长期施肥对黄壤有机碳平衡及玉米产量的影响

摘要

基于长期定位试验，以黔中典型黄壤为研究对象，采用单因素方差分析、可持续性指数、稳定性指数等方法对长期定位试验获取的数据进行分析和比较，以探讨长期不同施肥处理对黄壤有机碳含量、有机碳平衡量、玉米产量稳定性、可持续性及其相互关系的影响。结果表明：（1）与施化肥和对照处理相比，施有机肥处理土壤有机碳含量明显升高，按大小排序依次为：M＞MNPK＞1/2M+1/2NPK＞1/4M+3/4NPK；（2）施有机肥处理黄壤有机碳平衡量为正值，且随有机肥施用量增加而增加，相反，施化肥和对照处理均为负值，大小依次为：MNPK、M＞1/2M+1/2NPK＞1/4M+3/4NPK＞NPK＞NK＞NP＞N、CK＞PK，各处理差异显著；（3）有机肥与化肥配施、有机肥单施及氮磷钾化肥协调施用更有利于提高玉米产量，排序为：MNPK＞1/4M+3/4NPK、1/2M+1/2NPK＞NPK、M＞NP＞NK、PK、N＞CK；（4）适量有机肥与化肥配施可提高玉米产量稳定性和可持续性（可持续性指数＞0.6，变异系数＜0.3），其中，1/4M+3/4NPK处理玉米产量稳定性和持续性最好；（5）玉米年产量与黄壤有机碳平衡量相关度较高，而玉米可持续性、稳定性则主要受有机碳含量影响。综上，有机肥与化肥配施有利于黄壤有机碳含量提升、玉米维持高产稳产。按适量“减肥”原则，以25%有机肥配施75%氮磷钾化肥效果最佳。%Objective] Based on a long-term fertilization experiment on yellow soil typical of Central Guizhou,analysis was done to explore relationship between soil organic carbon(SOC)content and crop yield sustainability in yellow soil and to make case-specific rational fertilization recommendations, because few of the studies in the past did much work on the aspects.[Method]Therefore,data of the 11 year-long(2004—2014)field experiment that had 10 different treatments,that is CK(no fertilizer), treatment NPK(balanced chemical fertilizer application),treatment N(PK deficiency),treatment PK (N deficiency),treatment NK(P deficiency),treatment NP(K deficiency),treatment M(manure only),treatment MNPK(manure plus balanced chemical fertilizer),treatment 1/2M+1/2NPK(50% manure plus 50% chemical fertilizer)and treatment 1/4M+3/4NPK(25% manure plus 75% chemical fertilizer),were analyzed and compared with the single factor variance analysis,sustainable yield index (SYI)and stability index(CV)methods,with a view to exploring effects of the treatments on SOC content and SOC balance in the yellow soil,their effect on crop yield stability and sustainability,and their interrelationships,clarifying the relationship between SOC and crop yield,and providing some theoretic bases for building of soil fertility,improvement of crop yield,development of sustainable agriculture, expansion of carbon sink and reduction of carbon emission.[Result]Comparison between the treatments demonstrates that treatments M and MNPK were significantly higher in SOC content than all the others, displaying an order of M> MNPK> 1/2M+1/2NPK> 1/4M+3/4NPK. In treatments M and MNPK,content of SOC was gaining in budgeting,and the higher the application rate of manure,the more significant the gain,while it was losing in all the other treatments,displaying an order of MNPK & M> 1/2M+1/2NPK> 1/4M+3/4NPK> NPK> NK> NP> N & CK> PK. Application of manure plus chemical fertilizers, manure alone or balanced NPK was more conducive to improvement of crop yield than the other patterns of fertilization,and in terms of crop yield,the treatments followed an order of MNPK> 1/4M+3/4NPK & 1/2M+1/2NPK> NPK & M> NP> NK,PK & N> CK. Application of NPK coupled with appropriate of organic manure improved maize yield sustainability(SYI)and yield stability(CV),especially treatment 1/4M+3/4NPK that was the highest in both of the indices,with SYI being> 0.6 and CV being< 0.3. The research also found that annual yield was closely related to balance of SOC content,whereas,yield sustainability and stability was to SOC content.[Conclusion]To sum up,application of chemical fertilizer coupled with organic manure is conducive to accumulation of SOC content in yellow soil and maintenance of stable and sustainable maize yield,and in response to the fertilizer reducing principle,the application of 1/4M+3/4NPK is recommended to be the optimal practice.