Nutrient dynamics in soils of intensively cultivated sugarcane - sugarcane cropping system

Field studies were conducted to forecast the emerging nutrient deficiencies, toxicities in soils and plants due to intensive sugarcane-sugarcane cropping system and increasing use of fertilizer and its management practices in Irugur, Palathurai and Athipalayam soil series. The soils were low in available nitrogen (N) and organic carbon, medium in available phosphorus (P) and high in available potassium (K) and sulphur (S). The diethylene triamine penta acetic acid (DTPA) extractable iron (Fe), manganese (Mn), zinc (Zn) and copper (Cu) were sufficient in all soil series except Zn in Palathurai series. The order of macronutrient uptake was K > N > P>S and the micronutrient was of Fe > Zn > Mn > B > Cu in Irugur and Palathurai soil series while it was Fe > Zn > Mn > Cu > B in Athipalayam series. The available nutrient status of the soil showed wide variations in their availability and it was heavily depleted by continuous cropping system. Nutrient balance studies revealed that there was a positive balance maintained for macronutrients in almost all locations. However, the negative balance of Fe, Zn, Cu and B in Irugur series; Fe, Zn and B in Palathurai and Athipalayam series observed in most of the locations indicated that the yield was limited by these nutrients and needed regular application of those nutrients. The overall data indicated that the necessity for the use of a balanced dose of both macro and micronutrients through integrated nutrient management (INM) practices to maintain the crop yield and soil fertility on sustainable basis in the intensive sugarcane - sugarcane cropping system