耕作与施肥对黑土团聚体粒级分布及水稳定性的影响

试验共设6个处理:深耕常规施肥(DCF)、深耕常规施肥增施有机肥(DM)、深耕常规施肥增施生物炭(DB)、旋耕常规施肥(SCF)、旋耕常规施肥增施有机肥(SM)、旋耕常规施肥增施生物炭(SB),利用湿筛法得到不同粒级土壤水稳性团聚体并测算其稳定指标,探明耕作与施肥对黑土团聚体粒级分布及水稳性的影响,确定科学合理耕作施肥方式,为东北黑土持续利用提供科学依据。结果表明,各处理水稳性团聚体以5～2 mm、1～0.5 mm粒径为主。0～20 cm土层SM处理,20～40 cm土层DB、SB处理及40～60 cm土层DCF、SB处理,MWD、WSA、GMD值较高而PAD、D值较低,上述处理水稳性指标较优、土壤结构性状明显改善,为合理耕作施肥方式。结果分析可知,0～20 cm土层耕作与施肥通过单独作用对团聚体粒级组含量分布产生显著影响,而施肥及耕作施肥相互作用分别为改变20～40 cm、20～60 cm土层水稳性团聚体粒径分布主要作用因素,其中>5 mm及5～2 mm粒径团聚体与各水稳性指标显著相关,说明不同耕作与施肥方式通过提升上述粒径团聚体含量改善黑土团聚体水稳性和结构特性。

Effect of tillage and fertilization on particle size distribution and water stability of black soil aggregate

There were six treatments in the test: deep tillage conventional fertilization(DCF),DCF+ application of organic fertilizer(DM), DCF+ application of biochar(DB), Rotary tillage conventional fertilization(SCF), SCF+ application of organic fertilizer(SM), and SCF+ application of biochar(SB). All samples were separated into six aggregate-size classes by wet sieving. Water stability indices of the aggregates were determined. The experiment aimed to clarify the effects of tillage and fertilization on the grain size distribution and water stability of black soil aggregates, and determined the scientific and rational tillage fertilization methods to provided a scientific basis for the sustainable used of black soil in northeast China. The results showed that wet sieving increased the amount of 5-2 mm and 1-0.5 mm water stable aggregate. SM treatment of 0-20 cm soil layer, DB and SB treatment of 20-40 cm soil layer and DCF, SB treatment of 40-60 cm soil layer had higher MWD, WSA, GMD values and lower PAD, D values. Therefore, the above-mentioned treatments water stability index were better and the soil structural traits were also significantly improved, which was a more reasonable tillage and fertilization method. According to the analysis results, it could be seen that the tillage and fertilization had significant effect on the particle size distribution of water-stable aggregates in 0-20 cm soil layer. The fertilization method and their interaction were the main factors effecting the particle size distribution of water-stable aggregates in 20-40 cm and 20-60 cm soil layers, respectively. Among them, >5 mm and5-2 mm particle size aggregates had significant correlation with water stability indexes. It was indicated that different tillage and fertilization methods improved the water stability and structural characteristics of black soil aggregates by increasing the aggregate size of the above-mentioned particles.