Effects Of Biochar On Topsoil Quality And Corn Growth In Dry Areas

Under the background of food security threat and climate warming,the demand for improving soil quality and efficiency,carbon sequestration and emission reduction in arid area is increasing day by day.It is urgent to take effective measures to improve soil fertility in arid area.Biochar has become a research hotspot in the fields of agriculture,ecology,environment and energy due to its broad industrial development prospects.However,the problem of whether biochar can improve the quality of dryland soil needs to be solved.The ’ Xianyu 335’ was used as research materials.The effects of biochar on soil physical and chemical properties(0～40 cm),soil enzyme activity and maize growth and yield in dry were studied.The research results are as follows:1.Biochar mainly affects the physical properties of topsoil(0～20 cm).Compared with CK,Biochar treatment significantly reduced bulk density by 3.41%-9.43%,Gross porosity increased significantly by 7.83%～16.43%,The content of 0.25 mm mechanical stable aggregates in soil increased significantly by 13.49～36.10%,R value significantly decreased by 16.12%～34.70%,The solid phase value decreased significantly by 3.03%～8.39%(P<0.05).2.The pH value,organic carbon and available potassium content of topsoil increased with the increase of biochar application rate.Compared with CK,the pH value of biochar treatment increased by 0.11%～1.15%,but not significantly(P>0.05),the organic carbon content increased by 3.91%～47.97%(P<0.05),and the content of available potassium was significantly higher after flowering stage(P<0.05).The contents of total nitrogen,available nitrogen,nitrate nitrogen,ammonium nitrogen,total phosphorus and available phosphorus in the topsoil of the arid area first increased and then decreased with the increase of biochar application rate,and the turning point was at T3 treatment.Among them,the total nitrogen content of topsoil(0～20 cm).Treated with biochar was significantly higher than that of CK during the whole growth period(P<0.05),and reached the maximum at the flowering stage.At this time,the total nitrogen content was significantly increased by 25.45%～47.27%compared with CK(P<0.05)The content of available nitrogen in topsoil(0～40 cm)of biochar treatment was significantly higher than that of CK except at jointing stage,and the content of nitrate nitrogen was significantly higher than that of CK after flowering stage(P<0.05)but there was no significant difference among biochar treatments.The content of ammonium nitrogen in topsoil(0-20 cm)of biochar treatment was significantly higher than that of CK at jointing stage,and reached the maximum at flowering stage,which was significantly increased by 14.22%～28.75%(P<0.05)compared with CK at this time,and the content of ammonium nitrogen in topsoil(20～40 cm)was significantly higher than that of CK at the later growth stage.Biochar had no significant effect on total phosphorus content of topsoil in arid area,but significantly increased available phosphorus content in most periods.3.Biochar had a great influence on the activities of catalase,urease and invertase in the topsoil of arid area.In most periods,biochar increased the activities of these three kinds of soil enzymes in general,especially T3 treatment had the most significant effect on soil enzyme activities,while biochar application had no effect on alkaline phosphatase activities.4.Plant height,stem diameter,leaf area index,relative chlorophyll content,dry matter accumulation parameters and root activity of maize increased first and then decreased with the increase of biochar application rate,and high biochar application rate in late growth stage was easy to cause premature senescence of maize.Biochar significantly increased maize ear length,ear diameter,row number,ear weight and ear weight,and significantly increased yield by 6.85%～18.40%compared with CK(P<0.05).5.Principal component analysis was used to comprehensively evaluate the quality of topsoil of each treatment.The results showed that the comprehensive score of topsoil quality of each treatment was T3>T4>T2>T1>CK,which was consistent with the growth index and yield performance of maize.Therefore,in this experiment,when the biochar application rate was 22.5 t·hm-2(T3),it was the best to improve the quality of topsoil,promote the growth and yield of maize.