Optimal uptakes of nitrogen, sulfur and N:S for plantation of high yielding sugarcane

Abstract

Optimal uptakes of nitrogen (N) and sulfur (S) required for producing high yield sugarcane was pertained in this research. Sugarcane roots, stalks, and leaves of 2 cane varieties LK92-11 and K84-200, were collected continually from planting (0) to harvesting (360 days after planting or DAPS). Samples were collected from plantation fields, located in Nakhon Ratchasima and Burirum provinces, expecting to have yields of 5, 10, 15, 20, and 25 ton/rai. Each sample was measured for its total biomass, dry mass, concentrations of N and S. Michaelis-Menten kinetics described relationships between uptake of either N or S as functions of DAPS quite well. Non-linear response of yield versus either N or S uptake was found for both cane varieties. Their derivatives indicated that at high yield level, the margin of yield per a unit of either N or S input is greater than that of the low yield level. The dimensionless analysis showed that the S-shape described relationships between either N or S uptake as functions of DAPS quite well. Their derivatives indication of the N uptake began as soon as the start of planting and was ceased at 180 DAPS. While N uptake for stalk biomass was ceased at 252 DAPS. During 180 DAPS to harvest, sugarcane stalks uptaked N mainly for continuing their activity. The S uptake for the whole cane biomass was ceased at 240 DAPS while for stalks was ceased at harvest. This strongly indicated that S is a necessarily nutrient in accordance with N to be used for sucrose formation and sucrose transportation.