Browsing by Author "Manang, Emiliano Z."

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    Effects of nitrogen, phosphorus and phosphorus placement methods on the growth and yield of Tomatoes
    (University of Dar es Salaam, 1976) Manang, Emiliano Z.
    Two experiments were conducted to investigate the effects of nitrogen, phosphorus and phosphorus placement techniques on growth and yield of tomatoes. In the first experiment, rates of 80, 320, and 640kgN/ha applied as calcium nitrate and 40, 160 and 280kg p/ha applied as single superphosphate were used. In the second experiment, the rates were 0, 40 and 80kgN/ha applied as ammonium sulphate and 0, 40, 80 and 120kg p/ha applied as triple superphosphate. The methods of P application were “banding”, “broadcasting” and drilling” Nitrogen significantly increased tomato total yield by more than 20% and the number of truses to the first harvest by 10%. The number of flowers in the first truss, the plant height and tissue nitrogen content were also significantly increased by N applications (P= 0.05). The main effect of P on total marketable and early yields and the plant height were non-significant. Tissue P content, however, increased significantly with increasing rates of P application. The main effect of Pon total marketable and early yields and the plant height were non-significant. Tissue P content, however, increased significantly with increasing rates of P application. The NP interaction on mean fruit weight was significant (P= 0.05) Though effects due to methods due to methods of P application were non-significant “banding” seemed to be superior while “drilling” was least effective in respect to most of the parameters studied. Approximately 17% and 11% of the total fruit yield were ventrally and concentrically cracked, respectively. The cracking that occurred on the tomato fruits seemed to be related to the adverse weather conditions that prevailed during the period of field experimentation. For tomatoes grown in soils with characteristics similar to those under which this trial was conducted rates of 80 kg N/ha and 40kg p/ha would seem adequate. When the fifth leaf from the plant apex is sampled at flowering stage the data on plant tissue analysis indicate that values of 4% total N and 0.35% P in the leaf were critical for tomato plant growth. Depending on the characteristics of the soil this technique could be used to assess nutrient requirements of tomatoes.