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1.
Dryland wheat is the major contributor to wheat production in the world, where water deficiency and poor soil fertility are key factors limiting wheat grain yields and nutrient concentrations. A field experiment was carried out from June 2008 to June 2011 at Shilipu (latitude 35.12°N, longitude 107.45°E and altitude 1200 m above sea level) on the Loess Plateau (a typical dryland) in China, to investigate the effects of rotation with soybean (Glycine max) green manure (GM) on grain yield, total N and total Zn concentrations in subsequent wheat (Triticum aestivum L.), and on nitrate-N and available Zn in the soil. The benefits of crop rotation with soybean GM on wheat grain yields became more evident with time. In the second and third years, the grain yields of wheat rotated with soybean GM reached 4871 and 5089 kg ha−1 at the 108 kg N ha−1 rate. These yields were 21% and 12% higher than the highest yields of wheat under a fallow-winter wheat (FW) rotation. Rotation with soybean GM reduced the amount of N fertilizer required to obtain wheat grain yields and biomass levels similar to wheat grown in the FW rotation by 20–33%. In the first 2 years, average grain N concentrations over all N rates increased by 6% and 12%, and those of Zn increased by 26% and 14% under the soybean GM-winter wheat (SW) rotation, compared with the FW rotation. The increased grain N and Zn concentrations were found to be related to the increased concentrations of nitrate-N and available Zn in the soil, particularly at the sowing of winter wheat. However, grain N and Zn concentrations were not improved by rotation with soybean GM in the third year. This was attributed to the dilution effect caused by the more grain yield increase than its nutrient export. In conclusion, planting soybean for GM in fallow fields reduced the need for N fertilizer to enhance wheat yields in this dryland region. Change in wheat grain N and Zn concentrations was related to soil nutrient concentrations, and to the balance between increased grain yield and its nutrient export. 相似文献
2.
《European Journal of Agronomy》2000,12(1):37-54
APSIM Nwheat is a crop system simulation model, consisting of modules that incorporate aspects of soil water, nitrogen (N), crop residues, and crop growth and development. The model was applied to simulate above- and below-ground growth, grain yield, water and N uptake, and soil water and soil N of wheat crops in the Netherlands. Model outputs were compared with detailed measurements of field experiments from three locations with two different soil types. The experiments covered two seasons and a range of N-fertiliser applications. The overall APSIM Nwheat model simulations of soil mineral N, N uptake, shoot growth, phenology, kernels m−2, specific grain weight and grain N were acceptable. Grain yields (dry weight) and grain protein concentrations were well simulated with a root mean square deviation (RMSD) of 0.8 t ha−1 and 1.6 protein%, respectively. Additionally, the model simulations were compared with grain yields from a long-term winter wheat experiment with different N applications, two additional N experiments and regional grain yield records. The model reproduced the general effects of N treatments on yields. Simulations showed a good consistency with the higher yields of the long-term experiment, but overpredicted the lower yields. Simulations and earlier regional yields differed, but they showed uniformity for the last decade.In a simulation experiment, the APSIM Nwheat model was used with historical weather data to study the relationship between rate and timing of N fertiliser and grain yield, grain protein and soil residual N. A median grain yield of 4.5 t ha−1 was achieved without applying fertiliser, utilising mineral soil N from previous seasons, from mineralisation and N deposition. Application of N fertiliser in February to increase soil mineral N to 140 kg N ha−1 improved the median yield to 7.8 t ha−1 but had little effect on grain protein concentration with a range of 8–10%. Nitrogen applications at tillering and the beginning of stem elongation further increased grain yield and in particular grain protein, but did not affect soil residual N, except in a year with low rainfall during stem elongation. A late N application at flag leaf stage increased grain protein content by several per cent. This increase had only a small effect on grain yield and did not increase soil residual N with up to 40 kg N ha−1 applied, except when N uptake was limited by low rainfall in the period after the flag leaf stage. The economic and environmental optima in winter wheat were identified with up to 140 kg N ha−1 in February, 90 kg N ha−1 between tillering and beginning of stem elongation and 40 kg N ha−1 at flag leaf stage resulting in a median of 8.5 t ha−1 grain yield, 14.0% grain protein and 13 kg N ha−1 soil residual N after the harvest. The maximum simulated yield with maximum N input from two locations in the Netherlands was 9.9 t ha−1. 相似文献
3.
