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1.
The concentration of water soluble carbohydrates (WSC) is a main determinant of the ensiling potential of forages and the aerobic stability of silages. The aims of the present study were to assess the impact of genotype on the seasonal changes of WSC concentration, to adapt and calibrate the FONSCH (FOrage NonStructural CarboHydrates) model – originally developed for forage grasses – for silage maize, and finally to conduct a long-term simulation study for quantifying weather-related variability of WSC content. A 3-year field experiment (2001–2003) was conducted in northern Germany to evaluate differences in WSC content among commercial silage maize varieties and to provide calibration data for modelling. Eight varieties covering three maturity groups (early, mid-early and mid-late) were investigated. On six dates throughout the vegetation period the plants were harvested, separated into ear and stover, and freeze–dried for subsequent determination of WSC. Ear, stover, and whole crop WSC content was influenced by genotype and environmental conditions. Genotypic effects were most pronounced in the early grain filling period. At silage maturity, an effect of variety on whole crop WSC content was found in the mid-early group only, accounting for a difference of 44.8 g WSC kg−1 DM. FONSCH model calibration showed good agreement between observed and calculated WSC contents, with RMSE below 27.6 g WSC kg−1 DM and r2 above 0.84. Parameter estimates revealed a substantial influence of temperature and solar radiation on WSC content, while plant available soil water had minimal impact. Successful model validation with an independent data set allowed us to perform a 30-year simulation study, where variation among varieties and years of up to 68.8 and 186.5 g WSC kg−1 DM, respectively, demonstrated a larger impact of environmental conditions compared to genotype.  相似文献   

2.
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   

3.
Increased land degradation and shortage of forage resources for animal production over-winter have accentuated the need for alternative cropping systems in northeast China. While short frost-free period and cool temperatures are major limitations to cereal grain production in the northern regions of China (45°N, 122°E), crop varieties that are able to produce food and feed in short growing season and tolerant to low temperature may extend the total cropping period. Three hulless oat (Avena sativa L.) lines, Baiyan 9015, Baiyan 9017 and Baiyan 9044, were bred and tested for 3 years (2004–2006) to determine their suitability for summer seeding in a double cropping system. The new lines were sown both in the spring and summer to provide growers with opportunities to harvest two grain-crops in a year. Averaged across 3 years, Baiyan 9044 produced 2.5 and 1.6 Mg ha−1 yr−1 grain yield when sown in spring and summer, respectively. The new lines seeded in 20th or 21st July and harvested in early October allowed utilization of an average of over 1500 growing degree days (GDDs). For grain yield alone, the net income for two oat crops a year was up to 1390 Chinese yuan (RMB) ha−1, more than that of growing a single oat crop in 3 years, or in most cases, equivalent to monocultured corn (Zea mays L.) production, the dominant crop in the region. In addition, an average of 5 Mg ha−1 of oat straw was produced as valuable forage fodder for the livestock industry, which was in great demand for over-wintering animals. Furthermore, in the traditional single small grain cereal cropping system, bare ground after harvest leads to severe water and wind erosions. Our results indicate that the new oat lines could be a potential crop for summer seeding, particularly when spring-seeded crops fail due to abiotic (hail, drought, etc.) or biotic (e.g. insects) stresses. The double cropping system provides growers with a potential opportunity to facilitate the farming strategy of food, cash crops and control soil erosion in the region.  相似文献   

