生物炭在新疆棉田的应用效果研究

农业是新疆经济和社会的基础,维系着全疆广大农牧民的生计,也关系到民族团结、边疆稳定和各族人民生活水平。寻求新技术提高绿洲农业生产力是新时期新疆经济和社会发展的要求。我们将小麦秸秆生物炭应用于喀什绿洲的灌淤土,研究了其对土壤pH和土壤水分的影响以及对棉花生长和产量的促进作用。结果显示,10%生物炭施用量可以倍增田间持水量,并提高土壤pH值0.36。但后一作用会随土壤灌溉和淋滤作用的增加而降低;在混合施用方式下,生物炭显著提高棉花产量,5%的施用量提高皮棉产量26%。这种增产效果产生的原因是生物炭的施用增加了土壤的营养成分和供水能力,从而增强了植株的株高、果枝数和单株铃数等。但条施方式对棉花的增产效果不显著,其施用过程会伤及作物根系和/或纯生物炭的高碱性影响植株的生理作用,从而造成棉株的枯萎、迟滞作物的生长。上述结果表明生物炭技术是提高绿洲农业生产力很有潜力的一条途径,但施用方式是一个很重要的影响因素。本研究结果不仅可以直接指导新疆绿洲的棉花生产,还可以为我国北方广大干旱区农业生产和管理提供借鉴。

The Effects of Biochar Application in the Cotton Fields of Kashgar Oasis, Xinjiang Uygur Autonomous Region, China

Agriculture is the foundation for the economic and social development of the Xinjiang Uygur Autonomous Region, China, and the agricultural production involves 95% of its whole population and thus is crucial to the national unity, the harmony of the society and the livelihood of the people. At the explosion of population and quick expansion of cities in recent decades in the region, new technologies are imperatively needed to promote the agricultural productivity in the oasis fields. Based on these understandings, this study applied biochar of wheat straw to the fields of cotton, a predominant economic plant in Xinjiang, and observed the effect on soil pH, water holding capacity, as well as the growth and production of the plant. The results indicated that the biochar improved significantly the water-holding capacity of soil, so much as doubling the water content at 10% application rate (w/w). Meanwhile, the application of charcoal also increased soil alkalinity, by as much as 0.36 on average at the same application rate. This effect, however, was subdued quickly with leaching incurred in irrigation or precipitation. By mixing the biochar with soil at the top 15 cm depth, the charcoal increased the net productivity by 26% at the 5% application rate. The enhancement of productivity results geochemically from the nutrients and water holding capacity increased by the application of biochar, which apparently helped improve the plant growth by increasing the height, the number of stems and cotton buds in the individual stand. Much different from the mixing method, the amendment of charcoal by burying in ditches dug in between the lines of the cotton seedlings only slightly increased the production. This application may cut down some of the roots in digging and/or impair, the growth due to high alkalinity once the newly grown roots reached the bulk biochar buried in the ditch, and thus caused the wilting of the plants. These findings suggested that biochar holds the high potential as a new technology in promoting the productivity in the oasis so long as the application method is appropreated. This study contributed directly to the cotton production in Xinjiang oases, but also helped with the agricultural management in the arid northern part of China.