Organic Fertilizer Efficacy and Financial Viability in Upland Rice (Oryza sativa L.) Production

The study was conducted in a Lipa clay loam soil at Los Baños, Laguna, Philippines during the 2012 and 2013 wet cropping seasons to compare the growth and yield performance of upland rice (<i>Oryza sativa</i> L.) varieties under organic and inorganic fertilization. The parameters considered include periodical changes in soil nutrient status, agronomic efficiency of nitrogen (AEN), grain yield and return on investment (ROI). The treatments were arranged in split-plot design fitted into a randomized complete block design, with varieties as the main plots and varying fertilizer management treatments using organic (Pureganic and Vermicompost) and inorganic fertilizers as the subplots. NSIC Rc9 variety performed better in terms of growth and grain yield than Inipot-Ibon, a traditional variety; it had higher harvest index, number of spikelets, filled grains and AEN. Generally, inorganic fertilizers improved the grain and straw yields as well as the AEN of NSIC Rc9 compared with Inipot-ibon. Applying organic fertilizer did not increase the grain yield of both NSIC Rc9 and Inipot-ibon in two consecutive croppings. No significant effect of varieties or fertilizer management was observed on the soil organic matter (SOM), total available nitrogen, available phosphorus and exchangeable potassium but the values tended to decline every season after cropping of upland rice. In general, the ROI obtained from upland rice production was either break-even or had negative returns, making upland rice production less profitable.