Fertilizer Application Based on Soil Testing and Irrigation in Dry Season in Immature Rubber Trees

Abstract

Optimal nutrients and soil moisture are an important for plant growth. This experiment was studied to compare growth of immature rubbers (RRIT 251) which were fertilized with soil test and irrigated in dry season of rubber farmer plantation in Nan province. The experiment was designed as split plot in Completely Randomized Design. The main plots were rainfed and irrigated conditions. The subplots were control (no-fertilizer), using 20-10-12 mixed fertilizer recommended by RRIT and fertilizer based on soil test. Trunk girth at 150 cm. from surface soil, fresh biomass of rubber and bark thickness were investigated at the end of experiment. The results found that an irrigation and fertilizing were not interaction on rubber growth. Both irrigated and fertilized trees showed the trunk girth and fresh biomass were not significant difference (p>0.05), but the growth of irrigated trees were tend to higher than rainfed trees. And, the soil test fertilized trees showed higher growth than 20-10-12 mixed fertilized and controlled trees, respectively. Bark thickness were significant difference (p<0.05) in both irrigation and fertilizing treatments.