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1.
This article reports on field experiments with 4 different rotations that are commonly used throughout Haryana in NW India (rice-wheat, cotton-wheat, pearl millet-wheat, cluster bean-wheat), where we assess wheat yield and chapatti quality measures with different crop establishment methods and input of micronutrients. In a series of experiments conducted on farmers’ fields in 2007-2008 and 2008-2009 winter seasons, the addition of micronutrients and sulphur to wheat crops was used alongside the use of a common farmer practice, the use of farmyard manure (FM) and best practice inputs of N-fertilizer (150 kg N ha−1), P-fertilizer (26 kg P ha−1) and K-fertilizer (33 kg K ha−1). The application of FM with the recommended NPK treatment produced 9-13% more grain yield in the rice-wheat rotation when compared with the recommended NPK only treatment. Given that the farm sites used here had low levels of soil P, this may suggest that the recommended rate of 26 kg P ha−1 for the rice-wheat rotation is too low. The addition of FM did not improve any grain quality outcomes at any of the sites. There were no yield responses with S application with any of the rotations but the S input resulted in more wheat protein from all sites (average 8%). The addition of S also gave similar increases in grain hardness and the chapatti score. The inclusion of micronutrients (boron, copper, iron, zinc and manganese) with the recommended NPK treatment did not increase the grain yield at any of the sites when compared with the recommended NPK treatment, and sometimes, but not consistently, gave small responses with protein, grain hardness and chapatti score. In concurrent experiments wheat growth and chapatti quality were compared in zero till and conventionally sown systems, and with and without S fertilizer amendment. Here too there were no grain yield responses to S, and the protein, grain hardness and chapatti score were increased with S addition. Grain yields with zero till and conventional wheat were similar in the rice-wheat system and zero till sowing resulted in small increases in yield at all of the non-rice sites. The grain from the zero till treatments had higher protein (1-3%), grain hardness (3-10%) and chapatti score from all 4 rotations. Zero till has substantial adoption in the rice-wheat districts of Haryana but little farmer awareness and adoption in the areas where the other rotations are used. The data given here show that with zero tillage and an integrated practice of nutrient management farmers in Haryana can maintain grain yields of wheat whilst improving quality outcomes.  相似文献   

2.
Rotations are important practices for managing soil fertility on smallholder farms. Six cropping sequences (cassava, pigeonpea, mucuna–maize–mucuna, cowpea–maize–cowpea, maize–maize–maize, and speargrass fallow) were evaluated during 2003–2004 in Wenchi district of Ghana for their effects on the profitability of the different rotations and the productivity of subsequent maize. Soil chemical properties were not significantly affected by cropping sequence. On the researcher-managed and farmer-managed plots maize grain yields were significantly influenced by cropping sequence. On the researcher-managed plots maize grain yield ranged from 1.0 t ha−1 after speargrass fallow to 3.0 t ha−1 with cassava cropping when N fertiliser was not applied to maize and from 2.1 t ha−1 with continuous maize to 4.2 t ha−1 with mucuna–maize–mucuna when 60 kg N ha−1 was applied to maize. On the farmer-managed plots where N fertiliser was not applied to maize, maize grain yields ranged from 0.4 t ha−1 on speargrass fallow to 2.2 t ha−1 on plots previously cropped to pigeonpea. High maize grain yields associated with the cropping sequences involving cassava, mucuna and pigeonpea were related to the faster decomposition and N release of the biomass compared with the slower release of N by the poorer quality materials like maize stover and speargrass. Return on investment of the different rotational sequences ranged from −22% with speargrass/maize to 235% with cassava/maize when no N application was made to maize, and from 29% with continuous maize to 196% with cassava/maize when N fertiliser was applied to maize. Cassava/maize rotation was ranked by native farmers as the most preferred rotation whereas migrant farmers ranked cowpea–maize–cowpea–maize as the most preferred rotation. Among natives, male farmers ranked rotation involving cowpea as the next most preferred rotation after cassava/maize. In contrast, female farmers ranked pigeonpea/maize rotation as the second most preferred rotation, due to low labour and external input requirements of pigeonpea compared with cowpea. The choice of a particular rotational sequence is related to access to resources and the needs of the farmer. The study therefore suggests that, in a heterogeneous farming community like Wenchi, technology development should be targeted to suit the needs and resources available to each particular group of farmers.  相似文献   

