麦棉两熟多年秸秆还田对土壤养分的影响
毕业论文关键词：麦棉两熟、秸秆还田、土壤养分、钾素
Effects of straw returning on soil nutrients in perennial wheat-cotton rotation system
Abstract：Straw returning, as an effective conservation tillage technique, has been widely concerned. It can not only avoid the environmental pollution caused by burning straw, but also reduce the cost of agriculture. Crop straw contains a lot of potassium, can be added to the soil after returning to potassium, which is particularly important for China's current situation of potassium deficiency. The study on 2011-2016 in Jiangsu city of Nanjing province （118°50´E, 32°02´N）and Jiangsu province （120°20´E，33°12´E） for two crops of wheat and cotton straw for test, selection of Surabaya No. 3 as experimental material, wheat straw returning set also, half of the amount of farmland and returning full three levels in the cotton season, namely 0、4500、9000kg hm-2, cotton straw returning in the wheat season, half returning and returning full three levels, namely 0、3750、7500kg and hm-2, a total of 9 straw returning treatment combination, and set two K treatment 150、300kgK2O. hm-2. Wheat and cotton crop straw could increase soil organic matter content of 3.6%, increase soil water soluble organic carbon content of 25.2%, 7.5% increase the content of total nitrogen in soil, improve soil available potassium content decreased 20.1%, soil nitrate content of 56.7%, influence on ammonium nitrogen content in soil was not significant. The application of potassium treatment can significantly increase the content of available potassium 60.4%, improve the total nitrogen content of 5.3%, the total organic matter, water soluble organic carbon, nitrate nitrogen and ammonium nitrogen content has no significant effect.
Key words: wheat-cotton rotation system；straw returning；soil nutrients；potassium
目 录
摘要3
关键词3
Abstract3
Key words3
引言4
1材料与方法4
1.1试验设计4
1.2测定内容与方法 4
2结果与分析5
2.1有机质5
2.1.1总有机质5
2.1.2水溶性有机碳6
2.2氮素6
2.2.1全氮6
2.2.2铵态氮7
2.2.3硝态氮8
2.3钾素（速效钾）9
3结论9
致谢10
参考文献11
麦棉两熟多年秸秆还田对土壤养分的影响
中国每年农田可产生秸秆总量达8. 1 ×108吨，这些秸秆能提供氮7.5 × 106吨、P2O5 2.3 × 106吨和 K2O 1.2 × 107吨[1]，其中只有16.2%的秸秆被还田[2]，大量的秸秆被焚烧和废弃，即对环境造成了污染，又是对秸秆资源的浪费[3,4]。作物秸秆中含有大量植物所需养分，其中碳、磷、氮等元素主要以有有机态存在于秸秆中，而钾元素则以离子态形式存在[5]，在秸秆还田后90天内，对土壤钾素影响最大[6]。如果能提高20%的秸秆还田率，就可节省360万吨的钾肥[7]。因此，有必要进一步研究在不外施钾肥的情况下，多年秸秆还田对土壤养分的影响。棉花的花铃期是棉花产量形成的最为关键的时期，此时期养分的吸收量占总吸收量的59.7%-67.0%[19]，为保证棉花养分的充分供应，应保证花铃期土壤养分的含量，因此对于多年秸秆还田的土壤养分测定应在花铃期进行。