4.
Estimating maize nutrient uptake requirements   总被引：6，自引：0，他引：6  
Generic, robust models are needed for estimating crop nutrient uptake requirements. We quantified and modeled grain yield–nutrient uptake relations in maize grown without significant biotic and abiotic stresses. Grain yield and plant nutrient accumulation in above-ground plant dry matter (DM) of commercial maize hybrids were measured at physiological maturity in on-station and on-farm experiments in Nebraska (USA), Indonesia, and Vietnam during 1997–2006. These data were used to model the nutrient requirements for yields up to 20 Mg ha−1 using the QUEFTS (QUantitative Evaluation of the Fertility of Tropical Soils) approach. The model required estimation of two boundary lines describing the minimum and maximum internal nutrient efficiencies of N, P and K (IE, kg grain per kg nutrient in plant DM), which were estimated at 40 and 83 kg grain kg−1 N, 225 and 726 kg grain kg−1 P and 29 and 125 kg grain kg−1 K, respectively. The model predicted a linear increase in grain yield if nutrients are taken up in balanced amounts of 16.4 kg N, 2.3 kg P and 15.9 kg K per 1000 kg of grain until yield reached about 60–70% of the yield potential. The corresponding IEs were 61 kg grain kg−1 N, 427 kg grain kg−1 P and 63 kg grain kg−1 K. The model predicted a decrease in IEs when yield targets approached the yield potential limit. A spherical model was derived from QUEFTS model outputs and found to be particularly suitable for practical applications such as estimating fertilizer needs. The proposed spherical model offers generality across environments and management practices, allowing users to estimate the optimal N, P and K uptake requirements based on two inputs: estimated yield potential and yield target. Further improvements in modeling the relationship between N uptake and grain yield can be made by taking into account differences in harvest index. Accuracy in the simulation of N uptake using the spherical model was improved from an RMSE of 35 kg N ha−1 to 25 kg N ha−1 when harvest index was accounted for, suggesting that the relationship between N uptake and actual yield is affected by both yield potential and efficiency in biomass partitioning.  相似文献   

5.
Two experiments describe the ensiling potential of whole‐crop forage peas (Pisum sativum) and field beans (Vicia faba). In Experiment 1, forage peas (cv. Magnus) and field beans (cv. Mayo) were harvested at 10, 12 and 14 weeks after sowing, and ensiled in 10 kg mini‐silos either untreated or treated with an inoculant (Lactobacillus plantarum). In terms of yield and ensiling potential, the optimum growth stage for harvesting forage peas occurred at 12 weeks of growth. In contrast, delaying the harvest of field beans until 14 weeks gave the highest yields of dry matter (DM) and crude protein (CP). Changes in crop maturity had little effect on the chemical composition of the fresh forages, but between‐harvest date differences were observed in the DM, ammonia‐N, CP, water‐soluble carbohydrates (WSC), acid‐detergent fibre (ADF), neutral‐detergent fibre (NDF), lactic acid and volatile fatty acids (VFA) concentrations and pH of the corresponding silages. Fermentation was improved by applying an inoculant. In Experiment 2, forage peas and field beans were harvested at 14 weeks after sowing and ensiled as round‐bale silage, either untreated or treated with an inoculant. The yields of the crops were similar, and the only difference in the chemical composition of the wilted forages was a higher CP concentration in the field beans. However, after the ensiling process was complete, the forage pea silages were found to have significantly higher DM, WSC, starch and butyric acid concentrations compared with the field bean silages, and lower ammonia‐N, CP, ADF, acetic acid and lactic acid concentrations. Inoculation was found to increase the lactic acid concentration and reduce the pH and ammonia‐N and acetic acid concentrations of the silages. Each of the silages produced in Experiment 2 was offered to six Suffolk crossbred wether lambs, aged 10 months. Voluntary DM intakes were similar on all treatments, despite the apparent digestibility of the forage pea silages being significantly higher than that of the field bean silages. Nitrogen retention was higher for lambs offered forage pea silage. Application of an inoculant was found to have a negative effect on the amount of N retained, indicating the necessity for more detailed investigations into proteolytic activity within these crops during the fermentation process.  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.
This experiment was conducted to evaluate the effects of two irrigation regimes (control and water stress) and two nitrogen (N) levels (0 and 112.5 kg/ha) on forage yield and silage quality in millet. Bastan (Setaria italica (L.) P. Beauv) and Pishahang (Panicum miliaceum) were sown at two different dates during 2015 and 2016. Both cultivars exhibited reduced dry-matter (DM) yields (45% and 51% in Bastan and Pishahang respectively) due to drought stress. Proline and phenolic contents increased as a result of drought and were significantly and negatively correlated with DM yield and digestibility. Moreover, Pishahang had a reduced acid detergent fibre (ADF) content but improved leaf/stem ratio, digestible dry matter (DDM), relative feed value (RFV), net energy for lactation (NEL), digestibility and silage quality as a result of drought stress, while no significant effects on these traits were observed in Bastan. Silage quality was greatly cultivar-dependent. Both cultivars had higher levels of DDM, RFV and NEL at early sowing dates. Nitrogen supply had greater positive effects on increasing ash, crude protein (CP) content and DM yield under normal irrigation than under water-stress conditions. In summary, given the importance of the energy received per unit of forage from an animal husbandry viewpoint and the significance of DM yield per unit area from an agricultural viewpoint, the obtained results might help farmers in choosing not only the best sowing dates but also proper irrigation and N management practices to achieve their quantitative and qualitative objectives in forage production.  相似文献   

