Resumen
Frequent application of fertilizer in plantations to overcome nutrient loss often results in negative impacts such as soil acidification, nutrient lockout, eutrophication, and greenhouse gas emissions. This study investigated the application of a novel staged-release fertilizer, Xpike, in paddy fields to improve crop yield and quality with reduced nutrient loss. The release pattern of the fertilizer and the nutrient uptake of the crop were studied with different Xpike formulations and dosages to improve the yield of Bario rice in Sarawak. Additionally, a qualitative study was carried out investigating the effect of Xpike on the presence of plant growth-promoting bacteria (PGPB). Two different Xpike formulations (XP 38: High-N-Low-K and XP 39: High-K-High-Si) were applied at three dosages of 40 kg/acre, 30 kg/acre, and 20 kg/acre, in comparison with a control plot using the conventional fertilizer, over one crop cycle. Results showed Xpike demonstrating stage release of nutrients, with a more K released into soil initially, at 0.27 % soil dry matter, dropping to 0.06% after 1st month. This signalled root-hair growth in the transplanted seedlings, followed by subsequent steady release of remaining macro/micronutrients to crop for vegetative growth and flowering stages. Yield results were favourable, with the highest yield attained at 0.083 kg grain/m2 using XP 38 at 40 kg/acre, which was 54% higher than the yield of the control plot at 0.054 kg grain/m2. Meanwhile XP 39 Xpike grew healthier crops than those of other formulations in which an unfavourable bacteria strain was found. Effective pH stabilisation was not demonstrated due to unusual high rainfall and poor levelling of the plots. In conclusion, Xpike shows promising results for improved crop yield and quality. Further studies are required to understand the role of PGPB and to optimise the fertilizer formulation and dosage in terms of crop yield and the fertilizer cost.