Development And Application Of Biochar-based Slow Released Nitrogenous Feitilizer

Amount of nitrogen fertilizer is the largest of all kinds of fertilizers in crop production; itcan improve crop yields significantly, while it has the biggest environmental risks.International utilization of nitrogen fertilizer on crop is only about33%; there is a veryserious waste of resources. As a result, slow/controlled release fertilizer is into being.Biochar, as a new multi-functional material, is mostly used on improving soil physical andchemical properties in recent years; there are few studies on biochar as a carrier. Studies haveshown that biochar has a huge surface area, strong adsorption capacity, and strongperformance ion exchange properties, besides, biochar is rich in reactive chemical functionalgroups; therefore, it can be used as a sustained release carrier to delay the release of fertilizernutrients to reduce nutrient leaching and fixation losses and improve the utilization offertilizer nutrients. More importantly, biochar can still play a role in soil amendments whenthe fertilizer nutrient of biochar-based nitrogen fertilizer is completely released.In this paper, three kinds of biochar-based nitrogenous fertilizers (BNFs) were made bythree compound processes; its physical properties, chemical properties, and nutrient releasecharacteristics were evaluated in lab. Then the BNFs were applicated to soil in order to studythe effects of BNFs on soil physical properties, chemical properties, and biological activities.Finally, the yield and biomass of winter wheat was analyzed, the relevant nitrogen utilizationof winter wheat was calculated. The results and conclusions are as follows:1、There is difference on capacity and strength of loading ammonium nitrate of BNFs,the ractive-processed BNF (RP) loads maximum and absorbs intensity strongest, followed bythe adsorption-processed BNF (AP), the blend-processed BNF (AP) to a minimum. Threekinds of BNFs can control the release of nitrogen in a certain extent, the effects of controlledrelease of RP is optimal, followed by AP and BP.2、Effects of biochar and BNFs on soil bulk density and water content were notsignificant differences between all the treatments. After the application of BNFs, soil organicmatter content were increased compared with the control CK, in which the AP, BP and BCtreatments are significantly different from control CK, and organic matter content of BP issignificantly higher than RP. There is no significant difference between the other treatments.Different BNFs have a significant effect on the accumulation of soil ammonium nitrogen, the average content of ammonium nitrogen of AP and RP is greater than the control (CK). Fortotal nitrogen, nitrate and nitrite cumulative effects of nitrogen amount was not significant.After post-harvest, there are no significant differences in all treatments on soil total nitrogen,total phosphorus, total potassium, available phosphorus, available potassium, pH and CECcontent.3、The application of BNFs increase the activities of soil nitrate reductase, decrease thenitrite reductase activities and the urease activities, but there are no significant effects on thesethree BNFs. The fluctuation range of microbial biomass carbon content in winter wheatgrowth period is small, and there are no significant differences among the treatments, whichexperienced a trend as first increased and then decreased again a slight rise, differenttreatments peak at different time. Microbial biomass nitrogen content shows a significantseasonal variation with the advance of winter wheat, which increased compare with beforeplanting in seedling and winter stage, and for BP and RP treatment the content of microbialbiomass nitrogen increased to the highest in the jointing stage, these two compared with theother four treatments to achieve significant levels.4、Panicles, grain weight, biomass and yield of winter wheat of BNFs significantlyimproved compared with the control CK, increased by an average of5.50%、8.46%、23.85%and23.42%, respectively. For grain nitrogen accumulation, three kinds of BNFs significantlyincreased compared with the control CK and BC treatment, but For the phosphorus andpotassium accumulation in the grain and straw, there are no significant differences among allthe treatments. Integrated the utilization of nitrogen in winter wheat, the RP BNF performsbest, compared with the application of AN treatments, its apparent utilization of nitrogen andnitrogen agronomic efficiency increases34.74%,56.72%, respectively.