8.
Abstract Sole crops and intercrops of wheat (Triticum aestivum L.) and bean (Vicia faba L.), at three harvest dates, representing successive growth stages, were evaluated for biomass production of whole‐crop forage and quality characteristics of crude protein (CP), neutral‐detergent fibre (NDF), acid‐detergent fibre (ADF), water‐soluble carbohydrate (WSC) concentrations and ash content. These tests were carried out for two field experiments, respectively, drilled during the spring of 1997 and autumn of 1997 on Imperial College Farm, Wye, UK. Results indicated that optimum forage yield and quality were obtained from the second to third harvest dates for the spring‐drilled experiment and the second harvest for the autumn‐drilled experiment. Wheat and bean intercrops were higher in total forage dry matter (DM) yield than either wheat or bean grown as sole crops. Field bean intercropped with wheat led to increased forage quality (CP and NDF concentrations) compared with sole wheat, and higher WSC concentrations compared with sole bean. Intercrops also enhanced weed suppression compared with sole bean. It is suggested that winter wheat–bean intercrops may have considerable potential as a moderate‐yielding, relatively high‐quality, low‐input and environmentally benign forage crop with considerable potential with regard to yield and quality and warrant further study.  相似文献   

9.
Twenty ley and whole‐crop samples were analysed before and after ensiling to determine the proportion of dry matter (DM) that could be accounted for by the sum of 12 chemical assays for ash, ash‐excluded‐amylase‐treated neutral detergent fibre (aNDFom), starch, water‐soluble carbohydrates (WSC), pectin, crude protein (CP), CP in aNDFom (CPndf), ammonia, crude fat, phenolics, plant organic acids and liquid fermentation products (acids and alcohols). Crop components, utilized during silage fermentation and the possibility of predicting silage composition from that of the crop, were also investigated. Samples consisted of timothy and red and white clover, harvested at early and late maturities in two cuts per maturity and of whole‐crop barley, wheat and maize, harvested at early, intermediate and late stages of maturity. Ley crops were wilted to reach a DM content of approximately 400 g/kg, whereas whole crops (WC) were not wilted (151–757 g DM/kg) before ensiling. The average sum of analytes was 1022 and 981 g/kg DM for crops and silages respectively. An overall closeness to complete recovery indicates that no major plant components were missing from the analyses. Relative proportions of pectin, plant organic acids and phenolics, which are rarely analysed, were approximately 60:40:2 (w/w). Ash, aNDFom, crude fat and CP were almost completely recovered after ensiling, whereas partial metabolism reduced recoveries of starch (81%), CPndf (62%), plant organic acids (65%), pectin (64%) and WSC (29%). Only the four analytes with high silage recoveries could be reasonably well predicted from parent crop levels with mean prediction error from 0.065 for aNDFom to 0.167 for crude fat.  相似文献   

