| 何学敏,吕光辉,秦璐,李岩,刘晓星.干旱地区棉田连作对土壤氮素含量及氮转化速率的影响[J].干旱地区农业研究,2019,37(2):64~71 |
| 干旱地区棉田连作对土壤氮素含量及氮转化速率的影响 |
| Effect of continuous cotton cropping on soil nitrogen content and its transformation rate in arid area |
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| DOI：10.7606/j.issn.1000-7601.2019.02.10 |
| 中文关键词: 连作棉田；氮素形态；氮转化速率 土壤pH值；土壤水分；干旱地区 |
| 英文关键词:cotton field for continuous cropping nitrogen forms nitrogen transformation rate soil pH soil moisture arid area |
| 基金项目:新疆维吾尔自治区重点实验室开放课题(2015KL004)；新疆大学博士科研启动基金(BS150258) |
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| 中文摘要: |
| 为研究干旱地区棉田不同连作年限对土壤氮素含量和氮转化速率的影响，选取新疆艾比湖流域内精河县托托乡和农五师91团0、1、5、10、20 a和30 a棉田为研究对象，以棉田连作下土壤理化性质变化为基础，结合土壤氮素含量和氮转化速率，定量研究了连作棉田土壤氮转化速率变化规律及生态驱动因素。结果表明：（1）旱区连作棉田土壤硝态氮为无机氮主要组成，不同连作年限中土壤硝化作用均能将铵态氮转化为硝态氮，年限间差异不显著且硝态氮总量普遍偏低（平均为5.56±0.28 mg·kg-1）；土壤碱解氮含量均显著低于未开垦土壤，仅为对照样地的16.37%～28.40%（P<0.05），土壤铵态氮和亚硝态氮含量随着连作年限的增加逐渐达到动态平衡。（2）连作初期会降低土壤硝化和反硝化速率，连作10 a旱区棉田土壤硝化率和反硝化率均降到最低（分别为23.62±1.45 μg·kg-1·h-1和5.673±4.632 μg·kg-1·h-1），至连作后期显著增加。（3）土壤pH值对土壤硝化速率和反硝化速率的影响最大（总效应分别为0.5310和0.6516），土壤硝化率和反硝化率分别在土壤pH值达到阈值范围（8.37和8.01）时达到最大值（91.333 μg·kg-1·h-1）和最小值（19.271 μg·kg-1·h-1）；土壤水分是影响反硝化作用的第二重要因子。 |
| 英文摘要: |
| Continuous cotton cropping has certain negative effects on soil nutrients status, especially nitrogen (N) content and its transformation rate. Investigating the differences and their influence factors of soil N and N transformation rates in different continuous cropping years in arid area, which could provide a theoretical basis for the sustainable development of farmland in arid area. Soil samples from 0~20 cm layers were collected from uncultivated land (0 year, as a control) and five continuous cropping cotton fields at different cultivation times of 1, 5, 10, 20, and 30 years, respectively. Based on the changes of soil physical and chemical properties in the continuous cotton cropping field, combined with soil N contents and N transformation rates, we studied the change of N conversion rate and ecological driving factors in the continuous cotton cropping field. The results showed that: (1) Soil nitrate N was the main component of inorganic N in the continuous cotton cropping field in arid area. There was no significant difference among years and total nitrate N was generally low with an average of 5.56±0.28 mg·kg-1. Soil available N content in the soil was significantly lower than in uncultivated soil, which were only 16.37%~28.40% of the control (P<0.05). Soil ammonium N and nitrite N reached balance with years of continuous cropping; (2) The early stage of continuous cropping had significantly lower soil nitrification and denitrification rates that reached the lowest at 10 years (23.62±1.45 μg·kg-1·h-1 and 5.673±4.632 μg·kg-1·h-1, respectively). Then, it increased with increasing time, especially, in the later time; (3) Soil pH had the most influence on soil nitrification and denitrification rates (The total effects were 0.5310 and 0.6516, respectively). The thresholds of soil pH values for the soil nitrification and denitrification were 8.37 and 8.01, at which the soil nitrification and denitrification rates were at the maximum of 91.333 μg·kg-1·h-1 and the minimum rate of 19.271 μg·kg-1·h-1, respectively. Soil moisture was the second important factor affecting denitrification. |
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