3.
Wheat-maize double cropping is the most important cropping system on the Hebei Plain and is one of the most important cropping systems in China. In a scenario of greater food demand, and increasing water and rural labour scarcity, it is critical that the annual productivity of the system is improved in water-energy-cost efficient and low carbon ways. Based on farm surveys, this paper benchmarked the performance of wheat-maize double crops on the Hebei Plain during the 2004-2005 season. These farm yields were assessed both against experimental yields collected from on-farm maximum yield trials conducted during the same 2004-2005 season and relative to simulated estimates of the climate-driven potential productivity of the region.The survey of 362 farms in six counties of the Hebei Plain during the 2004-2005 season found wheat yields ranging from 3375 kg ha−1 to 9000 kg ha−1 with an overall average yield of 6556 kg ha−1. Maize yields averaged 7549 kg ha−1 and ranged from 3375 kg ha−1 to 11,250 kg ha−1. The aggregate production for the wheat-maize double crops grown in the 2004-2005 season averaged 14,105 kg ha−1 across the six counties. This was 72% of the average production (19,586 kg ha−1) recorded from on-farm trials conducted in each of the six counties and 60% of the simulated average production potential (24,147 kg ha−1) for the Hebei Plain in the 2004-2005 season. Thus, the annual productivity of the current cropping system could be increased with currently available technologies by 28%, while a yield increase of 42% is possible if farm yields approach the simulated yield potential.Based on farmer interviews and field observations, a number of real and perceived reasons for the current yield gaps in farmers’ fields were recognised. For instance, irrigation at stem-elongation of wheat is a current recommendation, yet only a proportion of the surveyed farmers were able to follow this strategy due to lack of access to shared irrigation facilities. Improving the region's infrastructure to enable more timely irrigation of crops will be a necessary prerequisite to improved productivity.The results from the farm surveys and on-farm trials indicate that, with current recommended practices, farmers can improve their annual farm productivity and close the current yield gaps. However, the survey identified that increasing system performance and efficiency will require a focus on both agronomic and socio-economic issues.  相似文献   

4.
Aerobic rice describes a management adaptation to reduced irrigation water supplies but, due to reduced intervals of flooding in this system, this requires revised weed management approaches to reduce costs and provide effective weed control. One approach is to make the crop more competitive and reduce the effects of weeds on the crop by using higher rice seeding rates. A study was conducted in the Philippines and India in 2008 and 2009 to assess the relations of seeding rates (15-125 kg ha−1) of hybrid and inbred varieties to crop and weed growth in aerobic rice. Plant densities, tillers, and biomass of rice increased linearly with increased in seeding rates under both weedy and weed free environments. Weed biomass decreased linearly with increasing seeding rates from 15 to 125 kg ha−1. Panicles and grain yields of rice in competition with weeds increased in a quadratic relation with increased seeding rates at both locations; however, the response was flat in the weed free plots. A quadratic model predicted that seeding rates of 48-80 kg ha−1 for the inbred varieties and 47-67 kg ha−1 for the hybrid varieties were needed to achieve maximum grain yield when grown in the absence of weeds, while rates of 95-125 kg seed ha−1 for the inbred varieties and 83-92 kg seed ha−1 for the hybrid varieties were needed to achieve maximum yields in competition with weeds. On the basis of these results, seeding rates greater than 80 kg ha−1 are advisable where there are risks of severe weed competition. Such high seeding rates may be prohibitive when using expensive seed, and maximum yields are not the only consideration for developing recommendations for optimizing economic returns for farmers. Results of the present study do suggest however that increasing seeding rates of aerobic rice does suppress weed growth and reduce grain yield losses from weed competition. This information could be incorporated in integrated crop management packages to manage weeds more effectively.  相似文献   