10.
The sowing method of spring‐type canola (Brassica napus L. var. oleifera) for forage has a major influence on its productivity and agronomic management. A field experiment was conducted in Matamoros, Coahuila, Mexico, during two growing seasons (2008–2009 and 2009–2010) to determine dry matter (DM), crude protein (CP) and net energy for lactation (NEL) yields, as well as canola forage chemical composition as a function of six sowing methods. The treatments assessed were broadcast sowing and five different row spacings: 0·19, 0·38, 0·57, 0·76 and 0·95 m (double row, 0·20 m apart). In the first year, with a mean growing season temperature of 17·2°C, sowing methods did not affect DM yield, but CP and NEL content and yield were higher in 0·19‐m row spacing. The mean temperature in the second year (13·5°C) was slightly lower than the long‐term mean (14·8°C) in the region, resulting in the highest DM (8840 kg ha?1), CP (2486 kg ha?1) and NEL yields (51 103 MJ ha?1) with 0·19‐m row spacing. In row‐sowing methods with over 0·19‐m row spacing, DM, CP and NEL yields decreased by 19·3–39·7, 20·4–42·1 and 21·2–42·7% respectively. Results indicate that sowing methods significantly affected canola forage productivity.  相似文献   

11.
Grain growth in wheat depends on current photosynthesis and stem water-soluble carbohydrates (WSC). In semiarid regions with terminal drought, grain filling in wheat crops may depend more on stem WSC content than on current assimilates. Reduction in grain yield under drought is attributed to shorter duration of linear grain growth despite increased contribution of stem reserves to grain yield. The amount of stem reserves is measured either by changes in stem dry weight (indirect method) or by stem WSC content (direct method). Genotypic variation in the rate and duration of linear grain growth and in percent contribution of stem reserves to grain yield has not been evaluated in wheat. The objectives of this study were: (i) to quantify the relationship between the direct and indirect measurement of stem reserves during and across the grain-filling period and (ii) to measure the extent of genotypic variation in rate and duration of linear grain growth and in percent contribution of stem reserves to grain yield. Dry weight, WSC content and grain yield of the main stem were measured at 10-day intervals in 11 diverse wheat genotypes under well-watered and droughted-field conditions across 2 years. Drought reduced stem WSC content from 413 to 281 mg and grain yield from 4.6 to 2.5 t ha−1. Stem WSC content and dry weight were positively correlated. Genotypic differences in linear rate of grain growth were significant in well-watered (ranging from 48.9 to 72.4 mg spike−1 day−1) and in droughted-field (ranging from 33.2 to 59.9 mg spike−1 day−1) conditions. Drought, on average, reduced the linear rate and duration of grain growth by 20 and 50%, respectively. Reduction in linear rate ranged from 13 to 43%. The amount of current assimilates and stem reserves contributed to grain yield was reduced, respectively, by 54 and 11% under drought. Genotypic differences in percent contribution of stem reserves to grain yield were significant in well-watered (ranging from 19.1 to 53.6%) and in droughted-field (ranging from 36.6 to 65.4%) conditions. The wheat genotypes responded differently to drought. Main spike grain yield was reduced by 43% under drought due to 26 and 11% reduction in grain weight and number of grains, respectively. Grain yield was correlated with linear grain growth under well-watered (r = 0.96) and droughted (r = 0.83) conditions. The genotypic variation observed indicates that breeding for a higher rate of linear grain growth and greater contribution of stem reserves to grain yield should be possible in wheat to stabilize grain yield in stressful environments.  相似文献   

12.
Groundnut as a pre-rice crop is usually harvested 1–2 months before rice transplanting. During this lag phase much of N in groundnut residues could be lost due to rapid N mineralization. Mixing of abundantly available rice straw with groundnut residues may be a means for reducing N and improve subsequent crop yields. The objectives of this experiment were to investigate the effect of mixing groundnut residues and rice straw in different proportions on (a) growth and yield of succeeding rice, (b) groundnut residue N use efficiency and (c) N lost (15N balance) from the plant–soil system and fate of residue N in soil fractions. The experiment consisted of six treatments: (i) control (no residues), (ii) NPK (at recommended rate, 38 kg N ha−1), (iii) groundnut residues 5 Mg ha−1 (120 kg N ha−1), (iv) rice straw 5 Mg ha−1 (25 kg N ha−1), (v) 1:0.5 mixed (groundnut residues 5 Mg: rice straw 2.5 Mg ha−1), and (vi) 1:1 mixed (groundnut residues 5 Mg: rice straw 5 Mg ha−1). After rice transplanting, samples of the lowland rice cultivar KDML 105 were periodically collected to determine growth and nutrient uptake. At final harvest, dry weight, nutrient contents and 15N recovery of labeled groundnut residues were evaluated.  相似文献   

