment on phosphorus, GA3 and 30 kg P ha−1 individually enhanced the yield, but interaction of GA3 and P remained non-significant. The fatty acid composition of oil in both experiments was significantly affected only by nitrogen and phosphorus treatments for oleic acid and erucic acid. It was found that return in the form of yield was more for every kg applied fertilizer under GA, spray treatment. The response was more for N fertilizer in comparison to P. GA3 at a low level of fertilization significantly increased the return from fertilization.  相似文献   

12.
A field study was conducted to estimate the nitrogen fixation by soybean [ Glycine max (L.) Merr.], using the A-value and the N-difference methods, and to examine the N partitioning within the plant. The cultivar Clark and its non-nodulating isoline (as reference crop) were grown in a silty clay (Typic Xerothent) soil, in 1991 and 1992. 15N-Labelled fertilizer was surface applied in solution, at rates of 20 and 100 kg N ha−1 to the nodulating and non-nodulating soybean, respectively. Plant samples were taken at full bloom (R2), beginning of seed growth (R5) and physiological maturity (R7). There was little nitrogen fixation at the early growth stages but it increased rapidly during the seed filling period. At R7 nitrogen fixed was estimated by the A-value method as 155 kg N ha-1 in 1991 and as 240 kg N ha−1 in 1992. The corresponding estimates by the N-difference method were significantly smaller. The seeds had a higher, and the vegetative parts smaller, proportion of fixed nitrogen compared to the whole plant. During the seed filling period, the translocation efficiency for fixed nitrogen was greater (93 % in 1991 and 85 % in 1992) compared to the N derived from soil (75 and 56 %, respectively). It was estimated that, after the harvest of pods, the soil was depleted by a net amount of 121 kg N ha−1 in 1991 and 90 kg N ha−1 in 1992.  相似文献   

13.
Structure, microbial metabolism and potentially mineralizable nitrogen pools in organically and conventionally farmed clay soils
Soil physical, soil chemical and biological studies were carried out on two differently cultivated clay soils. One soil, under organic farming system (TNL), was not ploughed for the last 14 years, the 0–10 cm layer was tilled by a rotowator system. The other soil was tilled conventionally and was ploughed down to 22 cm (TKL). For comparison the topsoil of a pasture was investigated.
The saturated hydraulic conductivity (depicted as frequency distribution from kt values) was very high in the TNL soil and in the pasture soil. The TKL soil showed a lower conductivity and pore continuity than the other soils, especially in the layer of 0–10 cm (Aprhonzon). Aggregate stability (measured as total settlement) was highest in the pasture soil, followed by the 10–20 cm layer of TKL soil. The small fragments of TNL soil resulted in a decline of the aggregate stability.
Dehydrogenase activity was similar in the TNL soil and the pasture, and lower in the TKL soil. Potentially mineralizable nitrogen showed the same trend as dehydrogenase activity. Soil respiration was higher in the TKL soil than in the TNL soil. This was attributed to higher amounts of microbial available carbon probably because of the presence of undecomposed crop residues in the TKL soil.  相似文献   

14.
A simple randomized field experiment was conducted to assess the growth and yield of rape-seed-mustard in relation to sulphur and nitrogen interaction. Three levels of sulphur (0, 40 and 60 kg ha−1) in combination with three levels of nitrogen (60, 100 and 150 kg ha−1) were tested as treatments, T1, T2, T3, T4, and T5. Results indicated significant favourable effects of sulphur and nitrogen, when applied together, on yield components, seed and oil yield. Maximum response was observed with treatment T3 (having S and N of 40 and 100 kg ha1, respectively). Percentage oil content of seed was maximal at T4 (having S and N of 60 and 100 kg ha1) in both cultivars. The increase in N dose from 100 to 150 kg ha−1 without any change in applied S, i.e. 60 kg ha1 (T5), decreased the percentage oil content. The seed and oil yield, however, were similar to T3. Favourable responses of S and N interaction on leaf area index, rate of photosynthesis and biomass production were also observed.  相似文献   

