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P. VINOD KUMAR*, N. HARIPRASADA RAO AND B. PRASANNA KUMAR
Horticultural College and Research Institute, Venkataramannagudem Dr YSR Horticultural University, VR Gudem, West Godavari Dist., Andhra Pradesh.
A study on Palak (Beta vulgaris var. bengalensis Hort.) was carried out during rabi season, 2010-2011 at college farm of Horticulture College and Research Institute, Venkataramannagudem, West Godavari district, Andhra Pradesh, to determine the Studies on the effect of integrated nutrient management practices on dry matter production and nutrient uptake”. It revealed that the highest dry matter production (5395 kg ha-1) and nutrient uptake of nitrogen, phosphorus and potassium (102.81,18.06 and 98.667 kg ha-1) was recorded with the application of 100% RDF through inorganic (80:40:50 kg of NPK ha-1) and was on par with the dosage of 75% RDF through inorganic fertilizers + 25% recommended dose of nitrogen through poultry manure and 75% RDF through inorganic fertilizers + 25% recommended dose of nitrogen through vermicompost.
Palak, Dry matter and Nutrient uptake
Palak (Beta vulgaris var. bengalensis Hort.) belonging to the family Chenopodiaceae is the most popular leafy vegetables with good nutritive value. It is a commonly grown leafy vegetable throughout the tropical and subtropical regions (Veeraragavathatham, 1998) for its tender succulent leaf and petiole and it is a cheap and rich source of Vitamin-A which helps in improving the eyesight. It is also a good source of Vitamin-C and mineral elements like iron, calcium, phosphorus and amino acids. In India, farm yard manure (FYM) remains as the most popular organic manure applied to fields and it can potentially supply about 6.8 million tons of N, P and K per year (Sarkar and Rattan, 1995) . Bio-fertilizers and organic manures together can make significant contribution in maintaining soil health and balancing soil fertility through supply of plant nutrients at an optimum level. However, application of organic manures alone is not adequate to meet the nutrient demand of the recent high yielding varieties of crops because of their scarce availability, low nutrient content and slow nutrient releasing nature. Improved varieties require higher amount of nutrients to reap higher yields, but continuous usage of chemical fertilizers without any or little addition of organic manures may not sustain the soil fertility. The
problem of nutrient depletion is being further aggravated with the decreasing availability and consequent low rates of application of organic manures. Therefore, combined use of chemical, organic manures and bio-fertilizers seems to be the only way out to replenish the soil nutrient reserve. In this context, Integrated Nutrient Management (INM) holds a great response in meeting the growing nutrient demands of intensive agriculture and maintaining crop productivity at fairly high level. The conjunctive use of organic and inorganic sources will improve soil health and help in maximizing production as it involves utilization of local resources and hence turned out to be rational, realistic, eco-friendly and economically viable way of supply of nutrients to the crops.
The field experiment was laid out in a randomized block design with three replications during rabi, 2010-2011 at College Farm of Horticulture College and Research Institute, Venkataramannagudem, West Godavari district, Andhra Pradesh on red sandy loam soil. The studies were carried out using palak cv Arka Anupama with 11 treatments viz., 75% RDF + 25% RDN through VC (T1), 75% RDF + 25% RDN through FYM (T2), 75% RDF +25% RDN through PM (T3), 50% RDF + 50% RDN through VC (T4), 50% RDF + 50% RDN through FYM (T5), 50% RDF + 50% RDN through PM (T6), 25% RDF + 75% RDN through VC (T7), 25% RDF + 75% RDN through FYM (T8), 25% RDF + 75% RDN through PM (T9), 100% RDF through organic (33%VC, 33% FYM and 33%PM) (T10) and 100% through RDF (80:40:50 kg of NPK ha-1). A common application of bio-fertilizers (Azospirllum@ 5 kg ha-1 and PSB @ 2 kg ha-1) was given to all treatments. Total quantity of vermicompost, farm yard manure and poultry manure along with bio-fertilizers were applied to the soil as a basal dose as per the treatments. Dosages of different organic manures were arrived to meet the recommended dose of nitrogen as per the available nitrogen content in the respective organic manures. The inorganic source of nitrogen was applied in four equal splits in the form of urea as a basal dose (1/4th of the total nitrogen) and remaining thee splits were applied after each leaf cutting. The inorganic source of phosphorus and potassium were applied as a basal dose only in the form of single super phosphate and muriate of potash respectively. The seeds were sown at a spacing of 20 cm between rows and 10 cm within the row. To determine the dry matter production, the samples were dried in hot air oven at 60±2°C temperature till constant weights were obtained. The dry matter was worked out from the dried leaf samples and expressed in kg ha-1. The available NPK was estimated through nitrogen by Micro-Kjeldahl distillation method, phosphorus by Colorimetric phosphor-Vando Molybdate method and potassium by Flame photometer method in the dried leaf samples of palak respectively. The uptake of nutrients was computed by using the following formulae.
Uptake of nutrient (kg ha-1) =Percentag of nutrient × Total drymatter in kg ha −1 100
The data were analyzed statistically applying the analysis of variance procedures for Randomized Block Design as stated by Panse and Sukhatme, (1967).
The experiment conducted on the effect of integrated nutrient management practices on dry matter production and nutrient uptake of major nutrients of N, P and K in palak revealed that the application of 100% RDF through inorganic sources @ 80:40:50 kg of NPK ha-1 recorded the highest total production (Table 1) (5395.00 kg ha-1)
which was significantly superior to all other treatments. This was followed by 75% RDF through inorganic fertilizers + 25% RD of nitrogen through poultry manure 5298.88 kg ha-1 and the treatment dose of 75% RDF through inorganic fertilizers + 25% RD of nitrogen through vermicompost (5222.77 kg ha-1) and they were significantly superior to rest of the treatments. The lowest total dry matter production (3517.77 kg ha-1) was recorded with 100% RD of nutrients supplied through organic manures. This could be attributed to increased plant height, number of leaves and higher leaf area during the crop growth period in respective treatment doses. These factors might have contributed more to the photosynthetic leaf surface area, higher carbohydrate assimilation with better supply of nutrients and the inadequate availability of nitrogen due to its slow release from organic manures might have resulted in shorter plants and reduced leaf area which has ultimately resulted in reduced photosynthetic efficiency and crop growth leading to low dry matter production as conformed by Vachani and Patel 7(1993) and Raghava Rao (2003) in onion.
The nutrient uptake is a positive function of dry matter yield (Ramakal et al. 1988). The highest N, P and K uptake @ 102.81, 18.06, and 98.67 kg ha-1 and dry matter production respectively was recorded with 100% RDF through inorganic (5395.00 kg ha-1) which was significantly superior to all other treatments but was on par with 75% RDF through inorganic fertilizers + 25% RD of nitrogen through poultry manure (5298.88 kg ha-1). The lowest N, P and K uptake at harvest was observed with 100% nitrogen through organic sources along with bio-fertilizers application (Table 2). The increased N, P, and K uptake resulted in increased dry matter yield and the lowest N, P, and K uptake in 100% organic sources of nutrients resulted in the decreased dry matter yield. This is in consonance with the findings of Mallangouda et al. (1995) in onion and Prabakaran (2003) in tomato. The uptake of N P K was higher with poultry manure because of higher nutritive value in respect to major nutrients and also the improvement of soil condition by the organic manure. Similar results were reported by Raghava Rao, (2003) in garlic.
