MULTI-RATOONING POTENTIAL OF SUGARCANE UNDER INTEGRATED NUTRIENT MANAGEMENT IN HIGH GANGES RIVER FLOODPLAIN SOILS OF BANGLADESH

摘要

Aims: Field experiments (one plant + 3 ratoons) were laid out during four consecutive years of 2001 to 2005 at Bangladesh Sugarcane Research Institute farm soil to study the effect of integrated use of organic materials and inorganic fertilizers on plant crop (first crop after planting) and subsequent first, second and third ratoon crops of sugarcane. The aims of the study were to evaluate the yield potentiality of sugarcane (variety Isd 20) and juice quality of plant and ratoon crops as well as soilproperties. Methods and Results: The organic materials included press mud, farmyard manure (FYM) and green manure (GM) of Sunhemp (Crotalaria juncea) and the fertilizers were urea, triple superphosphate (TSP), muriate of potash (MOP), gypsum and zinc sulphate. When FYM at 15 tha~(-1) accompanied with chemical fertilizer (N_(178)P_(53)K_(54)S_(26)Zn_(2.6) kgha~(-1)) applied cane yields of 108.4, 96.8 73.5 and 71.5 tha~(-1) were obtained in plant cane, first, second and third ratoon crops respectively. Cane yields in the first, second and third ratoon crops were 89.3, 67.0 and 66.0% of plant crop yields respectively. Juice quality parameters viz., Brix, pol and purity progressively increased up to second ratoon crops when compared with plant cane. The organic carbon (OC), total nitrogen (N), available phosphorus (P), exchangeable potassium (K) and available sulphur (S) contents of soils increased slightly due to incorporation of organic materials as compared to control. Significance of study: Thus it may be concluded that a 25% reduction of inorganic fertilizer (N_(138)P_(40)|K_(40)S_(20)Zn_2. kgha~(-1)) with either FYM or press mud at 15 tha~(-1) was found optimum to boost up plant crop yield. In case of ratoon crops, additional N (50% extra dosage)keeping all the fertilizer at same level i.e. N_(207) P_(40)K_(40)S_(20)Zn_2 kgha~(-1) + press mud or FYM at 15 tha~(-1) was more effective in improving the ratoons yield without deterioration in soil fertility.