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This study identifies the socio-economic factors that influences the use of organic fertilizer by oil palm nursery operators in the face of rising fertilizer prices in the markets. A sample of 80 nursery operators was randomly selected for data collection in two divisions of the Littoral region where the activity is prevalent. A Logit model was used to estimate and to isolate the variables affecting the use of the strategy. The results of the model show a correlation between socio-economic variables and the use of organic manure in the nursery for oil palm seedling production. Thus, variables such as, household size, access to market and access or not to training in setting up an oil palm nursery, are the factors that significantly influence the adoption of organic manure. In addition, sensitivity analysis of the probability of adoption with respect to explanatory variables shows that some socioeconomic variables have the strongest marginal effects. In addition, some variables positively affect the propensity to adopt the strategy, while others negatively affect the propensity. In a context of increase in fertilizer prices in the markets, a strong use of organic manure is necessary and strong actions must be implemented by the stakeholders. [ABSTRACT FROM AUTHOR]

The aim is to increase the mobile nutrient content in the soil by applying optimal nitrogen and potassium fertilizers without the use of phosphorus fertilizers on irrigated typical gray soils moderately supplied with mobile phosphorus. Significant differences are observed in the amount of mobile phosphorus in the soil from the beginning and till the end of the vegetation. It ranged between 24.28-27.15 mg / kg in the driving layer and between 15.20-19.05 mg / kg in the sub-driving layer. The amount of N-NO3 increased during the vegetation to 29.1-34.4 mg / kg in the driving layer, N-NH4 in the driving layer changed to 3.1-4.2 mg / kg. Exchangeable potassium was found to fluctuate between 148.72–177.82 mg / kg in the driving layer at the end of the vegetation period and varied between 179.2–182.75 mg / kg in the sub-driving layer.

Soil Characteristics Under Savanna and Natural Forest on the Bateke Plateau in the Democratic Republic of Congo. In order to develop a sustainable farming system adapted to the conditions of the Batéké plateau, a preliminary trial was conducted between January 2012 and March 2013 at the Ibi agro-forestry domain after a fallow of 10 years (the last three years without destruction of the vegetation by bush fires) in sandy soil according to a randomized complete block design with four replications. Five treatments were compared: the cassava sole cropping (Maribuata variety) with and without application of 40 kg N, 40 kg P2O5 and 40 kg K2O ha-1, cassava and maize (Samaru variety) intercropping with and without application of 40 kg N, 40 kg P2O5 and 40 kg K2O ha-1, and cassava and maize intercropping with application of 40 kg N, 40 kg P2O5, 40 kg K2O ha-1 and 15 t ha-1 of biochar. The results show that in the edaphic and climatic conditions of the test, the simultaneous installation of cassava and maize at the start of short rains provides a gross added value significantly higher than that of cassava sole cropping. The application of mineral fertilizers hardly improves the gross value added for cassava sole cropping while they however benefits to maize when it is associated with cassava in absence of biochar application. The combined application of mineral fertilizer and biochar make it possible to almost double cassava yield and triple the one of maize compared to the no-input control. Gross profit generated by the combination of cassava and maize with mineral fertilizers and biochar application is about twice higher than what is obtained for the control. The combined application of biochar and mineral fertilizer resulted in a significant increase in pH. This should have been accompanied by improved availability of Phosphorus, Calcium and Magnesium in the soil.

Effects of the Association of Compost and Mineral Fertilizer on the Productivity of Cotton and Maize Cropping System in Burkina Faso. To improve the productivity of a cotton - maize rotation using organic and mineral fertilization, a study was carried out in experimental station from 2008 to 2010. Five levels of compost (0, 2, 6, 9 and 12 t of dry matter ha­1) combined to four rate of mineral fertilizer were compared in split­plot statistical design. The physical and chemical characteristics of soil, crop yields, as well as the mineral nutrition of maize and cotton plants were evaluated. The results show that the content of assimilable P and available K was significantly improved in amended soils by compost which had no significant effect on the carbon content. In amended soils, compost improved plants nutrition which was correct in nitrogen and potassium for cotton and deficient in nitrogen and phosphorus for maize. Compared to control soil, compost combined to mineral fertilizers increased significantly yields with a better efficacy for the recommended mineral manure. The application of 2 t ha­1 of compost per year was as effective as high doses of compost in the second year, and more effective than the latter in the third year. An economy on the recommended dose of mineral fertilizer could be considered, with an annual input of 2 t ha­1 of compost to the mineral fertilizers necessary to maintain the productivity of the cotton­cereal cropping systems.

Crops Residues Management Effects on Crops Yields and Mineral Balance in a Cotton- Maize- Sorghum Rotation in Burkina Faso. The effect of crop residues management on crops yields and nutrients balances in a cotton-cereals cropping system was studied in a long-term experiment carried out from 1982 to 2006. The experimental design was a simple nonrandomized blocks comparing extensive management of crops residues (T1), semiintensive management of crops residues (T2) and intensive management of crops residues (T3). Crops yields, soil chemical properties and mineral balances were measured. Results showed that after 25 years, soil carbon contents decrease was respectively 44%, 15% and 13%, with an extensive, semi-intensive and intensive management of crops residues. Total phosphorus decrease was 25% in all the treatments. Exchangeable Ca and Mg declined from 2.43 to 1.37 cmol+ kg-1 and 0.9 to 0.29 cmol+ kg-1 respectively while the Sum of Exchangeable Bases declined from 3.79 to 1.79 cmol+ kg-1. Recycling crops residues to compost and manure increased cotton yields from 13 to 22 %, maize yields from 45 to 60 %, and sorghum yields from 19 to 44%. Mineral balance in N, P, K and S was improved after 25 years of continuous cultivation while using compost or manure. At the same time, the decline of soil properties was due to nutrients losses which need to be evaluated. This study recommends integrated crops residues management and the use of rock phosphate to improve sustainability in cottoncereals cropping systems.