《European Journal of Agronomy》2007,26(1):39-53
Fourteen durum wheat (Triticum durum Desf.) cultivars introduced in Italy between 1900 and 1990 were grown for 2 years (2001 and 2002) at Foggia (Italy) in field trials with three agronomic treatments in order to assess the genetic improvement in agronomic and qualitative parameters. The traits were measured in the field to describe the biomass production and its partitioning to the grain, the phenological behaviours and the photosynthetic properties. Grain protein content, alveograph's W-index, carotenoid pigments content, ash content and the glutenin and gliadin subunit compositions were then measured to assess grain quality. The results showed that differences in agronomic traits among durum wheat cultivars released in Italy in the last century are generally similar to differences observed in hexaploid wheat, with an annual genetic yield gain of 19.9 kg ha−1 year−1. The genetic gain was most clearly associated with a higher kernels number m−2 indicating a larger grain-sink size and a higher number of spikes m−2. The gradual reduction in plant height associated with an increased harvest index has represented the main breeding goal with an effect on the sink capacity and on the biomass partitioning. The progressive incorporation into recent cultivars, of favourable alleles (7 + 8 glutenin subunit composition) coding for superior quality subunits reflects the improvement in pasta making quality of the recent genotypes. 相似文献
4.
《European Journal of Agronomy》2005,22(1):95-100
In recent years, the cultivation of the pseudocereal species amaranth, quinoa, and buckwheat has gained rising attention. This study was undertaken to explore nitrogen (N) fertility requirements and nitrogen use efficiency of these species. For this purpose, a 2-year field experiment with N rates of 0, 80, and 120 kg N ha−1 for amaranth and quinoa and 0, 30, and 60 kg N ha−1 for buckwheat and two cultivars of each species was conducted.Grain yield of amaranth responded to N and ranged between 1986 and 2767 kg ha−1. Nitrogen utilization efficiency (NUtE) ranged from 13.9 to 15.4 kg grain yield per kg above-ground plant N and decreased with increasing N rate. Higher grain yields and NUtEs seemed to be mainly inhibited by the low harvest index (0.22–0.23) of the investigated amaranth cultivars.Quinoa yielded between 1790 and 3495 kg grain ha−1 and responded strongly to N fertilization. NUtE averaged 22.2 kg kg−1 and did not decrease with increasing N rates.The grain yield of buckwheat did not respond to N fertilization and averaged 1425 kg ha−1. N uptake increased only slightly with N fertilization. NUtE ranged from 16.1 to 20.0 kg kg−1. Main problems occurring with the application of N to buckwheat were grain scattering and lodging. 相似文献
5.
Poor soil and drought stress are common in semiarid areas of China, but maize has a high demand for nitrogen (N) and water. Maize production using the technique of double ridges and furrows mulched with plastic film are being rapidly adopted due to significant increases in yield and water use efficiency (WUE) in these areas. This paper studied N use and water balance of maize crops under double ridges and furrows mulched with plastic-film systems in a semiarid environment over four growing seasons from 2007 to 2010. To improve precipitation storage in the non-growing season, the whole-year plastic-film mulching technique was used. There were six treatments which had 0, 70, 140, 280, 420 or 560 kg N ha−1 applied in every year for maize. In April 2011, spring wheat was planted in flat plots without fertilizer or mulch following four years of maize cultivation. After four years, all treatments not only maintained soil water balance in the 0–200 cm soil layer but soil water content also increased in the 0–160 cm soil layer compared to values before maize sowing in April 2007. However, under similar precipitation and only one season of spring wheat, soil water content in the 0–160 cm soil layer sharply decreased in all treatments compared to values before sowing in April 2011. Over the four years of maize cultivation, average yield in all treatments ranged from 4071 to 6676 kg ha−1 and WUE ranged from 18.2 to 28.2 kg ha−1 mm−1. In 2011, the yield of spring wheat in all treatments ranged from 763 to 1260 kg ha−1 and WUE from 3.5 to 6.5 kg ha−1 mm−1. The potential maximum grain yield for maize was 6784 kg ha−1 with 360 kg N ha−1 applied for four years, but considerable NO3N accumulated in the soil profile. A lesser application (110 kg N ha−1) to this tillage system yielded in 82% of the maximum, increased nitrogen use efficiency and mitigated the risk of nitrogen loss from the system. This study suggests that double ridge–furrow and whole-year plastic-film mulching could sustain high grain yields in maize with approximately 110 kg N ha−1 and maintain soil water balance when annual precipitation is >273 mm in this semiarid environment. 相似文献
6.