15.
15N-aided investigations were conducted to ascertain the Nj fixation and the nitrogen (N) contribution by mungbean ( Vigna radiata L.) and groundnut ( Aracbis hypogaea L.) when intercropped with maize ( Zea mays ). The study involved growing seven genotypes of the above legumes with maize in alternate rows in two separate experiments. A sole crop of maize was used as the reference crop to determine N2 fixation by the 15N methodology. Significant genotypic differences in pod yield and stover N content were observed in intercropped mungbean and groundnut. The percentage N derived from the atmosphere showed a genotypic variation of 31 to 45 % (7 to 10 kg N2 fixed ha−1O in mungbean and 47 to 69 % (9 to 18 kg N2 fixed ha−1) in groundnut. Harvest index for N varied from 58 to 77 % in mungbean and 55 to 75 % in groundnut. In groundnut, the uptake of soil N was significantly affected by the genotype. Assuming that the N contribution to the soil by the helow-ground plant parts was negligible, the removal of seeds at maturity resulted in a negative N balance in the soil in all the genotypes of mungbean. In groundnut, some genotypes produced a positive N balance in the soil. Owing to high N2 fixation capacity and low harvest index for N, groundnut showed a greater N supplementing ability than mungbean.  相似文献   

16.
节水减氮对土壤硝态氮分布和冬小麦水氮利用效率的影响   总被引:8,自引:0,他引:8  
针对当前关中平原冬小麦生产中氮肥投入过量、灌溉水资源不足的问题,研究节水减氮栽培模式下冬小麦籽粒产量、水氮利用及硝态氮淋失情况,能为确定冬小麦节水减肥环保增效的生产模式提供理论依据。于2017—2019年在陕西杨凌开展冬小麦节水减氮田间栽培试验,采用二因素裂区设计,施氮量为主处理,灌水量为副处理,设施氮量处理N300 (300 kg hm–2)、N225 (225 kg hm–2)、N150 (150 kg hm–2)、N75 (75 kg hm–2)、N0 (不施氮)和灌水量处理W2 (1200 m3 hm–2)、W1 (600 m3 hm–2)、W0 (0),分析小麦产量、水氮利用效率及土壤硝态氮淋失情况。结果表明,2017—2018年和2018—2019年小麦季灌水处理较不灌水处理分别增产14.88%~15.01%和4.11~4.16倍,但处理间差异不显著,而越冬期灌水600 m3 h...  相似文献   

17.
N-uptake and N utilization of different fertilizer types by winter wheat – pot experiments with 15N
The efficiency of top dressing urea, ammonium nitrate and ammonium sulphate fertilizers on winter wheat grown on loamy sand and loessial black soil was studied. At a rate of 0.5 g N per pot on the loamy sand 20 % volatilization losses of NH3 occurred with urea and 10 % on the loessial black soil with urea resp. ammonium sulphate.
The grain yields an N removal correspond to these results. At an amount of 1.6 g N per pot the N-uptake of 15N ranged from 0.589 g (urea) on sandy soils to 1.279 g (ammonium nitrate) which agrees with 76 % an 91 % of the total N uptake. On black soil 0.675 g (urea) and 1.038 g (ammonium nitrate) or 44 % and 51 % of the total uptake are found.  相似文献   