5.
Retention and/or reincorporation of plant residues increases soil organic nitrogen (N) levels over the long-term is associated with increased crop yields. There is still uncertainty, however, about the interaction between crop residue (straw) retention and N fertilizer rates and sources. The objective of the study was to assess the influence of straw management (straw removed [SRem] and straw retained [SRet]), N fertilizer rate (0, 25, 50 and 75 kg N ha−1) and N source (urea and polymer-coated urea [called ESN]) under conventional tillage on seed yield, straw yield, total N uptake in seed + straw and N balance sheet. Field experiments with barley monoculture (1983-1996), and wheat/barley-canola-triticale-pea rotation (1997-2009) were conducted on two contrasting soil types (Gray Luvisol [Typic Haplocryalf] loam soil at Breton; Black Chernozem [Albic Argicryoll] silty clay loam at Ellerslie) in north-central Alberta, Canada. On the average, SRet produced greater seed yield (by 205-220 kg ha−1), straw yield (by 154-160 kg ha−1) and total N uptake in seed + straw (by 5.2 kg N ha−1) than SRem in almost all cases in both periods at Ellerslie, and only in the 1997-2009 period at Breton (by 102 kg seed ha−1, 196 kg straw ha−1 and by 3.7 kg N ha−1) for both N sources. There was generally a considerable increase in seed yield, straw yield and total N uptake in seed + straw from applied N up to 75 kg N ha−1 rate for both N sources at both sites and more so at Breton, but the response to applied N decreased with increasing N rate. The ESN was superior to urea in increasing seed yield (by 109 kg ha−1), straw yield (by 80 kg ha−1) and total N uptake in seed + straw (by 2.4 kg N ha−1) in the 1983-1996 period at Breton (mainly at the 25 and 50 kg N ha−1 rates). But, urea produced greater straw yield (by 95 kg ha−1) and total N uptake in seed + straw (by 3.3 kg N ha−1) than ESN in the 1983-1996 period at Ellerslie. The N balance sheets over the 1983-2009 study duration indicated large amounts of applied N unaccounted for (ranged from 740 to 1518 kg N ha−1 at Breton and from 696 to 1334 kg N ha−1 at Ellerslie), suggesting a great potential for N loss from the soil-plant system through denitrification and/or nitrate leaching, and from the soil mineral N pool by N immobilization. In conclusion, the findings suggest that long-term retention of crop residue may gradually improve soil productivity. The effectiveness of N source varied with soil type.  相似文献   

6.
In the low-input rice–wheat production systems of Nepal, the N nutrition of both crops is largely based on the supply from soil pools. Declining yield trends call for management interventions aiming at the avoidance of native soil N losses. A field study was conducted at two sites in the lowland and the upper mid-hills of Nepal with contrasting temperature regimes and durations of the dry-to-wet season transition period between the harvest of wheat and the transplanting of lowland rice. Technical options included the return of the straw of the preceding wheat crop, the cultivation of short-cycled crops during the transition season, and combinations of both. Dynamics of soil Nmin, nitrate leaching, nitrous oxide emissions, and crop N uptake were studied throughout the year between 2004 and 2005 and partial N balances of the cropping systems were established. In the traditional system (bare fallow between wheat and rice) a large accumulation of soil nitrate N and its subsequent disappearance upon soil saturation occurred during the transition season. This nitrate loss was associated with nitrate leaching (6.3 and 12.8 kg ha−1 at the low and high altitude sites, respectively) and peaks of nitrous oxide emissions (120 and 480 mg m−2 h−1 at the low and high altitude sites, respectively). Incorporation of wheat straw at 3 Mg ha−1 and/or cultivation of a nitrate catch crop during the transition season significantly reduced the build up of soil nitrate and subsequent N losses at the low altitude site. At the high altitude site, cumulative grain yields increased from 2.35 Mg ha−1 with bare fallow during the transition season to 3.44 Mg ha−1 when wheat straw was incorporated. At the low altitude site, the cumulative yield significantly increased from 2.85 Mg ha−1 (bare fallow) to between 3.63 and 6.63 Mg ha−1, depending on the transition season option applied. Irrespective of the site and the land use option applied during the transition season, systems N balances remained largely negative, ranging from −37 to −84 kg N ha−1. We conclude that despite reduced N losses and increased grain yields the proposed options need to be complemented with additional N inputs to sustain long-term productivity.  相似文献   

7.
The crop-soil simulation model CropSyst was used to simulate growth, water- and N-uptakes of irrigated winter wheat (Triticum aestivum L. cv. Kupava) in Khorezm, in the dry lands of northwest Uzbekistan, Central Asia. CropSyst was calibrated using the findings of field experiments of 2005/06 and 2006/07 and validated for the 2007/08 season. A relative root mean squared error of 11% proved the accuracy between simulated and observed aboveground biomass and grain yield in 2007/08. Scenario analyses showed that N-leaching was high and ranged from 63 to 106 kg ha−1 when irrigated between 749 and 869 mm during the first two cropping seasons. The simulated N-leaching was lowest and ranged from 7 to 15 kg ha−1 when irrigation was only 148–395 mm during 2007/08. The considerable N losses during leaching and high N-uptakes by wheat together resulted in a negative N-balance even during applications of 180 and 240 kg ha−1 of N-fertilizer. N scarcity in the N-balance was reduced with increasing N-fertilizer amounts and ranged from −29 to −153 kg N ha−1 in 2005/06 and 2006/07. Despite a common shallow groundwater table in the region during some time of the year, scenario analysis revealed that only full irrigation water (580 mm) and N supply according to crop demand (180 kg ha−1) guaranteed high grain yields, unless the water table is permanently shallow to overcome irrigation deficits. Limited irrigation and N application (40% and 55% of ‘optimal’, respectively) in combination with a groundwater table below 3 m resulted in a 55% yield decline. The CropSyst wheat model proved a robust tool for assessing the influence of water and N dynamics under conditions of varying irrigation and shallow groundwater tables. It thus has potential as a decision support not only in northwest Uzbekistan, but also in comparable regions of Central Asia.  相似文献   

