PARTIAL REPLACEMENT OF INORGANIC N FERTILIZER BY USING HUMIC ACID, COMPOST ENRICHED WITH ACTINOMYCES AND SPIRULINA PLATENSIS ALGAE IN STRAWBERRY CV. FESTIVAL

Abstract

seasons, the possibility of replacing 25 to 75 % of inorganic N fertilizer in strawberry cv. Festival by using humic acid at 3 kg/ fed. compost enriched with actinomyces at 4 ton/ fed. and Spirulina platensis algae at 3 L/ fed. was investigated. Results reveal that decreasing percentages of inorganic N from 100 to 50 % out of the suitable N rate accompanied with the application of humic acid, compost enriched with actinomyces or Spirulina platensis algae resulted in major promotion on growth, diameter and weight of fruit, yield as well as chemical characteristics of the fruits. Application of inorganic N combined with compost enriched with actinomyces was preferable than using mineral N plus humic acid in promoting yield quantitively and qualitatively. A supreme and outstanding effect on the production of Festival strawberry was observed when Spirulina platensis algae was added to the present two organic manures rather than using organic manures alone. Unvafourable effects on production were noticed when percentages of mineral N were reduced to 25 % even with the application of organic and biofertilizers. The best results with regard to growth, yield and quality of strawberry cv. Festival were obtained by supplying the plants with 50 % inorganic, N. compost enriched with actinomyces at 4 kg/ fed. and Spirulina platensis algae at 3 L/ fed.