Effects of Fertilizers Containing Calcium and/or Magnesium on the Growth, Development of Plants and the Quality of Tomato Fruits in the Western Highlands of Cameroon

摘要

The study was undertaken to determine the effects of calcium and magnesium nutrients on the development of plants and subsequent postharvest conservation of tomato fruits. Tomato plants were treated by applications of N/P/K (9.5/8/10) and fertilizerscontaining Ca~(2+) and/or Mg~(2+). Control plants received only N/P/K. Two fertilizer combinations (N/P/K + foliar spray of Manvert Magnesium and N/P/K + calcium nitrate at 800 kg ha~' + foliar spray of Manvert Magnesium) induced a significant delay in the flowering of plants. Combinations of soil applications of N/P/K and calcium nitrate at 200 kg ha~(-1) with foliar sprays of Manvert Calcium and/or Manvert Magnesium led to significant increases in the content of Ca~(2+) in mature-green fiuits and subsequently to the delay of their ripening and the prolongation of the conservation period. Combinations of N/P/K + calcium nitrate at 200 kg ha~(-1) + Manvert Magnesium and N/P/K + calcium nitrate at 400 kg ha~(-1) + Manvert Calcixmi + Manvert Magnesium led to significant increases in the Mg~(2+) content in fruits. Fruits produced by plants that received these fertilizer combinations also showed a prolongation of the duration of ripening period and that of the conservation. The longest shelf-life was obtained after simultaneous applications on soil of N/P/K and calcium nitrate at 200 kg ha~(-1) and foliar sprays of Manvert Calcium and Manvert Magnesium. These results indicated that calcium and magnesium could be considered as key elements of fertilizerswith regard to the delay of ripening of mature-green tomato fhiits and to the prolongation of the shelf-life of the red-ripe ones.