13.
Renewable energy sources are necessary to reduce the U.S. dependence on foreign oil. Sorghum (Sorghum bicolor L.) may be a reasonable alternative as an energy crop in the southern U.S. because it could easily fit into existing production systems, it is drought resistant, and it has large biomass production potential. An experiment was conducted to evaluate several types of sorghum as bioenergy crops in Alabama: grain sorghum - NK300 (GS), forage sorghum - SS 506 (FS), and photoperiod sensitive forage sorghum - 1990 (PS). These sorghum crops were compared to forage corn (Zea mays L.) - Pioneer 31G65 in 2008 and 2009 with and without irrigation, and under conventional (total disked area, 0.15 m deep) and conservation tillage (in-row subsoiling, 0.30 m deep) in a strip-split-plot design. The parameters evaluated were: plant population (PP), plant height (PH), sorghum/corn aboveground dry matter (ADM), biomass moisture content (ABMC), and biomass quality (holocellulose, lignin, and ash). Sorghum had greater ADM than corn; however, corn had lower ABMC than sorghum. Lodging was observed in PS and FS, probably due to high plant populations (>370,000 plants ha−1). Irrigation affected ADM positively in both years, but conservation systems improved ADM production only in 2009. Holocellulose, lignin, and ash variation differed significantly among crops but were lower than 8.3%, 2.0% and 1.9%, respectively, for both years and considered minor. Under conditions of this study, PS was considered the best variety for ADM production as it yielded 26.0 and 30.1 Mg ha−1 at 18 and 24 weeks after planting (WAP).  相似文献   

14.
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   

15.
Mixtures and pure stands of perennial ryegrass, tall fescue, white clover and red clover were grown in a three‐cut and a five‐cut system in southern Norway, at a low fertilization rate (100 kg N ha?1 year?1). The nutritional quality (annual weighted averages) of the dried forage from the two‐first harvesting years was analysed. There was no significant effect of species diversity on crude protein (CP) concentration. In the three‐cut system, we found a significant species diversity effect leading to 10% higher concentrations of acid detergent fibre (ADF), 20–22% lower concentrations of water‐soluble carbohydrate (WSC) and 4% lower net energy for lactation (NEL) concentrations in mixtures compared with pure stands (averaged across the two‐first years). In the five‐cut system, similar effects were seen in the first year only. This diversity effect was associated with a reduction in WSC and NEL concentrations and an increase in ADF, NDF and CP concentrations in the grass species, and not in red clover, when grown in mixtures. This is thought to be a combined result of better N availability and more shading in the mixtures. Species diversity reduced the intra‐annual variability in nutritional quality in both cutting systems.  相似文献   

16.
Livestock producers are interested in growing forage soybean [Glycine max (L.) Merr.] in summer and ensiling alone or in mixtures with corn or sorghum. Four row spacings (20, 40, 60, and 80 cm), four seeding rates (50, 100, 150, and 200 kg seeds per hectare) and four harvesting stages for forage production (V5, R2, R4, and R6) were evaluated under irrigated conditions in a randomized split–split plot design with three replications in three different locations in Turkey with Mediterranean-type climate in 2004 and 2005. Dry matter (DM) yield was significantly reduced with increased row spacings in all locations. There was no significant difference between 20, 40, or 60 cm row spacings while 80 cm provided the lowest yield. Increased seeding rates (50, 100, 150, and 200 kg seeds per hectare) generally increased DM yield, although the most suitable row spacing varied by location. DM yield was significantly affected by harvest maturity increasing with advancing maturity in all locations. DM constituent plant components were generally unaffected by row spacing and seeding rate but harvest maturity did significantly affect DM partitioning. As expected, leaf blade fractions decreased continually as plant maturity increased, while stem and flower plus pod fraction increased from V5 to R6. In general, row spacing and seeding rate did not significantly affect crude protein, degradable protein, and in vitro dry matter digestibility of soybean forage, but all decreased significantly with advancing maturity. These studies demonstrated soybeans managed for forage in a Mediterranean-type environment can average of 9.3 and 11.3 t ha−1 dry matter yield at R4 and R6 stages, respectively, while averaging 13.3% crude protein, 8.2% degradable protein, and 60.6% in vitro dry matter digestibility.  相似文献   

