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石灰土具有高的有机碳的积累,但营养成分的供给速率偏低,导致土壤贫瘠。本文通过室内模拟实验,研究相同来源玉米秸秆在岩溶土与非岩溶土中的降解情况,对秸秆降解率、土壤理化性质、土壤肥力等进行动态检测,结果表明:(1)总体上岩溶土秸秆降解速率比非岩溶土快。秸秆降解速度最快主要集中在最初60天,之后呈缓慢上升趋势,到98天基本达到平衡。非岩溶土降解峰值出现时间为第42天,岩溶土为第28天,峰值出现时间前者比后者滞后14天。总降解时间持续160天,岩溶土降解率为77%,非岩溶土为75%。(2)秸秆降解期间,土壤p H值前期有下降的趋势,后期慢慢回升,这与秸秆降解过程中不同时期降解产物变化规律相吻合。秸秆还田可以提高土壤肥力,其中速效氮和速效钾含量增加非常明显。(3)与岩溶土相比,全量检测结果显示各肥力指标在非岩溶土含量低,但升幅百分比高;有效态检测结果显示非岩溶土速效磷和速效钾含量高。说明秸秆还田一些营养元素有效态在非岩溶土中更易于释放,而岩溶土由于其土壤质地的特殊性,许多养分被土壤粘土矿物牢固结合,营养元素供给速率慢,但因此也易于养分全量的累积。
Lime soil has a high organic carbon accumulation, but nutrient supply rates are low, resulting in poor soil conditions. In this paper, the degradation of corn stalks in karst soil and non-karst soil from the same source was studied through indoor simulation experiments. The dynamic changes of straw degradation, soil physical and chemical properties, soil fertility and so on were investigated. The results showed that: (1) Degradation rate faster than non-karst soil. The fastest straw degradation mainly concentrated in the first 60 days, then showed a slow upward trend, basically reached the balance 98 days. The peak time of non-karst soil degradation peaked on the 42nd day, that of karst soil on the 28th day, and the former peak time lagged behind the latter for 14 days. The total degradation time lasted 160 days, with 77% karst soil degradation and 75% non-karst soil. (2) During the period of straw degradation, the p H value of soil decreased at the early stage and then slowly rose at the later stage, which was consistent with the variation law of degradation products in different stages of straw degradation. Straw return to soil can increase fertility, including available nitrogen and available potassium content increased significantly. (3) Compared with karst soil, the full-scale test results showed that each fertility index had a low content of non-karst soil, but the percentage of increase was high. The results of effective test showed that the contents of available and available potassium in non-karst soil were high. The results show that some nutrient elements in straw returning are more easily released in non-karst soil. Due to the particularity of soil texture, karst soil is strongly bound by soil clay minerals and nutrient supply rate is slow, but it is also easy to nutrient-full The accumulation.