Effects of Organic Amendments on Cocoa Soil and Leaf Nutrient Contents

Abstract

Comparative effects of two organic soil amendments on soil and leaf nutrients composition were evaluated on cocoa seedlings planted in 10kg soils in plastic pots at Cocoa Research Institute of Nigeria Headquarters, Ibadan, South-west zone of Nigeria. The treatments consisted of Cocoa pod husk ash (CPHA) and oil palm bunch ash (OPBA) applied at 0, 0.005, 0.010, 0.015, 0.020 and 0.030gmN/ pot which were equivalent to 0, 1, 2, 3, 4 and 5kgNha^?1 and laid out in a completely randomized design (CRD) in three replicates. Prior to commencement of the study, a composite soil samples were collected, air dried, sieved to pass through a 2mm sieve and was analyzed for its chemical and physical properties. Two cocoa beans were sown per pot and later thinned to one per pot three weeks after emergence. Treatments were imposed on each of the pots one month after emergence. Watering was done twice throughout the period of the experiment. At harvest, soil and leaf samples were collected per treatment, processed and analyzed for leaf and soil nutrients contents. Results show that ash from CPHA and OPBA had a significant (p< 0.05) impact on soil N, P, K, Ca, Mg, organic matter and pH at 5kgNha^-1 . Results also reveal that CPHA and OPBA significantly improved leaf nutrients uptake relative to control treatments.

Keywords: cocoa pod husk ash, oil palm bunch ash, nutrient uptake, organic matter, ash