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Yield Response (yield + response)
Selected AbstractsGrowth and Yield Response of Facultative Wheat to Winter Sowing, Freezing Sowing and Spring Sowing at Different Seeding RatesJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2006A. Ozturk Abstract Growth and yield of wheat are affected by environmental conditions and can be regulated by sowing time and seeding rate. In this study, three sowing times [winter sowing (first week of September), freezing sowing (last week of October) and spring sowing (last week of April)] at seven seeding rates (325, 375, 425, 475, 525, 575 and 625 seeds m,2) were investigated during the 2002,03 and 2003,04 seasons, in Erzurum (Turkey) dryland conditions, using Kirik facultative wheat. A split-plot design was used, with sowing times as main plots and seeding rates randomized as subplots. There was a significant year × sowing time interaction for grain yield and kernels per spike. Winter-sown wheat produced a significantly higher leaf area index, leaf area duration, spikes per square metre, kernel weight and grain yield than freezing- and spring-sown wheat. The optimum time of sowing was winter for the facultative cv. Kirik. Grain yields at freezing and spring sowing were low, which was largely the result of hastened crop development and high temperatures during and after anthesis. Increasing seeding rate up to 525 seeds m,2 increased the spikes per square metre at harvest, resulting in increased grain yield. Seeding rate, however, was not as important as sowing time in maximizing grain yield. Changes in spikes per square metre were the major contributors to the grain-yield differences observed among sowing times and seeding rates. Yield increases from higher seeding rates were greater at freezing and spring sowing. We recommended that a seeding rate of 525 seeds m,2 be chosen for winter sowing, and 575 seeds m,2 for freezing and spring sowing. [source] Yield Responses of Barley to Leaf Stripe (Pyrenophora graminea) under Experimental Conditions in Southern SyriaJOURNAL OF PHYTOPATHOLOGY, Issue 8-9 2004M. I. E. Arabi Abstract The seed-borne pathogen, Pyrenophora graminea is the causal agent of barley leaf stripe disease. Field trials were undertaken to investigate the impact of leaf stripe on barley yield in two growing seasons in Southern Syria, by comparing plots with and without artificial inoculation. Ten barley cultivars originating from widely dispersed areas were used. The overall response to leaf stripe differed with the differences in susceptibility levels of the cultivars. Grain yield, the number of tillers, kernel weight and plant biomass decreased as disease severity increased. Diseased plants had fewer tillers, and as a consequence a reduced grain yield per plant. High yield losses resulted from leaf stripe in susceptible cultivars in Arrivate, Furat 1, WI2291 and Arabi Abiad with 44%, 50%, 73% and 92%, respectively. The cultivar Banteng had the best level of resistance to the disease, and is a candidate donor for resistance in future breeding programmes. As leaf stripe can dramatically reduce barley yields under favourable conditions, the disease should be considered by crop improvement programmes in Mediterranean and similar environments. [source] Yield response of wheat and barley to inoculation of plant growth promoting rhizobacteria at various levels of nitrogen fertilizationJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 2 2003Ali Ozturk Abstract The yield response of a wheat (Kirik) and a barley (Tokak 157/37) cultivar to inoculation with Azospirillum brasilense Sp246 and Bacillus sp. OSU-142 was studied in relation to three levels of N fertilization (0, 40, and 80 kg ha,1) under field conditions in Erzurum, Turkey, in 1999 and 2000. Seed inoculation with A. brasilense Sp246 significantly affected yield and yield components, both in wheat and barley. On average of years and N doses, inoculation with A. brasilense Sp246 increased spike number per m2, grain number per spike, grain yield, and crude protein content by 7.2, 5.9, 14.7, and 4.1,% in wheat and by 6.6, 8.1, 17.5, and 5.1,% in barley, respectively, as compared to control. Inoculation with Bacillus sp. OSU-142 significantly increased kernel number per spike in wheat, but no significant effect was determined in the other characteristics. Grain yields and yield components were also higher at all levels of nitrogen fertilizer in the inoculated plots as compared to the control. However, these increases diminished at high fertilizer levels. These results suggest that application of the growth promoting bacteria A. brasilense Sp246 may have the potential to be used as a biofertilizer for spring wheat and barley cultivation in organic and low-N input agriculture. No translation. [source] Nitrate leaching from cut grassland as affected by the substitution of slurry with nitrogen mineral fertilizer on two soil typesGRASS & FORAGE SCIENCE, Issue 1 2010J. J. Schröder Abstract A field experiment was conducted to find out whether there is any difference in risk of N leaching to groundwater when cattle slurry and/or mineral fertilizer-N was applied to cut grassland. The experiment was carried out over two consecutive years on two sites (one with a relatively wet sandy soil and one with a relatively dry sandy soil). Treatments were mineral fertilizer-N at annual rates of 0,510 kg N ha,1 year,1 and combinations of sod-injected cattle slurry (85, 170, 250 and 335 kg N ha,1 year,1) and mineral fertilizer-N (289, 238, 190 and 139 kg N ha,1 year,1). Yield responses indicated that in the short run, 0·44,0·88 (average 0·60) of the slurry-N was as available as mineral fertilizer-N. The total N input from mineral fertilizer and slurry was a