Yield performance and the amount of green feed were observed in conditions of slightly dry climatic region without irrigation in 1986-1989 in early winter catch crops (winter rape cv. Silesia, the hybrid of turnip rape cv. Perko), medium-early (rye, vetch-rye mixture) and late winter catch crops (wheat, vetch-wheat mixture). Silage maize followed. Brassicacea winter catch crops provided 2.24 t of dry matter, catch crops with rye 4.37 t and late catch crops on the base of wheat 2.39 t dry matter per ha in the average of the years. Wheat and vetch-rye mixture did not regularly provide the link-up harvest after rye up to the 1st mowing of perennial fodder crops. On the average silage corn provided 10-12 t of dry matter per ha after winter catch crops. Winter catch crops plus silage maize (except for the group after wheat and vetch-wheat mixture) was more productive in the total yield than maize sown in spring.

Impact of nitrogen fertilizers on winter wheat grown on turf carbonate soil was studied in the period of 1991-1994. Grain yield and quality of two wheat varieties "Kosack" and "Mironovskaya" were analysed. The results of the trials show that yields and particularly the gluten content and quality depend on meteorological conditions during vegetation. It is pointed out that a sufficient amount of fertilizers can compensate the negative effect of weather.

Jointed goatgrass is a serious weed in winter wheat, and presently no herbicides are available for its selective control. This study examined the effect of time of emergence and removal on jointed goatgrass interference in winter wheat, as well as its rate of development and soil water extraction. The goal of this study was to suggest cultural practices that minimize jointed goatgrass interference in winter wheat. Jointed goatgrass development was identical to 'Vona' winter wheat in two crop seasons, even though precipitation differed drastically between seasons. Depth of soil water extraction of both species was also similar. Jointed goatgrass at 18 plants m-2 reduced grain yield 27 and 17% when emerging 0 and 42 d after Vona, respectively. The relationship between time of jointed goatgrass emergence after winter wheat and grain yield loss was Y = 30.6 - 0.29X (X = days, r = 0.72), indicating that plants emerging in late fall still caused yield loss. Removing jointed goatgrass by early March prevented winter wheat grain yield loss. The interference data suggests that producers assess infestation levels and plan control measures in early March.

In 1986-1988 in the Experimental Farm of the Lithuanian Institute of Agriculture farm-technological trials were conducted to investigate the intensive technology of winter wheat cultivation with the objective to obtain grain yield of 55-60 dt/ha and more. Three technologies were tested: conventional (up to 1985) and two new ones-intensive with permanent tramlines on the sowing and intensive with unsown permanent tramlines. It was concluded that it is expedient to use intensive winter wheat cultivation technologies on light loamy soils of the Republic.

Field experiments over 3 yr at Lethbridge, Alberta, determined the effect of various downy brome densities and times of its emergence on winter wheat biomass and seed yield. Downy brome reduced wheat biomass up to 59% and seed yield up to 68%. Time of downy brome emergence relative to wheat affected the magnitude of these yield reductions more than the density of downy brome. At comparable densities, downy brome caused 2- to 5-fold greater reductions in yield when it emerged within 3 wk after winter wheat than when it emerged 6 wk after wheat or in early spring. Late-emerging downy brome caused significant wheat yield or biomass losses only at densities of 200 to 400 plants m-2. Late-emerging downy brome plants were strongly shaded (70 to 90%) by winter wheat throughout much of the growing season.

