Nutrient Status of the soil and plant as influenced by spacing and continued manuring in Coconut

Abstract

A study was conducted during 1995-96 at Coconut Research Station, Balaramapuram of Kerala Agricultural University to asses the nutrient status of . the soil and plant in West Coast Tall coconuts planted at three different spacings and manured with three levels of macro nutrients. The treatments were three spacings (5 m x 5 m, 7.5 m x 7.5 m and 10 m x 10 m) and three fertilizer levels (control i.e., zero NPK, the lower level i.e., 340 g N + 225 g P205 + 450 g K20 per palm per year and the higher level i.e., 680 g N + 450 g P205 + 900 g K20 per palm per year). The basic experiment was started in 1964 and being continued. The data collected during the study (1995-96) was statistically analysed and the results are presented here under. Closer spacing increased height of palms. The spacings of7.5 m x 7.5 m was statistically superior since it gave the highest nut yield per palm per year. Manuring increased height of palms, girth and leaf production. At the highest level of NPK closer spacing of 5 m x 5 m could give the highest yield per unit area. Female flower production was higher under 7.5 m x 7.5 m spacing. Fertilizer application also increased flower production. Fruit setting was not influenced by palm density and fertilizer application significantly increased fruit setting. Number of nuts per bunch was higher at the spacing of 7.5 m x 7.5 m and progressively increased with manuring. The weight and volume of unhusked nut was the lowest at the closest spacing and in unfertilized palms.

There was increase in weight of husk with increase in spacing. Similarly there was an increase in the ratio of weight of husk to unhusked nut with increasing spacing. Maximum thickness and weight of kernal was recorded at the spacing of 7.5 m x 7.5 m. Copra out turn was more at the spacing of 7.5 m x 7.5 m. In manured palms there was a higher copra out turn per hectare contributed by the higher yield. The oil content of copra was negatively correlated with per palm yield. Available NPK of soil decrease with wider spacing. The soil nutrient status increased with application of macronutrients and the accumulation of fertilizer was more in the upper layer of 0 to 25 cm. There was decline in NPK status with increase in depth. The Ca and Mg content of soil decreased with increase in spacing up to 7.5 m x 7.5 m. Both Ca and Mg content of soil decreased with increase in macro nutrient application. Ca content of soil decreased with increase in depth. However, the decrease of Mg content was seen only up to 50 cm depth. Available micro nutrients (Fe, Cu, Mn and Zn) decreased with increase in spacing and application of fertilizers. Available Fe, Cu and Mn content of soil decreased with increase in depth. Nand P content of leaf of coconut increased with wider spacing. However K content decreased with spacing. All the three macro nutrients increased with increase in fertilizer application. Ca and Mg content of leaf also increased with increase in spacing and fertilizer application. By fertilizer application Fe, Mn and Cu content of leaf increased whereas Zn and Na decreased.