Yield Response Of Winter Wheat Research Articles

Growth and yield of winter wheat in the first 3 years of a monoculture under varying N fertilization in NW Germany

Different preceding crops interact with almost all husbandry and have a major effect on crop yields. In order to quantify the yield response of winter wheat, a field trial with different preceding crop combinations (oilseed rape (OSR)–OSR–OSR–wheat–wheat–wheat), two sowing dates (mid/end of September, mid/end of October) and 16 mineral nitrogen (N) treatments (80–320 kg N ha −1) during 1993/1994–1998/1999, was carried out at Hohenschulen Experimental Station near Kiel in NW Germany. Single plant biomass, tiller numbers m −2, biomass m −2, grain yield and yield components at harvest were investigated. During the growing season, the incidence of root rot ( Gaeumannomyces graminis) was observed. Additionally, a bioassay with Lemna minor was used to identify the presence of allelochemicals in the soil after different preceding crops. Averaged over all years and all other treatments, wheat following OSR achieved nearly 9.5 t ha −1, whereas the second wheat crop following wheat yielded about 0.9 t ha −1 and the third wheat crop following 2 years of wheat about 1.9 t ha −1 less compared with wheat after OSR. A delay of the sowing date only marginally decreased grain yield by 0.2 t ha −1. Nitrogen fertilization increased grain yield after all preceding crop combinations, but at different levels. Wheat grown after OSR reached its maximum yield of 9.7 t ha −1 with 210 kg N ha −1. The third wheat crop required a N amount of 270 kg N ha −1 to achieve its yield maximum of 8.0 t ha −1. Yield losses were mainly caused by a lower ear density and a reduced thousand grain weight. About 4 weeks after plant establishment, single wheat plants following OSR accumulated more biomass compared to plants grown after wheat. Plants from the third wheat crop were smallest. This range of the preceding crop combinations was similar at all sampling dates throughout the growing season. Root rot occurred only at a low level and was excluded to cause the yield losses. The Lemna bioassay suggested the presence of allelochemicals, which might have been one reason for the poor single plant development in autumn. An increased N fertilization compensated for the lower number of ears m −2 and partly reduced the yield losses due to the unfavorable preceding crop combination. However, it was not possible to completely compensate for the detrimental influences of an unfavorable preceding crop on the grain yield of the subsequent wheat crop.

Water — Yield Relation and Water — Use Efficiency of Winter Wheat in Western Turkey

The yield response of winter wheat to water deficit was measured in the western Turkey during the 1998-1999 and 1999-2000 cropping season. Four wheat genotypes (MV-17, Flamura 85, Saraybosna and Kate-A-1) were grown underfive different irrigation treatments varied in amount. The amounts ranged from zero to 100 % of soil water replenishment in 25 % increments. As a result, irrigation significantly increased crop water use and therefore grain yield. When compared with the no irrigation treatment, the average grain yield increased by about 37 %, 48 %, 53 % and 66 % with the application of 25 %, 50 %, 75 % and full crop water requirement. Grain yield was linearly related to seasonal ET with a slope of 1.21 kg m - 3 for Flamura 85, 1.22 kg m - 3 for Saraybosna, 1.39 kg m - 3 for Kate-A-1 and 1.69 kg m - 3 for MV-17. The yield of MV-17, Flamura 85 and Kate-A-1 were similar to each other and higher than that of Saraybosna. The yield response factor (ky), representing relative yield decrease to relative evapotranspiration deficit, was found as 0.79, 0.74, and 0.56 for Saraybosna, MV-17, and both Flamura 85 and Kate-A-1, respectively.

Previous cropping and soil mineral nitrogen as predictors of yield response of winter wheat to nitrogen on silt soils in United Kingdom

Previous cropping and soil mineral nitrogen as predictors of yield response of winter wheat to nitrogen on silt soils in United Kingdom

Previous cropping and soil mineral nitrogen as predictors of yield response of winter wheat to nitrogen on silt soils in United Kingdom

Abstract. The fertilizer nitrogen requirement of winter wheat was assessed in sixteen experiments on marine silt soils in Eastern England. Eight experimental sites followed potatoes (Solanum tuberosum), six vining peas (Pisum sativum) and two wheat (Triticum aestivum). The yield response to nitrogen fertilizer was much less following peas than potatoes or wheat, five sites following peas showed little response to more than 30 kg N ha–1. Previous crop explained some 79.7% of the variation in nitrogen optima. When autumn soil mineral nitrogen was also taken into account 81.9% of the variation in optimum nitrogen rate was explained (P<0.001). The study revealed noticeably higher levels of autumn soil mineral nitrogen following vining peas on some sites than those found elsewhere in the UK and as assumed in the standard national fertilizer recommendation system.

