Abstract: Field experiments were conducted to study the effects of integrated plant nutrient system (IPNS) on the yield and yield contributing parameters of sugarcane at Ishurdi, Thakurgaon and Sreepur under High Ganges River Flood plain, Old Himalayan Piedmont Plain and Madhupur Tract, respectively. The use of organic and inorganic fertilizer showed significant effect on the yield and yield attributes like tillers, millable stalk and juice quality of sugarcane. The results revealed that yield increase was to the extent of 22.86, 49.2 and 74.0 % at Ishurdi, Thakuragaon and Sreepur, respectively due to the application of 12.5 t ha -1 press mud/cowdung accompanying chemical fertilizers applied on the basis of soil test for HYG over present recommended rates of chemical fertilizer (as per FRG´97) for MYG. Press mud alone increased 16-20 per cent cane yield over the dose of N, P, K, S, Zn and Mg fertilizers based on soil test for HYG at all locations. Incorporation of dhaincha (Sesbania aculeata) as green manure increased cane yield and contributed about 42-46 kg N ha -1 in soil.
Introduction
Sugarcane is the only source of white sugar in Bangladesh, cultivated on an area about 0.17 million hectares annually with an average yield of 41t ha–1(BBS, 1998). Being a long duration and heavy feeder of nutrients it uptakes considerable amount of plant nutrients from soil. As a result, the nutrient ability of soil to supply plant nutrients is declining day by day which leads to decline productivity of sugarcane till recently. It is well agreed that a blend of organic and inorganic fertilizer can improve the cane production besides maintaining the soil health.
Rabindra et al. (1990) reported that continuous application of farmyard manure (FYM) along with NPK fertilizer improves physico-chemical properties of soil, cane yield and juice quality. Press mud is an organic by product of sugar mills and one ton of millable cane gives about 30 kg of press mud (Quilloy, 1974). It is a rich source of organic carbon (35-37%) and supplies 1.0-1.5 % N, 2.5-3.5% P2O5 and 0.3-0.8 % K2O. Besides, it is a good source of micro-nutrient and qualities to amend the soil nature. It is also reported that the slow decomposition of press mud may benefit the ratoon cane (Kale, 1981). So, considering the above facts a study was conducted with the following objectives:
a) to evaluate the fertility status of soil by using organic and inorganic fertilizer, b) to improve soil health through IPNS for sustainable sugarcane production and c) to study the productivity and profitability of different fertilizer management packages.
Materials and Methods
Three field experiments were conducted in 1999-2000 cropping season at Ishurdi, Thakurgaon and Sreepur site under High Ganges River Flood plain, Old Himalayan Piedmont Plain and Madhupur Tract, respectively. The soil of Ishurdi site was calcareous in nature, near to neutral in reaction and deficient in organic matter, nitrogen, phosphorus, sulphur and zinc. Potassium was near to critical level. The Thakurghaon and Sreepur soils are non-calcareous, acidic in reaction, low in available nitrogen, potassium and medium in available phosphorus. Sulphur was quite adequate and low in zinc (Table 2). Experiments were laid out in randomized complete block design with four replications. The unit plot size was 8x6m2. Two budded soil bed settlings of variety Isd 26 and Misrimala (local) were used as test material at Ishurdi and Sreepur site, respectively. Thirty-five days-aged poly bag settlings of Isd 28 were used as seed material at Thakurgaon site. All the recommended cultural management practices were followed when required. N as urea and P as MP were applied in three splits; first at 20-30 days after transplanting, second at peak tillering stage and finally one month after second top dressing. Full amount of TSP, Gypsum, Zinc sulphate, MgO and organic fertilizers were applied in the trenches and mixed thoroughly with soil by spade. Cowdung was used only at Sreepur site. Dhaincha as green manure were raised and incorporated in situ after 50 ± 5 days of seed sowing. The N, P and K contents of cowdung and press mud were 0.78, 0.10 and 0.50 and 0.55, 0.15 and 0.20 per cent respectively. The N, P and K contents of mustard oil cake and green manure were 3.5, 1.4 and 1.3 and 1.24, 0.02 and 0.3 percent respectively. The incorporated green manure Dhaincha contained 1.65 % N. Necessary data were recorded and analyzed using the Least Significant Differences Test (LSD) at P=0.05. Economics of different treatments were calculated on the basis prevailing market prices during the study period. Sugarcane crop was harvested 13 months after planting. Initial soils at the depth of 0-15 cm were collected and analyzed following the standard procedure. The treatment wise different rates of organic and inorganic fertilizer of different locations are presented in Table 1.
The treatments are as follows:
| T0: | Control |
| T1: | Recommended fertilizer rate (as per FRG’ 97) for MYG |
| T2: | 12.5t ha–1 press mud/ cowdung + T1 |
| T3: | Fertilizer rate based on soil test value for HYG |
| T4: | 12.5t ha–1 press mud/ cowdung + T3 |
| T5: | GM ( dhaincha) + T3 |
| T6: | 500Kg MOC + T3 |
FRG = Fertilizer Recommendation Guide, 1997; MYG = Moderate Yield Goal (80 ± 10 t ha–1) ; HYG = High Yield Goal (100 ± 10 t ha–1) ; MOC = Mustard Oil Cake
Results and Discussion
Yield attributes and yield
High Ganges River Flood plain (Ishurdi site): The effects of organic and inorganic fertilizers on tiller, millable cane stalks, yield and brix (%) are presented in the Table 3a. Significantly lowest number of tillers (161.7x103 ha–1), millable cane stalks (96.0x103 ha–1) and yield (67.3 t ha–1) of cane were obtained from the control (T0), while the highest number of tillers (212.2 x 103 ha–1), millable cane stalks (151.3 x 103 ha–1), yield (127.5t ha–1) and brix (20.58 %) were obtained from T4 combination which received 12.5 t ha–1 press mud with chemical fertilizers based on soil test value for HYG. The cane yield increased at T6, T5, T4, T3, T2 and T1 was 65.69, 75.28, 89.33, 60.92, 71.56 and 54.11 %, respectively compared with control, respectively. Addition of different organic manures increased yield about 2.9, 8.9 and 17.65% at T6, T5, and T4 compared with T3 (only chemical fertilizers were applied on soil test value for HYG). From the above study it was noticed that addition of organic manure/green manure with chemical fertilizers produced higher cane yield as compared with treatments where only chemical fertilizers were used.
