基于整合分析的黄土高原苹果施氮增产效应研究

Analysis of effect of nitrogen application on apple yield on Loess Plateau using meta-analysis

为探讨施氮条件下黄土高原苹果增产效应的影响因素,以公开发表的试验数据为依据,采用整合分析法定量分析了施氮条件下,气候、海拔、土壤类型、树龄、栽植密度、氮肥用量对产量的影响,并对各影响因素进行了通径分析。结果表明:当年降水量小于500 mm时,施氮增产率为29.83%,且随年降水量的增加其增产效应不明显;年均温≥10℃时,施氮对苹果产量的提高有积极作用,年均温<10℃时增产效应不显著(P>0.05)。在黑垆土、[土娄]土上施氮均能有效提高苹果增产率,分别为26.10%(95%CI:13.08%~39.11%)(CI为置信区间,下同)、34.53%(95%CI:13.88%~55.19%),黄绵土上施氮增产不显著(P>0.05)。当海拔<850 m时,施氮条件下苹果增产率显著提高(P<0.05),并随着海拔的增加而降低。树龄高的果树在施氮条件下增产效应明显,当树龄≥10 a时,增产率为26.93%(95%CI:14.64%~39.22%),并随树龄的减小而降低。在不同栽植密度下施用氮肥存在不同的增产效应,55~110株·666.7m-2时效果最佳,增产28.70%(95%CI:18.12%~39.28%)。施氮量在0.25~0.50 kg·株-1时,增产效应明显(P<0.05);施氮量≥0.50 kg·株-1时,不存在显著的增产效应(P>0.05)。通径分析结果表明,栽植密度、年降水量和施氮量是施氮条件下影响苹果增产率的三大主导因素,海拔次之,年均温和树龄对苹果增产效果接近但比较小。由此可见,施氮的增产效果与外界因素关系密切,综合上述各条件在适宜范围施氮更有利于苹果增产。

In order to explore the influencing factors of nitrogen(N)application on apple yield on the Loess Plateau,this research was based on published experimental data,and used the meta-analysis method to quantitatively analyze the influence of climate,altitude,soil type,tree age,land area per plant,N consumption on the yield with N application,and carried out path analysis on each influencing factor.The results showed that when the annual precipitation was less than 500 mm in the same year,the yield increased by 29.83%,which decreased with the increase in the annual precipitation.When the average temperature was more than or equal to 10℃,the effect of N on yield was positive,but when the average temperature was less than 10℃,the effect was not significant(P>0.05).Nitrogen treatment in Heilu soil and Lou soil was effective in increasing the yield by 26.1%(95%CI:13.08%~39.11%)(CI was the confidence interval,the same below)and 34.53%(95%CI:13.88%~55.19%),respectively,but no significant increase in loess(P>0.05).When the altitude was less than 850m,the yield increase rate of apple from N application was significantly increased(P<0.05),and the yield increased by 29.46%(95%CI:16.98%~41.93%),and decreased with the increase in altitude.With N application,the yield increase of the fruit trees with older tree was more obvious.When the tree was more than 10 years,the yield increase rate was 26.93%(95%CI:14.64%~39.22%),which decreased with the decrease of tree age.Application of N fertilizer in different planting densities had different yield increasing effect,and the best effect was 55~110 plant·666.7m^-2,reaching 28.70%(95%CI:18.12%~39.28%).When N application was 0.25~0.50 kg·plant-1,the stimulation effect was most obvious(P<0.05).When N application was more than 0.50 kg·plant-1,there was no significant stimulation effect(P>0.05).Path analysis results showed that planting density,annual precipitation and N application rate were the three major factors that affected apple yield increase under N application,followed by altitude,and the average annual temperature and the tree age had similar but little effect on apple yield increase.It can be seen that N fertilization was closely related to external factors,and a suitable range of N comprehensively combined with the above conditions was more conducive to increase production,and can also provide references for fertilization and field management in the area.