17.
One of the options to ameliorate the deleterious effects of sodic water irrigation is to apply gypsum to soil. We examined whether the application of organic manures or crop residue can reduce the need for gypsum in calcareous soils. A long-term field experiment with annual rice-wheat cropping rotation was conducted for 15 years (1991-2006) on a non-saline calcareous sandy loam soil (Typic Ustochrept) in northwestern, India. The irrigation water treatments included good quality canal water (CW) and sodic water (SW) with residual sodium carbonate (RSC) of 10 mmolc L−1 from 1991 to 1999 and of 12.5 mmolc L−1 from 2000 onwards. Gypsum was applied at 0, 12.5, 25, and 50% of the gypsum requirement (GR), to neutralize RSC of the SW. Three organic material treatments consisted of application of farmyard manure (FYM) at 20 Mg ha−1, Sesbania green manure (GM) at 20 Mg ha−1, and wheat straw (WS) at 6 Mg ha−1. The organic materials were applied every year to the rice crop. Continuous irrigation with sodic water for 15 years without gypsum or organic materials resulted in a gradual increase in soil pH and exchangeable sodium percentage (ESP), deterioration of soil physical properties, and decrease in yields of both rice and wheat. The cumulative yield loss in SW irrigated plots without gypsum and organic materials remained <1.5 Mg ha−1 for up to eight years in the case of rice and up to nine years in the case of wheat. Thereafter, marked increase in pH and ESP resulted in further depression in yields of rice by 1.6 Mg ha−1 year−1 and wheat by 1.2 Mg ha−1 year−1. Application of gypsum improved physical and chemical properties of the soil. The beneficial effects on crop yields were visible up to 12.5% GR in rice and up to 50% GR in wheat in most of the years. All the organic materials proved effective in mobilizing Ca2+ from inherent and precipitated CaCO3 resulting in decline in soil pH and ESP, increase in infiltration rate, and a increase in the yields of rice and wheat crops. Although the application of organic materials resulted in comparable reductions in pH and ESP, the increase in yield with SW was higher for both crops with FYM. Pooled over the last six years (2000-2006), application of FYM resulted in 38 and 26% increase in rice and wheat yields, respectively, over SW treatment; corresponding increases in 50% GR treatment (recommended level) was 18 and 19%. During these years, application of GM and WS increased wheat yields by 20%; for rice, GM resulted in 22% increase compared to 17% in WS amended SW irrigated plots. Combined application of gypsum and organic materials did not increase the yields further particularly in the case of FYM and GM treated plots. This long-term study proves that organic materials alone can be used to solubilize Ca from inherent and precipitated CaCO3 in calcareous soils for achieving sustainable yields in sodic water irrigated rice-wheat grown in annual rotation. The results can help reduce the dependency on gypsum in sodic water irrigated calcareous soils.  相似文献   

18.
In wheat, the ability to store and remobilise large amounts of stem water soluble carbohydrates (WSC) to grain constitutes a desirable trait to incorporate into germplasm targeted to regions with frequent terminal drought. The main aim of this paper was to examine the relationships between WSC storage, grain number and grain weight across several environments. A small set of recombinant inbred lines (2–4) contrasting in stem WSC were grown in six field trials where water availability, sowing date and/or N level were manipulated, with line yields ranging from 400 to 850 g m−2 across experiments. Biomass, N and WSC concentration (WSCc, mg g−1 dry weight) and amount (WSCa, g m−2) were monitored. A resource-oriented area-based model [Fischer, R.A., 1984. Growth and yield of wheat. In: Smith, W.H., Bante, S.J. (Eds.), Potential Productivity of Field Crops Under Different Environments. International Rice Research Institute, Los Baños, pp. 129–154] and intrinsic rates of organ growth were used to investigate the consequences on grain number of potential competition between spike and stem around flowering.  相似文献   

