运用DSSAT-CENTURY模型研究长期施肥对黑土碳氮循环的影响

发布时间：2018-01-28 08:00

本文关键词： DSSAT-CENTURY模型土壤有机碳土壤无机氮氮淋失　出处：《吉林农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：东北黑土地区是我国重要的粮食产业基地,近年来随着不合理的施肥耕作导致黑土日益退化,这样不仅对我国的粮食产量造成了严重的影响,而且对生态环境也产生了巨大的威胁。因此运用DSSAT-CENTURY土壤模型,研究不同长期施肥措施对土壤碳氮循环的变化规律,以及不同长期农业耕作措施对土壤碳库以及氮淋失的影响,不仅有助于利用模型系统对土壤时效性进行评价和预测,为模型的区域发展提供理论支持,而且有助于实现农业的可持续发展。本研究以吉林省公主岭市长期定位试验基地为研究对象,通过四个施肥处理(1)CK:不施肥(2)NPK:施氮磷钾肥(3)MNPK:施有机肥和氮磷钾化肥(4)1.5MNPK:1.5倍有机肥和氮磷钾化肥,运用DSSAT-CENTURY土壤模型探讨长期施用有机肥条件下对玉米产量、土壤有机碳、全氮含量、土壤C/N的动态变化规律,并且通过模拟不同碳库的含量比例变化,无机氮平衡以及不同耕层土壤硝态氮和铵态氮含量的分布,得出以下结论:NPK相比,长期施用有机肥能够显著提高作物产量,受降水量较少的干旱年份影响显著。有机肥对土壤有机碳和全氮含量的影响较大,土壤SOC含量由高到低依次为1.5MNPKMNPKNPK,土壤全氮含量与有机碳变化趋势基本一致。有机肥与无机肥配施能够显著减少土壤无机氮含量和降低氮淋失的风险。通过模型模拟得出的C/N比值也可说明:施用有机肥的C/N升高表明土壤有机碳的增加速度高于有机氮,且土壤慢性库SOM2的变化决定土壤有机碳含量的变化。总有机碳库受慢性碳库的影响较为显著,而惰性碳库的变化最不显著,而在CK处理下的惰性碳库比例显著上升说明土壤在逐渐老化。降水量较多的年份土壤氮淋失量表现出显著增加的趋势,说明降水造成土壤硝态氮向土壤深层次淋溶,通过施用有机肥使得土壤矿化氮(无机氮)总量显著增加,说明土壤矿化作用处于较高水平。不同耕层中的硝态氮含量不同,而不同施肥措施造成硝态氮的淋溶峰值不同,施用有机肥后峰值显著向根区移动,淋失风险降低。各个土壤耕层的铵态氮含量变化基本一致,深层次土壤变化不如硝态氮变化明显。因此在氮肥投入的同时,应当重视有机肥碳素的归还水平,因此大力推广使用农家肥来提高土壤养分含量,实现农业生态环境的综合可持续发展。
[Abstract]:The Northeast Black soil region is an important food industry base in China. In recent years, with unreasonable fertilization and tillage, black soil is increasingly degraded, which not only has a serious impact on China's grain production. Therefore, DSSAT-CENTURY soil model was used to study the changes of soil carbon and nitrogen cycle with different long-term fertilization measures. The effects of different long-term agricultural practices on soil carbon pool and nitrogen leaching are not only helpful to evaluate and predict the soil timeliness by using the model system, but also provide theoretical support for the regional development of the model. And it is helpful to realize the sustainable development of agriculture. This study takes the long-term positioning test base of Gongzhuling City of Jilin Province as the research object. Through four fertilization treatments, CK: no fertilization, 2n, NPK, N, P, K, N, P, K, N, P, K, N, P, K, N, P, K, N, P, K, N, P, K, and N, P, K, 1.5 MNPK: 1.5 times organic fertilizer and nitrogen, phosphorus and potassium fertilizer. DSSAT-CENTURY soil model was used to study the dynamic changes of maize yield, soil organic carbon, total nitrogen content and soil C / N under long-term application of organic fertilizer. And through the simulation of different carbon pool content ratio, inorganic nitrogen balance and the distribution of nitrate and ammonium nitrogen in different topsoil, the following conclusions are drawn: 1. Long-term application of organic fertilizer could significantly increase crop yield, especially in dry years with less precipitation. Organic fertilizer had a great effect on soil organic carbon and total nitrogen content. The content of SOC in soil was 1.5MNPKMNPKNPK from high to low. The total nitrogen content of soil is basically consistent with the change trend of organic carbon. The combination of organic fertilizer and inorganic fertilizer can significantly reduce the content of inorganic nitrogen in soil and reduce the risk of nitrogen leaching. The C / N ratio obtained by model simulation can also be explained. The increase of C / N in organic fertilizer indicated that the increasing rate of soil organic carbon was higher than that of organic nitrogen. The total organic carbon pool was significantly affected by the chronic carbon pool, but the inert carbon pool was the least significant. But the proportion of inert carbon pool increased significantly under CK treatment, which indicated that the soil was aging gradually. The nitrogen leaching loss of soil showed a significant increase trend in the years with more precipitation. The results showed that precipitation resulted in soil nitrate leaching, and the total amount of soil mineralized nitrogen (inorganic nitrogen) increased significantly by applying organic fertilizer. The results showed that the mineralization of soil was at a high level. The nitrate content in different tillage layer was different, but the leaching peak value of nitrate nitrogen was different with different fertilization measures, and the peak value moved to root area significantly after application of organic fertilizer. The risk of leaching is reduced. The change of ammonium nitrogen content in each soil tillage layer is basically the same, and the change of nitrate nitrogen is less obvious in the deep layer soil than in the deep soil layer. Therefore, the carbon return level of organic fertilizer should be paid more attention to while the nitrogen fertilizer input. Therefore, the use of farm manure to improve soil nutrient content and realize the comprehensive sustainable development of agricultural ecological environment.
【学位授予单位】：吉林农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S158.5

【参考文献】