Farmers obtain high yield when proper crop management is matched with favourable weather. Nitrogen (N) fertilization is an important agronomic management practice because it affects profitability and the environment. In rainfed environments, farmers generally apply uniform rates of N without taking into account the spatial variability of soil available water or nutrient availability. Uniform application of fertilizer can lead to over or under-fertilization, decreasing the efficiency of the fertilizer use. The objective of this study was to evaluate the impact of variable rate nitrogen fertilizer application on spatial and temporal patterns of wheat grain yield. The study was conducted during the 2008/2009 and 2009/10 growing seasons in a 12 ha field near Foggia, Italy. The crop planted each year was durum wheat (Triticum durum, Desf.) cultivar Duilio. The field was subdivided into two management zones High (H), and Average (A). Three N rates were identified using a crop model tested on the same field during a previous growing season. The N rates were: low N (T1: 30 kg N ha−1), average N (T2: 70 kg N ha−1), and high N (T3: 90 kg N ha−1). The ANOVA test showed that there were no effects of the N levels for the first growing season for the H and A zone. For the 2009/10 growing season with higher rainfall there was a significant difference in grain yield for the A zone (2955 kg ha−1), but not in the H zone (3970 kg ha−1). This study demonstrates the optimal amount of N for a given management zone is not fixed but varies with the rainfall amount and distribution during the fallow and growing season. 相似文献
7.
《European Journal of Agronomy》2005,22(1):71-84
Different preceding crops interact with almost all husbandry and have a major effect on crop yields. In order to quantify the yield response of winter wheat, a field trial with different preceding crop combinations (oilseed rape (OSR)–OSR–OSR–wheat–wheat–wheat), two sowing dates (mid/end of September, mid/end of October) and 16 mineral nitrogen (N) treatments (80–320 kg N ha−1) during 1993/1994–1998/1999, was carried out at Hohenschulen Experimental Station near Kiel in NW Germany. Single plant biomass, tiller numbers m−2, biomass m−2, grain yield and yield components at harvest were investigated. During the growing season, the incidence of root rot (Gaeumannomyces graminis) was observed. Additionally, a bioassay with Lemna minor was used to identify the presence of allelochemicals in the soil after different preceding crops.Averaged over all years and all other treatments, wheat following OSR achieved nearly 9.5 t ha−1, whereas the second wheat crop following wheat yielded about 0.9 t ha−1 and the third wheat crop following 2 years of wheat about 1.9 t ha−1 less compared with wheat after OSR. A delay of the sowing date only marginally decreased grain yield by 0.2 t ha−1. Nitrogen fertilization increased grain yield after all preceding crop combinations, but at different levels. Wheat grown after OSR reached its maximum yield of 9.7 t ha−1 with 210 kg N ha−1. The third wheat crop required a N amount of 270 kg N ha−1 to achieve its yield maximum of 8.0 t ha−1.Yield losses were mainly caused by a lower ear density and a reduced thousand grain weight. About 4 weeks after plant establishment, single wheat plants following OSR accumulated more biomass compared to plants grown after wheat. Plants from the third wheat crop were smallest. This range of the preceding crop combinations was similar at all sampling dates throughout the growing season.Root rot occurred only at a low level and was excluded to cause the yield losses. The Lemna bioassay suggested the presence of allelochemicals, which might have been one reason for the poor single plant development in autumn.An increased N fertilization compensated for the lower number of ears m−2 and partly reduced the yield losses due to the unfavorable preceding crop combination. However, it was not possible to completely compensate for the detrimental influences of an unfavorable preceding crop on the grain yield of the subsequent wheat crop. 相似文献
8.
The objective of this study was to characterize physiologically wheat cultivars released in different decades and identify selection criteria for the continued genetic progress in Brazil. Ten cultivars released from 1940 up to 2009 were tested during 2010 and 2011 crop seasons. The following traits were evaluated: grain yield (GY), thousand-kernel weight (TKW), grain number per m−2 (GN), plant height (PH), harvest index (HI), above-ground biomass (BIO), relative Chlorophyll content and leaf gas exchanges. The increase in grain yield was 29 kg ha−1 yr−1 a genetic gain of 0.92%, annually. Grain yield improvement was largely associated with HI (0.94**), number of grains m−2 (0.93**), BIO (0.88**) and reduced PH (−0.93**). The post-anthesis Chlorophyll content, stomatal conductance and pre/post-anthesis photosynthetic rate were positively correlated with GY. Genetic gains of Brazilian wheat are mainly related to the increases of HI, GN, and BIO. These improvements were achieved by reducing PH and raising gas exchanges and chlorophyll content. 相似文献
9.
