Effects of different straw returning methods on soil aggregate stability and organic carbon content in cold and arid regions
In order to clarify the impact of returning spring corn straw on soil aggregates and their organic carbon components under low temperature and water scarcity conditions in farmland,and to provide scientific basis for the method of returning spring corn straw to farmland in the northwest cold and arid region of Hebei,three methods of returning straw to farmland were set up in field experiment,namely,returning straw to farmland through plowing(JF),returning straw to farmland through rotary tillage(JX),and returning straw to farmland through large ridge rotation(JL).Using no straw returning to farmland as control(CK),the effects of straw returning methods on the distribution,stability and organic carbon component content of soil aggregates with different particle sizes were analyzed.The results showed that in 0-20 cm soil layer,all returning methods significantly increased the proportion of 1.00-2.00 mm aggregates,while JX treatment significantly increased the proportion of＞5.00 mm aggregates.The average weight diameter(MWD)of soil aggregates under JX treatment was the highest,and the stability of aggregates was strong.JL and JX treatments significantly increased the proportion of 2.00-5.00 mm aggregates,while JL treatment had a higher geometric mean diameter(GMD)of soil aggregates.Each returning method increased soil MWD and GMD by 10.32%-15.46%and 16.23%-18.35%,respectively,which could increase soil aggregate stability.The organic carbon content of soil aggregates with different particle sizes ranged from 42.88-54.72 g·kg-1.The JL treatment significantly increased the organic carbon content of aggregates by 2.00-5.00 and 0.50-1.00 mm,with an increase greater than the other two returning methods.The active organic carbon content of soil aggregates with different particle sizes under different returning methods ranged from 4.18 to 8.29 g·kg-1,and the active organic carbon content of each aggregate was higher than that of CK.Returning straw to the field increased the black carbon content of aggregates of 1.00-2.00 and 0.50-1.0 mm,while JF and JX treatments increased the black carbon content of aggregates of＞5.00 and 2.00-5.00 mm.JL treatment increased the carbon content of aggregate humus of＞5.00,2.00-5.00,1.00-2.00,and 0.25-0.50 mm.The increase in organic carbon content in 0-20 cm soil layer by various returning methods was higher than that in 20-40 cm soil layer,while the carbon content of aggregate humus in 20-40 cm soil layer treated with CK and JF was higher than that in 0-20 cm soil layer.The black carbon contents of aggregates＞5.00,2.00-5.00,and 1.00-2.00 mm with CK,JF,and JX treatments were the highest in 0-20 cm soil layer.Based on comprehensive analysis,it was suitable to adopt the method of rotating spring corn in large ridges and returning straw to the field in the cold and arid areas of northwest Hebei.
the way of straw return to the fieldsoil aggregatesstabilityparticle size distributionsoil organic carbonspring maize
NETL
NSTL
万方数据
