Evaluation of deterioration index in soil nutrients due to cultivation of different cocoa species in southwest Nigeria

The study uses the index of soil deterioration to evaluate the soil nutrient status as a result of cultivating different species of cocoa in Idanre, Odigbo and Owo areas of Southwest Nigeria. Soil samples were randomly taken and analyzed using standard methods. The results indicated variation in soil properties under both species due to the difference in nutrient uptake. Results also show that soil properties deteriorate more under hybrid than on indigenous cocoa plantations. Amongst the nutrients, phosphorus had the highest rate of increase for indigenous than hybrid cocoa plantations. Average weight of cocoa pod ranges from 0.50 to 0.60kg in indigenous and 0.56 to 0.85kg in hybrid species. Removal of the nutrients is directly linked to the rapid development of the hybrid species, their weight and size as opposed to the indigenous species. The study recommends seasonal relocation of podhusk deposit sites and spread of accumulated podhusk across the farm, application of chemical and podhusk fertilizer, and development of cocoa variety with low soil fertility tolerance.Keywords: Cocoa, hybrid, indigenous, specie

Evaluation of the Capacity of Agroforestry of Cocoa Trees in Atmospheric Carbon Dioxide Reduction

The emission of greenhouse gases into the earth’s atmosphere has been credited as the major cause of climate change which is being experienced all over the world. Climate change mitigation is one of the strategies that have been suggested as a way of stabilising  the concentration of greenhouse gases in the atmosphere. This study assessed the capacity of agroforestry of cocoa trees in reducing atmospheric carbon dioxide. The carbon content in the cocoa plant variables made up of bean, litter, leaf and podhusk were determined in the laboratory through standard procedure. The laboratory results were subjected to descriptive and inferential statistical techniques. The study showed the magnitude order of carbon storage in cocoa agroforestry as cocoa bean (2.86 kg) > pod husk (2.73 kg) > cocoa litter (2.65kg) > cocoa leaves (2.62 kg) > soil (1.14 kg)..The ability of cocoa and forest soils to retain nitrogen, leaf and litterfall to stock more carbon proved that cocoa agroforestry has a higher potential of mitigating climate change in the tropical region. The study recommended the adoption of agroforestry systems which are capable of sequestering carbon as a means of addressing the challenge of climate change

Weather variability in derived savannah and rainforest agroecologies in Nigeria: Implications for crop yields and food security

Weather variability and its effects on agricultural and food systems are burgeoning global concerns. This study examined the effects of weather variability in the derived savannah and rainforest agroecologies, on crop yields in Southwest Nigeria, and what it portends for food and nutrition security in the region. The trends in the distribution of rainfall and temperature were analysed using the Sens method. The effects of weather variability on crop yield and inferences on what it portends for food security were determined using a stepwise regression model. The results revealed that rainfall fluctuations decreased the yields of cassava ( Manihot esculenta ) and yam (Dioscorea spp.) in the derived savannah; while a decrease in temperature may support improved yields for maize ( Zea mays ), sorghum ( Sorghum bicolor ) and cowpea ( Vigna unguiculata ). The increase in yields of cocoa ( Theobroma cacao ) and cocoyam ( Colocasia esculenta ) would be hampered by increasing maximum temperatures in the rainforest agroecology. Increasing rainfall and temperature would impact warmer conditions that support rapid crop putrefaction, flooding, droughts, challenging postharvest crop management, pest and disease proliferation, and ultimately, reduced crop yields. On the other hand, perpetually low rainfall and temperature conditions will cause poor seedling emergence and growth, seed and total crop loss. It is, therefore, imperative that effective climate adaptation and mitigation mechanisms be put in place across the agroecologies in the region.La variabilit\ue9 m\ue9t\ue9orologique et ses effets sur les syst\ue8mes agricoles et alimentaires sont des pr\ue9occupations mondiales en plein essor. Cette \ue9tude a examin\ue9 les effets de la variabilit\ue9 m\ue9t\ue9orologique dans les agro\ue9cologies d\ue9riv\ue9es de la savane et de la for\ueat tropicale humide sur les rendements des cultures dans le sud-ouest du Nigeria, et ce qu\u2019elle pr\ue9sage pour la s\ue9curit\ue9 alimentaire et nutritionnelle dans la r\ue9gion. La tendance de la distribution des pr\ue9cipitations et de la temp\ue9rature a \ue9t\ue9 analys\ue9e \ue0 l\u2019aide de la m\ue9thode Sens. Les effets de la variabilit\ue9 m\ue9t\ue9orologique sur le rendement des cultures et les d\ue9ductions sur ce qu\u2019elle pr\ue9sage pour la s\ue9curit\ue9 alimentaire ont \ue9t\ue9 d\ue9termin\ue9s \ue0 l\u2019aide d\u2019un mod\ue8le de r\ue9gression progressive. Les r\ue9sultats ont r\ue9v\ue9l\ue9 que les fluctuations des pr\ue9cipitations diminuaient les rendements du manioc ( Manihot esculenta ) et de l\u2019igname (Dioscorea spp.) dans la savane d\ue9riv\ue9e ; tandis qu\u2019une diminution de la temp\ue9rature pourrait favoriser l\u2019am\ue9lioration des rendements du ma\uefs ( Zea mays ), du sorgho ( Sorghum bicolor ) et du ni\ue9b\ue9 ( Vigna unguiculata ). L\u2019augmentation des rendements du cacao ( Theobroma cacao ) et du cocoyam ( Colocasia esculenta ) serait entrav\ue9e par l\u2019augmentation des temp\ue9ratures maximales dans l\u2019agro\ue9cologie de la for\ueat tropicale. L\u2019augmentation des pr\ue9cipitations et de la temp\ue9rature aurait un impact sur des conditions plus chaudes qui favorisent la putr\ue9faction rapide des cultures, les inondations, les s\ue9cheresses, la gestion des cultures post-r\ue9colte difficile, la prolif\ue9ration des ravageurs et des maladies et, en fin de compte, la r\ue9duction des rendements des cultures. D\u2019autre part, les pr\ue9cipitations et les conditions de temp\ue9rature perp\ue9tuellement basses entra\ueeneront une mauvaise \ue9mergence et croissance des semis, des semis et une perte totale de r\ue9colte. Il est donc imp\ue9ratif que des m\ue9canismes efficaces d\u2019adaptation et d\u2019att\ue9nuation du climat soient mis en place dans les agro\ue9cologies de la r\ue9gion