Effects Of Straw Incorporation Modes On Soil Physicochemical Properties And Spring Maize Yield

In order to investigate the feasibility of straw strip incorporation mode in North of Liao Ning Province,field trial was conducted in Zhang-zhuang village,Tie-ling city,Liaoning province during 2017~2018.In 2017,compared to whole-layer rotary tillage without straw strip incorporation(CK),we investigated the influence of inter-row rotary tillage plus straw strip incorporation(T1S1),inter-row plowing tillage plus straw strip incorporation(T2S1),whole-layer rotary tillage plus straw strip incorporation(T1S0)and whole-layer plowing tillage plus straw strip incorporation on soil organic carbon,total nitrogen and C/N ratio.In the same year,the effects of straw strip incorporation on the distribution of water-stable aggregates,the stability of water-stable aggregates and organic carbon was conduct.The four treatments included inter-row rotary tillage plus straw incorporation(T1S1),inter-row plowing tillage plus straw incorporation(T2S1),inter-row rotary tillage without straw incorporation(T1S2)and inter-row plowing tillage without straw incorporation(T2S2).On this basis,we continue to study the influence of different straw strip incorporation modes on the distribution of soil water and nitrogen,soil water use efficiency and crop yield in 2018.The results shows that:1.Straw incorporation treatments significantly increased contents and storages of soil organic carbon and total nitrogen.The storage of SOC of T1S1 is the largest,T2S1 took the second place.The contents and storages of TN fit in with SOC.The C/N ratio in all soil layers of T1S1 and T2S1 are significantly higher than other three treatments,but there is no significant different between the two treatments.The stratification ratio of SOC for surface(0 ~ 10 cm)to all other depths of straw incorporation treatments was significantly higher than CK,TN is consistent with SOC.2.T1S1 and T2S1 treatments changed the composition of water-stable aggregates and improve the stability of water-stable aggregates.T1S1 and T2S1 treatments increased the percentages of > 2 mm and 0.25 ~ 2 mm aggregates and the contrary effect was found in < 0.053 mm aggregates at 0 ~ 40 cm depth.At the meantime,T1S1 and T2S1 treatments improved the mean weight diameter.T1S1 treatment performed best.T1S1 and T2S1 treatments improved the protection of soil organic carbon in large aggregates.T1S1 and T2S1 treatments mainly increased the content of soil organic carbon in large aggregates and micro-aggregates at 0 ~ 20 cm and the soil organic carbon contribution rate of large aggregates in all soil depth.3.T1S1 and T2S1 treatments improved the soil moisture retention capacity.At seeding stage,T1S1 and T2S1 treatments increased the deep soil water content.At the tasseling stage,soil water content in T1S1 treatment was significantly higher than that in the other three treatments,water infiltration and evaporation was hindered by straw layer.4.T1S1 and T2S1 treatments changed the distribution of soil NO3--N.Before sowing,the average content of soil NO3--N is the largest at 0 ~ 100 cm soil depth.At seeding stage,soil NO3--N was concentrated in 0 ~ 40 cm,the content of soil NO3--N of T2S1 is the largest at 40 ~ 100 cm soil depth.Tasseling stage,soil NO3--N of the two straw strip incorporation treatments appeared obvious zonal distribution,which was concentrated in the tillage and straw incorporation area,forming a symmetrical distribution on both sides of the plants.5.Straw strip incorporation treatments didn't show obvious yield advantage in normal years(2017),but they improved water use efficiency and reduce yield loss in extreme years(2018).6.Above all,inter-row rotary tillage plus straw incorporation is the suitble straw incorporation mode for North of Liao Ning Province.