Influences On Soil NPK Dynamic Characteristics And Peanut Biomass Formation By Biochar

Biochar and biochar-based formula fertilizer have gained widely recognition in the aspect of improving soil physical and chemical properties and increasing crop yield.The nature of biochar,such as richness of carbon,high surface area,abundant oxygen-containing groups and property of alkaline,could increase organic matter content,porosity and the capability of soil water and fertility retention.Combining application of biochar and chemical fertilizer or employing biochar-based formula fertilizer not only endows soil sustaining mineral nutrient from chemical fertilizer,but makes up for the nutrient lack with using biochar singly,which generate complementary and synergistic effect in the variation of soil nutrient and crop yield.We sat micro-location experiment（2m²）for 8 years and the farmyard manure of conventional organic material as the control treatments.There are 4 treatments:biochar（BIO）,biochar-based formula fertilizer（BF）,piggery manure compost（PMC）and corn straw-returning（CS）,which under the condition of equal nutrient inputting（i.e.N,P,K）,all treatments were designed for 3 repeats randomized block arrangement.This study aimed to investigate the dynamic variation of soil nutrient（i.e.N,P and K）during crop growing season and dry matter accumulation and distribution in different crop organs,in addition provide a theoretical basis for efficient utilization in agriculture with biochar.The results are shown below:1.Compared with the other treatments,BIO significantly increased the soil nitrate concentration in the early stage of peanut,that in the seedling stage with 3 and 1 times higher than CS and PMC respectively and in the flower-needle stage it was higher than CS and PMC with 4.5 and 2.3 times respectively,beyond that enhanced the rate significantly after the fruit-filling stage.The release rate of available phosphorus and the concentration of available potassium were performed well that BIO was.As to soil nitrogen concentration between BF and other treatments,it was in the initial stage of peanut that there were very notable difference,that the ammonium and nitrate content of seedling stage with BF were 10.44mg·kg^-1 and 42.69mg·kg^-1 respectively which higher than others,with the exception of ammonium the release rate of other nutrient were the highest of BF.2.The peanut yield of BIO(7231.69kg·hm^-2)was significantly higher Thanthose of BF and PMC（accounting for 82.41%and 83.83%of BIO respectively）and the lowest treatment was CS(5623.93kg·hm^-2).It was different that the characteristics of dry matter accumulation and nutrient distribution of four Growth periods among different treatments.The dry matter and NPK mainly accumulated in stem-leaf in the Earlyier stages,and turned to pod after the podding stage.BF had a higher content of dry matter and NPK,Especially had a higher nutrient partition coefficient before the stage of podding compared with the control treatments.BIO had obvious superiority in dry matter accumulation at the maturation stage(6294.68kg·hm^-2),which was significantly higher than those of BF,CS and PMC（exceeded43.18%,36.11%and 50.89%,respectively）.N,P,K accumulation of BIO continued to increase to 236.44kg·hm^-2,21.69kg·hm^-2 and 77.76kg·hm^-2,respectively,Meanwhile the ratio of dry matter in stem and leaf reached to 34.55%,which was significantly higher than that of the control.The application of biochar shows significant higher effect than biochar-based formula fertilizers and piggery manure compost in promoting the dry matter and NPK accumulation,especially in the dry matter and nutrient distribution in late growth period,which is conducive to higher yield and nutrient use efficiency of peanut.Biochar-based formula fertilizer and piggery Manure compost show similar effect in yield and nutrient accumulation and distribution.3.Leaf photosynthetic performance of BIO in the later growth stage was the highest,and BIO improved some indexes（i.e.photosynthetic rate,stomata conductance,and transpiration rate）largely compared with other treatments,meantime performed well on photosynthetic nitrogen and phosphorus nutrient use efficiency either.The photosynthetic characteristic advantages of BF consist before flowering stage,that photosynthetic rate reached23.53μmol·CO₂·m^-2·s^-1 at the seedling stage which was significantly higher than other treatments.