GREEN-MANURED FALLOW IS AN AGRICULTURAL TECHNIQUE FOR REDUCING ROOT ROT PROPAGATION

Abstract

Effects of green manure crops (pea-oats mixture, rape, clover) and ways of their tillage down into the soil on common root rot propagation in spring wheat were studied. Root rot pathogens affecting the rhizosphere and plants of spring wheat during its growing period were revealed. Investigations were carried out in Irkutsk Region in 2012-2015 in a three-course grain-fallow crop rotation with the variants of bare (control) and green-manured fallows and two ways of tilling green manure crops down into the soil by plowing to the 20-22 cm depth and disking to the 10-12 cm depth. Phytopathologic expert examination revealed high affection of seeds before sowing. The analysis of phytopathogenic fungi complex showed that the fungi of the Fusarium type dominated in the rhizosphere, at pre-root parts of the stems, and the roots of spring wheat from coming-up to ripening. The best phyto-reclaimer against root rot was rape when tilled by disking to the 10-12 cm depth. On the average for four years, it provided, with both ways of tillage down, the lowest propagation of wheat root rot. The gain in grain yields of spring wheat, in this case, was 0.18 t/ha on the average for four years. As the gain in grain yields, the best variant proved to be clover as green manure both with plowing and disking its green mass down into the soil. Disking green manure crops into the soil to the 10-12 cm depth, as compared with plowing to the 20-22 cm depth, reduces root rot propagation in the seedling phase of wheat after pea-oats mixture, rape, clover by 7.5, 8.4 and 9.7%, respectively, and provides the gain in wheat grain yields by 0.07-0.43 t/ha.