Results of the four-year experiments on the effect of the 9-, 10-, 11- and 12-year monoculture of winter wheat and winter rye and of the 5-year crop rotation control on the development of segetal vegetation at a lack and application of herbicides are analyzed. The efficiency of the Mixi Tor S (winter wheat) and Igran 50 (winter rye) herbicides was estimated on the basis of their effect on the yield structure and grain production in both cereals

In the pot experiment on winter wheat yields depending on seed fullness and sowing depth it was found that an increase of sowing depth to 5 cm resulted in a decrease of the wheat grain yield by 12%. Fuller seed did not affect the grain yield, increasing, instead, the straw length and decreasing the effective tillering of winter wheat

The response of winter wheat to sowing after cereals in the three-field crop rotation links was investigated. It was found that the wheat cultivation after cereals with a field bean as a forecrop led to a drop of its yield. The worst forecrop proved to be spring barley. The decrease of the unit productivity of grain occurred in consequence of heavier infestation of winter wheat with stem foot disease and of a growth of the weediness degree of the field. An increase by 50% of the NPK level increased winter wheat grain yields on the average by 7.2%. Fertilization was more efective when wheat was cultivated after cereals than after field bean

Synthetic results of eight-year static experiments are presented. Increased share of winter wheat in the crop rotation ranging from 50 to 100%, mineral NPK fertilization level of 200 and 365 kg per hectare and two winter wheat varieties: Starke and Eros replaced periodically by the varieties of Grana and Winnetou and Grana and Holme, were applied. Subsequent increase of the frequency of wheat cultivation on the same field led to the following mean grain yield decrease relating to control: wheat - wheat - field beans - 5.0%, wheat - wheat- wheat - field bean - 7.2%, wheat - wheat - wheat - wheat - field bean - 8.8% and eventually the wheat monoculture - 11.6%.

In a pot experiment winter wheat was cultivated on two slightly acid soils optimum supplied with available phosphorus. At the end of tillering very deficient nitrogen concentrations in plants have been found (N/P = 4,8-5,5). The nitrogen fertilization at the beginning of stem elongation, in doses up to 150 kg N/ha, determined no damages to the young plants but significant yield increases. High correlations were established between nitrogen rates and nitrogen concentrations in the two upper leaves of winter wheat at heading, nitrogen rates and grain yields, nitrogen concentrations in leaves and grain yields. Preliminary limits for interpreting foliar analysis of winter wheat at heading are presented.

In previous field studies a 46 cm spacing of preplant bands of N and P fertilizer has caused uneven growth of winter wheat (Triticum aestivum L.), with better growth immediately atop the preplant bands. Narrower spacing of fertilizer bands could improve plant growth uniformity and grain production by winter wheat. The objective of this study was to evaluate N-P fertilizer band spacing on wheat growth and grain yield. The effect of P band spacing on fertilizer P uptake from a preplant band was studied in the greenhouse with winter wheat. Phosphorus uptake from the fertilizer band was influenced by the lateral distance from the wheat row to the P band at 33 days after planting. By 40 days after planting, however, uptake of fertilizer P was the same from bands placed 0, 10, and 20 cm from the wheat row, while P uptake was significantly less from the band placed 30 cm from the row, apparently due to another row of wheat shielding the fertilizer P from uptake. Field studies consisting of combinations of spacings of preplant bands (25, 38, and 50 cm) and rates of P fertilizer (0,6, 12, and 24 kg/ha), all with 84 kg N/ha, were conducted on winter wheat. All treatments were deep-placed preplant band applications of liquid ammonium polyphosphate (APP, 10-15-0) and anhydrous ammonia (82-0-0). Wheat was drilled perpendicular to the direction of the preplant band application. Early season growth of winter wheat increased with increasing P rate and by decreasing the distance between preplant bands. Final grain yield, however, was influenced only by P rate, and not by P band spacing. Plant samples taken from 12.5 cm of drill row centered over the band and 12.5 cm of drill row centered between preplant bands of each treatment indicated differences between those areas in dry matter production, P uptake, spike density, and grain yield due to P rate and band spacing. Thus, more uniform growth resulted from the closer band spacing of 38 and 25 cm which could result in higher grain yields under optimum wheat production conditions.

Four crop rotations at increasing share of winter wheat: 50, 67, 75 and 100% and two NPK fertilization levels: 150 and 300 kg per hectare, intermitted by a regenerating plant, were estimated basing on the results of 9-year experiments located on medium-heavy soil. A distinct decrement of grain yields (13%) occurred only after three-fold sowing wheat after wheat (75%). In the continuous 9-year monoculture the yields decreased by 21%. At the 75% share of winter wheat the protein yields decreased by 16% as compared with 50% share in the crop rotation and as much as 30% in the 9-year monoculture