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Pak. J. Bot., 40(4): 1521-1531, 2008. |
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Updated: 09-07-09 |
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EFFECT OF DIFFERENT SOURCES AND RATES OF NITROGEN AND SUPRA OPTIMAL LEVEL OF POTASSIUM FERTILIZATION ON GROWTH, YIELD AND NUTRIENT UPTAKE BY SUGARCANE GROWN UNDER SALINE CONDITIONS
M. YASIN ASHRAF1 , FAQIR HUSSAIN1, JAVED1 AKHTAR1, ATTIYA GUL1, MARCUSS ROSS2 AND GEORG EBERT2
Abstract: The results of our pervious studies indicated that application of potassium @150 kg K2O ha-1 is effective in achieving economical sugarcane yield and optimum nutrient uptake under saline conditions. Keeping in view these findings, experiments were conducted on salt-affected soils at three sites of Punjab, Pakistan to select a suitable source and rate of N for obtaining optimum sugarcane yield and nutrient uptake from salt-affected soils. The experiments were conducted with two sugarcane varieties, salt tolerant (SPSG-26) and sensitive (CP-77400) using supra optimal level of K (150 kg K2O ha-1) as sulphate of potash SOP, P @ 100 kg P2O5 ha-1 as DAP (diammonium phosphate) and N @100 and 200 kg N ha-1 as urea or calcium ammonium nitrate (CAN). The results showed that cane length and diameter, number of tillers per plant, cane yield and sugar recovery increased with the application of N in both the sugarcane varieties under normal or saline conditions. Sugarcane growth and yield increased with increasing N rate from 100 to 200 kg N ha-1 in case of both urea and CAN. However, CAN as N source was more effective in enhancing sugarcane growth and yield than urea. The concentration of Na+ increased in both the sugarcane varieties due to salinity, however, application of K and N decreased its concentration. The combined application of NPK also significantly reduced Na+ uptake in leaves, however, the best combination observed was DAP+SOP+CAN. It was also observed that salt tolerant variety (SPSG-26) had lesser accumulation of Na+ than that of sensitive one (CP-77400). Application of N fertilizers significantly enhanced the nutrient (K, P, and N) uptake in both the varieties at both N rates (100 and 200 kg N ha-1) under normal as well as saline conditions. However, maximum uptake of nutrients was recorded at the highest dose (200 kg N ha-1) but CAN treated plants performed better than that of urea. On the basis of above results, the application of K as SOP and N as CAN was recommended for salt-affected soils to enhance the sugarcane yield. The salt tolerant variety for higher yield in salt-affected soil is also necessary for improving the cost benefit ratio. The results revealed that if salinity level of soil would exceed 10 dS m-1, considerable reduction in sugarcane yield could occur.
1Soil Science Division, Nuclear Institute for Agriculture and Biology (NIAB), P.O. Box 128, Jhang Road, Faisalabad, Pakistan. 2 Agricultural Advisory Departments, K+S KALI, GmbH, Kessel, Germany. Correspondence Author: niabmyashraf@hotmail.com ; myashrafsp@yahoo.com |
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