PRODUCTIVITY OF SPRING WHEAT IN CROP ROTATIONS
Results of researches for two rotation biologize crop rotations are generalized. On hydrothermal factor for vegetation of plants three groups of years on humidifying conditions are allocated: droughty, moderated and damp. Quantitative dependence of productivity of spring wheat on weather conditions of the vegetative period is established. On a natural background of fertility the maximum productivity of spring wheat is reached in damp years. At application of fertilizers the greatest gathering of grain in crop rotations is received in moderate years on humidifying. The share of participation of weather conditions in fluctuations of crops of wheat has made 38,8, and a food background - 40,4 %. Use of biological factors in crop rotations has allowed to level influence of predecessors on efficiency of summer grain culture. Regular application of mineral and organic fertilizers promoted reception of additional gathering of grain within 0,91 - 1,21 t/hectares depending on the predecessor. Recoupment of 1 kg operating substance the brought fertilizers on the average for rotation has made 10 - 15 kg of grain, the return maximum isn'ted on a mineral background of a food.