worse predictor of nitrate leaching ( 0·11) than the N surplus (i.e. the difference between total N input and harvested N) ( 0·60). The effective N surplus, based on the difference between the summed inputs of the plant-available N and harvested N, proved to be the best indicator of leaching ( 0·86). Annual N application rates of up to 340 kg plant-available N ha,1 complied with the target nitrate concentration in groundwater of 11·3 mg N L,1 set by the European Union in both years on the wet sandy soil, whereas on the dry sandy soil none of the treatments did. [source] The effects of organic and inorganic fertilizer applications to Miscanthus×giganteus, Arundo donax and Phalaris arundinacea, when grown as energy crops in Wales, UKGCB BIOENERGY, Issue 4 2010R. SMITH Abstract Two pot trials and one field trial were established to investigate the effects of organic and inorganic fertilizer applications to energy crops grown in mid-Wales. Chicken litter and sewage cake applied at a high level in excess of MAFF recommendations produced an increased yield response in Miscanthus and Arundo plants. Miscanthus plants exhibited an increased growth response to all fertilizers applied in its second year. Fertilizer applications in accordance with MAFF recommendations produced no significant differences in yields for Miscanthus or Arundo potted plants. In the field there was an increased yield response of Miscanthus to inorganic nitrogen applications compared with organic manures, but not with control plots. Analysis of the Miscanthus plant material at harvest showed significant differences in the nitrogen, potassium and copper content between treatments. No mineral content differences were shown for Miscanthus rhizome material or Arundo plant material. The Phalaris plants did not exhibit significant differences in growth or yield parameters, but their plant matter showed differences in nitrogen, phosphorus, potassium, calcium, sulphur and boron content between treatments. [source] From agriculture based on fossil fuel resources to agriculture based on biological interactions and matter cycling in agroecosystemsGRASSLAND SCIENCE, Issue 1 2005Masae Shiyomi Abstract The modern system of agriculture, which depends on the consumption of large quantities of fossil fuel, will be forced to change to a system in which matter cycling and the various interactions operating among organisms and between organisms and their environment are effectively used. Three key factors will necessitate this change: the depletion of readily available fossil fuel resources; the leveling-off of the growth and yield response of crops in response to the increase in the use of fertilizers, agrochemicals and big machinery; and the degradation of the environment associated with the consumption of fossil fuels and derived agrochemicals. Therefore, it is essential to further promote the following two types of study: (i) the elucidation of the structure and use of complex biological interactions, and the cause-and-effect relationships among and between organisms in relation to their environment; and (ii) the effective use of matter cycling in agricultural ecosystems. Efficient use of biological interactions and matter cycling will reduce the dependence of agriculture on fossil fuel. [source] A Method for Evaluating Horizontal Well Pumping TestsGROUND WATER, Issue 5 2004David E. Langseth Predicting the future performance of horizontal wells under varying pumping conditions requires estimates of basic aquifer parameters, notably transmissivity and storativity. For vertical wells, there are well-established methods for estimating these parameters, typically based on either the recovery from induced head changes in a well or from the head response in observation wells to pumping in a test well. Comparable aquifer parameter estimation methods for horizontal wells have not been presented in the ground water literature. Formation parameter estimation methods based on measurements of pressure in horizontal wells have been presented in the petroleum industry literature, but these methods have limited applicability for ground water evaluation and are based on pressure measurements in only the horizontal well borehole, rather than in observation wells. This paper presents a simple and versatile method by which pumping test procedures developed for vertical wells can be applied to horizontal well pumping tests. The method presented here uses the principle of superposition to represent the horizontal well as a series of partially penetrating vertical wells. This concept is used to estimate a distance from an observation well at which a vertical well that has the same total pumping rate as the horizontal well will produce the same drawdown as the horizontal well. This equivalent distance may then be associated with an observation well for use in pumping test algorithms and type curves developed for vertical wells. The method is shown to produce good results for confined aquifers and unconfined aquifers in the absence of delayed yield response. For unconfined aquifers, the presence of delayed yield response increases the method error. [source] Irrigation Level Affects Isoflavone Concentrations of Early Maturing Soya Bean CultivarsJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2007A. M. Al-Tawaha Abstract Field experiments were conducted in 2003/2004 in Québec to determine the effects of irrigation levels (none, low and high) and cultivars (AC Orford, AC Proteina and Golden) on soya bean [Glycine max (L.) Merr.] isoflavone concentrations and yields. Seed yield, yield components, and oil and crude protein (CP) concentrations were concurrently determined. Response to irrigation was greater in 2003, which was substantially warmer and drier than in 