18.
小麦宽幅匀播技术氮、磷、钾施肥效果及推荐施肥量研究   总被引:4,自引:2,他引:2  
为了探讨宽幅匀播小麦的肥料高效利用和土壤养分吸收的机理,采用多点田间小区试验,应用“3414”田间肥料试验设计方法,分析在不同肥力水平下小麦宽幅匀播技术氮、磷、钾的施肥效果和推荐用量。结果得出,宽幅匀播小麦氮、磷、钾养分利用率随施肥水平提高而显著降低,随土壤肥力增加呈先增高后降低,从高到低依次为:中肥力>较低肥力>低肥力>较高肥力>高肥力。随土壤肥力由低到高增加,宽幅匀播小麦最佳施肥效益的推荐施肥量分别是N 107.9~171.8 kg/hm2、P2O5 88.2~112.1 kg/hm2和K2O 35.4~56.2 kg/hm2,平均分别为:N 138.3 kg/hm2、P2O5 101.4 kg/hm2、K2O 45.4 kg/hm2,三要素比例为N:P2O5:K2O=1:0.73:0.33。由于不同土壤类型的速效氮磷钾含量有一定差异,小麦宽幅匀播适宜施肥量应因土壤类型而适当调整。  相似文献   

19.
为探究华北地区夏玉米低碳生产的氮肥管理措施,以典型夏玉米田为对象,设置了不施氮(N0)、施氮100 kg/hm2(N1)、施氮150 kg/hm2 (N2)、施氮200 kg/hm2 (N3)4个处理,通过土壤温室气体排放、农事投入间接碳排放和作物固碳综合评估了不同施氮水平对夏玉米农田生态系统净碳效应的影响。结果表明,农田土壤CO2、N2O排放随施氮量升高而升高,CH4吸收量随施氮量的升高而下降,N1、N2和N3处理土壤温室气体总排放的碳当量分别较N0提高14.91%、24.19%、29.67%;氮肥投入贡献了较高的间接排放,达到135.27~270.55 kg/hm2;施氮促进了作物固碳,N0、N1、N2、N3净初级生产力固碳量分别为1965.56、3125.68、4345.55、4663.64 kg/hm2。综合系统碳流来看,各处理均表现为碳汇,净碳效应分别为258.33、1034.99、2032.82、2192.16 kg/hm2,碳可持续指数分别为0.15、0.50、0.88、0.89。200 kg/hm2施氮量下能够以相对较低的碳耗换取较高的固碳率,表现出较高的净碳效应,可推荐为氮素适宜投入量。  相似文献   

20.
土壤氮素和水分含量对小麦产量和品质有重要影响。为优化水肥管理实现优质高效栽培, 2014—2015和2015—2016小麦生长季在河南省温县大田水氮长期定位试验地块, 以中筋品种豫麦49-198为材料进行灌水与施氮两因子裂区试验。主区为灌水处理, 设全生育期不灌水(W0)、拔节期750 m 3 hm -2 (W1)和拔节期750 m 3 hm -2 +开花期750 m 3 hm -2 (W2) 3个水平, 副区为氮素处理, 设不施氮(N0)及总氮量180 (N1)、240 (N2)和300 kg hm -2 (N3) 4个水平。与W0处理相比, 2个灌水处理均显著降低耕层土壤(0~20 cm)中的硝态氮含量, 灌水处理的籽粒支链淀粉含量、总淀粉含量、淀粉峰值黏度、谷值黏度和最终黏度均显著高于不灌水处理。灌水还增加了籽粒中小淀粉粒(粒径<5.0 μm)的体积百分比, 2014—2015年度增幅显著, W1、W2处理分别较W0处理增加3.4%和4.8%。施氮提高耕层土壤硝态氮含量, 但籽粒直链淀粉含量和小淀粉粒体积百分比低于不施氮处理。在0~240 kg hm -2施氮量范围内, 籽粒支链淀粉含量、总淀粉含量及峰值黏度、谷值黏度、最终黏度均随施氮量增加而增加。相关分析表明, 耕层土壤硝态氮含量与总淀粉含量、峰值黏度、谷值黏度和最终黏度间呈极显著正相关。拔节期灌1水、施氮量240 kg hm -2条件下, 耕层土壤硝态氮含量为19.64~20.55 mg kg -1, 小麦籽粒黏度值较高, 同时改善了淀粉品质。  相似文献   

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