Effects of Casuarina equisetifolia Composted Litter and Ramial-Wood Chips on Tomato Growth and Soil Properties in Niayes, Senegal

Abstract

ABSTRACT A field experiment was conducted to study the effects of ramial chipped wood (RCW) and litter compost (LC) of Casuarina equisetifolia on tomato (Lycopersicon esculentum) growth and soil properties in Niayes, Senegal. The RCW and LC were applied to a sandy soil at 10, 20 and 40 t ha−1 and compared with a control and recommended fertilizer mixture. Soil and plant samples were taken at 45 days of tomato growth and at harvest time for analysis. Residual effects of the materials were evaluated by establishing a second tomato crop on the same plots. Application of RCW depressed tomato growth and yield during the first cropping and this was attributed to RCW inducing intense N immobilization in the soil due its wide C:N ratio. Improvements in growth and yield were observed during the second cropping and ascribed to improved nitrogen release following the extended incubation of the RCW in the soil. In order to derive short-term benefits from RCW application, it should be applied in combination with experimentally determined amounts of mineral fertilizers. Litter compost improved tomato growth and yield during both croppings owing to increased soil levels and tomato uptake of N, P and K following its incorporation in soil. This was attributed to the narrower C:N ratio of LC, which facilitated its decomposition in the soil. The residual effects of LC were, however, much less, suggesting that LC had limited residual nutrients value. Both RCW and LC increased the soil organic matter content and water holding capacity, and reduced the bulk density of the soil, suggesting that their regular application could result in the long-term improvement of its productivity.