Previous-Crop Effects on Sugarcane Responses to Nitrogen Fertilization
- Robert P. Wiedenfeld *
Nitrogen fertilizer recommendations have been developed for sugarcane (Saccharum officinarum L.) based on numerous fertility trials, with the primary variables affecting those recommendations being soil type and crop age. Cropping history influences subsequent crop responses to N fertilization, but such effects have not been determined for sugarcane. The objective of this research was to evaluate previous-crop effects on sugarcane growth and response to N fertilization. Eight 2-jr previous-crop treatments consisted of N-fertilized and unfertilized corn (Zea mays L.), sorghum [Sorghum bicolor (L.) Moench], and cotton (Gossypium hirsutum L.); unfertilized soybean [Glycine max (L.) Merr.]; and fallow. These treatments were followed by sugarcane grown for 3 yr at four different levels of N fertilizer application. Previous-crop treatments containing corn and sorghum contributed more biomass back to the soil than cotton or soybean. None of the crops grown prior to sugarcane responded to N fertilization, resulting in 90% of the N fertilizer applied remaining in the soil. Sugarcane yield and quality in the plant-cane crop were affected primarily by previous-crop treatments, in the first ratoon by both previous crop and N fertilizer application, and in the second ratoon primarily by N fertilizer application. Sugarcane responses to N fertilization were generally lowest following those treatments which had the most N returned from plant residue, or the most measured residual N. Inorganic soil N measurements correlated better with sugarcane responses to N in the plant cane crop, while mineralizable soil N levels correlated better with sugarcane responses to N in the first ratoon crop. Soybean resulted in low inorganic and mineralizable soil N, yet sugarcane following soybean failed to respond to N fertilizer application, indicating that N following soybean is less readily released but does later become available.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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