AGRICULTURAL RESEARCH COMMUNICATION CENTRE www.arccjournals.com/www.ijarjournal.com *Corresponding author’s e-mail: muthusamyprabhu@gmail.com Indian J. Agric. Res., 52 (3) 2018 : 290-294 Print ISSN:0367-8245 / Online ISSN:0976-058X Effect of intergrated nutrient management on acidlime [Citrus aurantifolia. Swingle (L.)] M. Prabhu*, S. Parthiban, A. Ramesh Kumar, B. Usha Rani and A. Vijayasamundeeswari Horticultural College and Research Institute, Tamil Nadu Agricultural University, Periyakulam-625 604, Tamil Nadu, India. Received: 10-01-2018 Accepted: 10-04-2018 DOI: 10.18805/IJARe.A-4978 ABSTRACT The nutritional need of acid lime is unique and differs from other fruit crops as it has continuous flowering and heavy fruiting habit. An experiment was conducted with the key objective of studying the effect of integrated nutrient management system on yield and quality of acid lime, variety PKM 1. In this study, application of 100 per cent recommended dose of fertilizers (600:200:300 g NPK plant -1 year -1 )+ Azospirillum (100g plant -1 ) + phosphobacteria (100g plant -1 ) + Arbuscular Mycorrizhal Fungi (500g plant -1 ) + Trichoderma harzianum (100g plant -1 ) has showed a superior performance regarding yield, yield attributing components and quality attributes of acidlime. INTRODUCTION India is the largest producer of acid lime in the world. The nutritional need of acid lime is unique and differs from other fruit crops as it has continuous flowering and heavy fruiting habit. Tandon (1987) studied the nutrient uptake and indicated that 30 t. ha -1 of citrus crop removed 100kg N, 60kg P 2 O 5 , 350kg K 2 O, 40kg MgO and 30kg S. In Tamil Nadu, the current nutritional recommendation for acid lime is 600:200:300 g NPK tree -1 year -1 applied in two split doses during the month of October and March. Indian soils are poor in organic matter as well as in nitrogen. Phosphorous deficiency is less wide spread while, potassium deficiency generally occurs in compact areas (Patnaik, 1987). In any crop nutrient management a sufficient quantity is more essential to ensure maximum productivity. The intensive agriculture calls for the heavy dependence on fertilizers and chemicals, which are not only costly but also cause soil and water pollution. It is therefore, necessary to supply the plant nutrition in an integrated way and to maintain the overall balance, flow of nutrients, better productivity, ecological health, economics and sustainability. Use of bio-fertilizers is now getting momentum as a part of nutrient management. Azospirillum, Phosphate Solubilizing Bacteria (PSB) and Arbuscular Mycorrhizal Fungi (AMF) are some of the popularly used bio-fertilizers. Bio-control agents have been employed in many crop species to control soil borne pathogens. Baker et al. (1984) found that Trichoderma viride can stimulate growth of plants by the production of growth hormones, enhancing nutrient uptake by the plant or by the control of one or more pathogens. The use of Trichoderma harzianum as a bio-control agent has been reported in acid lime (Ingle et al., 2004). With this background, an experiment was conducted with the key objective of studying the effect of integrated nutrient management system on yield and quality of acid lime, variety PKM 1. MATERIALS AND METHODS The experiment was conducted at Department of Fruit Crops, Horticultural College and Research Institute, TNAU, Periyakulam in acidlime variety PKM 1. The inorganic fertilizers viz., urea, single super phosphate and muriate of potash were used as source of nitrogen, phosphorous and potassium respectively. The experiment was laid out in randomized block design with five treatments replicated four times. Eight years old acid lime ‘PKM 1’ trees of uniform age, size and stature, spaced at 5 X 5 m were selected for the experiment. Four trees were selected for each treatment in each replication. The treatment details are as follows: Fifty per cent of recommended dose of fertilizers was applied as first split during October and the remaining dose as second split during the month of March. Bio- inoculants were mixed with 10 kg farm yard manure at the time of application. Bio-inoculants were applied in two split doses, twenty days after the application of inorganic fertilizers. The fruit set was recorded at pea stage and expressed in percentage. Number of fruit set Fruit set percentage = Total number of flowers Number iof fruits retained Fruit retention percentage = at harvest Number of fruits set X 100 X 100 Key words: Acid lime, Bio fertilizers, Nutrient management, Yield and quality.