model for estimation of the potential yield of walnut trees
2014
Hassani, D. | Dastjerdi, R. | Soleimani, A. | Jaffaraghaei, M. | Razaee, R. | Vahdati, K. | Dehghani, A. | Hadadnejhad, H. | Asefnokhostin, M. | Mozaffari, M. | Eskandari, S.
Walnut trees are subject to damage of several detrimental agents including frost, hail, drought, pest and diseases. Insurance of walnut trees against these factors is necessary to alleviate damages caused by these disasters. Accurate estimate of amount of yield is necessary previous to damages. Therefore, developing of an efficient model to estimate yield and crop damage has specific importance. In this research, according to some important characteristics that could be evaluated before flowering, a model TY=tcsa(ti(1+pr)(1+(db+ci+om))w) was defined to estimate the yield of trees in walnut orchards. In the model: TY is number of fruit/tree; tsca is cm2 of trunk cross sectional area; ti is a primary coefficient for production based on trunk cross sectional area and planting distance; pr is another coefficient for type of bearing and growing habit; db, ci and om are coefficients for shoots die back, presence of bearing shoots inside canopy and orchard management receptively. The W is a coefficient for soil quality and water availability. The coefficients were estimated using the walnut collected data from research stations and commercial orchards. The coefficient of determination with other sets of collected data for model validation was around 0.8. The model is prepared for the Iranian Insurance Fund for walnut insurance and is under experimental use in walnut production areas.
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