Site specific nutrient management for maize grown in paddy fields

Results showed that high yield of 9-10t/ha could be achieved for maize in paddy fields of Nueva Ecija and Tarlac [Philippines] with optimized plant population and non-limiting nutrient management. Yield of NPK was more than 2t/ha higher than in FFP [Farmers Fertilizer Practices]. During the 2005-2006 dry season planting, it was observed that at lower planting density, (75cm x 20cm and 65cm x 25cm at 66,667 plants/ha) the grain yield at 2 N split is higher than at 3 N split application, but at higher planting density of 83,333 (60cm x 20cm) the mean grain yield using the 3 N split is slightly higher than the 2 N split, however, the difference for the different populations is not statistically significant. During the 2006-2007 dry-season cropping and using high population density of 83,333 plants/ha, it was noted that higher grain yields were recorded/observed in 7 out of 9 farms which applied N in 3 split compared to 2 split N application. From the 7 farms, the yield advantage ranged from 0.1-3.0t/ha. One of the reasons for the high yield potential of maize is the supplemental irrigation coming from the shallow tube well pumps (STWP), a common practice in the area. The relative higher solar radiation in the area during the maize cropping season, which is needed during plant photosynthesis, contributed to this high yield potential. Reasonable yield and net benefit require effective population of about 60,000 to 70,000 plants/ha (with maximum of 10-15% barren plants) and optimal nutrient use. The use of farm tools in planting, like the locally manufactured maize seeder called 'farmalite' provides more uniform plant germination, thereby higher plant population at harvest. Initial results using the leaf color chart (LCC) indicated that this technology could be used in real time nitrogen management for corn to improve the nitrogen-use efficiency whenever water is available for irrigation. It was also observed that application of fertilizer nitrogen at a rate of 40 kg per ha will result to a yield response equivalent to one ton per ha based on the agronomic efficiency of 25 kg grain increase/ kg N added. Yield response to fertilizer N, P, and K used in the newly developed and adjusted fertilizer SSNM rates during the DS 2006-2007 cropping showed improved net benefits.