Nutritional charecteristic in relation to growth and productivity of cashew (Anacardium occidentale L.)

Abstract

Three field experiments and one green house study were conducted at Cashew Research Station (CRS), Madakkathara, Thrissur, Kerala during 1997 -99 with the objective to study the response of graft raised cashew to varying levels of nutrient regimes and to assess the variation in leaf nutrient status in relation to nutrient regimes and to develop yield prediction model based on tissue nutrient status; to study the varietal variation in tissue nutrient status of eighteen promising varieties in relation to yield; to assess the effect of lime and Mg S04 on the growth and productivity of cashew in late rite soils; to develop a nutritional strategy in the cashew nursery for the production of healthy root stocks. Exp. I Influence of nursery technique on growth of cashew root stocks a) Effect of potting media and nutrient supplements b) Effect of lime incorporation in potting media A study was also carried out to standardize a nutrient management strategy in the nursery to produce vigorous root stock. Three different potting media (soil, sand and FYM in 1: 1: 1; soil and FYM in 1: 1; soil and sand in 1: 1 ratio) and four nutrient supplements (control, 100 g N; 200 g N + 100 g PZ05; 200 g N, 100 g PZ05 and 200 g KzO 100 kg-1 potting media) in a factorial combination. The potting media containing 1: 1 soil : FYM mixture supplemented with 200 g N, 100 g PZ05, 200 g KzO per 100 kg potting media is best for producing good quality cashew seedlings. Investigation conducted to study the effect of incorporation of lime in potting media at different levels varying from 0 to 500 g 100 kg-1 potting media revealed that the response of cashew seedlings to the application of lime was limited.

Exp. 11 Effect of soil nutrient regimes on leaf nutrient status and yield of graft raised cashew This study involving four nutrient reqirnes - namely, 375:165:375; 750:325:750; 1125:390:1125 and 1500:650:1500 g N, P20S and K20 tree-1 year" and an absolute control was conducted for three years on graft raised cashew variety Madakkathara-1. Flower production and yield characters were significantly influenced up to a level of 750:325:750 g NPK tree-1 year" .The chlorophyll a and b was highest both at flushing and flowering stages with the application of 750:325:750 g NPK tree-1 year". At pre- flushing and pre-flowering stages, Nand K concentration in leaf, the total uptake of N and K, the highest nut yield as well as kernel yield was highest with the application of 750:325:750 g NPK tree" year". Exp. III Effect of soil application of lime and magnesium sulphate on growth and productivity of graft raised cashew Investigation was carried out on five year old cashew grafts of variety Madakkathara-1, to study the effect of application of lime and MgS04 at four levels each (0, 500, 1000 and 1500 g tree" year") in a factorial combination on growth and productivity of cashew. The results showed that primary factors regulating the productivity of cashew was the number of flushes per unit area and application 500 g lime and 1500 g MgS04 has registered 85 per' cent reproductive flushes. Application of 1500 g lime and 1000 g MgS04 increased bisexual flowers, nut panicle" and nut weight. Increase in the contents of N, P and K was associated with decrease in the contents of Fe, Mn, Zn and Cu, which explains the fact that these micronutrients restricted the uptake of primary elements.

Exp. IV Varietal variation in leaf nutrient status and its relation with nut yield Among the 18 varieties tested in the varietal evaluation trial, three varieties namely V-5 and V-4 (Vengurla selections) and M-26/2 (Vridhachalam selection) were found to be promising in terms of nut yield, the most important commercial criteria in cashew. In most of the parameters related to yield, the above varieties were found comparatively better. Photosynthetic efficiency measured in terms of leaf chlorophyll content was also higher in these varieties. Leaf nutrient concentration (N and K) was also comparatively high in the high yielders.