Wang Qian, Li Jun, Ning Fang, Sun Lei, Wen Peng Fei
College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China.
Collegeof Forestry, Northwest A&F University, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2018 Sep;29(9):2925-2934. doi: 10.13287/j.1001-9332.201809.030.
Soil fertility properties described by four physical indices and seven chemical indices in the 10-year long-term experiment of wheat fields in Weibei Highland were used to investigate the cumulative effect of 11 soil indices under six long-term conservation tillage treatments. The principal component analysis was performed to comprehensively evaluate the cumulative effect of soil fertility under different tillage treatments, so as to provide scientific basis for soil sustainable utilization and management in Weibei Highland. The results showed that, compared with continuous conventional tillage (CT/CT), soil bulk density by no-tillage/subsoiling rotational tillage (NT/ST), subsoiling/conventional tillage rotational tillage (ST/CT) and conventional tillage/no-tillage rotational tillage (CT/NT) decreased by 6.6%, 5.9% and 6.6%, respectively, and no significant difference was found between continuous no-tillage (NT/NT) and CT/CT. NT/NT had the highest content of >0.25 mm mechanical stable aggregate, and no-tillage/subsoiling rotational tillage (NT/ST) had the highest content of >0.25 mm water stable aggregate. Compared with CT/CT, the mechanical stable aggregate contents under other five tillage treatments increased by 1.7%-10.1%, soil organic matter increased by 0.6%-11.2%, and the contents of nitrogen, phosphorus, and potassium contents also increased. By principal component analysis, 11 soil indices were divided into two principal components to comprehensively characterize soil quality. The contribution rate of the first principal component was 75.5%, where the major contributors were soil organic matter, water stable aggregate, total nitrogen, total phosphorus, total potassium, alkaline hydrolysis nitrogen, available phosphorus, available potassium, bulk density and soil porosity. The contribution rate of the second principal component was 13.2%, where the major contributor was mechanical stable aggregate. Together, those two principal components accounted for 88.6% of the original variables. The soil fertility performance was in the sequence of NT/ST>ST/CT>CT/NT>NT/NT>ST/ST>CT/CT after gradually accumulating the effects of long-term conservation tillage. NT/ST was the most appropriate tillage patterns for the wheat fields in Weibei Highland, due to the resulting balanced and high-quality soil environment.
利用渭北旱塬麦田10年长期试验中4个物理指标和7个化学指标描述的土壤肥力特性，研究了6种长期保护性耕作处理下11个土壤指标的累积效应。通过主成分分析对不同耕作处理下土壤肥力的累积效应进行综合评价，为渭北旱塬土壤可持续利用与管理提供科学依据。结果表明，与连续传统耕作（CT/CT）相比，免耕/深松轮耕（NT/ST）、深松/传统耕作轮耕（ST/CT）和传统耕作/免耕轮耕（CT/NT）的土壤容重分别降低了6.6%、5.9%和6.6%，连续免耕（NT/NT）与CT/CT之间差异不显著。NT/NT的>0.25 mm机械稳定团聚体含量最高，免耕/深松轮耕（NT/ST）的>0.25 mm水稳性团聚体含量最高。与CT/CT相比，其他5种耕作处理下机械稳定团聚体含量增加了1.7%-10.1%，土壤有机质增加了0.6%-11.2%，氮、磷、钾含量也有所增加。通过主成分分析，将11个土壤指标分为两个主成分，以综合表征土壤质量。第一主成分贡献率为75.5%，主要贡献指标为土壤有机质、水稳性团聚体、全氮、全磷、全钾、碱解氮、有效磷、速效钾、容重和土壤孔隙度。第二主成分贡献率为13.2%，主要贡献指标为机械稳定团聚体。这两个主成分共占原始变量的88.6%。长期保护性耕作效应逐渐累积后，土壤肥力表现为NT/ST>ST/CT>CT/NT>NT/NT>ST/ST>CT/CT。NT/ST是渭北旱塬麦田最适宜的耕作方式，因其能营造出均衡、优质的土壤环境。