8.
The CERES-sorghum module of the Decision Support System for Agro-Technological Transfer (DSSAT) model was calibrated for sorghum (Sorghum bicolor (L.) Moench) using data from sorghum grown with adequate water and nitrogen and evaluated with data from several N rates trials in Navrongo, Ghana with an overall modified internal efficiency of 0.63. The use of mineral N fertilizer was found to be profitable with economically optimal rates of 40 and 80 kg N ha−1 for more intensively managed homestead fields and less intensively managed bush fields respectively. Agronomic N use efficiency varied from 21 to 37 kg grain kg−1 N for the homestead fields and from 15 to 49 kg grain kg−1 N in the bush fields. Simulated grain yield for homestead fields at 40 kg N ha−1 application was equal to yield for bush fields at 80 kg N ha−1. Water use efficiency generally increased with increased mineral N rate and was greater for the homestead fields compared with the bush fields. Grain yield per unit of cumulative evapo-transpiration (simulated) was consistently higher compared with yield per unit of cumulative precipitation for the season, probably because of runoff and deep percolation. In the simulation experiment, grain yield variability was less with mineral N application and under higher soil fertility (organic matter) condition. Application of mineral N reduced variability in yield from a CV of 37 to 11% in the bush farm and from 17 to 7% in the homestead fields. The use of mineral fertilizer and encouraging practices that retain organic matter to the soil provide a more sustainable system for ensuring crop production and hence food security.  相似文献   

9.
Long-term (over 15 years) winter wheat (Triticum aestivum L.)–maize (Zea mays L.) crop rotation experiments were conducted to investigate phosphorus (P) fertilizer utilization efficiency, including the physiological efficiency, recovery efficiency and the mass (the input–output) balance, at five sites across different soil types and climate zones in China. The five treatments used were control, N, NP, NK and NPK, representing various combinations of N, P and K fertilizer applications. Phosphorus fertilization increased average crop yield over 15 years and the increases were greater with wheat (206%) than maize (85%) across all five sites. The wheat yield also significantly increased over time for the NPK treatments at two sites (Xinjiang and Shanxi), but decreased at one site (Hunan). The P content in wheat was less than 3.00 g kg−1 (and 2.10 g kg−1 for maize) for the N and NK treatments with higher values for the Control, NP and NPK treatments. To produce 1 t of grain, crops require 4.2 kg P for wheat and 3.1 kg P for maize. The P physiological use efficiency was 214 kg grain kg−1 P for wheat and 240 kg grain kg−1 P for maize with over 62% of the P from P fertilizer. Applying P fertilizer at 60–80 kg P ha−1 year−1 could maintain 3–4 t ha−1 yields for wheat and 5–6 t ha−1 yields for maize for the five study sites across China. The P recovery efficiency and fertilizer use efficiency averaged 47% and 29%, respectively. For every 100 kg P ha−1 year−1 P surplus (amount of fertilizer applied in excess of crop removal), Olsen-P in soil was increased by 3.4 mg P kg−1. Our study suggests that in order to achieve higher crop yields, the long-term P input–output balance, soil P supplying capacity and yield targets should be considered when making P fertilizer recommendations and developing strategies for intensively managed wheat–maize cropping systems.  相似文献   

10.
Forages could be used to diversify reduced and no-till dryland cropping systems from the traditional wheat (Triticum aestivum L.)-fallow system in the semiarid central Great Plains. Forages present an attractive alternative to grain and seed crops because of greater water use efficiency and less susceptibility to potentially devastating yield reductions due to severe water stress during critical growth stages. However, farmers need a simple tool to evaluate forage productivity under widely varying precipitation conditions. The objectives of this study were to (1) quantify the relationship between crop water use and dry matter (DM) yield for soybean (Glycine max L. Merrill), (2) evaluate changes in forage quality that occur as harvest date is delayed, and (3) determine the range and distribution of expected DM yields in the central Great Plains based on historical precipitation records. Forage soybean was grown under a line-source gradient irrigation system to impose a range of water availability conditions at Akron, CO. Dry matter production was linearly correlated with water use resulting in a production function slope of 21.2 kg ha−1 mm−1. The slope was much lower than previously reported for forage production functions for triticale (X Triticosecale Wittmack) and millet (Setaria italic L. Beauv.), and only slightly lower than slopes previously reported for corn (Zea mays L.) and pea (Pisum sativa L.) forage. Forage quality was relatively stable during the last four weeks of growth, with small declines in crude protein (CP) concentration. Values of CP concentration and relative feed value indicated that forage soybean was of sufficient quality to be used for dairy feed. A standard seed variety of maturity group VII was found to be similar (in both productivity and quality) to a variety designated as a forage type. The probability of obtaining a break-even yield of at least 4256 kg ha−1 was 90% as determined from long-term precipitation records used with the production function. The average estimated DM yield was 5890 kg ha−1 and ranged from 2437 to 9432 kg ha−1. Regional estimates of mean forage soybean DM yield ranged from 4770 kg ha−1 at Fort Morgan, CO to 6911 kg ha−1 at Colby, KS. Forage soybean should be considered a viable alternative crop for dryland cropping systems in the central Great Plains.  相似文献   

