Root rot of spring wheat in field crop rotations in the forest-steppe of the Irkutsk region

Abstract

The paper presents the results of the studies to assess the prevalence of root rots and yields of spring wheat in the forest-steppe zone of the Irkutsk region in field crop rotations on different back-grounds of fertilization and tillage practices. The experiment scheme: forecrops – fallow in crop rotation (fallow – wheat – oats), pea-oat mixture and corn in crop rotation (pea-oat mixture – wheat – corn – wheat); tillage methods – plowing with PLN-5-35 plow to a depth of 20-22 cm, BDT-3 disking to a depth of 12-14 cm; fertilization - no fertilizer, complete mineral fertilizer N45P45K45. The prevalence of root rot decreased on average for 3 years in the crop rotation with 33 % saturation of wheat and its sowing on a fallow forecrop in comparison with 50 % saturation in pea-oats by 6.1 %, in corn by 0.9 %; disc tillage compared to plowing in fallow forecrop by 11.8 %, in pea oats by 4.7 %, in corn by 9.2 %; on fertilized background in three-field crop rotation in fallow by 4 %, in pea oats by 1.9 %, in corn by 4.8 %. Statistically reliable highest yield of spring wheat was observed in three-field crop rotation with 33 % saturation of wheat on fallow at soil plowing, which is higher than similar soil treatment in crop rotation with 50 % saturation of wheat at sowing on pea and oat mixture by 31.3 %, on corn by 23.8 %. Application of mineral fertilizers N45P45K45 increased the yield, while tillage with discing and the forecrops such as pea and oat mixture and corn decreased the yield. Over the rotation, root rot incidence decreased from baseline with a concomitant increase in yield – with 33 % wheat saturated in the rotations by 9.0 % and 35.0 %, and with 50 % wheat saturated in the rotations by 6.6 % and 45.7 %.