METHODS, AMOUNTS, AND TIMING OF SPRINKLER IRRIGATION FOR WINTER WHEAT

The yield response of winter wheat to LEPA double-ended-sock, LEPA bubble and overhead spray sprinklermethods was measured in the Southern High Plains with four irrigation amount and two irrigation timing treatments.Irrigation amount treatments ranged from zero to 100% of soil water replenishment in 33% increments. Irrigation timingtreatments were shortening the 100% irrigation season by delaying irrigation until booting or by terminating irrigationduring early grain filling. TAM 202 variety wheat was raised on Pullman clay loam soil, and irrigations were appliedwith a lateral move irrigation system during the 1993-1994 and 1994-95 cropping seasons. Grain yields did not varysignificantly among the spray and LEPA sprinkler methods although in 1995 yields with the spray method were generallylarger. In 1994, grain yields increased a statistically significant 1 Mg/ha for each 33% increase in irrigation, butsignificant yield increases occurred only for the first two irrigation increments in 1995. Deficit irrigation with the 33%and 66% irrigation amounts, generally increased the grain yield per unit of irrigation water more than deficit irrigationwith the two irrigation timing treatments.

Winter Wheat Responses to Surface and Deep Tillage on the Southeastern Coastal Plain

AbstractConservation tillage practices have seldom been used to produce winter wheat (Triticum aestivum L.) on the U.S. southeastern Coastal Plain, primarily because of inadequate planting equipment and the need for deep tillage. Despite improved equipment, little is known about the effects of surface and deep tillage (ST and DT) systems on winter wheat development and grain yield on the Coastal Plain. Objectives of this 2‐yr study were to (i) determine whether ST affects the grain yield response of winter wheat to DT and (ii) examine the effects of ST and DT on winter wheat development. The soil was a Goldsboro loamy sand (fine‐loamy, siliceous, thermic Aquic Kandiudult). Treatments were ST (disked twice or no surface tillage) and DT (deep tilled using a ParaTill or no deep tillage). Averaged over years and levels of DT, the number of emerged seedlings was 16% less with no ST than with disking. With DT, the number of heads per square meter was similar for the two levels of ST treatment, indicating that wheat grown with no ST produced more heads per plant than with disking. Soil water contents were usually lower in 1995 than in 1994 for all treatments (<2 g kg−1 prior to inflorescence emergence in 1995). Aboveground dry weights near inflorescence emergence, kernel no. m−2, and grain yields averaged 39, 26, and 22% less, respectively, in 1995 than in 1994. Deep tillage increased aboveground dry weight, kernel no. m−2, and grain yield more for wheat in no‐surface‐tillage plots than in disked plots. When deep tilled, ST had no effect on grain yield in 1994, but yields were 25% greater for wheat grown with no ST in the drier year of 1995. There may be no need to disk the soil if DT is performed and proper planting equipment is used to produce winter wheat on the southeastern Coastal Plain. Yield increases due to DT in this region should be greater with no ST than with disking.

A Bayesian Network for predicting yield response of winter wheat to fungicide programmes

Abstract Bayesian Probability Networks (BNs) present a powerful tool for incorporating uncertainty in decision support systems. They provide a basis for probabilistic inference, to calculate the changes in probabilistic belief as new evidence is entered into the model. In practice, for agricultural systems, the construction of a BN is challenging, as there is often insufficient data for computing the prior and conditional probabilities required for the network. This paper illustrates the possible applications of BNs by describing a BN for yield response of winter wheat to spray programmes. It uses experimental data from ADAS trials and makes some assumptions in order to complete these data.

