Indian Journal of Plant Physiology

An experiment was carried out at the research farm of the Department of Soil Science, CSKHPKV, Palampur during Rabi 2006 to study the effect of organic manures and chemical fertilizers on quality and productivity of potato. The experimental soil was silty clay loam in texture, acidic in reaction (pH 5.8), high in organic carbon, low in available N and medium in available P and K. Fourteen treatment combinations comprising vermicompost or farmyard manure alone, 100% NPK (120:35:50 kg/ha) alone, conjoint use of vermicompost or farmyard manure and chemical fertilizers and absolute control were laid out in randomized block design with 3 replications. Highest contents of starch (13.20%), protein (10.94%), ascorbic acid (24.36 mg/100g), N (1.75%), P (0.290%), K (1.21%), Fe (161.46 ppm), Mn (50.98 ppm), Zn (29.83 ppm) and Cu (12.53 ppm) were recorded in the treatment comprising 100% NPK + 25 tonnes vermicompost/ha. The results demonstrated that conjoint application of chemical fertilizers and organic manures recorded significantly higher contents of different quality parameters than sole use of inorganic fertilizers. The contents of biochemical components namely starch, protein and ascorbic acid under 100% NPK + 25 tonnes vermicompost/ha were higher by 15.8, 12.5 and 8.3% over 100% NPK and the corresponding increase in case of mineral constituents viz. N, P, K, Mn, Zn and Cu were 15.9, 8.6, 15.2, 59.9, 22.2, 24.2, 8.2%. Furthermore, the contents of ascorbic acid were higher under the treatments involving organics and even sole use of organics recorded higher ascorbic acid contents than 100% NPK alone. Application of 100% NPK + 25 tonnes vermicompost/ha recorded 42.4% higher tuber yield than 100% NPK alone. The results suggested that integrated use of vermicompost along with inorganic fertilizers is an important nutrient management option of improving the quality and productivity of potato.