11.
Nitrogen rates and plant genotypes effects yield and quality of medicinal plants therefore, this experiment was conducted in order to determine the effects of nitrogen rates on fennel accessions quality and quantity. The experimental design was a split plot with nitrogen rate (0, 40, 80, 120 and 160 Kg N ha−1) as main and accession (Isfahan, Tehran, Yazd and EU11486) as sub plots and replicated four times. The experiment was conducted at the Isfahan University of Technology Experimental Station, Isfahan, Iran during 2008-2009. Plant height, number of umbel per plant, 1000seed weight, number of seeds per umbel, seed yield, seed essential oil yield, seed and foliage essential oil contents and seed ash, protein and fiber contents were measured. Nitrogen fertilization increased all measured traits, but reduced ash content. On average, the highest seed and foliage essential contents and seed essential yield were produced at 160 kg per N ha−1 and EU11486 was a superior cultivar for these traits. However, there was an interaction between N rate and accession on all traits. Isfahan (11.65 kg ha−1), EU11486 (38.26 kg ha−1), Tehran (15.32 kg ha−1) and Yazd (22.06 kg ha−1) produced the highest seed essential oil yield under application of 160, 80, 160 and 120 kg N ha−1, respectively. Foliage of the accessions contained 0.45-0.91% essential oil and seeds of accessions contained 17.6-18.2% protein and 8.9-9.4% ash suggesting that foliage of fennel also is a good source of essential oil and seeds of fennel are good sources of protein and minerals. The results showed that N fertilization and accession can affect yield and quality of fennel and accessions responded differently to N fertilization rates, thus selection among the accessions and N rates for better fennel production is possible.  相似文献   

12.
Despite large variation among crop genotypes in response to Fe fertilization, there is no reliable indicator for identifying Fe-deficiency tolerant wheat genotypes with high grain yield. The aim of this investigation was to compare the grain yield response of 20 spring and 30 winter bread wheat genotypes to Fe fertilization under field conditions and to select high grain yield Fe-deficiency tolerant genotypes using a stress tolerance indicator (STI). Two individual trials, each one consisting two field plot experiments, were conducted during 2006–2007 and 2007–2008 growing seasons. Spring wheat genotypes (Trial l) and winter wheat genotypes (Trial 2) were planted at two different locations. Two Fe rates (0 and 20 kg Fe ha−1 as Fe-EDTA) were applied. Spring and winter wheat genotypes differed significantly (P < 0.01) in the grain yield both with and without added Fe treatments. Application of Fe fertilizer increased grain yield of spring wheat genotypes by an average of 211 and 551 kg ha−1 in Karaj and Isfahan locations, respectively. By Fe application, the mean grain yield of winter wheat genotypes increased 532 and 798 kg ha−1 in Karaj and Isfahan sites, respectively. Iron efficiency (Fe-EF) significantly differed among wheat genotypes and ranged from 65% to 113% for spring wheat and from 69% to 125% for winter wheat genotypes. No significant correlation was found between Fe-EF and grain yield of spring wheat genotypes under Fe deficient conditions. For winter wheat genotypes grown in Mashhad, Fe-efficiency was not significantly correlated with the grain yield produced without added Fe treatment. The STI was significantly (P < 0.01) varied among spring and winter wheat genotypes. The interaction between location and genotype had no significant effect on the STI. According to these results, the STI should be considered as an effective criterion for screening programs, if a high potential grain yield together with more stable response to Fe fertilization in different environments is desired.  相似文献   

