Receiving of winter rapeseed constant yields under unsteady moistening

摘要

Stable yields of winter rape in conditions of unsteady moistening of Northem Caucasus can be received only in the successful wintering of crops which firstly depends on sowing and seedlings appearance dates. This is the reason to direct the preparation system of field to the winter sowing at keeping of residuary water after preceding crop harvesting and its recharge due to precipitations. The researches on substitution of plowing with surface treatment under the winter rape after the harvesting of preceding crops, conducting since 80-s of last century on the chemozem of different fertility, have shown that seedlings are simultaneous in the years with moisten summer in plowing and subsurface tillage. In drough years subsurface tillage allows receiving of simultaneous seedlings in optimum dates as in plowing seedlings are poor or seeds germinate only after rains, sometimes before winter. As a rule, rather weak plants freeze. On poor humus chemozems nonplow tillage on depth 6-8 sm. leads to the sufficient differences to the sowing on moisten,solidity and volume weight of surface and subsurface soil horizons. Plants develop surface roots and lowered the productivity. On deep chemozems in soil treatment with heavy disks on depth 12-14 sm. after cereal preceding crops yield was 3.51ton/ha on average in 1997-1998 and in variant with surface treatment - 3.25 ton/ha. In the later studies the negatives of surface treatment were eliminated by means of mineral fertilizers and plant protection preparations. On average a yield at surface treatment was on 5-6% higher than at plots with plowing in 2003-2005.