Impact of Cocoa Pod Husk-Based Composts on Okra (Abelmoschus esculentus (L.) Yield and Soil Chemical Properties in South Western Nigeria

Abstract

Cocoa pod husk (CPH) could be used to prepare composts which enhance soil fertility
and crop yield. Therefore, this study investigated the influence of CPH-based composts
on the yield of okra and soil chemical properties of Alfisol and Ultisol in south western
Nigeria. The treatments applied comprised three CPH-based compost: CPH+ Neem leaf
(CPH+ NL), CPH+ Poultry manure (CPH+ PM) and CPH+ PM + NL. The results were
compared with soils treated with NPK 15-15-15 and a control that received neither NPK
nor compost using two varieties of okra (NH47-4 and LD88) as test crops. The
treatments were replicated three times in a randomized complete block design.
Residual effects of the treatments were also observed. Pre- and post-cropping soil
analyses were carried out. Data collected were subjected to statistical analysis using
analysis of variance (ANOVA) with the means separated by Duncan multiple range test
(DMRT). There was significant (p<0.05) difference in the fruit yield (FY) of okra with
composts and NPK in both locations. On Alfisol, CPH + PM +NL produced the highest
FY (4.80 t/ha) which was significantly higher than the other treatments. On Ultisol,
CPH +PM + NL produced the highest FY (4.81 t/ha), however, there was no significant
difference in the FY obtained from CPH+PM and NPK (3.88 and 3.78 t/ha
respectively).The control produced the lowest yield on Alfisol and Ultisol (1.78 and
1.70 t/ha respectively). Residual effect of fertilizer was significant in both locations,
CPH+PM+NL significantly produce the highest FY (3.53 and 3.48 t/ha respectively)
on Alfisol and Ultisol. Variety LD88 produced FY (3.78 and 3.6 t/ha respectively) that
was significantly higher than NH47-4 (3.7 and 3.48 t/ha respectively) in Alfisol and
Ultisol in the main planting, however there was no significant difference between the
varieties during the residual planting. The CPH-compost also improved the soil pH, N
P, K, Ca and Organic Carbon (OC) content after the main and residual cropping in both
Alfisol and Ultisol compared to the control and NPK treatments because the values
obtained were higher than the initial soil test values. It was evident that CPH+PM+NL
had significant impacts in improving soil fertility and okra yields in the selected soils.