Excessive application of N fertilizer in pursuit of higher yields is common due to poor soil fertility and low crop productivity. However, this practice causes serious soil depletion and N loss in the traditional wheat cropping system in the Loess Plateau of China. Growing summer legumes as the green manure (GM) crop is a viable solution because of its unique ability to fix atmospheric N2. Actually, little is known about the contribution of GM N to grain and N utilization in the subsequent crop. Therefore, we conducted a four-year field experiment with four winter wheat-based rotations (summer fallow-wheat, Huai bean–wheat, soybean–wheat, and mung bean–wheat) and four nitrogen fertilizer rates applied to wheat (0, 108, 135, and 162 kg N/ha) to investigate the fate of GM nitrogen via decomposition, utilization by wheat, and contribution to grain production and nitrogen economy through GM legumes. Here we showed that GM legumes accumulated 53–76 kg N/ha per year. After decomposing for approximately one year, more than 32 kg N/ha was released from GM legumes. The amount of nitrogen released via GM decomposition that was subsequently utilized by wheat was 7–27 kg N/ha. Incorporation of GM legumes effectively replaced 13–48% (average 31%) of the applied mineral nitrogen fertilizer. Additionally, the GM approach during the fallow period reduced the risk of nitrate-N leaching to depths of 0–100 cm and 100–200 cm by 4.8 and 19.6 kg N/ha, respectively. The soil nitrogen pool was effectively improved by incorporation of GM legumes at the times of wheat sowing. Cultivation of leguminous GM during summer is a better option than bare fallow to maintain the soil nitrogen pool, and decrease the rates required for N fertilization not only in the Loess Plateau of China but also in other similar dryland regions worldwide. 相似文献
10.
No tillage (NT) in wheat (Triticum aestivum L.) offers a pragmatic option for resolving the time and edaphic conflicts in rice (Oryza sativa L.)–wheat cropping system (RWS). However, poor stand establishment is an issue in NT wheat, which adversely affects crop growth, grain yield, and profitability. Therefore, a 2-year field study was conducted to assess the potential role of seed priming in improving the stand establishment, grain yield, water productivity and profitability of NT and plough till (PT) wheat grown after direct seeded aerobic (conservation) and puddled transplanted flooded (conventional) rice-based systems. For seed priming, wheat seeds were soaked in aerated water (hydropriming) or solution of CaCl2 (ψs −1.25 MPa; osmopriming) for 12 h, and non-primed seeds were used as control. After harvest of rice, grown as direct seeded aerobic and puddled transplanted flooded crop, primed and non-primed wheat seeds were sown following NT and PT. In both years, stand establishment of NT wheat after direct seeded aerobic and puddled transplanted flooded rice was impeded. Nonetheless, seed priming improved the stand establishment which was visible through earliness and better uniformity of seedling emergence. Overall, primed seeds completed 50% emergence in 6.4 days, against 7.8 days taken by non-primed seeds in NT wheat. The highest emergence index (41.7) was recorded in primed seeds versus 32.0 for non-primed seeds. Improved stand establishment enhanced growth, grain yield, water productivity and profitability in NT wheat. In this regard, osmopriming was the most effective, and produced grain yield of 4.5 Mg ha−1 against 3.8 Mg ha−1 for non-primed seeds in NT wheat. Water productivity of the NT wheat grown from osmoprimed seeds was 8.72 kg ha−1 mm−1 while that from non-primed seeds was 7.21 kg ha−1 mm−1. Among the RWSs, the maximum wheat biomass was produced with PT after direct seeded aerobic rice. However, grain yield, water productivity, and profitability were the highest in NT wheat following direct seeded aerobic rice. Wheat yields grown after direct seeded aerobic rice and transplanted flooded rice were 4.4 and 4.2 Mg ha−1 respectively. Planting NT wheat after direct seeded aerobic rice provided the highest system productivity (1.80) than other RWSs. Thus, seed priming is a viable option to improve the stand establishment, grain yield, water productivity and profitability of NT wheat in the RWS. Nonetheless, osmopriming was a better option than hydropriming in this regard. 相似文献
11.