Winter Wheat (Triticum aestivum) Yield Response to Winter Annual Broadleaf Weed Control

Selected herbicide treatments from 25 winter annual broadleaf weed control experiments conducted across Oklahoma from 1979 to 1993 were examined for winter wheat yield response to weed control. All experiments contained one or two of the same three weeds (henbit, bushy wallflower, or cutleaf eveningprimrose) as the primary target(s). Herbicide treatments included chlorsulfuron at 8.8 or 17.6 g ai/ha, and/or 2,4-D at 420 g ae/ha, all broadcast POST to wheat. Most herbicide treatments controlled the weeds, but increased wheat grain yield at only one site, wherein bushy wallflower density was 830/m2. Correlation analysis found no relationship between weed densities and wheat yield when chlorsulfuron at 8.8 g/ha was applied for henbit or moderate levels of bushy wallflower or cutleaf eveningprimrose. There was a significant positive relationship favoring spraying of bushy wallflower when the correlation analysis included data from one site with a density of 830 plants/m2.

Design, Operation and Performance of a Gantry System: Experience in Arable Cropping

The background to the development of a two-wheel drive agricultural gantry system, its assessment and evolution into a commercial machine are described. Details of the main frame, transmission, implement attachment linkages and vehicle control systems are discussed and their performance assessed. Soil and crop responses to gantry systems are presented. A minimum power-to-weight ratio of 15 Kw/t is recommended for adequate performance. To maintain vehicle stability, the ratio of the weight on the drive wheels to that on the undriven castor wheels should not exceed 75:25. Up to 70% tillage energy savings can be made by removing all traffic from the cultivated area and plough resistance may be reduced by up to 50%. Conventional traffic on the soil increases aggregate size and reduces porosity compared with zero traffic operations. The yield of spring barley in 1991 on a clay soil was increased by around 0·75 t/ha under zero compared with conventional traffic, confirming a similar winter wheat yield response in 1990. It is concluded that suitably engineered gantries are able to carry out most operations on a farm and that they offer significant advantages over existing tractor systems in many aspects of their operation. The effect of improved boom stability on chemical applications needs to be quantified as well as the precise bout matching made possible by gantry systems.

Assessment of Spatially Variable Nitrogen Fertilizer Management in Winter Wheat

Spatially variable N application may improve N use efficiency, grain yield, and net returns of winter wheat (Triticum aestivum L.) in fields exhibiting wide ranges of soil characteristics. The objectives of this study were to (i) determine the variability in optimal economic grain yield and in the amount of N required to produce a unit of grain at optimum yield, the unit N requirement (UNR), among landscape positions; (ii) evaluate landscape position as a criterion for dividing fields into units of equal productivity; and (iii) assess the economic benefits of spatially variable N fertilizer application [...]

CROP ROTATIONS WITH FULL AND LIMITED IRRIGATION AND DRYLAND MANAGEMENT

ABSTRACT Irrigated cropping systems need to maximize the economic value of both rainfall and irrigation water, especially in areas of declining groundwater. This study compared water management systems in a winter wheat (Triticum aestivum, L.)-corn {Zea mays, L.)-soybean (Glycine max, L.) (W-C-S) and continuous corn (CC) rotation in west central Nebraska for dryland, limited irrigation (150 mm/yr), and full irrigation. Crop yield, evapotranspiration, and soil water storage were determined from field studies conducted at North Platte, Nebraska, on a Cozad silt loam (Fluventic HaplustoU) soil. Dryland com used 21.5% more evapotranspiration (ET) in the W-C-S rotation compare to CC. ET for the limited and full irrigation com was 4.6% and 4.9% more for the W-C-S rotation compared to the CC and was statistically significant at the P > 0.08 level. Water use efficiency, defined by the slope of the linear relationship between grain yield and ET (3Y 3ET-^), was the same for com in the W-C-S and CC rotations. Com grain yield response to irrigation and ET was more than the yield response of winter wheat and soybean. The W-C-S rotation increased com grain yields in two out of three years at this location for dryland management and increased the seasonal ET of corn compared to continuous corn. Full irrigation management did not consistently increase winter wheat and soybean grain yields above the limited irrigation treatments. Soil water storage for the full irrigation management was greatly reduced compared to dryland and limited irrigation management for both rotations.

Examination of Winter Wheat Yield Response to Seed Source

The incentive for private sector seed development is examined by looking at market forces in the seed industry. Differences in yield between private sector developed seed and bin run seed (grain from a previous harvest) were assessed to determine yield advantages of purchased seed and potential markets for seed firms. Winter wheat (Triticum aestivum L.) yield differences between bin run and purchased seed were estimated through regression analysis on field level data. In many cases, the estimated yield differences indicate that seed firms and farmers both could gain by substituting purchased seed for bin run seed. While a seed firm can expect to sell more seed by producing a more effective variety, providing the farmer more information on seed performance, either through increased advertising or encouraging their retailers to work more closely with farmers, could also increase the use of purchased seed. Some state and federal policy changes can also provide incentives for private sector seed development, including increased extension services, increased public promotion of purchased seed, better Plant Variety Protection Act enforcement, increased funding for public research and development (R&D) that complements private R&D, tax incentives, and commodity trade enhancement.

