Response of Sugarcane to Filter Press Mud and N, P, and K Fertilizers. II. Effects on Plant Composition and Soil Chemical Properties

The effect of filter press mud (FPM) on the composition of macro- and micronutrients of sugarcane leaf has not been studied. Therefore eight field experiments, four plant cane and four ratoons, were conducted to study the effect of FPM and N, P, and K fertilizers and their interaction on leaf N, P, and K content of sugarcane (Saccharum officinarum L.). The effects of FPM and P-fertilizer on leaf Ca, Mg, Zn, Fe, Mn, Cu, B, Mo, and Al content, as well as on extractable soil P, K, Ca, Mg, Zn, Mn, and Al, and on pH were also studied. These experiments were conducted over 2 years on seven sites. A split plot design was used with FPM on main plots (rates were 0, 20, and 40 metric tons/ha or 0 and 34 metric tons/ha dry wt with two or four replications) and N, P, and fertilizer rates on subplots (two or four replications). The rates of fertilizers were as follows: N = 0, 94, and 188 kg/ha or 47, 94, and 141 kg/ha; P = 0, 45, and 90 kg/ha or 0 and 45 kg/ha; K = 0 and 112 kg/ha. Filter press mud increased leaf N in one experiment while N-fertilizer increased it in all experiments. In two experiments there were significant FPM ✕ N interactions. Filter press mud and P-fertilizer increased leaf P in six and seven experiments, respectively. Significant interactions on leaf P were FPM ✕ P, FPM ✕ N, and FPM K. At the rates tested FPM-P was a more efficient source of P than fertilizer-P. Filter press mud increased the leaf K significantly in three experiments. Leaf Ca and Mg were increased as a result of FPM application in two experiments and one experiment, respectively. Extractable soil Ca and Mg values were similarly increased as a result of FPM application in all four experiments. Filter press mud reduced leaf AI in four experiments, leaf Zn and Fe in two experiments, and leaf Mn in one experiment. P-fertilizer applied together with FPM did not further reduce Zn or Fe in the leaf. Extractable soil Zn was increased as a result of FPM application and changeable A1 was reduced. Filter press mud slightly increased soil pH. Leaf Cu, B, and Mo were not affected by FPM or P. These results showed that FPM was a more effective source of P than triple superphosphate at the rates tested, and that FPM could be used as a substitute for K fertilizers where a maintenance dressing is required. Filter press mud also supplied secondary nutrients but it has no consistent effect on micronutrient nutrition.