| Table 1: | Amount of nutrients (kg ha–1) used in different treatments in the experimental sites |
*Quantity of N, P, K and S derived from organic sources were adjusted to T2, T4, T5 and T6 keeping the chemical fertilizer dose same | |
| Table 2: | Initial and final soil status of the experimental sites of different fertilizer packages for sugarcane at different sites |
| - Indicates not available. | |
| Table 3a: | Yield and yield attributes of sugarcane as influenced by IPNS at Ishurdi [Figures with same letter do not differ significantly at 5 % level as per DNMR test} |
| Table 3b: | Yield and yield attributes of sugarcane as influenced by IPNS at Thakurgaon |
| Table 3c: | Yield and yield attributes of sugarcane as influenced by IPNS at Sreepur |
| Table 4a: | Economic analysis of different fertilizer management packages of sugarcane through IPNS at Ishurdi |
| Table 4b: | Economic analysis of different fertilizer management packages of sugarcane through IPNS at Thakurgaon. |
| Table 4c: | Economic analysis of different fertilizer management packages of sugarcane through IPNS at Sreepur |
| Price of input and output and labour wages was considered on local market | |
It is expected that use of organic manures in the soil, had a positive effect on cane yield and soil properties as well. Singh et al. (1995) reported that press mud alone or in combination with nitrogen improved the cane yield and quality of plant and ratoon crops.
Old Himalayan Piedmont plain (Thakurgaon site): Data on tillers, millable cane stalks and yield were significantly influenced by the application of fertilizer through integrated plant nutrient system (IPNS) and are shown in Table 3b. The highest number of tillers of 197.9 x 103 ha–1 was produced at T2 treatment followed by T3 treatment while the lowest number of 107.6 x103 ha–1 was produced for T0 (control) treatment. Highest number of millable cane stalks (134.8 x103 ha–1) and cane yield (119.6 t ha–1) were obtained with the application of 12.5 t ha–1 press mud with chemical fertilizers based on soil test value for HYG (T4) which was similar to T3 and T5 treatments. The average yield increase at T4 was 116.8, 49.2, 35.1 and 17.2 % compared with T0, T1, T2, and T3, respectively. The yield increase was superior with those treatments where a blend of organic and inorganic fertilizer was applied. Significant effect was not observed in brix per cent of cane juice.
Madhupur Tract (Sreepur site): Sugarcane yield and its components, viz. tillers, millable cane stalks were significantly influenced by the application of different levels of organic and inorganic fertilizers (Table 3c). The highest number of tillers (145.6 x1 03 ha–1) millable cane stalks (96.5 x 103 ha–1) and higher cane yield (121.7 t ha–1) were produced at T4 treatment, where 12.5 t ha–1 cowdung with chemical fertilizers based on soil test value for HYG was applied. The increase in cane yield at T4 was 126.6, 74.0, 25.4 and 18.1 % compared with T0, T1, T2 and T3 treatment. At Ishurdi and Thakurgaon site, comparatively higher yields were also found with the application of organic and inorganic fertilizers. Brix percent was not significantly differed among the treatments.
Soil fertility status: The status of soil pH, organic carbon, total N, available P, K, S and Zn in initial soil as well as post harvest soil of one cycle of sugarcane are presented in Table 2. No perceptible changes were observed in soil characteristics due to the use of varying fertilizer packages. The application of green manure, press mud or cowdung brought some increase in soil organic matter at Thakurgaon and Sreepur. Bokhtiar et al. (2001) and Islam et al. (1998) obtained similar results. The changes in total N, available P, K and S in soil were not conspicuous.
Economics of fertilizer use: Farmers’ of our country are continuously facing multifarious problems in crop production and strongly considered the economics of fertilizer use by which they can benefited. Hence an economics of different fertilizer management packages of Ishurdi, Thakurgaon and Sreepur site are presented in the Tables 4a 4b & 4c, respectively. An economic analysis of different fertilizer packages was done considering the total variable cost and return where all other costs involved were same for all the treatments. At different sites the highest net benefit and BCR varied, as it was associated with the yield production as well as fertilizer requirement in the treatments. At Ishurdi, the highest BCR of Tk. 3.92 was obtained in T2 treatment followed by Tk. 3.73 in T4 treatment with highest net benefit. At Thakurgaon, the highest net benefit and BCR of Tk. 3.53 was found in T4 treatment followed by Tk. 3.09 in T3 and Tk. 3.06 in T5. At Sreepur, the highest BCR of Tk. 3.97 was found in T5 treatment, which was close to T4 treatment (3.89) with highest net benefit.
Use of 12.5 t ha–1 press mud/cowdung with chemical fertilizers based on soil test value for high yield goal may be suggested for maximizing sugarcane production and achieving higher economic benefit. In situ green manure incorporation increased sugarcane yield and supplemented about 42 to 46 kg N ha–1 in the subsequent cane crop as well. The application of press mud, cowdung, mustard oil cake and green manure should be incorporated in soil to maintain soil fertility for sustainable sugarcane production.
Acknowledgments
The senior author is grateful to the funding agency DANIDA and project manager of SFFP for the financial assistance to perform this study.