Potentials of cocoa pod husk-based compost on Phytophthora pod rot disease suppression, soil fertility, and Theobroma cacao L. growth

Abstract

Cocoa black pod disease caused by Phytophthora megakarya and reduced soil fertility are major constraints to cocoa production resulting in high yield losses. In the absence of effective control measures and constraints related to the use of chemical fungicides and fertilizers, there is a need to develop additional and sustainable disease and fertilization management strategies. With the lack of studies related to the use of compost in cocoa cultivation, the present study aims to evaluate the potential of cocoa pod husk (CPH)-based compost as a soil amendment to reduce the severity of cocoa black pod disease and enhance plant growth. In vitro antagonism test showed that compost water extracts (CWE) reduced mycelial growth with inhibition rate reaching 100% associated with microorganisms. Disease score of cocoa plantlets grown on compost-amended soils significantly reduced compared to plantlets grown on non-amended soil (control). All compost rates tested significantly increased populations of actinomycetes and fungi and biological activity in the soil. Compost application increased soil pH and majority of the essential elements but decreased Al content, which is toxic to cocoa growth in acidic soils. Soil application of compost at the dose of 20% (v/v) significantly increased stem length and number of leaves compared to the control. This study shows that CPH-based compost can not only improve soil fertility and cocoa growth but also reduce cocoa black pod disease severity by direct effects on inoculums level in the soil and by inducing resistance in the plant.

Maternal environment alters dead pericarp biochemical properties of the desert annual plant Anastatica hierochuntica L.

“…This includes beneficial substances in DOEEs that can increase food and feed quality, seeds as a fundamental agricultural entity where DOEEs can improve germination rate and capacity and confer seedling vigor as well as seeds as the basic element for conservation of genetic resources in gene banks where DOEEs can increase viability and germination capacity under storage condition. Finally, we have to take into consideration that the effect exerted by climate change on plant biodiversity and population dynamics can be mediated, at least partly, through the effect on DOEE properties, which in turn impact seed performance (including persistence in the soil and germination) and fate, soil microbiota and soil fertility [ 80 – 82 ].…”

Dead but Not Dead End: Multifunctional Role of Dead Organs Enclosing Embryos in Seed Biology

“…Stress conditions that are expected to increase in severity, over large areas of the world, due to climate change not only modify the embryo properties but also the properties of the DOEEs, which in turn impact seed performance and fate, soil properties, and consequently plant population dynamics and diversity [78,87,88].…”

Integrated Soil Fertility Management for Small Holder Cocoa Farms: Using Combination of Cocoa Pod Husk Based Compost and Mineral Fertilizers

“…Compost plus NPK fertilization significantly reduced black pod losses compared to sole compost, NPK, and control ( [38]. The observed inhibition of mycelial growth of the pathogen by CWE will limit the production of sporangia and zoospores that germinate from mycelium, which is a principal source of the inoculum.…”

“…The observed inhibition of mycelial growth of the pathogen by CWE will limit the production of sporangia and zoospores that germinate from mycelium, which is a principal source of the inoculum. Thus, the reduction of primary and secondary inoculum will result in the reduction of the disease incidence and severity [38]. The inhibition of cocoa pod disease pathogen has been attributed to the antagonistic effects of beneficial microorganisms [39,40] and chemical composition of the organic materials [41].…”