SUGARCANE IN MONOCULTURE OR IN ROTATION WITH SWEET CORN

Farmers in many regions of the world grow a horticultural or grain cro p between sugarcane (a complex hybrid of Saccharum spp.) cycles. This additional crop often requires higher amounts of P or K fertilizers th an does sugarcane. Some sugarcane growers in Florida precede 2- to 5-y ear cycles of sugarcane with one crop of spring-harvested sweet com (Z ea mays L.). A disadvantage perceived with this rotation is that the h igher amounts of P fertilizer applied to sweet com may reduce sugar yi elds of sugarcane. The primary objective of this study was to compare the sugarcane yields of a sugarcane and sweet com rotation with those of monocropped sugarcane. Phosphorus and K fertilizers were also added to sugarcane at different rates in each rotation to form four croppin g practices. Responses of four sugarcane cultivars were also tested am ong these cropping practices. Sugarcane experiments were conducted at three diverse field locations. Each location was harvested twice, firs t in the plant crop and about 1 year later in the first-ratoon crop. A t least one cropping practice including sweet com at each location had sugar yields (t sugar/ha) comparable to those of the highest monocrop ped sugarcane yields. Responses to cropping practices differed by loca tion. Also, cultivars responded differently to cropping practices. By determining location-specific sugarcane fertilizers and cultivars, gro wers can grow sweet com and sugarcane in rotation without reducing sug ar yields of sugarcane. More research to determine appropriate cultiva rs and fertilizer rates could probably improve yields of sugarcane sub jected to the sugarcane-sweet corn rotation and its residual fertilize rs.