13.
Non-leaf green organs of wheat plants may have significant photosynthetic potential and contribute to grain yield when the plants are subjected to stress at late growth stages. Canopy structure, change of green non-leaf organ area (e.g., ear, peduncle, sheath), the proportion of green non-leaf organs area to total green area and the contribution proportion from different organs’ photosynthate to grain yield in winter wheat (Triticum aestivum L.) were studied at Wuqiao Experiment Station of China Agricultural University, Hebei, China, in 2001-2002 and 2002-2003 using two winter wheat cultivars, Shijiazhuang8 (SJZ-8) and Lumai21 (LM-21). Four irrigation treatments used were W0 (no water applied during spring), W1 (750 m3 ha−1 water applied at elongation), W2 (1500 m3 ha−1 applied 50% at elongation and 50% at anthesis) and W4 (3000 m3 ha−1 applied 25% at upstanding, booting, anthesis and grain filling), respectively. Results showed that the area of top three leaf blades decreased and the proportion of green non-leaf organ area to the total green area at anthesis increased with the decreasing of water supply. Root weight increased in the 0-100 cm soil layer and decreased in the 100-200 cm layer when water supply increased, suggesting reducing irrigation enhanced root weight in deep soil layer. The photosynthetic contribution of non-leaf organs above flag leaf node to grain yield increased with decreasing water supply, and was significantly higher than that of the flag leaf blade contribution. Winter wheat grain yield increased, but water use efficiency (WUE) decreased, with increase in water supply. Higher light transmission ratio in the canopy after anthesis was achieved with smaller size and high quality top leaf blades, higher grain-leaf ratio and larger proportion of green non-leaf area, which lead to higher canopy photosynthetic rate and WUE after anthesis. Irrigation of 1500 m3 ha−1 applied in two parts, 750 m3 ha−1 applied at elongation and another 750 m3 ha−1 applied at anthesis, was the best irrigation scheme for efficient water use and for high yield in winter wheat.  相似文献   

14.
Rainfed crop production in northern China is constrained by low and variable rainfall. This study explored the effects of tillage/crop residue and nutrient management practices on maize (Zea mays L.) yield, water use efficiency (WUE), and N agronomic use efficiency (NAE) at Shouyang Dryland Farming Experimental Station in northern China during 2003–2008. The experiment was set-up using a split-plot design with 3 tillage/crop residue methods as main treatments: conventional, reduced (till with crop residue incorporated in fall but no-till in spring), and no-till (with crop residue mulching in fall). Sub-treatments were 3 NP fertilizer rates: 105–46, 179–78 and 210–92 kg N and P ha−1. Maize grain yields were greatly influenced by the growing season rainfall and soil water contents at sowing. Mean grain yields over the 6-year period in response to tillage/crop residue treatments were 5604, 5347 and 5185 kg ha−1, under reduced, no-till and conventional tillage, respectively. Grain yields under no-till, were generally higher (+19%) in dry years but lower (−7%) in wet years. Mean WUE was 13.7, 13.6 and 12.6 kg ha−1 mm−1 under reduced, no-till, and conventional tillage, respectively. The no-till treatment had 8–12% more water in the soil profiles than the conventional and reduced tillage treatments at sowing and harvest time. Grain yields, WUE and NAE were highest with the lowest NP fertilizer application rates (at 105 kg N and 46 kg P ha−1) under reduced tillage, while yields and WUE tended to be higher with additional NP fertilizer rates under conventional tillage, however, there was no significant yield increase above the optimum fertilizer rate. In conclusion, maize grain yields, WUE and NAE were highest under reduced tillage at modest NP fertilizer application rates of 105 kg N and 46 kg P ha−1. No-till increased soil water storage by 8–12% and improved WUE compared to conventional tillage, thus showing potentials for drought mitigation and economic use of fertilizers in drought-prone rainfed conditions in northern China.  相似文献   

15.
We conducted experiments in 2006 and 2007 in south-western Kenya to reduce labour and input cost of soybean production through different planting systems (point-placement was compared to planting in trenches and broadcasting), weeding frequencies (once or twice), and the use of local inputs (at 20 kg P ha−1). Di-ammonium phosphate (DAP) was compared to manure, ashes, combinations of those, 1/2 Tithonia 1/2 DAP (TD) and no input. 1/3rd of the labour was saved when placing seeds in trenches as compared to individual holes without losing significant grain yield. Broadcasting requires 1/9th of the planting time while losing only 15% grain. 5% grain was lost by weeding once instead of twice, while saving 36% of the time. The time saved at planting can be more productively invested in collecting inputs. Plots without input yielded 537 kg ha−1 grain and 642 kg ha−1 biomass in 2006. Inputs increased both grain and biomass yields significantly with 27–51%, without significant difference between local and mineral inputs (with exception of TD). Using local input is thus a reasonable decision for farmers. Farmers concluded that the experiments had led to options for different types of farmers, with different access to resources, to increase their soybean production.  相似文献   

