SOME SOIL, WATER AND PLANT FACTORS AFFECTING NUT PRODUCTION AND ALTERNATE BEARING OF PECAN TREE

Abstract

Pecan tree alternate bearing or irregular production shows values from 23 to 94 % in the Comarca Lagunera Region. This was assessed in fourteen orchards in production evaluated during the period 1995 to 1997. The purpose of this study was to evaluate the relationship between salinity, sodicity, soil fertility, irrigation frequency and plant characteristic on pecan nut production and alternate bearing. Variables evaluated were soil physical and chemical properties, root number per tree, foliar concentration of 10 nutrients, trunk crosssectional area, nut yield per tree, weight per nut, kernel percentage and irrigation frequency across the season. A multivariate technique based on principal components was used for data analysis. Interchangeable sodium values above 3 % reduced trunk cross-sectional area and nut yield per tree. However, the alternate bearing decreased because yield was stabilized. Electric conductivity greater than 3 dS m-1 was associated to a reduced trunk cross-sectional area and nut yield per tree. Irrigating at intervals less than 20 days during kernel development, increased root number per tree, trunk cross-sectional area and nut yield per tree, whereas foliar zinc concentration was reduced.