土层复配方案对治沟造地新增耕地土壤肥力的影响

    Effects of soil-layer compounding schemes on the soil fertility of newly-constructed cultivated land

    • 摘要: 新增耕地质量的提升对于延安"治沟造地"项目实施后耕地的有效利用意义重大。为探索一种快速改良"治沟造地"新增耕地质量的有效方法,该研究在延安羊圈沟流域((109°31′~109°71′E,36°42′~36°82′N))开展了为期4 a的新造耕地土层复配试验。试验基于红黏土(Red Clay,RC)和马兰黄土(Malan Loess,ML)结构上的互补性,利用不同比例的RC和ML对新造地块0~30 cm的土层进行复配重构(T0,未复配的原状土;T1,100%的RC;T2,83.3%的RC和16.7%的ML;T3,66.7%的RC和33.3%的ML;T4,50%的RC和50%的ML;T5,33.3%的RC和66.7%的ML;T6,16.7%的RC和83.3%的ML;T7,100%的ML),通过对土壤的理化性质和作物生长情况的分析,结合主成分分析,探索了不同土层复配方案对土壤肥力和作物产量的影响。结果表明:T2和T3处理>0.25 mm水稳性团聚体分别较对照组T0显著提高了13.7、15.2倍;T3处理>0.25 mm水稳性团聚体的几何平均直径(Geometric Mean Diameter,GMD)和平均重量直径(Mean Weight Diameter,MWD)较T0处理分别增大20.9%和29.1%,而容重较T0处理减小11.1%,孔隙度增大15.3%。T3处理有机质和硝态氮含量较T0处理分别增加了24.5%和100%;T2、T3处理有效钾较T0处理分别增加了29.3%和17.6%。主成分分析结果显示,土体结构是土壤肥力形成的结构基础,土壤养分是土壤肥力的重要组成部分,二者共同决定土壤的肥力状况;综合评价结果显示各处理土壤肥力综合得分由高到低依次为T3、T2、T1、T5、T6、T4、T7、T0。T3处理玉米具有最大地上生物量和千粒质量,且玉米产量也相对较高。综合土壤肥力和玉米生长状况,认为当RC为66.7%,ML为33.3%时,复配方案相对较优,能提高土壤的肥力。试验初步表明土层复配是一种可行的快速营造高质量土壤的技术方法,研究为提升"治沟造地"工程新增耕地质量及今后类似土地整治工程的实施提供实践参考。

       

      Abstract: Abstract: The improvement of the quality of the newly-constructed cultivated land is of great significance to the effective utilization of the newly-constructed cultivated land after the implementation of the "Gully Land Consolidation Project" (GLCP) in Yan' an. To explore an effective method that can be used to quickly improve the newly-constructed cultivated land with poor quality of GLCP, a 4-year soil-layer compounding experiment was carried out in Yangjuangou watershed (109°31'-109°71' E, 36°42'- 36°82' N). Based on the complementary structure of the Red Clay (RC) and Malan Loess (ML), the different ratios of RC and ML were used for reconstruction of the 0-30 cm soil layer of the newly-constructed cultivated land (T0, undisturbed soil; T1, 100% RC; T2, 83.3% RC and 16.7% ML; T3, 66.7% RC and 33.3% ML; T4, 50% RC and 50% ML; T5, 33.3% RC and 66.7% ML; T6, 16.7% RC and 83.3% ML; T7, 100% ML) . The chemical and physical properties of the soil and the condition of crop were measured, and the soil fertility of each scheme was comprehensively evaluated by principal component analysis. The results of experiment showed: The >0.25 mm water-stable aggregates in T2 and T3 increased by 13.7 and 15.2 times, respectively, compared with T0. Compared with T0 treatment, the geometric mean diameter (GMD) and mean weight diameter (MWD) of water-stable aggregates >0.25 mm in T3 treatment were 20.9% and 29.1% higher while bulk density decreased by 11.1% and porosity increased by 15.3%. The contents of organic matter and nitrate nitrogen in T3 increased by 24.5% and 100%, respectively, compared with the control group. Compared with T0 treatment, the available potassium values in T2 and T3 treatment were increased by 29.3% and 17.6%, respectively. The results of principal component analysis showed that soil structure was the structural basis of soil fertility, and soil nutrient was an important part of soil fertility, which jointly determined soil fertility. And the order of the comprehensive fertility score from high to low was T3, T2, T1, T5, T6, T4, T7, T0. The maize in T3 treatment had the maximum aboveground biomass and 1000-grain weight, and the maize yield was also relatively high. It could be concluded that the scheme was the optimal one when the volume ratio of RC and ML was 66.7% and 33.3%, respectively for the soil having the highest comprehensive fertility and the crops growing relatively well. In conclusion, the experimental results show that soil-layer compounding is a feasible method to construct soil with high quality quickly, and the study provides practical reference for the improvement of the quality of newly-constructed land in the GLCP and the implementation of similar projects in the future.

       

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