Effects Of Biochar-based Slow-released Nitrogenous Fertilizer On Soil Microbial Biomass And Soil Enzymes And Crop Yield

Biochar is a kind of highly aromatic refractory and difficult soluble solid material which produced by thermal cracking or carbonized of the biomass such as wood, plant tissue, wastes of agriculture, forestry and animal bones or waste under limited or absent supply of oxygen, and relatively low temperature(< 700 ℃). Recently, it is advocated to use in agricultural mostly focused on improving soil physical and chemical properties, reducing greenhouse gas emissions and controlling soil heavy metal pollution and so on, but use it as the carrier of slow or controlled release fertilizer research is less. Studies have shown that biochar has larger porosity, specific surface area and high stability and adsorbability. Therefore, biochar can use fertilizer slow release carrier preparation slow or controlled release fertilizer which can adsorb fertilizer nutrients, delay the release of nutrients, reduce fertilizer nutrient leaching loss, and improve the utilization rate of fertilizer.In this study, three kinds of biochar-based nitrogenous fertilizer were made by biochar preparation of the abandoned branches through three kinds of complete process. This study was conducted by a fertilizer experiment platform with winter wheat-summer maize rotation system and chosen six fertility treatments: control(CK), biochar(BC), ammonium nitrate control(AN), simple mixed type of biochar- based nitrogen(CH), solid-liquid adsorption type biochar-based nitrogen(XF), chemical reaction type biochar- based nitrogen(FY). This study was designed to explore the effects of Biochar and Biochar-based ammonium nitrate fertilizers on soil chemical fertility factors, the influence of crop yield and yield components, the content and the seasonal rule of soil nitrate and ammonium nitrogen and soil microbial biomass carbon and nitrogen and changes of enzyme activity in different period of three(0-20 cm, 20-40 cm, 40-60 cm) layer. And obtained the utilization ratio of various kinds of nitrogen fertilizer. The main results are as follows:1. BC and 3 kinds of biochar-based nitrogen were significantly increase arable layer soil organic carbon content,BC, CH, XF, FY treatment increased by 9.77%, 6.74%, 4.46%, 6.74%, and in turn FY > CH > XF.ANtreatment soil total nitrogen content is the highest, in addition to BC, other treatment significantly increased soil total nitrogen content than CK treatment, among them, in turnincreased by 20.75%, 16.04%, 11.93%, 10.81%. Soil available P content in turn by BC > XF > CK > FY > CH > AN. Soil rapidly-available potassium content of CK and AN treatment were higher thanadded biochar and biochar-based nitrogen treatment, and in turn by CK > AN > XF > BC > FY > CH. Different fertilizer treatments on summer corn growth periods, 0-20 cm soil layer of soil nitratenitrogen content was present a change trend that increased rapidly at first and then fell rapidly; and in the 20-40 cm soil layer of soil nitratenitrogen content was present a change trend that slowly rising first then rapidly increased and the last declined; in 40-60 cm soil layer of soil nitratenitrogen content was present a change trend that rising first and then a slight decline in the last drops rapidly. Different fertilizer treatments from summer maize sowingto tasseling stage soil ammonium nitrogen content of three soil layers(0-20 cm, 20-40 cm, 40-60 cm)are present a gradual decline change trend, and to the summer maize mature soil ammonia nitrogen content of three kinds of biochar-based nitrogen fertilizer treatmentsare present a gradually rising trend, and soil ammonia nitrogen content of CK, BC and AN treatments are present still falling.2. During maize growth period,soil enzyme activity changes significantly. Among them,the active peak of soil sucrase and alkaline phosphatase are appeared in the corn tasseling stage, and the active peak of soilcatalase is appeared in before maize sowing stage, the active peak of soilurease is appeared in maize mature. In general, during maize growth period,the soil invertase activityin 0-20 cm soil layer present a change trend that increased at first and then declined, and in 20-40 cm and 40-60 cm soil layer present a change trend that declined at first then increased and finally declined. Soil alkaline phosphatase activity showsthe trend that gradually increased at first and then declined. While catalase and urease activity present less season volatile in the season of summer maize growth period.3. During maize growth period, soil microbial biomass showed obvious seasonal fluctuations and present a change trend that gradually increased at first and then declined. Among them,in 0-20 cm soil layer,the peak value of soil microbial biomass carbon content was appeared in tasseling stage. In 20-40 cm and 40- 60 cm soil layer, the peak value of soil microbial biomass carbon content was appeared in maize jointing stage. In general,fromthe average content of microbial biomass carbon in maize growth period showed that the maximum value of soil microbial biomass carbon content was appeared in 0-20 cm and 20-40 cm soil layer was CH treatment, while in 40-60 cm soil layer was FY treatment. The change trend of soil microbial biomass nitrogen content are similar to the change trend of microbial biomass carbon. Soil microbial biomass nitrogen content of three soil layers all reached maximum value. In general,fromthe average content of microbial biomass nitrogen in maize growth period showed that the maximum value of soil microbial biomass nitrogen content was appeared in 0-20 cm and 20-40 cm soil layer was XF treatment, while in 40-60 cm soil layer was FY treatment.4. Three kinds of biochar-based ammonium nitrate nitrogen fertilizer CH, XF, FY have significant increased effect on summer maize plant height, ear height, leaf number, ear length, eardiameter, ear row number, line grain number and hundred grain weight and have significant reduced effect on bare top length. Three kinds of biochar-based ammonium nitrate nitrogen fertilizer CH, XF, FYcould significant increase yield of summer maize. Compared to CK, stimulation ratio of summer maize in this order 45.94%, 69.92% and 97.69%, compared to AN, stimulation ratio in this order 17.46%, 36.96% and 59.35%. Partial productivity of nitrogen fertilizer, agriculture utilization efficiency of nitrogen fertilizer, physiological efficiency of nitrogen fertilizer and apparent utilization efficiency of nitrogen fertilizer all reduce in this order FY > XF > CH > AN and have significant difference among all treatments. For nitrogen harvest index, reduce in this order XF > FY > CH > AN.