北疆连作棉田施用生物炭对土壤养分及酶活性的影响

Effect of Biochar on Soil Nutrients and Enzyme Activity in the Continuous Cropping Cotton Field in Nortnern Xinjiang

采用大田试验和盆栽试验相结合的方法，研究北疆垦区灰漠土连作棉田施用生物炭对土壤养分变化和酶活性特征的影响，为农业废弃物的合理利用和防治棉花连作障碍提供科学依据和理论指导。大田和盆栽结果表明：施用生物炭可降低北疆灰漠土容重，提高土壤呼吸强度，适量施用生物炭可增加土壤含水量，大量施用降低土壤含水量；施用生物炭可增加灰漠土土壤pH值、电导率、有机质、全氮、全磷、碱解氮、速效磷、速效钾、交换性镁的含量；大田试验表明施用生物炭可能减少土壤有效锰、有效铜、有效锌含量，而盆栽试验结果表明，大量施用生物炭能够增加土壤土壤有效铁、有效锰、有效铜、有效锌含量，并且随着施用量的增加有减少的趋势；大田和盆栽结果表明，施用生物炭增加土壤碱性磷酸酶、蔗糖酶、过氧化氢酶的活性，但是土壤脲酶的活性降低。

[Objective]The objective of this study was to explore the effects of biochar treatments on soil nutrients and micro- bial diversities of continuous cropping cotton fields in Northern Xinjiang. The results would provide a scientific basis and a practical guidance to optimize the utilization of agricultural wastes and to prevent continuous cropping problems of cotton. [ Method ]This pa- per used both field experiment and pot experiment to studying the effect that, under the condition of Northern Xinjiang＇s gray- desert soil continuous cropping cotton plantation, to what extent would biochar have effect on the changes of soil nutrient and en- zyme characteristics. [ Result ] Both field experiment and pot experiment showed that the application of biochar would reduce soil bulk density and increase the soil respiration intensity, while an appropriate component of biochar, the water preservation capacity would also be increased. Whereas it is noticeable that an excessive use of biochar would, however, reduce the water preservation capacity of soil. In addition, the results of experiments also indicated the fact that the application of biochar would be beneficial for the increase of PH value, conductivity, organic matter, total nitrogen, total phosphorus, alkaline hydrolysis nitrogen content, available phosphorus, available potassium and exchangeable magnesium value in desert grey soil. Field experiments further showed that the application of biochar would increase available Mn, Cu and Zn content in the soil; while pot experiments proved that biochar would also increase the availability of Fe, Mn, Cu, Zn content, despite the excessive use of biochar would decrease the availability. On the other hand, Field experiments and pot experiments showed the possibility that the application of biochar could increase soil alkaline phosphatase, sucrase, catalase activity, yet it could also decrease the soil urease activity.