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为了系统研究南方丘陵区红壤氮磷养分活化程度对长期施肥和玉米连作模式的响应规律,研究选取江西进贤红壤旱地双季玉米长期试验的不施肥(CK)、氮肥(N)、磷肥(P)、氮磷配施(NP)、氮磷钾配施(NPK)、2倍氮磷钾配施(HNPK)和氮磷钾肥与有机肥配施(NPKOM)等处理,分析其27a内(1986—2013年)土壤全氮、碱解氮、全磷、有效磷和氮磷活化度的时间序列变化,并研究了土壤氮磷的增加速率以及土壤有机碳与氮磷活化度的相互关系。结果表明,各处理对氮磷活化度的提升效果存在明显差异。试验27a间,施氮处理对氮活化度的提升效果在60.25%~105.35%之间,以NPK处理为最高,HNPK和NPKOM次之;施磷处理对磷活化度的提升效果在2.29~15.40倍之间,以NPKOM处理为最高,HNPK和P处理次之。NPKOM处理对碱解氮和速效磷的提升作用在所有处理中均为最高。施肥处理提升氮磷活化度的主要原因是提升了碱解氮和有效磷。与试验前相比,连续27a施肥后,NPKOM处理的土壤全氮和全磷仅增加了25.02%和145.16%,而碱解氮和全磷则分别增加了131.46%和38.39倍,导致氮磷活化度分别增加了85.14%和15.40倍。土壤氮活化度与土壤有机碳不存在线性关系,而磷活化度则表现出随土壤有机碳含量增加而逐渐增加的趋势,且土壤有机碳含量与磷素活化度呈显著的正相关关系(R~2=0.264 1,P<0.05)。因此,在红壤旱地双季玉米种植模式中,有机无机肥配施是提升土壤氮磷养分含量和氮磷活化度的重要措施,磷的活化程度明显高于氮,但速效氮磷养分的大幅增加也可能导致环境风险。
In order to systematically study the responses of long-term fertilization and maize continuous cropping patterns to the degree of activation of nitrogen and phosphorus in red soils in the hilly region of southern China, the effects of CK, N, P NPK, NPK, HNPK, NPKOM and other treatments were used to analyze the effects of N, P and K fertilizers (NPK) - 2013), and studied the time-series changes of soil total N, available N, total P, available P and N-P, and studied the relationship between the increase rate of soil N and P and the degree of activation of soil organic carbon and N and P. The results showed that there was a significant difference in the enhancement effect on the activation of nitrogen and phosphorus between treatments. During the experiment 27a, the effect of nitrogen application on the activation of nitrogen was between 60.25% and 105.35%, and NPK was the highest, followed by HNPK and NPKOM. The effect of phosphorus application on the activation of phosphorus was between 2.29 and 15.40 times Among them, NPKOM treatment was the highest, followed by HNPK and P treatment. NPKOM treatment on the promotion of available nitrogen and available phosphorus in all treatments are the highest. Fertilizer treatment to enhance the degree of activation of nitrogen and phosphorus is mainly due to elevated nitrogen and available phosphorus. Compared with the pre-treatment, the contents of total N and total P in NPKOM increased by only 25.02% and 145.16% after 27 days of fertilization, while the levels of total nitrogen and total phosphorus increased by 131.46% and 38.39 times, respectively, resulting in the activation of nitrogen and phosphorus Degrees increased by 85.14% and 15.40 times. There was no linear relationship between soil active carbon and soil organic carbon, but phosphorus activeness showed a trend of increasing with increasing soil organic carbon content. Soil organic carbon content was positively correlated with phosphorus activeness (R ~ 2 = 0.264 1, P <0.05). Therefore, in the double cropping maize cropping pattern in red soil dryland, the combination of organic and inorganic fertilizers is an important measure to enhance the nitrogen and phosphorus nutrient content and the activation of nitrogen and phosphorus in soil, the phosphorus activation is significantly higher than that of nitrogen, but the available nitrogen and phosphorus nutrients increased significantly It may also lead to environmental risks.