ROOT-SYSTEM MORPHOLOGY OF PEPPER AND MELON AT HARVEST STAGE GROWN WITH DRIP IRRIGATION UNDER DESERT CONDITIONS IN BAJA-CALIFORNIA, MEXICO

An international project between the Japanese and Mexican governments on crop production is being conducted in Guerrero Negro, Baja Californ ia, Mexico. The objective of the project is to establish a production system for vegetables and fruits with drip irrigation in the desert. T he root system morphologies of pepper and melon at the harvest stage w ere examined as one way of obtaining the goal. The root length density of pepper decreased with soil depth and rapidly so below 20 cm, while horizontal variation in the root distribution was relatively small. T he roots of ridge-cultured melon were distributed mainly on a ridge. M any lateral roots had tumors possibly damaged by nematode, The root le ngth densities at several coressponding sites and depth of both sides of the pepper row were statistically different depending on being with or without emitter. However, there was no significant difference in t he root length densities of both sides of the melon row, although the spatial distribution of roots was apparently asymmetric. This asymmetr ic distribution of roots in soil may be affected by drip irrigation in cluding the influence of fertilizers in irrigation water from the emit ter. At the same time, a preliminary observation suggested that an inc rease in root length density was caused by accelerated root branching, depending mainly on an increase in length of lateral roots.