Effects Of Full Straw Tillage On Soil Physical And Chemical Properties And Maize Yield

For the purpose of clarifying the pattern of straw returning under continuous maize cropping in northern Liaoning province,experiments were carried out in Changtu County with 30 cm of straw returning at interannual intervals and year after year.The experimental treatments included returning to field / rotary tillage(that is,returning to field in one year and not returning to field in one year),returning to field / no-tillage(that is,returning to field in one year,alternate between years of no-tillage sowing straw in one year)and returning to field in successive years,and analyzing the changes of soil nutrients and yield in two and three years.The results show that:(1)The soil compactness of 10?30 cm soil layer was mainly affected by each treatment.One year straw returning to the field / one year rotary tillage not returning to the field increased;one year no-tillage returning to the field / one year no-tillage returning to the field,successive years tillage straw returning to the field decreased,among which one year tillage straw returning to the field / one year no-tillage reduction was even greater.(2)Straw returning to the field affects the content of soil organic matter.The soil layer of 0?10 cm did not change,the organic matter content of soil layer of 10 and 20 cm of straw was increased for two and three years in a row,the content of soil layer was decreased cm 20 and 30 soil layers.(3)Straw returning to the field affected the content of alkaline nitrogen in soil.The content of alkali-hydrolyzed nitrogen in 10?20 cm soil layer increased and decreased in 20 and 30 cm soil layer for two and three consecutive years.After three years of experiment,the content of soil layer decreased 0?10 cm,the content of soil layer increased 20?30.(4)Straw returning to the field affected the content of available phosphorus in soil.The available phosphorus content of all soil layers treated with 0?10 cm decreased,and the amount of straw returning to the field 20?30 cm decreased.(5)Straw returning to the field affected the content of available potassium in soil.The content of available potassium was increased by 10?30 cm,the content of 0?20 cm decreased and 20% increased in one year.(6)One year straw returning to the field / one year rotary tillage not returning to the field,one year no-tillage not returning to the field does not affect the emergence rate,single ear weight,100 grain weight,three years of continuous tillage straw returning to the field seedling rate decreased but ear weight increased.One year tillage straw returning to the field / one year no-tillage not returning to the field two years to increase corn yield,one year tillage straw returning to the field / one year rotary tillage not returning to the field,continuous straw turning back to the field has no effect on the yield.(7)Combined with soil compactness,nutrient index,seedling emergence rate and corn yield and other indexes,the feasible technical model of three-year tillage straw returning to the field in the maize continuous cropping area in northern Liaoning is one year straw ploughing back to the field / one year no-tillage not returning to the field / one year straw ploughing back to the field.