Effects Of Straw Incorporation Approaches And Fertilization Managements On Soil Physical Properties And Spring Maize Production

Northeast China is an important main producing area of spring maize in China,with high yield of maize and abundant straw resources.It is very important to make scientific and reasonable use of straw resources,improve the way of straw returning to the field,and study the influence of straw returning to the field on soil and crop production.This paper studies the new straw counters-field pattern of spring maize in northeast China,the feasibility of producing in Liaoning province in 2016,Shenyang Agriculture University testbed,respectively in rotary tillage(T1)and tilling(T2),under the condition of straw returning full-thickness/stripe + put fertilizer on the soil of maize seedlings growing(F1S2 / F1S1),straw returning fullthickness/stripe + put fertilizer on the soil of maize seedlings growing and row(F2S2 / F2S1),a total of eight test treaments,contrast between each other by processing,study different straw counters-field model combined with different fertilization methods on soil physical properties,root growth and dry matter accumulation and yield,the main results were as follows: 1.The soil bulk density and porosity were mainly showed differences in 0 ~ 30 cm soil layer,under rotary tillage conditions,F2S1 decreased soil bulk density of 0 ~ 10 cm,increased the total porosity and capillary porosity,and in 20 ~ 30 cm,the soil capillary porosity under the condition of ploughing,S2 lower 0 ~ 10 cm soil layer soil bulk density,S1 reduced the bulk density of deep soil depth,in 20 ~ 30 cm soil layer,F2S1 significant decreased soil bulk density and increased total porosity.2.Compared with S2,S1 reduced the soil compactness between rows and increases the soil compactness against the belt of seedlings,which creates the soil compactness distribution of the soil loose between rows against the belt of seedlings and promotes the horizontal growth of the root system in the shallow layer and the vertical growth in the deep layer.The effect is more significant under F2 fertilization.However,full layer mulching of straw could reduce the compactness of interrow and seedling belt,especially under the effect of F1 fertilization.3.The content of soil aggregates with different particle sizes varied with the soil layer.The upper soil contained more large aggregates,while the deeper soil contained more powder and clay aggregates.Under rotary tillage,the content of large aggregates and soil aggregates stability were increased in 0~20 cm,among which F2S2 and F2S1 significantly increased the content of intermediate aggregates,while under tillage,the soil aggregates stability was improved by 20~30 cm,especially F2S2.4.Soil moisture content directly affects spring maize growth and development.Compared with rotary tillage,tilling increased soil moisture content of 0~ 20 cm soil depth at silking stage,and F2S2 significantly increased soil moisture content of 0~ 10 cm soil depth at silking stage.After maturity stage,soil moisture content of S2 was lower than S1 in soil layer of 0~ 20 cm,indicating that the whole layer of straw mulching could consume more moisture in later growth stage of maize.5.In 2017 and 2018,the vertical and horizontal root distribution changed,and the vertical root length distribution showed that,in 2017,T1F2S2 and T1F1S2 improved the root amount of 0~ 30 cm soil layer and soil layer 30~ 60 cm,respectively.Different from 2017,in 2018,T2F2S1 and T2F2S2 are more helpful to increase the amount of root system in soil layer 0~ 30 cm and soil layer 30~ 60 cm,respectively.However,the trend horizontal root length distribution data of two years was consistent,which reflected that S1 was beneficial to increase the root length distribution within the range of 20-30 cm from the plant,and F2S1 was superior to F1S1 in terms of fertilization method.However,S2 could improve root length distribution within 10 cm from the plant,and F1S2 was higher than F2S2.6.The root surface area of maize under each treatment was concentrated in the range of 20 cm directly below the plant,and the farther from the plant,the lower the root surface area.Compared with each other,S1 could increase root surface area in the horizontal direction in 0~30 cm soil depth,and then decrease with the deepening of the soil layer,and F2S1 had a more obvious effect.The surface area distribution of S2 roots decreased gradually along the horizontal and vertical directions with the plant as the center.The number of years of straw mulching had an impact on the root system.The total root surface of T2F2S1 increased with the number of years of straw mulching,which was significantly higher than that of other treatments in 2018.7.Straw returning years and rainfall significantly affect the accumulation and distribution of dry matter.With the returning years increasing,the dry matter accumulation increased at jointing stage and mature stage,and promoted the transport of dry matter to seeds.T1F1S1 and T2F1S2 accumulated the most dry matter at jointing stage and maturity stage,respectively.The distribution of dry matter in silking stage directly affects yield.Specifically,T2F2S2 presents the morphological characteristics of large leaf and thick stem in silking stage,which increases the accumulation of dry matter in later stages and directly affects grain filling,thus improved the grain yield.8.Maize yield is not only affected by external factors,but also by the transport and distribution of its own nutrients.In the early years after straw was returned to the field,there was no significant difference in yield and yield components between treatments.T2F1S2 was slightly higher than other treatments,followed by T1F2S1.In the second year of straw mulching,the yield of S2 increased and was higher than S1 due to the increase of rainfall and years of straw mulching.In S1,the yield of T2F2S1 decreased except that the yield of T2F2S1 showed a growing trend,mainly due to the decrease of spike number.