| 徐静波,苗壮,杨荣,赵经华.水肥耦合对地下滴灌核桃叶片养分及综合生长的影响机制研究[J].干旱地区农业研究,2025,(6):223~237 |
| 水肥耦合对地下滴灌核桃叶片养分及综合生长的影响机制研究 |
| Mechanisms of water\|fertilizer coupling effects on leaf nutrient dynamics and comprehensive growth index in subsurface drip\|irrigated walnut |
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| DOI：10.7606/j.issn.1000-7601.2025.06.22 |
| 中文关键词: 核桃 水肥耦合 叶片养分 地下滴灌 主成分分析 |
| 英文关键词:walnut water and fertilizer coupling leaf nutrient subsurface drip irrigation principal component analysis |
| 基金项目:天山英才培养计划三农骨干人才项目（2024SNGGGCC021）；新疆维吾尔自治区“十四五”重大专项（2023A02002-5） |
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| 中文摘要: |
| 针对西北干旱区核桃园水肥管理粗放、土壤盐渍化及产量下降等问题，为揭示地下滴灌条件下水肥耦合对核桃叶片养分动态及综合生长指数（CGI）的影响机制，明确不同生育期水肥调控的关键路径及叶片养分适宜范围，以新疆阿克苏地区‘温185’核桃为对象，基于作物蒸发蒸腾量（ETc）设置4种灌水梯度：75%ETc（W1）、100%ETc（W2）、125%ETc（W3）、150%ETc（W4）和3种施肥梯度：N 270-P 240-K 300 kg·hm-2（F1)、N 360-P 320-K 400 kg·hm-2（F2)、N 450-P 400-K 500 kg·hm-2（F3)，结合主成分分析与偏最小二乘结构方程模型，构建生育期特异性CGI模型，解析水肥耦合对叶片养分（叶片氮含量LNC、叶片磷含量LPC、叶片钾含量LKC）及生长指标的动态影响路径；采用概率分级法确定LNC、LKC的适宜阈值。结果表明：（1）水肥交互作用显著影响叶片养分，LNC随生育进程逐渐递减，施肥量为F3时灌水量与LNC呈正相关；LPC在生育期内呈先降后升趋势，施肥量为F2时灌水量对LPC的调控效果最优，当施肥量为F3时会削弱灌水量对LPC的影响；LKC在生育期内的变化趋势与LPC类似，同一施肥量下，LKC在灌水定额为W3时达到峰值，W3F3处理在各生育期内LKC含量均为最大值。（2）在全生育期内灌水量对CGI具有显著影响，叶片养分的中介效应主导核桃生长特征（总影响β为0.619~0.692），而生育后期灌水量和施肥量对光合特征的直接作用增强（总影响β为-3.17~0.360）。（3）LNC和LKC与CGI之间相关性较强，而LPC与CGI之间无显著相关关系。核桃LNC在开花坐果期、果实膨大期、硬核期、油脂转化期适宜含量分别为21.76~28.47、19.56~26.86、15.99~23.18、13.52~20.72 g·kg-1。LKC在各生育期适宜含量分别为14.56~17.40、11.11~13.96、13.23~16.05、12.26~15.08 g·kg-1。本研究通过动态模型解析了水肥耦合下叶片养分对核桃生长的中介效应，明确了生育期差异化的水肥调控路径及养分阈值，可为干旱区核桃精准管理提供理论依据。 |
| 英文摘要: |
| Targeting the issues of crude water and fertilizer management, soil salinization, and yield decline in walnut orchards of the northwest arid region, this study aimed to reveal the mechanism of water\|fertilizer coupling effects on walnut leaf nutrient dynamics and the comprehensive growth index (CGI) under subsurface drip irrigation. The study also sought to identify key pathways for water\|fertilizer regulation during different growth stages and establish appropriate thresholds for leaf nutrient levels, providing theoretical support for precision management of walnut cultivation in arid areas. A 16-year\|old “Wen 185” walnut orchard in Aksu, Xinjiang, was selected as the experimental site. Four irrigation gradients were applied: 75% ETc (crop evapotranspiration, W1), 100% ETc (W2), 125% ETc (W3), and 150% ETc (W4). Three fertilizer gradients were implemented: N 270-P 240-K 300 kg·hm-2 (F1), N 360-P 320-K 400 kg·hm-2 (F2), and N 450-P 400-K 500 kg·hm-2 (F3). Principal component analysis and partial least squares structural equation modeling were integrated to construct stage\|specific CGI models, elucidating the dynamic impact pathways of water\|fertilizer coupling on leaf nutrients (leaf nitrogen content, LNC; leaf phosphorus content, LPC; leaf potassium content, LKC) and growth indices. The probabilistic grading method was applied to determine the optimal thresholds for LNC and LKC. The results showed that(1) the interaction between water and fertilizer significantly influenced leaf nutrient dynamics. LNC gradually decreased with advancing growth stages, and a positive correlation between irrigation volume and LNC was observed under F3 fertilization. LPC exhibited a declining\|then\|increasing trend throughout the growth cycle, with optimal irrigation regulation effects under F2 fertilization; excessive fertilization (F3) weakened the influence of irrigation on LPC. The trend of LKC was similar to LPC; under the same fertilizer level, LKC peaked at the W3 irrigation level. The W3F3 treatment consistently yielded the highest LKC content across all growth stages. (2) Irrigation volume significantly affected CGI throughout the entire growth cycle. Leaf nutrient levels mediated walnut growth traits through strong indirect effects (total effect β was 0.619~0.692). In the later growth phase, both irrigation and fertilization exhibited enhanced direct effects on photosynthetic traits (total effect β was -3.17~0.360). (3) LNC and LKC showed strong correlations with CGI, while no significant correlation was found between LPC and CGI. The optimal LNC ranges across the entire growth cycle were 21.76~28.47 g·kg-1, 19.56~26.86 g·kg-1, 15.99~23.18 g·kg-1, and 13.52~20.72 g·kg-1, respectively. The optimal LKC ranges across the entire growth cycle were 14.56~17.40 g·kg-1, 11.11~13.96 g·kg-1, 13.23~16.05 g·kg-1, and 12.26~15.08 g·kg-1, respectively. This study, through dynamic modeling, elucidated the mediating role of leaf nutrients in walnut growth under water\|fertilizer coupling conditions and identified stage\|differentiated pathways for precision water\|fertilizer management along with specific nutrient thresholds. |
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