Integrated Fertilizer Management for Macadamia Production in Loei province

Abstract

This study aimed to evaluate appropriate technologies for improving the yield and quality of macadamia in Loei province. The research was conducted in macadamia orchards in Phu Ruea District, Loei province, involving 10 farmers from October 2024 to December 2025. Macadamia cultivar of the Chiang Mai 400 cultivar (HAES 660), of the same age, grown under strongly acidic soil conditions were selected. The study compared two treatments: 1) the experimental method, involving chemical fertilizer application based on soil and plant analysis combined with phosphate-solubilizing biofertilizer according to Department of Agriculture recommendations and 2) the farmers’ conventional practice. This course involves analyzing yield gaps, comparing mean yields (pair t-test) and analyzing economic data including revenue, costs, returns and the benefit-cost ratio (B/C ratio). Both methods followed DOA guidelines for general plot management and pest control. The result showed that the experimental method achieved a significantly higher average yield nut in shell weight and kernel weight at 17.6, 10.8 and 4.0 kg/plant, respectively, compared to the farmers' conventional practice, which yielded 15.7, 9.0 and 3.3 kg/plant, respectively. Regarding quality the experimental method showed a kernel percentage floating percentage and recovery percentage of 36.9, 94.0 and 34.7%, respectively, which were not significantly different from the farmers' conventional practice (37.4, 93.7 and 35.1%, respectively). Consequently, the experimental technology led to an increase in income and net returns by 20% and 22%, respectively, over the traditional method.