Fertilizer Usage and Soil Management Approach of Rubber Plantation in Lowland and Upland Areas in Songkhla Province

Abstract

Rubber cultivation has been currently expanding into lowland areas which are unsuitable. This study was to survey information of fertilizing, problem and soil management of rubber tree plantation in lowland and upland areas in Songkhla province. The results showed that most of the lowland soil texture was finer than the upland soil texture and rubber yield in the lowland area was lower than the upland area. The majority of farmers in lowland and upland areas used chemical fertilizersand chemical fertilizers with organic fertilizers, respectively. A mixed fertilizer of 20-8-20 formula was used for immature rubber trees and a 15-7-18 formula for mature rubber trees. A 15-15-15 mixed fertilizer was used in both immature and mature rubber trees in lowland and upland areas. Most of the upland farmers used the recommended fertilizer more than lowland farmers which used fertilizers recommended by their neighbors. The main reasons for lowland rubber cultivation were unprofitablerice production and high rubber price. Rubber cultivation in lowland areas was negatively effected by the following factors: waterlogging, powdery mildew and tapping panel dryness of rubber trees. Most farmers agreed to evaluate land suitability before planting. Waterlogging in rubber plantation should not last longer than 7 days. It is recommended to dig a ditch around a planting plot or making ridges by dredging soil between rubber rows and placing it onto the rows of rubber trees. In this way, it increases cost of rubber cultivation in lowland areas.