Effects Of Biochar On The Physical And Chemical Properties And Yield Of Soda Saline-alkali Rice Field

Soda saline soil is an important reserve land resource in China,and planting rice has become one of the effective methods to improve and utilize saline-alkali soil.The high pH stress,osmotic stress and ion toxicity of soda saline soil seriously endangered the growth and development of rice,and the soil was poor and the fertilizer utilization rate was low,which led to the low yield of rice,which seriously affected the sustainable use of soda saline soil.Biochar has the characteristics of porous,large surface area,strong adsorption,etc.,and application to the soil can improve soil state and increase crop yield.Therefore,in the case of soda saline-alkali field,this study used Changbai 9 as the test material,and set 4 biochar gradients,namely C0?0 t/hm²?,C1?33.75 t/hm²?,C2?67.5 t/hm²?.),C3?101.25 t/hm²?,explore the effects of biochar on the physical properties,chemical properties,soil nutrients and rice yield of soda saline-alkali soil.The research results can provide a theoretical basis for improving the soil properties of soda saline-alkali rice fields and increasing crop yield.The results of this pilot study are as follows:1.Effects of biochar on soil physical properties of soda saline-alkali rice fields:Biochar treatment significantly reduced the bulk density of soil.The two-year C1,C2,and C3 treatments decreased by 10.98%,14.13%,and 20.85%compared with C0;biochar increased significantly.The total porosity of the soil was the largest increase with C3 treatment,and the average C3 treatment increased by 33.52%compared with C0 treatment for two years.2.Effects of biochar on soil chemical properties of soda saline-alkali paddy fields:Biochar significantly increased soil CEC,showing C3>C2>C1>C0;biochar significantly reduced soil ENa and ESP,and treated with C3 for two years The reduction was the largest;biochar significantly increased the contents of K⁺,Ca²⁺,Mg²⁺and CO₃^2-in the soil,which was expressed as C3>C2>C1>C0;biochar significantly reduced the contents of Na⁺,HCO^3-and SO₄^2-in the soil,and It decreases as the amount of biochar applied increases.3.Effects of biochar on soil nutrients in soda saline-alkaline paddy fields:application of biochar significantly increased soil total nitrogen,available phosphorus,available potassium,and organic matter,and both showed C3>C2>C1>C0.The application of biochar significantly reduced the content of soil alkaline nitrogen and ammonium nitrogen,and both decreased with the increase of biochar application.At the same time,biochar significantly increased soil urease,alkaline phosphatase,sucrase,peroxidation,hydrogenase activity.4.Effect of biochar on the yield of soda saline-alkaline paddy fields:Biochar significantly increased rice biological yield and harvest index,and the biological rice treated with biochar for two years increased by 48.35%,52.09%and 57.47%on average,and the harvest index showed C2>C1>C3>C0.The addition of biochar significantly increased rice yield,with the increase in panicle number,1000-grain weight,and seed setting rate being the main factors.In summary,biochar improves the fertility of soda saline soil,improves soil physical and chemical properties,optimizes rice root environment,promotes rice yield,and slows soda salinity to rice stress;It is advisable to apply about 67.5 t/hm² of biochar in heavy soda saline-alkali rice fields.