Effect Of Biochar On Soil Aggregate And Potssium

Biochar could act as a soil amendment and increase crop yield.Biochar has many porous sturcture and rich nutrients.It can improve soil physical and chemical properties,adjust soil microbial community structure,and change soil water,fertilizer,gas and heat.Therefore,biochar has attracted more and more scholars' attention.In recent years,the phenomenon of structural degradation and crop yield decline has occurred in greenhouse soil.In addition,the amount of potash fertilizer in Yangling area is little,which affects crop yield.In order to explore the effect of fruit-made biochar on the soil aggregate structure and the potassium content of different forms of soil,two crops,spinach and lettuce,were used trough pot experiment,proposing a proper biochar addition in Yangling solar greenhouse.Five biochar treatments with 10,30,50,70 and 90t/hm~2,and a control group without any biochar treatment,were set up.The mean weight diameter,geometric mean diameter,damage rate,fractal dimension were calculated through the data got by the dry sieve method and the wet sieve method.The water-soluble potassium ion,exchangeable potassium ion,available potassium and total potassium content were tested by a flame photometer.The main conclusions are as follows:(1)After adding biochar spinach soil the dry aggregates increase significantly to 0.61?4.60mg/kg and the dry microaggregates decrease by 3.95%?32.62%compared with the control treatment.After the adding biochar,3?2mm,2?1mm and 1?0.5mm water stable large aggregates increase by 25.32%?41.20%,22.69%?74.16%,9.09%?46.40%individually;0.5?0.25mm water stable large aggregates decrease by 2.05%?18.10%.Biochar promotes the formation of small size microaggregates,yet biochar do not have a significant effect on microaggregate stability and microaggregates.Biochar may ameliorate the structure of soil aggregates.Taking soil aggregates and crop fields into account,the 70t/hm~2 biochar has the optimal effect in Greenhouse.(2)Biochar improved lettuce soil mechanical stability agglomerate structure,and biochar significantly affected the soil mechanical stability aggregate greater than 7?5mm,5?3mm,0.5?0.25mm.Biochar has the effect of increasing the stability of agglomerates of soil mechanical stability.Biochar improves soil water stable aggregates.Biochar significantly affects the soil aggregate content from 1?0.5,0.5?0.25mm.After adding biochar,the content of water-stable agglomerates in 1-?.5mm soil showed an upward trend,and the water-stable agglomerates in 0.5-0.25mm showed an increasing trend.Biochar has no significant effect on the stability of soil water-stable aggregates.When the amount of biochar addition was 30t/hm~2,the large agglomerates of soil mechanical stability increased the most,and the recommended amount of biochar in Yangling area was 30t/hm~2.(3)After adding biochar in spinach soil,the water-soluble potassium ions increased by 11.00%?365.23%,the exchangeable potassium ions increased by 8.99%?201.27%,and the available potassium ions increased by 8.05%?209.35%.There is an exponential relationship,which is y = aebx,between soil water-soluble potassium,available potassium,and exchangeable potassium ion content and biochar addition amount;soil pH significantly affected soil available potassium and exchangeable potassium ion contents.The addition of biochar in Guanzhong Lou Soil can enhance soil potassium conversion and effectively alleviate potassium deficiency in plants.Considering soil fertility,pH,it is best to add 50t/hm~2 biochar in Guanzhong area.(4)Biochar significantly increases the content of water-soluble potassium ions,available potassium ions,exchangeable potassium ions and available potassium ions in lettuce soil.Biochar and soil water-soluble potassium ions,available potassium ions,and exchangeable potassium ions are exponentially related.The more the amount of biochar addition,the more potassium content in the soil.When the amount of biochar added is low,there is little difference in soil potassium.As time goes by,soil potassium consumption is little,and because CO and C10 treatments do not have much difference,it is recommended to use 30t/hm~2 biochar treatment in Yangling area.(5)After adding biochar,the yield of spinach increased significantly.The yield of spinach increased by 68.74%?214.93%,and the yield of spinach was positively correlated with the amount of biochar.Among them,the weight per plant treated with 50,70,90t/hm~2 biochar increased the most,so in Lousoil,when the biochar addition was more than 50t/hm~2,the yield of spinach was the highest.(6)Biochar significantly increased the yield of lettuce,increasing by 7.05%?47.42%,and the more the amount of biochar was,the greater the crop yield.Among them,30,50t/hm~2 biochar treatment had significantly increased the yield of lettuce,and it was recommended to use 30t/hm~2 and 50t/hm~2 in the amount of biochar added in bauxite.