川中丘陵区耕地撂荒对土壤肥力的影响

Effects of Abandonment of Cultivated Land on Soil Particle Composition and Nutrients in Hilly Areas of Central Sichuan

为了了解川中丘陵区耕地撂荒对土壤的影响,以从2005年开始撂荒的紫色土坡耕地为研究对象,对比分析其撂荒13年前后土壤颗粒组成和养分的变化.结果显示:撂荒后土壤砂粒比例增加12.6%,粉粒比例减少13.5%,黏粒比例变化不大;撂荒后土壤有机碳、全钾、碱解氮比例虽略有增加,但是变化并无统计学意义(p>0.05),土壤全氮比例显著增加,增加幅度可达61.5%,而全磷、有效磷、速效钾比例分别显著降低14.0%,61.4%,22.6%(p<0.05);土壤碳氮比显著降低36.3%,碳磷比、氮磷比极显著升高(p<0.01),升高幅度分别为23.1%,89.0%;以所测的7种土壤养分为评价指标,用模糊数学法对撂荒前后的土壤肥力进行综合评价,结果表明撂荒前后土壤肥力等级相差不大.

In order to understand the effects of abandonment of cultivated land on soil in hilly areas of central Sichuan,purple sloping lands in this area abandoned since 2005 were taken as the research object,and the changes of soil particle composition and nutrients before and after abandonment of 13 years(2005-2018)were compared.The results showed that the content of soil sand increased by12.6%,the content of silt decreased by 13.6%,and the content of clay was little changed after abandonment.The contents of soil organic carbon,total potassium and alkaline hydrolytic nitrogen increased slightly after abandoning,but the change was non-significant statistically(p>0.05).The content of soil total nitrogen increased significantly(by 61.5%),while the contents of total phosphorus,available phosphorus and rapidly available potassium decreased significantly(p<0.05),by 14.0%,61.4%and 22.6%,respectively.Soil C/N ratio decreased significantly(by 36.3%),while C/P ratio and N/P ratio increased highly significantly(p<0.01),by 23.1%and 89.0%,respectively.Based on the seven soil nutrients measured,the comprehensive evaluation of soil fertility before and after abandonment was carried out by using the method of fuzzy mathematics.The results showed that there was little difference in the comprehensive grade of soil fertility before and after abandonment.