Effect Of Different Plant Density On Growth And Fruiting Of Walnut

Walnut?Juglansregia L.?is one of China's major economic forest tree species,ranking first among the four major nuts?walnuts,almonds,cashews,and hazelnuts?and is known as the"King of Woody Oil."In recent years,the planting area of walnuts has been continuously expanding.In some regions,the high-density?3×3m;3×4m?planting method has been used in the early development process.After entering the result period,the density is too large,which is unfavorable to the ventilation and light transmission of the walnut gardens.Orchards began to have phenomena of"closed lines between plants and closed lines between lines",which caused a decline in output and decreased quality.The suitable walnut planting density has important significance for the efficient cultivation of walnuts.This study used different walnut varieties:Xiang Ling,Qiang Tele,Xiluo No.3,Xifu No.1,Xifu No.2,Xilin No.2,Xilin No.3,and Xiluo No.3 walnuts as materials,using a tape measure and other tools.The length,thickness,crown width,yield,quality and other parameters of the same branch of the same tree in the same tree under different planting densities were measured every three days.The same planting densities in different varieties were measured using the LI-COR6400XT portable photosynthesis instrument.The photosynthetic parameters of different walnut varieties and the leaf area index were measured using LAI-2200c canopy analysis,and the indicators such as walnut disease index and fruit rate were calculated.Solid growth effect.The results showed that:?1?At the same time,the growth of Xiangling and Xilin No.3was the most under the planting density of 5m×6m,and the growth of Xiangling was the lowest under the planting density of 4m×4m.The same planting density condition was used for different varieties.The growth rate of Xiangling was higher than that of Xilin No.3.?2?Under the same variety of conditions,the maximum planting density of net photosynthetic rate?Pn?and transpiration rate?Tr?was 5m×6m and the minimum was 2.5m×6m.Under the planting density of 2.5m×6m,the net photosynthetic rate?Pn?was:Xilin 3>Xiangling>Xifu 1>Xilin 2>Xifu 2>Qiantler>Xiluo 3;transpiration The rate?Tr?size is Xilin No.3>Xiang Ling>Xifu No.1>Jangtale>Xilin No.2>Xifu No.2>Xiluo No.3.?3?Under the same variety conditions,the maximum planting density of WUE and LUE is 5m×6m,and the minimum planting density is 2.5m×6m;under the planting density of 2.5m×6m,Water use efficiency?WUE?size is Xilin No.2>Xifu No.1>Xifu No.2>Xiluo No.3>Xilin No.3>Juntale>Xiangling;light energy efficiency?LUE?size is Xilin No.3>Xiang Ling>Xifu No.1>Xilin No.2>Xifu No.2>Juntale>Xiluo.?4?The maximum planting density of leaf area index?LAI?is 2.5m×6m,and the minimum planting density is 5m×6m.?5?The variation trend of intercellular CO₂ concentration?Ci?and stomatal limitation value?Ls?in different planting densities and different cultivars is basically the same,indicating that cultivar and planting density do not affect photosynthetic rate caused by stomatal factors and non-stomatal factors.decline.?6?With the increase of row spacing,the yield per plant and the single fruit weight,the yield per mu,and the yield per mu have increased,indicating that the row spacing has a significant impact on the quality of walnuts and the output value of the production.?7?In the investigation of walnut diseases and pests under different planting densities,the pest damage degree was lighter under the planting density of 5m×6m,and the pest damage degree was severe under the planting density of 2.5m×6m and 3m×5m.Conclusion:different planting density on the growth of walnut solid state,under the condition of different planting density of walnut net photosynthetic rate?Pn?and water use efficiency?WUE?and light energy use efficiency?LUE?index increased with the decreasing of planting density,leaf area index?LAI?in the suitable planting density condition is helpful to reduce the disease index of nuts yield of walnut.