Response of Upper Amazon Hybrid bulk cocoa to N, P, and K fertilizers on latosol

Since Djatirunggo clones were selected from hybrids of spontaneous crossings between Venezuelan forastero and local Criollo, commercial estates in Indonesia used to grow these trinitario types. In the early seventies, however, attracted by its early maturing habit and its high yield potential, there was a growing interest to plant Upper Amazon Hybrids. Not much, however, was known about the growth and yield performance of this forastero type especially on acid soils. Related to this problem a 3 exponent 3 N, P, K, factorial experimental was conducted at Sumerbarang division of Wangunreja estate, PTP XIII, West Java. The soil was an acid and poor latosol which had a high total P2O5 content and a high clay content of 72.3 percent. The clay texture suggested a high phosphorus fixing capacity. The test plants were from an F2 Upper Amazon Hybrid population, the F1 of which had undergone further selection. Each plot consisted of 60 experimental trees surrounded by 36 border trees with a planting distance of 2 m by 4 m. The permanent shade came from Leucaena L2 trees. The fertilizer dose rates for the first application were 0 - 35 - 70 g of Urea/tree, 0 - 35 -70 g TSP/tree and 0 - 30 - 60 g KCl/tree which every six months were increased with the same three rates. This experiment was aimed at determinig the N, P and K levels for growth and yield. Plant height, stem length and stem girth were measured, soil and leaves analysed and the effect of fertilizers on fruiting recorded. Soil analysis data show positive effects of Urea on organic-C, total N and Mg cation content. TSP influenced positively a wide range of soil chemical characteristics but had a negative effect on soil-K. Muriate of Potash only increased the soil-K. The extremely high total P2O5, K2O and CaO after six treatments was due to the fact that the soil samples were taken from the application sites. Foliar analysis show sub-normal N and K levels and a deficient P level in 1983 while in 1984 the N level became normal. The P and K levels, however, were still below normal. The effect of fertilizers on leaf nutrients was limited to TSP on leaf-P. Growth figures show a positive effect of Urea and TSP either at the second level or at the third level, as well as at both levels. KCl did not exert any influence what so ever on growth. From the results of this experiment the following could be concluded: 1. The F2 population of Upper Amazon Hybrids responded well to nitrogen and phosphate fertilizers at the latosol of Sumurbarang. The second levels of N and P seemed to be adequate, therefore the N1 and P1 scheme in this experiment could be recommended. 2. As long as the leaf-K content is around 2 percent application of K fertilizers could be delayed till the end of the immature period.

Bibliographic Details

Main Authors:	42973 Angkapradipta, P., 130648 Warsito, T., 99934 Nurdin, M.S.
Format:	biblioteca
Published:	1988
Subjects:	THEOBROMA CACAO, HIBRIDOS, CLONES DEL ALTO AMAZONAS, FERTILIZANTES NPK, ETAPAS DE DESARROLLO DE LA PLANTA, DOSIS DE APLICACION, FERRALSOLES, INDONESIA,
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