This study aimed to get information on the cultivation of sweet pepper from the North West Region of Cameroon (Foumbot).  Data for the study were obtained from 92 farmers with the aid of well-structured questionnaires. Results obtained showed that among the sweet pepper farmers, males represented 80% of the sampled population and women 12%, all of them aged between 18 to 48 years old. Their level of education varies from primary school to University with the majority found between primary school (48%) and secondary school (30%).  41% of the sampled cultivators have the greatest level of experience in between 10 to 30 years and 52% with the lowest level of experience varying from 1 to 10 years. The sweetest pepper varieties cultivated was Yolo wonder and Simba. 89 % of respondents had a sweet pepper field with a surface area between 0.5 and 1 hectare.  According to farmers, the nursery is usually attacked by fungi after one week of growth, which always cause stems rot.  Fungicides (Mancostar 80WP) and insecticides (Mocap EC, Timik, Plantineb 80WP, Jumper and Ascot) are the most chemical products used to treat stems rot. Cypermethrin and Mancozeb represent respectively 63% and 85% of active ingredients used by the sampled growers to fight against sweet pepper diseases.  46 % of the sampled farmers said that they prefer spray pesticides in all stages while 44% of sweet pepper farmers did not take note of the number of times, they applied chemicals pesticides on their crops. NPK: 20.10.10 is the most chemical fertilizer used to grow sweet pepper. The major diseases and pests encountered in that region are (1) diseases: Mildew, cercospora leaf spot, phytophthora blight, fusarium wilt, anthracnose, ripe rot, tobacco mosaic virus, cucumber mosaic virus, and gal formations; (2) pests: flee beetles, cutworms, aphids, vegetable weevil, caterpillars, grasshoppers, pepper maggots and leaf miners.

The aim of this work was to study the effect of Cymbopogon citratus extract on nitrogen metabolism in relation to the increase of Nitrogen Use efficiency (NUE) in tomato plants. The culture substrates (δ) were prepared with fertilizations of 15g N and 5g N following the formula: δ + tomato plants + treatments (2%). Treatments included, Hydro Ethanol Extract (HEE) of C. citratus (2%), 2% Ridomil (R) and Control (C). The tomato seedlings were transplanted 32 days after sowing and (δ) sampled 12th, 24th, 36th and 48th days after transplanting and the following parameters determined: Total nitrogen, Electrical Conductivity (EC (dS/m)), Total Mineral content (TM (ppm)), pH water, nitrate (NO3-(ppm)), ammonium (NH4+ (ppm)) and NUE (kg -1 DM), using these techniques: Kjedahl, Electrochemistry, Spectrophotometry. The results from the dosage of N revealed that Tithonia diversifolia (Ti), Cow dung (Cd), soil/sand (2:1) mixture and NPK contained 3.32%, 2.13%, 0.23 %, and 23.00% of N respectively. The kinetics of mineralization in the δTi, δCd showed a primary mineralization while that in the δNPK and δC showed a secondary mineralization.

No abstract

Cassava peels are in large quantity and practically of no economic value in many developing nations such as Cameroon, where cassava is widely consumed and processed far beyond other crops. Cassava peels might be used in those countries to face declining soil fertility and soil erosion. This study aimed to evaluate the composting of cassava peels and the effect of the increasing quantity of cassava peels in the bin during the process of composting and to assess some physico-chemical qualities, biological properties and the phytotoxicity of the produced composts. After three months of composting the produced composts (C1; C2; C3 and C4)  had a dark brown color, relatively dry, uniform structure and its texture were similar to the soil's texture. The electrical conductivity of the various composts was in between 1499 and 1924 µS.cm-1. The pH (6.50-6.73), was slightly acid, favorable for the cultivation of sweet pepper. The composts were rich in minerals (Mg2+; Ca2+; K+; and Na+) and poor in heavy metals such as (Cu, Zn and Mn). The composts C/N ratios were between 13.15 to 13.42. The produced composts showed a germination index and the rate of germination higher than 80% at all amounts, indicating the absence of phytotoxicity. The increased amounts of cassava peels did not alter the process of composting and increased the fungal and bacterial populations. In conclusion, cassava peels are good substrates that can be used to produce stable and inclusive organic fertilizers, with high nutrient content, and less hazardous material which could be used in farms to remediate declining soil fertility and to promote sustainable agriculture.

The impact of the combination of plant (Tithonia diversifolia) (Td) plus cow dung (Cd) as biofertilizer and aqueous extract of Callistemon citrinus (CAL) leaves as biofungicide on physicochemical properties, and the microbial biomass in carbon (MBC) and nitrogen (MBN) of soil and on tomato yield were assessed under field condition. The experimental design was a complete block design with 2 factors (soil amendment and plant sprays) and 3 repetitions. The soil treatment included organic amendment (OA): Td + Cd at the ratio of 3:4 (w/w)/plant; inorganic amendment (IA): 21:8:8 NPK (26.2g/plant) and potassium sulfate (4g/plant); and control (unamended soil). The field treatments were plants sprayed with: 5% (w/v) CAL; 5% (w/v) Mancozeb (M); and water (W). All amendments except IA did not significantly modify the soil organic matter (˂2.4mg.kg -1 ) and organic carbon content. An increase of 23.15% and 30.60% of calcium concentration and cation exchangeable capacity (CEC) respectively, was recorded in OA soil compared to the soil before cultivation (SBC) (P˂0.05). Copper and zinc contents in OA soil were reduced respectively by 49% and 48.5% compared to SBC. The highest concentration of MBC was recorded in OA.M plot. The different combine treatments (OA.CAL, IA.M, and OA.M) increased tomato yield by 3.4; 3; and 5.3 fold, respectively compared to their controls. This study provided new information about the organic amendment on soil and plant sprayed with C. citrinus extract as a green alternative to conventional input that might improve soil quality and crop yield.