The reduction in crop diversity and specialization of cereal-based cropping systems have led to high dependence on synthetic nitrogen (N) fertilizer in many areas of the globe. This has exacerbated environmental degradation due to the uncoupling of carbon (C) and N cycles in agroecosystems. In this experiment, we assessed impacts of introducing grain legumes and cover crops to innovative cropping systems to reduce N fertilizer application while maintaining wheat yields and grain quality. Six cropping systems resulting from the combination of three 3-year rotations with 0, 1 and 2 grain legumes (GL0, GL1 and GL2, respectively) with (CC) or without (BF, bare fallow) cover crops were compared during six cropping seasons. Durum wheat was included as a common high-value cash crop in all the cropping systems to evaluate the carryover effects of rotation. For each cropping system, the water use efficiency for producing C in aerial biomass and yield were quantified at the crop and rotation scales. Several diagnostic indicators were analyzed for durum wheat, such as (i) grain yield and 1000-grain weight; (ii) aboveground biomass, grain N content and grain protein concentration; (iii) water- and N-use efficiencies for yield; and (iv) N harvest index. Compared to the GL0-BF cropping system, which is most similar to that traditionally used in southwestern France, N fertilizer application decreased by 58%, 49%, 61% and 56% for the GL1-BF, GL1-CC, GL2-BF and GL2-CC cropping systems, respectively. However, the cropping systems without grain legumes (GL0-BF and GL0-CC) had the highest water use efficiency for producing C in aerial biomass and yield. The insertion of cover crops in the cropping systems did not change wheat grain yield, N uptake, or grain protein concentration compared to those of without cover crops, demonstrating a satisfactory adaptation of the entire cropping system to the use of cover crops. Winter pea as a preceding crop for durum wheat increased wheat grain production by 8% (383 kg ha−1) compared to that with sunflower − the traditional preceding crop − with a mean reduction in fertilizer application of 40–49 kg N ha−1 during the six-year experiment. No differences in protein concentration of wheat grain were observed among preceding crops. Our experiment demonstrates that under temperate submediterranean conditions, properly designed cropping systems that simultaneously insert grain legumes and cover crops reduce N requirements and show similar wheat yield and grain quality attributes as those that are cereal-based. 相似文献
12.
Nitrogen (N) and plant density are two crucial factors that affect winter wheat (Triticum aestivum L.) yield and quality, but little is known regarding the effects of interactions between these two factors on the amount and size distribution of protein fractions and quality traits. We grew the bread wheat cultivar Jinan17 in two successive seasons (2012–2013 and 2013–2014) at three densities of 120 plants m−2 (low), 180 plants m−2 [the usual rate for a multiple-spike cultivar with high tillering ability in the North China Plain (NCP)], and 240 plants m−2 (high) and two levels of N fertilisation of 0 (low N availability treatment without N fertilisation) and 240 kg ha−1 (the usual N rate for winter wheat production in the NCP) to evaluate the effect of N level × plant density interaction on grain yield, grain protein concentration, the amount and composition of protein fractions, dough development time, dough stability time, and loaf volume. The effect of plant density on Jinan 17 grain yield and quality differed between the two N levels. As plant density increased, all the parameters listed above decreased under 0 kg ha−1 N fertilisation, but increased under 240 kg ha−1 N fertilisation. Stepwise regression analysis showed that the dough rheological properties and breadmaking quality of Jinan 17 were affected by plant density under both N levels, primarily through changes in the polymerisation degree of glutenins in the flour. 相似文献
13.
《European Journal of Agronomy》2007,26(2):154-165
Fertiliser recommendation systems should aim at a finer tuning of non-renewable P inputs for agronomic, environmental and economic reasons. Modern decision support systems should take into account the relevant soil characteristics, the P recycling capabilities of the cropping system, and crop requirements for attainable production in a range of soil/weather conditions. Unfortunately, information is still lacking for low input cropping systems in south-western France. In 1968 INRA Toulouse set up a P experiment, which has been going on for 36 years, on a deep alluvial silty-clay/clay soil with varying CaCO3. Four P regimes (P0, P1, P2, P4) were arranged in four blocks with periodic changes in the fertiliser dressings. Wheat, maize, sunflower, sorghum and soybean were tested for grain yield (GY) and grain P concentration (GPC) response to soil Olsen P concentration. The highest GY were observed in both P2 and P4, although P1 yields were significantly lower in only 4 years out of 36. P0 resulted 32 times in lower yields than P2–P4 and 27 times in lower yields than P1. Wheat was the crop most sensitive to the absence of P fertilization (GYP0/GYPmax = 0.72); maize and sorghum were intermediate (0.77) and sunflower was the less sensitive on average (0.83). As the highest GPC values were observed in the P4 treatments, P removal was maximum for P4 (21.9 kg P ha−1 year−1) and minimal in P0 (11.7 kg P ha−1 year−1). The critical soil Olsen P values for yield responses were determined using the Cate–Nelson and Mitscherlich approaches. Although the thresholds differ for the two methods (3.3–7.2 mg P kg−1 with Cate–Nelson; 4.4–11.2 mg P kg−1 with Mitscherlich), crops ranked similarly with both methods. Critical soil P values were lowest for maize and highest for sunflower, while wheat, soybean and sorghum had intermediate values. Because of low-input management and frequent water stress, critical values fall within the lower range of published values. Only in the P4 treatment were P-Olsen values potentially hazardous for the environment (>20 mg P kg−1) 8–10 years after the beginning of the experiment. Annual P dressings of 17.5 kg P ha−1 year−1 (P1) were sufficient to achieve good yields but P dressings of 35 kg P ha−1 year−1 (P2) were necessary to stabilize soil P around the critical level in the calcareous part of the experiment. 相似文献
14.
