Yield improvement of sulfur-deficient coconuts by gypsum (CaSO4.nH2O) application
1986
Margate, R.Z. | Padrones, G.D. (Philippine Coconut Authority, Bago-Oshiro, Davao City (Philippines). Davao Research Center)
A study to investigate the effect of CaSO4 on the yield of S-deficient coconuts and on the skirting disorder was conducted in 1982 to 1985. Increasing levels of CaSO4 (0, 0.75, 1.50, 2.25, 3.00 kg/tree/year) produced a significant linear response in nut production up to 2.25 kg per palm per year; quadratic up to 3.0 kg with an optimum rate of 2.5 kg producing 45 nuts per palm per year. The increases ranged from 48 to 64%. On copra weight per nut and per palm a linear response was noted giving increases of 6 to 16% and 47 to 79%, respectively. The most economical rate of 0.75 kg CaSO4 per palm per year produced the highest return of P1.02 per peso investment as against P0.74 from the control. The correction of S deficiency with CaSO4 application resulted to whiter and thicker copra as against rubbery and shrunken copra produced from the control. However, the same treatments did not correct the 'skirting' problems of the palms. Correlation analysis revealed that leaf-S was highly significantly correlated with all the three yield parameters while leaf-Ca and Mg were significantly correlated with nut yield and copra weight per palm. Sulfur accounted for 74.6, 35 and 63% contribution in the improvement of nut per palm, copra weight per nut and copra per palm, respectively. The application of CaS04 did not significantly affect the soil properties at the end of the experiment as well as the oil content of copra.
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