2004. In both years, most responses were observed with the lower of the two irrigation levels evaluated, which increased total isoflavones concentration by an average of 45 % compared with a non-irrigated control. Cultivars, however, responded differently to irrigation. In 2003, response of AC Proteina was greater than that of AC Orford, while Golden did not respond. In 2004, some responses were observed with AC Proteina and Golden but none with AC Orford. Overall, in both years, AC Proteina had the greatest isoflavone concentrations and AC Orford the lowest. Responses of seed yield and yield components depended on the year and were also greater in 2003. Both irrigation treatments generally increased seed yield and yield components compared with a non-irrigated control; the response was greater with the higher irrigation level. Irrigation had no effect on oil and CP concentrations. Finally, isoflavone yield response to irrigation was again greater in 2003, and depended on the cultivar. Results thus demonstrate that specific soil moisture levels will maximize soya bean isoflavone concentrations, excess irrigation sometimes negating any potential benefits. [source] How can we predict the effects of elevated CO2 on the balance between perennial C3 grass species competing for light?NEW PHYTOLOGIST, Issue 1 2002F. Teyssonneyre Summary ,,Changes in the balance between mixed plant species have been reported under elevated [CO2] compared with ambient atmospheric [CO2]. We hypothesized that species response to elevated CO2 in mixture can be explained by taking into account resource partitioning between mixed species. ,,This hypothesis was tested experimentally on three perennial C3 grass species (Lolium perenne, Festuca arundinacea and Holcus lanatus) grown in monocultures and in binary mixtures (Lolium,Festuca and Lolium,Holcus) under mild (frequent cuts) or severe (infrequent cuts) competition for light and at a high N supply (40 g N m,2). ,,Under mild competition for light, the dry matter yield response to elevated CO2 of the mixed grass species was similar to that observed in monocultures. By contrast, under severe light competition, the grass species that absorbed more light per unit leaf area (Holcus and Festuca), also had a greater response to elevated CO2 in mixture compared with monoculture. ,,Under our experimental conditions, we have shown that the dry matter yield response to CO2 in mixture can be predicted from both the species response in monoculture, and the light capture per unit leaf area in ambient CO2 of the mixed compared with the pure grasses. [source] Effects of chronic elevated ozone concentration on antioxidant capacity, photosynthesis and seed yield of 10 soybean cultivarsPLANT CELL & ENVIRONMENT, Issue 9 2010AMY M. BETZELBERGER ABSTRACT Crops losses to tropospheric ozone (O3) in the United States are estimated to cost $1,3 billion annually. This challenge is expected to increase as O3 concentrations ([O3]) rise over the next half century. This study tested the hypothesis that there is cultivar variation in the antioxidant, photosynthetic and yield response of soybean to growth at elevated [O3]. Ten cultivars of soybean were grown at elevated [O3] from germination through maturity at the Soybean Free Air Concentration Enrichment facility in 2007 and six were grown in 2008. Photosynthetic gas exchange, leaf area index, chlorophyll content, fluorescence and antioxidant capacity were monitored during the growing seasons in order to determine if changes in these parameters could be used to predict the sensitivity of seed yield to elevated [O3]. Doubling background [O3] decreased soybean yields by 17%, but the variation in response among cultivars and years ranged from 8 to 37%. Chlorophyll content and photosynthetic parameters were positively correlated with seed yield, while antioxidant capacity was negatively correlated with photosynthesis and seed yield, suggesting a trade-off between antioxidant metabolism and carbon gain. Exposure response curves indicate that there has not been a significant improvement in soybean tolerance to [O3] in the past 30 years. [source] Climate change impacts on investment in crop sowing machinery,AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 2 2009Ross Kingwell A model of investment in crop sowing machinery is applied to wheat production under current and projected climatic conditions at several locations in south-western Australia. The model includes yield responses to time of sowing at each location given current and projected climatic conditions. These yield relationships are based on wheat growth simulation modelling that in turn draws on data from a down-scaled global circulation model. Wheat price distributions and cost of production data at each location, in combination with the time of sowing yield relationships are used to determine a farmer's optimal investment in crop sowing work rate under each climate regime. The key finding is that the impacts of climate change on profit distributions are often marked, yet mostly modest changes in investment in work rate form part of the profit-maximising response to climate change. The investment response at high versus low rainfall locations mostly involves increases and decreases in work rates, respectively. However, changes to investment in work rate within a broadly similar rainfall region are not always uniform. The impacts of climate change on investments in work rate at a particular location are shown to require knowledge of several factors, especially how climate change alters the pattern of yield response to the time of sowing at that location. [source] Corn ethanol growth in the USA without adverse foreign land-use change: defining limits and devising policiesBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 3 2010Paul W. Gallagher Abstract This study addresses the question: ,How does a 15 billion gallon per year renewable fuel standard (RFS) compare to the capacity of the US corn market to generate necessary input supplies for the ethanol industry?' The analysis accounts for adjustments in world corn and soybean markets, including corn technology improvements (yield increases) that allow substantial production growth on the existing corn area, and byproduct (DDG) replacement of displaced corn-feed demand. Our midpoint estimate suggests that increased production on foreign lands only accounts for a small fraction (6%) of the RFS demand expansion. Further, corn yield response to moderate price increases would likely offset much of the foreign production increase. US policies that could sever any remaining link between US ethanol expansion and environmentally sensitive regions of the world feed economy are discussed. Copyright © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Pan-European regional-scale modelling of water and N efficiencies of rapeseed cultivation for biodiesel productionGLOBAL CHANGE BIOLOGY, Issue 1 2009MARIJN VAN DER VELDE Abstract The energy produced from the investment in biofuel crops needs to account for the environmental impacts on soil, water, climate change and ecosystem services. A regionalized approach is needed to evaluate the environmental costs of large-scale biofuel production. We present a regional pan-European simulation of rapeseed (Brassica napus) cultivation. Rapeseed is the European Union's dominant biofuel crop with a share of about 80% of the feedstock. To improve the assessment of the environmental impact of this biodiesel production, we performed a pan-European simulation of rapeseed cultivation at a 10 × 10 km scale with Environmental Policy Integrated Climate (EPIC). The model runs with a daily time step and model input consists of spatialized meteorological measurements, and topographic, soil, land use, and farm management practices data and information. Default EPIC model parameters were calibrated based on literature. Modelled rapeseed yields were satisfactory compared with yields at regional level reported for 151 regions obtained for the period from 1995 to 2003 for 27 European Union member countries, along with consistent modelled and reported yield responses to precipitation, radiation and vapour pressure deficit at regional level. The model is currently set up so that plant nutrient stress is not occurring. Total fertilizer consumption at country level was compared with IFA/FAO data. This approach allows us to evaluate environmental pressures and efficiencies arising from and associated with rapeseed cultivation to further complete the environmental balance of biofuel production and consumption. [source] A critical assessment of the suitability of phosphite as a source of phosphorusJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 6 2009Arne M. Ratjen Abstract Marketing of phosphite-containing preparations for foliar application, together with recent reports of positive yield responses, has revived the question as to whether phosphite (HPO) is a suitable P source for plants. Two experiments using zucchini (Cucurbita pepo L. convar. giromontina) have been conducted to evaluate the P-nutritional effect of phosphite either provided via the substrate or as a foliar spray. Plants grown in a P-deficient substrate were severely damaged when phosphite was applied as foliar fertiliser and more drastically when provided via the substrate. Growth of P-deficient plants receiving phosphite as a foliar spray was impaired in a dose-dependent manner after foliar P application (concentrations 0.0, 0.9, 2.7, and 4.5 g P L,1), while foliar provision of phosphate improved plant growth and yield. In the youngest leaves of phosphite-treated plants, which had developed after foliar spray, phosphite accumulated to considerable extent, reaching a similar concentration as phosphate at tissue level. These results confirm that P-deficient plants are very sensitive to phosphite, which represents a nutritionally ineffective form of P. It should thus not be considered as a form of P suitable for fertiliser manufacture. [source] Climate change impacts on investment in crop sowing machinery,AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 2 2009Ross Kingwell A model of investment in crop sowing machinery is applied to wheat production under current and projected climatic conditions at several locations in south-western Australia. The model includes yield responses to time of sowing at each location given current and projected climatic conditions. These yield relationships are based on wheat growth simulation modelling that in turn draws on data from a down-scaled global circulation model. Wheat price distributions and cost of production data at each location, in combination with the time of sowing yield relationships are used to determine a farmer's optimal investment in crop sowing work rate under each climate regime. The key finding is that the impacts of climate change on profit distributions are often marked, yet mostly modest changes in investment in work rate form part of the profit-maximising response to climate change. The investment response at high versus low rainfall locations mostly involves increases and decreases in work rates, respectively. However, changes to investment in work rate within a broadly similar rainfall region are not always uniform. The impacts of climate change on investments in work rate at a particular location are shown to require knowledge of several factors, especially how climate change alters the pattern of yield response to the time of sowing at that location. [source] | |||||||||||||