19.
CIMMYT hexaploid spring wheat (Triticum aestivum L.) germplasm has played a global role in assisting wheat improvement. This study evaluated four classes of CIMMYT germplasm (encompassing a total of 273 lines), along with 15 Australian cultivars (Oz lines) for grain yield, yield components and physiological traits in up to 27 environments in Australia's north-eastern region, where terminal drought frequently reduces grain yield and grain size.Broadly-adapted CIMMYT germplasm selected for grain yield had greater yield potential and improved performance under drought stress, being up to 5% greater yielding in High-yielding (mean yield 429 g m−2) and 4-10% greater yielding than adapted Oz lines in Low-yielding environments (mean yield 185 g m−2). Whilst maintaining statistically similar harvest index and spikes m−2 compared to broadly-adapted Oz lines across all environments, sets of selected CIMMYT lines had greater canopy temperature depression (0.18-0.27 °C), dry weight stem−1 (0.20-0.37 g), increased grains spike−1 (0.8-3.4 grains), grain number m−2 (ca. 20-800 grains), and maturity biomass (56-83 g m−2). Compared to selected Oz lines, broadly-adapted CIMMYT lines had a smaller reduction in Low compared to High-yielding environments for these traits, especially dry weight stem−1, such that CIMMYT lines had ca. 25% and 10% greater dry weight stem−1 than the Oz lines in Low- and High-yielding environment groups, respectively. Broadly-adapted CIMMYT germplasm also had slightly higher stem water soluble carbohydrate concentration at anthesis (ca. 6 mg g−1), which contributed to their higher grain weight (ca. 0.5 mg grain−1), and maintained an agronomically appropriate time to anthesis and plant height. Thus current CIMMYT germplasm should be useful donor sources of traits to enrich breeding programs targeting variable production environments where there is a high probability of water deficit during grain filling. However, as multiple traits were important, efficient introgression of these traits in breeding programs will be complex.  相似文献   

20.
Optimum plant densities are a key to maximise yields in most crops. However, such information is often lacking for more environmentally sound cropping systems, such as living mulches (LM) for small grains. In 2004 and 2005, three trials were conducted in the Swiss Midlands on fields managed in accordance with the Swiss organic farming guidelines. The objective of the study was to determine whether seeding density of winter wheat (Triticum aestivum L.) is a relevant factor for determining grain yield in a white clover (Trifolium repens L.) living mulch. The winter wheat cv. Titlis was directly sown in wide spaced rows (0.375 m) at densities of 300 (LM300), 450 (LM450) or 600 (LM600) viable grains m−2 in a white clover living mulch established at a seeding rate of 15 kg ha−1. A bare soil control treatment with a wheat density of 450 viable grains m−2 (BS450) was also included in the trials. Mean grain yields of LM300, LM450, and LM600 never reached the values observed in BS450. This was mainly due to a lower ear density, which, nevertheless, increased linearly with the seeding density within the living mulch in all trials, but the rate of increase depended on the environment. The decrease of the grain weight brought about by the increasing seeding density had only a marginal impact on the grain yield, which was increased from 1.31, 1.98, and 4.09 Mg ha−1 (LM300) to 1.97, 2.64, and 4.75 Mg ha−1 (LM600) for each of the three trials in the study. Significantly higher protein contents were observed for LM300 compared to the higher densities in the living mulch and to BS450. Our research showed that an increase of the seeding density is an effective mean to increase the grain yield in living mulch systems with white clover. However, it is likely that the control of the living mulch to reduce competition with the main crop is a more relevant factor.  相似文献   

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