Засорённость и продуктивность полевых культур в севооборотах при разных системах удобрений в условиях лесостепи Предбайкалья

At present, the basic method of weed control under conditions of the region is fallow/tillage which is supplemented by chemical weedings. The goal of our studies was to assess the influence of crop rotations and systems of fertilizers on weediness of sowings. The field trial included 3 short-term rotations: grain-fallow rotation with bare fallow, grain-fallow rotation with full fallow, green-manuring rotation. In all three crop rotations in comparison to absolute control we studied mineral, organic and organic-mineral systems of soil fertilizers. On the average, for three years the sowings of spring wheat, placed on bare fallow, were less weeded. Under spring wheat on full fallow the amount of weeds was greater by 20-25 %. The account of dry weight has shown that the amount of weeds in a whole volume of phytocenose did not exceed 5-7 %. Application of all kinds of fertilizers caused intensive emergence of weed seedlings and, especially, with organic system of fertilization. On the average, for three years the three-course crop rotation with full fallow was noted with the greatest weediness of sowings, and green manuring rotation took an intermediate position between grain-fallow and grain-grass crop rotations. As a result of studies it is stated that the most effective is organic-mineral system of fertilizers providing yield gain of grains 0,4-1,01/ ha, of corn 9,9 t/ha, of clover 4,1 t/ha. Mineral system of fertilizers is insignificantly inferior to organic-mineral one and gives yield gain of grains 0,3-0,9 t/ha, of corn 9,6 t/ha, of clover 3,7 t/ha. Organic system of fertilizers increases yields not so much (grains by 0,51/ ha, corn 1,4 t/ha and clover 2,7 t/ha).