INTEGRATED CROP MANAGEMENT PRACTICES FOR IMPROVING RATOON PRODUCTIVITY IN SUB TROPICAL INDIA

摘要

Aims: In sugarcane farming, ratooning is an important aspect owing to its low cost of production compared to plant (main) crop by saving in the cost of seedbed preparation, seed material and planting operations. Ratoons help to extend the crushing schedule of sugar factories for they mature earlier than the plant crop due to early dehydration of tissues and flushing out of N. However, most often ratoon crop yields are lower than the main (plant) crop due to soil compaction, decreased rate of soil fertility under continuous sugarcane cropping and inefficient use of applied fertilizers. Thus experiments were conducted at Indian Institute Sugarcane Research, Lucknow to improve sprouting and yield of early sugarcane variety vis-a-vis sustaining high yield and quality of mid late variety through integrated crop management approaches. Methods & Results: In 1st field experiment 8 treatments i.e. B_1: Control (Farmers practice). B_2: Farmers practice with application of 20 kg ha~(-1) Trichoderma viride @10~8 counts g~(-1) culture + 15 t/ha press mud cake (PMC) applied on stubble rows in the month of December at the time of ratoon initiation B_3. Farmers practice with application of 12.5 kg ha~-Acetobacter diazotrophicus @10~7 counts g~(-1) culture + 15 t/ha press mud cake (PMC) on stubble rows B_4: Farmers practice with application of 12.5 kg ha~-Phosphate solubilizing bacteria (Bacillus subtilis) @10~7 counts culture + 15 t/ha press mud cake (PMC) was applied on stubble rows in main plots. Subplots treatments included S_1: at the time of initiation of sugarcane ratoon stubble rows left uncovered, S_2: Soil cover of 3-4 cm was applied on the stubble rows. Thus 8 treatments were applied in split plot design with 3 replications. Sugarcane early variety,CoS 96668 was grown in the experiment. In 2nd field experiment three treatments of potassium were applied with irrigation water in standing sugarcane plant crop (variety, CoSe 92423). K_1: no irrigation and no K fertilization one month prior to harvesting. K_2: Standing sugarcane plant crop was irrigated one month prior to harvesting but no K fertilization. K_3: K@ 80 kg/ha was applied prior to one month before harvesting with irrigation water in plant cane. Covering of stubble with soil cover improvednumber of millable canes, individual cane length, diameter and weight. Ratoon cane yield was obtained to the tune of 65.56 t/ha which was significantly superior to uncovered /exposed stubble. Highest sugar yield (8.01 t/ha) was obtained with PSB+ PMC. Application of K in plant cane with irrigation water improved number of millable cane (94700) and ratoon cane yield (74.11t/ha) over no irrigation and K fertilization. Significance of Study: In subtropical conditions application of phosphate solubilisingbacteria with press-mud cake and covering of stubble during ratoon initiation improved cane and sugar yield. Application of K @ 80 kg/ ha (in plant cane one month prior harvesting) also improve ratoon cane and sugar yield.