This paper analyzes whether it is advantageous to use compost instead of mineral fertilizer for lettuce production in the Yaoundé urban and peri-urban areas. The field survey results show that, compost use leads to higher crop yields and profits. Results from the Cobb-Douglas production function prove that compost use is statistically significant in explaining the yield variation of lettuce and more importantly, compost is the most productive input. Further results show that, compost use leads to lower the crop's irrigation requirements and to improve the organic matter content of the soil. Thus, in spite that compost farms are more labour demanding, the use of compost agronomically provides a lot of benefits to farmers living in the areas surrounding Yaoundé. Therefore, programs of popularization of this input to encourage its adoption should be highlighted among the top priorities in the agricultural policy of the Cameroon's government.

In order to develop a sustainable farming system adapted to the conditions of the Batéké plateau, a preliminary trial was conducted between January 2012 and March 2013 at the Ibi agro-forestry domain after a fallow of 10 years (the last three years without destruction of the vegetation by bush fires) in sandy soil according to a randomized complete block design with four replications. Five treatments were compared: the cassava sole cropping (Maribuata variety) with and without application of 40 kg N, 40 kg P2O5 and 40 kg K2O ha-1, cassava and maize (Samaru variety) intercropping with and without application of 40 kg N, 40 kg P2O5 and 40 kg K2O ha-1, and cassava and maize intercropping with application of 40 kg N, 40 kg P2O5 40 kg K2O ha-1 and 15 t ha-1 of biochar. The results show that in the edaphic and climatic conditions of the test, the simultaneous installation of cassava and maize at the start of short rains provides a gross added value significantly higher than that of cassava sole cropping. The application of mineral fertilizers hardly improves the gross value added for cassava sole cropping while they however benefits to maize when it is associated with cassava in absence of biochar application. The combined application of mineral fertilizer and biochar make it possible to almost double cassava yield and triple the one of maize compared to the no-input control. Gross profit generated by the combination of cassava and maize with mineral fertilizers and biochar application is about twice higher than what is obtained for the control. The combined application of biochar and mineral fertilizer resulted in a significant increase in pH. This should have been accompanied by improved availability of Phosphorus, Calcium and Magnesium in the soil. [ABSTRACT FROM AUTHOR]

Un essai a été conduit de 1982 à 2006 dans l'objectif d'analyser les effets de la gestion des résidus de récolte sur les rendements et les bilans culturaux d'une rotation triennale coton-maïs-sorgho. Dans un dispositif expérimental en blocs simples non randomisés, la gestion extensive où les résidus sont exportés (T1) est comparée à la gestion semi-intensive (T2) et à la gestion intensive des résidus de récolte (T3) recyclés en compost et fumier, respectivement. Les rendements des cultures, l'évolution des propriétés chimiques du sol et les bilans culturaux ont été déterminés. Les résultats montrent que l'exploitation continue des terres affecte la plupart des caractéristiques chimiques du sol quelle que soit la gestion des résidus de récolte. Les teneurs en carbone ont baissé de 44%, 15% et 13% respectivement en gestion extensive (T1), gestion semi-intensive (T2) et gestion intensive (T3) des résidus de récolte. Le P total a chuté de 25% soit une perte annuelle de 1% sur tous les traitements. Avec l'exportation des résidus de récolte, les teneurs en Ca 2+ ont baissé de 2,43 à 1,37 cmol+ kg-1, celles en Mg 2+ de 0,9 à 0,29 cmol+ kg-1 ainsi que la Somme des Bases Echangeables qui est passée de 3,79 à 1,79 cmol+ kg-1 en 25 ans. Le recyclage des résidus de récolte en compost (T2) et en fumier (T3) augmente les rendements respectivement de 13 et 22% sur coton, 45 et 60% sur maïs, 19 et 44% sur sorgho. Les bilans culturaux en N, P, K et S sont positifs mais la baisse générale de la fertilité des sols met en évidence des pertes de nutriments dues à l'érosion qui mériteraient d'être évaluées. L'étude recommande une gestion intégrée des résidus de récolte et l'utilisation du phosphate naturel pour assurer la durabilité des systèmes de culture cotoncéréales.

Speciation within the African Coffee Pathogen. Cet article analyse s'il est avantageux d'utiliser le compost au lieu de l'engrais minéral pour produire la laitue dans la zone urbaine et péri-urbaine de Yaoundé. Les résultats de terrain montrent l'obtention de rendements et profits plus élevés lorsqu'on utilise le compost. Les résultats de la fonction de production Cobb-Douglas prouvent que l'utilisation du compost est statistiquement significative pour expliquer la variation de rendement de la laitue et que le compost est l'intrant le plus productif. D'autres résultats montrent que le compost fournit la matière organique utile au sol et que les besoins d'irrigation en eau de la culture sont réduits grâce à l'utilisation du compost. Par conséquent, malgré le fait que l'application du compost demande une main-d'oeuvre beaucoup plus élevée, son utilisation est généralement bénéfique pour les agriculteurs vivant aux alentours de Yaoundé. Les programmes de vulgarisation de cet intrant pour encourager son adoption devraient donc figurer parmi les points prioritaires dans la politique agricole du gouvernement camerounais.