Effects of moisture stress on growth and nutrient uptake in cacao seedlings

Abstract

The effects of four moisture stress regimes on plant growth and uptake of nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca) were studied in 3- month-old seedlings of three cacao cultivars grown in plastic pots under glass-house conditions. The objective was to determine watering regimes that favoured vigorous growth of the seedlings. The experiment was a 3 × 4 factorial in a randomised complete block design with three replicates. The moisture stress treatments studied were watering to pot capacity daily, watering to pot capacity on every 4th day, watering to pot capacity on every 8th day and watering to pot capacity only when plants showed signs of wilting (10-12 days intervals). The moisture stress treatments were applied for 12 weeks. Increasing levels of moisture stress resulted in decreased seedling growth rate, reduced relative water content (RWC), and increased level of leaf scorching. It also resulted in decreasing amounts of N, P, K, Ca and Mg (mg g-1) in leaves and stem. Cacao cultivar PA7 was more susceptible to moisture stress than UIT1 and SCA12 in that order. The interaction effects of cultivar and moisture stress treatment on seedling growth and nutrient uptake were not significant. Results of this study suggest that cacao seedlings raised in the nursery may be watered to pot capacity daily for healthier growth and development.

Ghana Journal of Agricultural Science Vol. 38, 2005: 55-64