The sustainability of growing a maize—winter wheat double crop rotation in the North China Plain (NCP) has been questioned due to its high nitrogen (N) fertiliser use and low N use efficiency. This paper presents field data and evaluation and application of the soil–vegetation–atmosphere transfer model Daisy for estimating crop production and nitrate leaching from silty loam fields in the NCP. The main objectives were to: i) calibrate and validate Daisy for the NCP pedo-climate and field management conditions, and ii) use the calibrated model and the field data in a multi-response analyses to optimise the N fertiliser rate for maize and winter wheat under different field managements including straw incorporation.The model sensitivity analysis indicated that a few measurable crop parameters impact the simulated yield, while most of the studied topsoil parameters affect the simulated nitrate leaching. The model evaluation was overall satisfactory, with root mean squared residuals (RMSR) for simulated aboveground biomass and nitrogen content at harvest, monthly evapotranspiration, annual drainage and nitrate leaching out of the root zone of, respectively, 0.9 Mg ha−1, 20 kg N ha−1, 30 mm, 10 mm and 10 kg N ha−1 for the calibration, and 1.2 Mg ha−1, 26 kg N ha−1, 38 mm, 14 mm and 17 kg N ha−1 for the validation. The values of mean absolute deviation, model efficiency and determination coefficient were also overall satisfactory, except for soil water dynamics, where the model was often found erratic. Re-validation run showed that the calibrated Daisy model was able to simulate long-term dynamics of crop grain yield and topsoil carbon content in a silty loam field in the NCP well, with respective RMSR of 1.7 and 1.6 Mg ha−1. The analyses of the model and the field results showed that quadratic, Mitscherlich and linear-plateau statistical models may estimate different economic optimal N rates, underlining the importance of model choice for response analyses to avoid excess use of N fertiliser. The analyses further showed that an annual fertiliser rate of about 300 kg N ha−1 (100 for maize and 200 for wheat) for the double crop rotation with straw incorporation is the most optimal in balancing crop production and nitrate leaching under the studied conditions, given the soil replenishment with N from straw mineralisation, atmospheric deposition and residual fertiliser.This work provides a sound reference for determining N fertiliser rates that are agro-environmentally optimal for similar and other cropping systems and regions in China and extends the application of the Daisy model to the analyses of complex agro-ecosystems and management practices under semi-arid climate. 相似文献
15.
Decreasing the corn (Zea mays L.) gap between the potential yield and farm yield and reducing the risk of grain yield of drought are very important for corn production in the Corn Belt of Northeast China (CBNC). To achieve a high and stable corn yield, the effects of supplementary irrigation on yield, water use efficiency (WUE) and irrigation water use efficiency (IWUE) were studied using a modelling approach. The Root Zone Water Quality Model 2 was parameterized and evaluated using two years of experimental data in aeolian sandy soil and black soil. The evaluated model was then used to investigate responses to various irrigation strategies (rainfed, full irrigation and 12 single irrigation scenarios) using long-term weather data from 1980 to 2012. Full irrigation guarantees a high and stable corn grain yield (12.92 Mg ha−1 and has a coefficient of variation (CV) of 14.8% in aeolian sandy soil; 12.30 kg Ma−1 and CV of 11.1% in black soil), but has a low water use efficiency (19.92 and 21.81 kg ha−1 mm−1) and a low irrigation water use efficiency (10.01 and 11.03 kg ha−1 mm−1). A single irrigation can increase corn yields by 3–35% for aeolian sandy soil and 5–35% for black soil over different irrigation dates compared with no irrigation. The most suitable single irrigation date was during late June to early July for aeolian sandy soil (yield = 10.73 Mg ha−1 and WUE = 27.94 kg ha−1 mm−1) and early to mid-July for black soil (yield = 11.20 Mg ha−1 and WUE = 27.70 kg ha−1 mm−1). The lowest yield risk of falling short of the yield goal of 8, 9, and 10 Mg ha−1 were 9.1%, 18.2%, and 33.33% in aeolian sandy soil and 3.0%, 15.25, and 21.2% in black soil when an optimized single irrigation was applied in late June or early July, respectively. Therefore, an optimized single irrigation should be applied in late June to early July with the irrigation amount to refill soil water storage of root zone to field capacity in CBNC. 相似文献
16.
