修剪与施氮对板栗叶片N、P营养及产量的影响

为探究修剪与施氮量对板栗树体叶片氮磷含量、氮磷比、产量、单粒重及出实率的影响,明确适宜当地板栗的修剪与施氮量的最佳组合,以13年生的板栗燕山早丰为试验对象,采用双因素随机区组试验,研究修剪强度(每平方米投影面积留结果母枝17~18、14~15和11~12个,分别记为X₁、X₂和X₃)与施氮量(施氮为0、375、750 kg·hm^-2,分别记为N₀、N₁和N₂,施磷均为164 kg·hm^-2,施钾为311 kg·hm^-2)的交互作用对板栗叶片氮磷含量、氮磷比、产量、单粒重及出实率的影响。结果表明,N₁(中等氮肥)和X₂(中等修剪)条件下叶片氮含量、结果枝叶片氮磷比、产量、单粒重及出实率最高。X₂N₁、X₁N₂处理的叶片氮磷含量及产量均较高,且2个处理的结果枝叶片氮含量及产量差异显著;X₃N₀处理的产量不高,但其单粒重和出实率均较高。其中,X₂N₁处理的结果枝及营养枝的叶片氮含量(23.179、23.650 g·kg^-1)、结果枝叶片氮磷比(13.67)、产量(3 502.80 kg·hm^-2)、单粒重(8.26 g)和出实率(41.48%)均为最高。板栗树体需氮量随着修剪强度的增强(即单位面积留枝量的减少)而降低,修剪与施氮量2种措施之间具有协同性。从叶片氮磷含量及产量等指标综合考虑,X₂N₁处理是当地修剪与施肥的最佳组合。综上,中等修剪强度配合中等氮肥在增加叶片营养的基础上,保证了板栗的单粒重和产量。本研究为迁西地区板栗高产栽培提供了理论依据。

Effect of Pruning and Nitrogen Rate on Nitrogen and Phosphorus Contents in Leaves and Yield of Castanea mollissima Bl.

To study the effect of pruning and nitrogen level on nitrogen and phosphorus contents, ratio of nitrogen to phosphorus, yield, single seed weight and bur nut rate of C. mollissima and determine the optimum combination of pruning and fertilizer in given area, thirteen-year-old C. mollissima Yanshanzaofeng was chosen as test material and random block experiment of two factors was conducted to investigate the interaction of pruning intensity (17~18,14~15,11~12 biennial bearing branches per square meter of crown projection area, donated as X₁, X₂, X₃) and nitrogen(N) application level (three N levels, 0,375,750 kg·hm^-2, donated as N₀, N₁ nad N₂. Phosphorus application level was 164 kg·hm^-2, and potassium application rate was 311 kg·hm^-2) on the contents of nitrogen and phosphorus ratio of nitrogen to phosphorus, yield, single seed weight and bur nut rate. The results showed that N contents in leaves, N/P in leaves of bearing branch, yield, single seed weight and bur nut rate were highest when pruning and nitrogen level were the middle level. The contents of N and P in leaves and yield of X₂N₁, X₁N₂ were higher than other treatments, and N content in leaves of bearing branch and fruit of two treatments were significantly different. Yield of X₃N₀ was not high, but single seed weight and bur nut rate were both high. Nitrogen content in leaves of bearing branch and vegetative shoot (23.179 g·kg^-1 and 23.650 g·kg^-1), N/P in leaves of bearing branch (13.67), yield (3 502.80 kg·hm^-2) single seed weight (8.26 g) and bur nut rate (41.48%) of X₂N₁ were the highest among all treatments. The results suggested that nitrogen requirement of C. mollissima tree body decreased with increasing pruning intensity (as the branches in unit area decreased). Pruning intensity was in coordination with nitrogen rate. Based on comprehensive consideration of nitrogen and phosphorus contents in leaves and yield, X₂N₁ was the optimum combination of pruning and fertilizer in given area. In a word, pruning and nitrogen level which were the middle level ensure single seed weight and yield of C. mollissima on the basis of increasing leaf nutrition, and provide a theoretical basis for high yield cultivation techniques of C. mollissima of Qianxi area.