16.
The paper investigates management and cultivar type effects on pearl millet stover yield and fodder quality. Sixteen pearl millet cultivars available to farmers in India were selected to represent three cultivar types: (1) traditional landrace germplasm from the arid/semi-arid millet production zones, (2) improved dual-purpose (grain and stover) open-pollinated varieties incorporating differing amounts of traditional landrace germplasm and (3) commercial, grain-type F1 hybrids, bred for use in the arid/semi-arid zone. The cultivars were grown for 2 years (2000 and 2001) at high fertility (HF: 65 kg N ha−1 and 18 kg P ha−1) and low fertility (LF: 21 kg N ha−1 and 9 kg P ha−1). Within each fertility level high (HP) and low (LP) plant population densities were established by varying sowing rate and then thinning to the target populations (HP: 11 plants m−2 and LP: 5 plants m−2). Stover fodder quality traits (nitrogen concentration, sugar content, in vitro digestibility and metabolizable energy content) were analyzed using a combination of conventional laboratory analysis and near infrared spectroscopy. In general, fertility level and cultivar type had strong effects on grain and stover yields, and on a range of stover nutritional quality traits, but with significant year interactions. In contrast, the effect of population density on these variables was largely insignificant. Higher fertilizer application significantly increased grain and stover yields and stover nitrogen concentration, in vitro digestibility and metabolizable energy content. As a result, fertilization resulted in significant increases in the yields of both digestible and metabolizable stover. Landrace cultivars as a group produced higher quality fodder than modern hybrids, but at a significant cost in grain yield. Dual-purpose, open-pollinated cultivars were generally intermediate between the landraces and hybrids, in terms of both stover quality and grain yield, but produced the highest yields of both digestible and metabolizable stover. The paper discusses the implications of these findings for Indian pearl millet farmers with various resource levels and farming objectives.  相似文献   

17.
Nitrogen (N) fertilizer represents a significant cost for the grower and may also have environmental impacts through nitrate leaching and N2O (a greenhouse gas) emissions associated with denitrification. The objectives of this study were to analyze the genetic variability in N-use efficiency (grain dry matter (DM) yield per unit N available from soil and fertilizer; NUE) in winter wheat and identify traits for improved NUE for application in breeding. Fourteen UK and French cultivars and two French advanced breeding lines were tested in a 2 year/four site network comprising different locations in France and in the UK. Detailed growth analysis was conducted at anthesis and harvest in experiments including DM and N partitioning. Senescence of either the flag leaf or the whole leaf canopy was assessed from a visual score every 3-4 days from anthesis to complete canopy senescence. The senescence score was fitted against thermal time using a five parameters monomolecular-logistic equation allowing the estimation of the timing of the onset and the rate of post-anthesis senescence. In each experiment, grain yield was reduced under low N (LN), with an average reduction of 2.2 t ha−1 (29%). Significant N × genotype level interaction was observed for NUE. Crop N uptake at harvest on average was reduced from 227 kg N ha−1 under high N (HN) to 109 kg N ha−1 under LN conditions while N-utilization efficiency (grain DM yield per unit crop N uptake at harvest; NUtE) increased from 34.0 to 52.1 kg DM kg−1 N. Overall genetic variability in NUE under LN related mainly to differences in NUtE rather than N-uptake efficiency (crop N uptake at harvest per unit N available from soil and fertilizer; NUpE). However, at one site there was also a positive correlation between NUpE and NUE at LN in both years. Moreover, across the 2 year/four site network, the N × genotype effect for NUpE partly explained the N × genotype effect for grain yield and NUE. Averaging across the 16 genotypes, the timing of onset of senescence explained 86% of the variation in NUtE amongst site-season-N treatment combinations. The linear regression of onset of senescence on NutE amongst genoytpes was not significant under HN, but at three of the four sites was significant under LN explaining 32-70% of the phenotypic variation amongst genotypes in NutE. Onset of senescence amongst genotypes was negatively correlated with the efficiency with which above-ground N at anthesis was remobilized to the grain under LN. It is concluded that delaying the onset of post-anthesis senescence may be an important trait for increasing grain yield of wheat grown under low N supply.  相似文献   

