Effects of chemical and bio-fertilization on the growth and the chemical constituents of spinach plants [electronic resource].

Includes reference.

Consumption of spinach with high nitrate and oxalate contents may be a health hazard to infants and adults. The crop accumulates N03-N and oxalic acid, when grown in a soil with high N03-N availability. Therefore, pot experiments were designed during the two successive years of 2000 and 2001 to evaluate the effects of different nitrogenous fertilizers, chemical and bio-fertilizers as well as their combinations on nitrate and oxalate in spinach. One objective of this study was to develop a mean for fertilization for maximum growth with useful components and minimum nitrate and oxalate contents. The trials involved 6 application ratios of the chemical fertilizer "Sangral" and the bio-fertilizer "nitrobine" 0/0, 100/0, 75/25, SO/50, 25/75 and 011 00). Results indicated that growth (monitored by the number of leaves, leaf area, fresh and dry weights) was enhanced when plants were provided with a mixture of chemical and biofertilizer, compared with the control or both fertilizers as single treatments. Nitrate concentration was reduced by SO/50 N-mixture compared with higher ratios of chemical fertilizer. Total and free oxalate in spinach leaves were reduced also by N-mixture of 50/50 compared with no N or either N form alone. The highest vitamin (vit. B 1, vit. B2, vit. C) and element (Ca, P, Fe) concentrations were found at 50/50 N¬-mixture with chemical and bio-fertilizer application. The data suggest that fertilization of N as a mixture of chemical and bio fertilizers (SO/50 ratio)

Summary in Arabic.

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