| Lou soil which is the main soil in Loess Area effecting on aggregate and nutrient was taken as the research object of different land use, including agricultural land(YN) and short-term abandoned land(YL) in Yangling, farmland(WN) and orchard(WG) in Wugong. Long-term Loess soil in Yangling was taken as the research object of fertilization which effecting on aggregate and nutrient, including no fertilizer(N0), low chemical NP fertilizers(N1) and high chemical NP fertilizers(N2). The main results are as follows:(1) Effect of short-term abandoned SOC and TN in shallow soil(0-40cm) was very small, while in 20-40 cm, TP and TK contents of YL were significantly higher than that of YN. Effect of land use on soil TN, TK, and SOC, TN of layer 20-40 cm were not obvious in Wugong, while SOC and TP contents of 0-20 cm soil layer in were WG>WN.(2) Effect of fertilization treatment on SOC, TN, TP showed N2>N1>N0. Except that difference of N2 and N0 on SOC was no significant, soil nutrients were significantly proved in N1 and N2. Compared with N1, effects of N2 on SOC and TN were not significant, while significantly improved TP content in the soil. TK content under different fertilization in performance for N0>N1>N2, the differences were not significant.(3) Expect contents of >5mm, 0.25-0.25 mm aggregates in YL respectively higher 9.37% and 4.59% than YN, the contents of oter size water stable aggregates in YN were slightly higher than YL, the differences were not significant. Effect of short-term abandoned on 0-20 cm soil WSA distribution is not obvious; but significantly reduced >5mm WSA content in 20-40 cm, and slightly increased other particle diameter WSA content. Abandoned improved 0-20 cm soil MWD and GMD values without significant differences, while 20-40 cm soil showed the opposite. For surface soil of Wugong, aggregate contents of >5mm, 2-5 mm, 1-2mm and micro particle diameter showed WN>WG, and 0.5-1mm and 0.25-0.5 mm showed WG>WN, aggregates MWD and GMD value showed WG>WN, which were not significan; >5mm WSA contents of WN and WG were 35.5% and 27.77% in 20-40 cm, WN was significantly higher than that of WG, other size diameter showed WG>WN, WN soil MWD and GMD value was significantly higher than that of WG.(4) Long term fertilization significantly improved the WSA content in each particle size of <1mm. Compared with N1, N2 significantly reduced >0.25 mm WSA content, while improved <0.25 mm WSA content. MWD and GMD of WSA under different fertilization showed N0>N1>N2.(5) Effect of abandoned on SOC and TN were consistent in 0-20 cm soil layer. Abandoned improved SOC and TN contents of >5mm aggregate, while effect of abandoned on other aggregates were not obvious. Expect <0.25 mm WSA in 20-40 cm, TP content of WSA in soil was correspondingly improved by YL. Effect of YL on 0-20 cm WSA TK were not obvious, but improved 20-40 cm WSA TK contents, especially in large aggregates. SOC and TN of WSA in Wugong 0-20 cm soil were WG > WN; in 20-40 cm, except the content of TN in WG 2-5mm WSA was significantly higher than that WN, differences of SOC and TN content were not significant in the same grain diameter, indicating that land use has little influence on SOC and TN. TP of 0-20 cm >5mm WSA in Wugong was WN > WG, while in micro aggregates was WG > WN. In 20-40 cm, content of TP in WSA of the same grain size were all shown as WN>WG. For 0-20 cm, expect micro aggregates, content of TK in WSA of the same grain size were all shown as WN > WG, But, TK content in the same grain size aggregate of 20-40 cm were WG > WN.(6) N1 and N2 were significantly improved SOC and TN content of >5mm, 2-5mm, 1-2mm, while effect of in micro aggregates were not obvious. N1, N2 treatments extremely significantly increased TP contents of WSA, the ability of different size aggregates on maintaining and supplying TK were different, Compared with N0, effect of N1 on soil aggregates TK were not obvious, while N2 treatment significantly increased the TK content of WSA in <2mm each particle diameter. Compared with N1, effect of N2 on aggregate SOC was not sensitive, but significantly improved TN content of WSA in 1-2mm greatly, also significantly increased the TP contents of WSA, and TK contents of 0.5-1mm, 0.25-0.5mm, micro-aggregate, increasing amplitudes were 7.02%, 5.73% and 5.6%, respectively. |
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