沙漠化过程中沙质旱作农田土壤环境的变化及其对生产力形成的影响

Changes of Soil Environment and Its Effects on Crop Productivity in Desertification Process of Sandy Farmlands

以地处半干旱风沙区的科尔沁沙地为对象,研究了沙漠化过程中旱作农田土壤环境的变化规律及其与生产力形成的关系。结果表明,随着农田的风蚀,土壤发生粗化,土壤环境明显恶化,导致生物产量大幅度下降。其中,严重沙漠化农田和非沙漠化农田相比,其土壤粘粒、有机质、水分、全养分、速效养分、生物量及光合效率分别下降84.3%,65.5%,74.8%,9.25%～72.8%,27.5%～69.0%,60.5%,56.8%,地温升高0.9℃。相关分析表明,土壤粘粒和有机质的吹蚀是导致土壤含水量下降的主要原因(相关系数分别为0.9534,0.9638),土壤粗化和含水量的减少引起地温上升(相关系数分别为0.9439和-0.9965),而作物产量的下降与土壤含水量、速效N的降低关系最为密切,相关系数分别为0.9202和0.9425。在科尔沁沙地,加强农田防护林建设,增加土壤含水量(发展灌溉)和增施肥料(有机肥及尿素)是防止农田沙漠化和提高作物产量的根本措施。

Changes of soil environment and its effects on crop productivity in desertification process of sandy farmlands in Horqin sandland were studied. Results showed that coarse grain content in soil and soil temperature tend to raise, water and nutrient content in soil and crop biomass decreased obviously with farmland desertification. Of which, soil clay grain, organic matter, soil water, total nutrient, quickact nutrient, biomass and photoefficiency decreased separately by 84.3%,65.5%,74.8%,9.25%~72.8%,27.5%~69.9%,60.5%,56.8% and soil temperature raised by 0.9℃ in serious desertificed farmland. Results of correlation analysis showed that a decline in crop production caused mainly by a decrease in content of water content, quickact N in soil(correlations coefficients were 0.920 2,0.942 5 separately), a decline in soil water content was closely interrelated with deflation of clay grain and organic matter from soil(correlations coefficients were 0.953 4 and 0.963 8 separately).Therefore, it is a basic measure for preventing farmland desertification and raising crop production to build farmland shelter belt and to develop irrigation and to apply more fertilizer.