Long term investigations on the combined effects of tillage systems and other agronomic practices such as mineral N fertilization under Mediterranean conditions on durum wheat are very scanty and findings are often contradictory. Moreover, no studies are available on the long term effect of the adoption of conservation tillage on grain yield of maize and sunflower grown in rotation with durum wheat under rainfed Mediterranean conditions. This paper reports the results of a 20-years experiment on a durum wheat-sunflower (7 years) and durum wheat–maize (13 years) two-year rotation, whose main objective was to quantify the long term effects of different tillage practices (CT = conventional tillage; MT = minimum tillage; NT = no tillage) combined with different nitrogen fertilizer rates (N0, N1, N2 corresponding to 0, 45 and 90 kg N ha−1 for sunflower, and 0, 90 and 180 kg N ha−1 for wheat and maize) on grain yield, yield components and yield stability for the three crops. In addition, the influence of meteorological factors on the interannual variability of studied variables was also assessed. For durum wheat, NT did not allow substantial yield benefits leading to comparable yields with respect to CT in ten out of twenty years. For both sunflower and maize, NT under rainfed conditions was not a viable options, because of the unsuitable (i.e., too wet) soil conditions of the clayish soil at sowing. Both spring crops performed well with MT. No significant N × tillage interaction was found for the three crops. As expected, the response of durum wheat and maize grain yield to N was remarkable, while sunflower grain yield was not significantly influenced by N rate. Wheat yield was constrained by high temperatures in January during tillering and drought in April during heading. The interannual yield variability of sunflower was mainly associated to soil water deficit at flowering and air temperature during seed filling. Heavy rains during this latter phase strongly constrained sunflower grain yield. Maize grain yield was negatively affected by high temperatures in June and drought in July, this latter factor was particularly important in the fertilized maize. Considering both yield and yield stability, durum wheat and sunflower performed better under MT and N1 while maize performed better under both CT and MT and with N2 rates. The results of this long term study are suitable for supporting policies on sustainable Mediterranean rainfed cropping systems and also for cropping system modelling. 相似文献
17.
Maize production plays an essential role in global food security. In order to maintain both high quality and maize production, there is a great demand for fertilizers. The main objective of this work was to study, over two experimental seasons, the effect of a biofertilizer obtained from sewage sludge (SS) on the yield and on the quality of maize crops (Zea mays L.). The biofertilizer was applied in two ways: (i) to soil, at rates of 0, 10 and 20 Mg ha−1 before sowing, and (ii) via foliar fertilization, applying 0, 3.6 and 7.2 l ha−1 three times during each growing season accounting for a total rate of 0, 10.8 l ha−1 and 21.6 l ha−1. This study is novel because there are no previous studies of the effect of this biofertilizer on any agricultural crops. The results obtained show that, when the SS was applied directly to the soil, the macro- and micronutrients analyzed in both soil and leaves showed no significant differences between either of the fertilizer treatments. Foliar application of SS, however, increased the leaf concentrations of macro- and micronutrients. When the SS rate was 7.2 l ha−1, grain protein concentration increased significantly by about 30% and the yield increased significantly by about 17% compared with the control treatment (SS not applied). These results suggested that, in order to improve agricultural maize yields, quality and nutritional, this SS should be applied as a foliar fertilizer instead of applying it to soil. 相似文献
18.
