Can Manure Type, Rate, and Number of Applications Affect Sweet Corn Dry Matter and Nutrient Partitioning?.

A field experiment was conducted at Waimanalo research station on O’ahu Island, Hawaii to study the effect of manure types (Chicken and dairy), rates (168, 336, and 672 kg/ha total N equivalent) and number of applications (one and two time) on sweet corn dry matter yield, and macro and micro nutrients partitioning.  This experiment was conducted in total of 48 plots as a factorial design within a strip plot (1.8 x 9 m) with 3 replicates. At harvest, one plant was randomly selected from each plot and its roots and shoots were collected. Root samples were washed and oven dried at 70^oC for 72 hours, then dry weights were documented. The dried roots and shoots were grounded using Thomas machine, and 0.5 g of plant samples processed by dry-ashing in muffle furnace at 550 ^oC for 6 hours and dissolving in 20 ml of 1 M HNO3 for elemental analysis by (ICP-OES). Results showed significant effect of types, rates, and number of manure applications on roots and shoots dry weight, and on macro and micro nutrient contents. Chicken and dairy manure had similar effects on nitrogen and carbon accumulation in roots tissues and increased with increasing rate of manure application. The two time manure amendment application treatments had significantly higher plant root and shoot dry weights, and macro and micro nutrients compared to the one time application treatments. There was a strong correlation between roots dry weights in one hand and macro nutrients on the other hand.