Influence of site factors on yield response of winter wheat to fungicide programmes in England and Wales, 1979–1987

Results of 460 field experiments between 1979 and 1987 incorporating one, two and three fungicide sprays, with a range of active ingredients, were analysed according to site factors including previous crop, sowing date and geographical area. The average untreated yield was 7–48 t/ha, although this fluctuated widely from 6 15 t/ha in 1985 to 9 411 ha in 1984. A single spray at flag‐leaf emergence gave an average yield increment of 0 59 t/ha over plots receiving no fungicide. The addition of a second spray at the first‐node growth stage gave an extra benefit of 0.22 t/ha, while an additional third spray at ear emergence gave a further 0.28t/ha. The effects on yield of different spray timings were modified by other factors, of which sowing date and previous crop were most important to the first‐node spray, and cultivar and geographical area to the ear emergence spray. The data suggest that all crops would benefit economically from a broad‐spectrum fungicide applied at flag‐leaf emergence. Additionally, crops sown in September, those following winter wheat and those in regions bordering the North Sea respond well at the first‐node stage to a fungicide active against eyespot.

Soil Profile and Site Characteristics Related to Winter Wheat Response to Potassium Fertilizers

AbstractEighteen sites throughout Montana were selected to study soil and climatic factors that influence the response of winter wheat (Triticum aestivum L.) to K fertilizer. Rates of 0, 22, 45, 90, and 135 kg K/ha were applied with 45 and 56 kg/ha of N and P, respectively. The sites were characterized according to Soil Taxonomy classification parameters. Fourteen chemical and physical properties were determined for each genetic horizon and seven site characteristics were identified. A stepwise multiple linear regression analysis was used to determine the relationship of the chemical, physical, and site characteristics to percent yield response of winter wheat to applied K. The genetic horizon variables were analyzed by major horizon as well as by sequence of horizons. Statistically significant variables (p < 0.1) from the major horizon analyses were grouped with significant site characteristics in a combined overall analysis. Variables with the highest correlation to percent yield response in the combined analysis, in decreasing order, were: (i) mean annual soil temperature at 50 cm as derived from SCS estimates; (ii) moist consistence of the Ap; (iii) moist and (iv) dry consistence of the B horizon; and (v) the clay content of the ca horizon. For these five variables an R2 of 0.88 was obtained.

Yield response of winter wheat to chronic doses of ozone

The relative sensitivity of 11 soft red winter wheat, Triticum aestivum L. cultivars, exposed as young plants to ambient levels of ozone (O3) was determined. On the basis of the shoot dry weight response, the cultivar Holly was determined to be significantly more sensitive than Oasis or Coker 47-27; Blueboy II showed intermediate sensitivity. Plants of these four cultivars, grown in pots or in the ground, were exposed for 54 days in open-top field chambers to different O3 concentrations added to existing levels of ambient oxidants for 7 h/day. The effects of O3 on foliar injury, growth, and yield were determined. For the four cultivars combined, the threshold O3 concentration (7 h/day seasonal mean) for significant injury and decreased growth and yield was between 0.06 and 0.10 ppm. For potted plants exposed to 0.10 and 0.13 ppm O3, seed weight yields were 10 and 27% less, respectively, than for those grown in "charcoal-filtered-air" chambers (0.03 ppm O3). For plants in the ground exposed to 0.10 and 0.13 ppm O3, the yields were 16 and 33% less, respectively, than for those at 0.03 ppm O3. The relative sensitivity of cultivars to O3 as young plants could not be used to predict O3 effects on seed yield.

Response of Winter Wheat to Phosphate as Affected by Soil and Climatic Factors1

SynopsisClimatic and agronomic variables are shown to be more closely related to yield response of winter wheat to phosphorus than is NaHCO3‐extractable P2O5. It appears that soil tests alone, or in combination with climatic and agronomic variables, are presently of limited value for predicting yield response of dryland winter wheat to phosphorus in the Southern Great Plains.