Malaysian Journal of Sustainable Agriculture (MJSA)

Both nitrogen deficiency and over-fertilization result in rice leaf damage and effect on yield production. Insufficient nitrogen supply gives raise to yellow leaves, whereas spraying too high concentrations of fertilizers can be recognized by leaf burn. This study used variable rate application (VRA) of organic foliar fertilization to fertilize the System of Rice Intensification (SRI) cultivation without application of granular fertilizer and used Soil Plant Analysis Development (SPAD) chlorophyll meter as a tool to measure chlorophyll-nitrogen content for fertilizer calculation. Based on a greenhouse experiment the effect of nitrogen regime on rice leaves damage was assessed. The experiment consisted of four nitrogen regimes (50% fixed rate, 100% fixed rate,150% fixed rate and VRA) arranged in a randomized complete block design (RCBD) with four replications. Experimental result showed that none of the treatments resulted in leaf burn, whereas chlorosis was observed for all the treatments. VRA had the lowest level of chlorosis with low supplied of nitrogen compared to uniform treatments. Application of organic liquid fertilizer in variable rate form and using SPAD chlorophyll meter able to help to diagnose accurately the nitrogen content in the rice leaves for fertilizer application and capable to reduce chlorosis effect on the rice leaves.