Studies on foliar diagnosis, yield and quality of Tapioca (Manihot utilissima Pohl.) in relation to nitrogen and phosphorus

Abstract

An investigation was carried out at the Agricultural College and Research Institute, Vellayani during the year 1966-68 to evolve a suitable diagnostic technique for the nutritional status of nitrogen and phosphorus in two varieties of tapioca (M-4 and H-105) by foliar analysis. The response of the two varieties to graded doses of nitrogen (0.75 and 150 kg. N/ha.) and phosphorus (0.50 and 100 kg. P2O5/ha.) and their interaction in relation to the pattern of uptake, yield and quality of tubers were also investigated. Potassium and calcium were kept constant at 250 kg and 1200 kg. per hectare respectively. A split - plot experiment in R.B.D. with three levels each of nitrogen and phosphorus in factorial combinations as major treatments and with the two varieties as minor treatments, was laid out. Leaf leminae and peticles each grouped into three morphological categories. were used for testing the suitability for the diagnostic analysis. The plant part thus standardised (reflect) was analysed at three stages of growth for nutrient content. Biometric observations were recorded at three stages of growth. Yield components and quality factors of tuber were assessed in relation to nutrition of the plants.