18.
Winter mustard (Brassica juncea L.) is not a common crop in the Southeastern United States. With increased interest in biodiesel production, there has been corresponding interest in mustard in this region. The objective of this study was to evaluate the effect of N fertilization (0, 50, 100, 150 kg N ha−1) on productivity, oil content, and oil composition of winter mustard ‘Pacific Gold’ grown at three locations in Mississippi (Stoneville, and two locations at Verona, namely Verona silt loam (Verona-SL) and Verona clay (Verona-C)). Nitrogen did not affect oil content (percent oil). Seed and oil yields (kg ha−1) increased with N application relative to the unfertilized control. At the Verona-C location, the concentration of oleic acid was higher in the 50 kg N ha−1 treatment. At Stoneville, linolenic acid concentration was higher in the 150 kg N ha−1 and lower in the 100 kg/N ha−1 treatment, while it was not different in the other treatments. Overall, the yield of the fatty acids (FA) palmitic, palmitoleic, stearic, oleic, linoleic, linolenic, arachidic, eicosanoic, behenic, erucic, lignoceric, and nervonic acid increased with higher N rates (100 or 150 kg N/h). The highest yield of FA in the two Verona locations were achieved in the 100 kg N ha−1, while greatest yield of FA at Stoneville was achieved in the highest N rate (150 kg N ha−1). Means of mustard oil yields in our study in the higher fertility treatment ranged from 737 to 1094 kg ha−1. This study demonstrated winter mustard production in Mississippi and possibly other areas in the Southeastern United States can be successful and could provide seed and oil yields comparable to yields from other production areas.  相似文献   

19.
Poor seed yield of soybean in Mediterranean-type environments may result from insufficient iron (Fe) uptake and poor biological nitrogen (N) fixation due to high bicarbonate and pH in soils. This study was conducted to evaluate the effects of N and Fe fertilization on growth and yield of double cropped soybean (cv. SA 88, MG III) in a Mediterranean-type environment in Turkey during 2003 and 2004. The soil of the experimental plots was a Vertisol with 176 g CaCO3 kg−1 and pH 7.7 and 17 g organic matter kg−1 soil. Soybean seeds were inoculated prior to planting with commercial peat inoculants. N fertilizer rates were 0, 40, 80, and 120 kg N ha−1 of which half was applied before planting and the other half at full blooming stage (R2). Fe fertilizer rates were 0, 200 and 400 g Fe EDTA (5.5% Fe and 2% EDTA) ha−1. It was sprayed as two equal portions at two trifoliate (V2) and at five trifoliate stages (V5). Plants were sampled at flower initiation (R1), at full pod (R4) and at full seed (R6) stages. Application of starter N increased biomass and leaf area index at R1 stage whereas Fe fertilization did not affect early growth parameters. N application continued to have a positive effect on growth parameters at later stages and on seed yield. Fe fertilization increased growth parameters at R4 and R6 stages, and final seed yield in both years. This study demonstrated an interactive effect of N and Fe fertilization on growth and yield of soybean in the soil having high bicarbonate and pH. There was a positive interaction between N and Fe at the N rates up to 80 kg N ha−1. However, further increase in N rate produced a negative interaction. Fertilization of soybean with 80 kg N ha−1 and 400 g Fe ha−1 resulted in the highest seed yield in both years. We concluded that application of starter and top dressed N in combination with two split FeEDTA fertilization can be beneficial to improve early growth and final yield of inoculated soybean in Mediterranean-type soils.  相似文献   

20.
Four two-year field trials, arranged in randomised split-plots, were carried out in southern Sweden with the aim of determining whether reduced N fertiliser dose in winter wheat production with spring under-sown clover cover crops, with or without perennial ryegrass in the seed mixture, would increase the clover biomass and hence the benefits of the cover crops in terms of the effect on the wheat crop, on a subsequent barley crop and on the risk of N leaching. Four doses of nitrogen (0, 60, 120 or 180 kg N ha−1) constituted the main plots and six cover crop treatments the sub-plots. The cover crop treatments were red clover (Trifolium pratense L.), white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) in pure stands and in mixtures. The winter wheat (Triticum aestivum L.) was harvested in August and the cover crops were ploughed under in November. The risk of N leaching was assessed in November by measuring the content of mineral N in the soil profile (0–30, 30–90 cm). In the following year, the residual effects of the cover crops were investigated in spring barley (Hordeum distichon L.) without additional N. Under-sowing of cover crops did not influence wheat yield, while reduced N fertiliser dose decreased yield and increased the clover content of the cover crops. When N was applied, the mixed cover crops were as effective in depleting soil mineral nitrogen as a pure ryegrass cover crop, while pure clover was less efficient. The clover content at wheat harvest as well as the amount of N incorporated with the cover crops had a positive correlation with barley yield. Spring barley in the unfertilised treatments yielded, on average, 1.9–2.4 Mg DM ha−1 more in treatments with clover cover crops than in the treatment without cover crops. However, this positive effect decreased as the N dose to the preceding wheat crop increased, particularly when the clover was mixed with grass.  相似文献   

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