《European Journal of Agronomy》2006,24(2):149-155
The major objective for clover in a winter wheat/white clover intercropping system is to supply nitrogen (N) for the wheat. A field experiment was repeated in 2 years on a loamy sand in Denmark to investigate the possibilities for increasing N supply to the winter wheat by cutting and mulching the clover between the wheat rows. The clover was cut with a weed brusher on three different dates in each year.Intercropped wheat with unbrushed clover had a lower grain yield than wheat as a sole crop. Brushing increased wheat N uptake and wheat grain yields. Intercropping with two or three brushing dates gave higher wheat yields than wheat as the sole crop. The largest increases in grain N uptake, 21–25 kg N ha−1, were obtained for the brushings around wheat flag leaf emergence. The highest yield increases with a single brushing, 0.98–1.11 Mg DM ha−1, were obtained when brushing was performed during the stem elongation phase. The largest grain yields for treatments with two brushings were obtained with a first brushing at start of stem elongation and a second around flag leaf emergence. The first brushing probably provided N to increase the wheat leaf area index and thus the light interception, while the second brushing provided N to sustain the leaf area during grain filling and reduced clover biomass and therefore competition for water. Intercropping wheat and clover increased grain N concentrations by 0.11–0.39%-point compared with wheat as a sole crop. Intercropping may thus offer possibilities for improving the bread-making quality of organically grown wheat. 相似文献
19.
The effects of soil tillage and straw management systems on the grain yield and nitrogen use efficiency of winter wheat (Triticum aestivum L. em. Thell.) were evaluated in a cool Atlantic climate, in central Ireland between 2009 and 2011. Two tillage systems, conventional tillage (CT) and reduced tillage (RT) each with and without incorporation of the straw of the preceding crop, were compared at five levels of fertiliser N (0, 140, 180, 220 and 260 kg N ha−1).CT had a significantly higher mean grain yield over the three years but the effect of tillage varied between years. Yields did not differ in 2009 (Year 1), while CT produced significantly higher grain yields in 2010 (Year 2), while RT produced the highest yields in 2011 (Year 3). Straw incorporation had no significant effect in any year.Nitrogen application significantly increased the grain yields of all establishment treatment combinations. Nitrogen use efficiency (NUE) ranged from 14.6 to 62.4 kg grain (85% DM) kg N ha−1 and decreased as N fertiliser rate was increased.The CT system had a significantly higher mean NUE over the three years but the effect of tillage varied with years. While there was no tillage effect in years 1 and 3, CT had a significantly higher NUE than RT in year 2. Straw management system had minimal effect on NUE in any year.The effect of tillage and N rate on soil mineral N content also varied between years. While there was no tillage effect in years 1 and 3, RT had significantly larger soil N contents than CT in the spring before N application, and post-harvest in year 2. N application rates had no effect on soil N in year 1, increased residual N content in year 2 and had an inconsistent effect in year 3. Straw management had no significant effect on soil mineral N content.These results indicate that RT establishment systems can be used to produce similar winter wheat yields to CT systems in a cool Atlantic climate, providing weather conditions at establishment are favourable. The response to nitrogen is similar with both tillage systems where the crop is successfully established. Straw management system has very little effect on crop performance or nitrogen uptake. 相似文献
20.
《European Journal of Agronomy》2007,26(2):121-129
The performance of a crop simulation model (agricultural production systems simulator model, APSIM-Nwheat) was tested using data obtained from several locations in the rain-fed environments of West Asia and North Africa (WANA) in Morocco and Jordan. The model was able to simulate wheat grain yields reasonably well except at one site in one season in Morocco. The model was subsequently used to analyze the effect of soil type (soil water-holding capacity), rate and timing of nitrogen (N) fertiliser, initial soil moisture storage, cultivars (early versus late), sowing dates and density and supplemental irrigation (SI) in optimizing wheat production using 20 years of historical weather records from Morocco. The simulation indicated that yields were often limited by the amount and timing of rainfall. While the effect of N fertiliser was minimal or detrimental in dry years, it improved grain yields in wet years and when crops were sown early combined with pre-sown stored plant available water in the soil. The analysis showed that early sowing is important for achieving high yields by avoiding terminal water deficit. There is little difference between grain yields when current practice of about 300 plants/m2 was compared with a density of 150 plants/m2. This implies that there is scope for reducing current planting density to save seeds without reducing yields. The simulation analysis highlighted that 40 mm of SI at sowing significantly improved average grain yields as a result of enabling early crop establishment, in particular with a N fertiliser application of 40 kg N/ha. The analysis indicated that wheat grain yields in the arid and semi-arid rain-fed regions of WANA can be improved compared to current yield levels by adjusting N management to soil type, pre-sowing soil water availability, sowing opportunity and the availability of SI. 相似文献