Use of green manure crops has become a preferred alternative source of N. The objectives of this 3-yr field study were to evaluate the N supplying power of 1, 2, and 3 Mg ha-1 of Austrian winter pea (Pisum sativum ssp. arvense L.) Poir), alfalfa (Medicago sativa L.), and wheat (Triticum aestivum L.) residue. Residues were incorporated in September and the N contribution of each amendment to a subsequent spring wheat crop was calculated. We measured inorganic soil N levels and wheat yields in northern Idaho on Latahco silt loam fine-silty, mixed, mesic Pachic Ultic Haploxeroll) soils. Soil samples were taken during July of each year to determine residual inorganic N. Plant material addition and incorporation affected spring wheat yield and soil inorganic N level in each study. Pea and alfalfa material applied at 3 Mg ha-1 resulted in the highest spring wheat yields. Austrian winter pea residue at 3 Mg ha-1 provided a N credit of 51 to 63 kg ha-1 to spring wheat, compared to 1 to 36 kg ha-1 for alfalfa applied at the same rate. Based on inorganic soil N in July, application of 3 Mg ha-1 of Austrian winter pea, alfalfa, and wheat residue provided an N credit of 16 to 24, 21 to 26, and - 1 to - 25 kg ha-1, respectively. Average total N credits (soil + plant uptake) for the 3 Mg ha-1 application of Austrian winter pea, alfalfa, and wheat materials were 76, 47, and -35 kg ha-1, respectively. Estimated N recovery of Austrian winter pea material after 10 mo of incorporation was 77% (58% in wheat and 19% in soil).

Use of green manure crops has become a preferred alternative source of N. The objectives of this 3-yr field study were to evaluate the N supplying power of 1,2, and 3 Mg ha⁻¹ of Austrian winter pea (Pisum sativum ssp. arvense (L.) Poir), alfalfa (Medicago sativa L.), and wheat (Triticum aestivum L.) residue. Residues were incorporated in September and the N contribution of each amendment to a subsequent spring wheat crop was calculated. We measured inorganic soil N levels and wheat yields in northern Idaho on Latahco silt loam (fine-silty, mixed, mesic Pachic Ultic Haploxeroll) soils. Soil samples were taken during July of each year to determine residual inorganic N. Plant material addition and incorporation affected spring wheat yield and soil inorganic N level in each study. Pea and alfalfa material applied at 3 Mg ha⁻¹ resulted in the highest spring wheat yields. Austrian winter pea residue at 3 Mg ha⁻¹ provided a N credit of 51 to 63 kg ha⁻¹ to spring wheat, compared to 1 to 36 kg ha⁻¹ for alfalfa applied at the same rate. Based on inorganic soil N in July, application of 3 Mg ha⁻¹ of Austrian winter pea, alfalfa, and wheat residue provided an N credit of 16 to 24, 21 to 26, and − 1 to − 25 kg ha⁻¹ respectively. Average total N credits (soil + plant uptake) for the 3 Mg ha⁻¹ application of Austrian winter pea, alfalfa, and wheat materials were 76, 47, and − 35 kg ha⁻¹, respectively. Estimated N recovery of Austrian winter pea material after 10 mo of incorporation was 77% (58% in wheat and 19% in soil). Paper number 91-7-94 of the Idaho Agric. Exp. Stn.

Influences of year and location on grain yield stability of some Kragujevac (Yugoslav) winter (facultative) triticale varieties and lines were shown in this paper. Two winter wheat varieties were used as standard. Grain yield of examined triticale was significantly influenced by year and location. Triticales had on average less yield than better yielding wheat. In comparison with worse yielding wheat standard, 4 examined triticales had higher yield, but not significantly. Triticale varieties and lines with highest yield didn't express satisfactory stability of grain yield.

Water production functions for summer corn, spring wheat, and winter wheat as well as cotton have been established according to the data of several irrigation experiment stations, the law for the sensitivity index (lambda) of these crops varying with the growing time has been analysed. The result has shown that these crops are the most sensitive to water deficit occurring in the stage of heading to milking, and the less sensitive in the stage of seeding and maturing periods. The relationship between the sensitivity index (lambda) and growing time is an unsymmetrical bell shape curve for summer corn, spring wheat and cotton, having the steeper slope on decreasing than on increasing period, but the curve of winter wheat has two maximum values, one is at tillering stage before winter season, and the other is at booting stage. A general method to determine optimal allocation of irrigation water use is discussed.