RESPONSE OF SUGARCANE PLANTED UNDER VARIOUS TRENCH SPACINGS TO FOLIAR APPLICATION OF ZINC AND IRON

Abstract

Sugarcane is a major cash crop of Pakistan which not only provides main stay to sugar industry but also raw material to many allied industries for alcohol and chip board manufacturing and a source of employment directly or indirectly to more than four million peoples of Pakistan (Naqvi, 2005). Average stripped cane yield of the country is 48.63 t ha -1 (Govt. of Pakistan, 2009); which is lower than the world production of 65.20 t ha -1 (FAO Stat., 2005). Conventional method of planting, poor management practices and imbalanced nutrient management are the major components of sugarcane agro- technology responsible for low cane and sugar yield production at farmer fields. Trench planting is considered more convenient and efficient planting system as it saves irrigation water and reduces lodging due to easy inter-culture and earthing up operations (Malik et al., 1996). Pakistani soils pH is high which have resulted antagonistic interaction of Zn and Fe with other nutrients and hence Zn and Fe availability is less to plants. A field trial was conducted for two years during spring 2007-08 and 2008-09 at PARS, University of Agriculture, Faisalabad, Pakistan, to evaluate the response of trench spacings regarding growth, development and radiation interception and to determine the most favorable dose of Zn and Fe for maximum yield and quality production of sugarcane. The treatments comprised; trench spacing (75, 90 and 120 cm apart) and foliar treatments as check, Zn (2.5, 5 and 7.5 Kg ha -1 ) and Fe (5, 10 and 15 Kg ha -1 ). Different trench spacings and levels of zinc and iron significantly affected all the quantitative and physiological parameters of sugarcane crop except tillers, millable canes, NAR and harvest index. As regards quality parameters, trench spacing did not significantly affect brix%, juice purity%, juice% and bagasse%, while different doses of Zn+Fe significantly affected all the qualitative traits except brix%. Crop planted at 120 cm spaced trenches and application of Zn+Fe @ 5.0+10.0 Kg ha -1 gave maximum stripped cane yield of 104.57 & 106.38 t ha -1 , respectively in 2007-08 and 112.78 & 110.38 t ha -1 during 2008-09. Maximum sugar yield (14.92 & 15.02 t ha -1 ) was measured by growing crop at 120 cm apart trenches and fertilized @ 5+10 Kg ha -1 of Zn+Fe, respectively during 2007-08 and 15.65 & 14.84 t ha -1 in the later year. Cumulative intercepted PAR increased with increase in trench spacing with linear trend, while in quadratic manner with the application of Zn+Fe. Higher benefit cost ratio of 1.52 and 1.75 during 2007-08 and 2008-09, respectively was achieved with foliar application of Zn+Fe @ 5+10 kg ha -1 on sugarcane crop sown at 120 cm apart trenches. Maximum marginal rate of return (463 and 463 %) was attained in crop grown at 120 cm spaced trenches with and without foliar application of zinc and iron during 2007-08, while in 2008-09, crop planted at 120 cm apart trenches without foliar application of Zn and Fe gave maximum marginal rate of return (525%). On an average, better NUE A of 884.0 and 707.7 Kg Kg -1 of Zn+Fe was recorded with the application of Zn+Fe @ 5+10 Kg ha -1 and 2.5+5 Kg Zn+Fe ha -1 , respectively. NUE P was also higher (109.8 kg g -1 of Zn+Fe) in the crop fertilized @ 5+10 Kg Zn+Fe ha -1 during 2007-08. On the basis of marginal rate of return it is recommended that the resource poor sugarcane growers of central Punjab (Pakistan) should grow sugarcane at 120 cm apart trenches without application of zinc and iron, while the progressive farmers may fertilize their crops with foliar application of Zn+Fe (5+10 kg ha -1 ) to get maximum net field benefits.