EFFECT OF CHEMICAL, BIO AND ORGANIC FERTILIZER TREATMENTS ON YIELD AND YIELD COMPONENTS OF SWEET POTATO (Ipomea batatas)

Abstract

Field experiments of the present study were carried out during the two successive seasons of 2008 and 2009 at Research Farm of Faculty of Agriculture, Minia University, EL - Minia, Egypt. Sweet potato c.v. Mabrouka was cultivated to study effect of the chemical NPK, bio and organic fertilizers on its yield and yield components under EL-Minia growing conditions. Eight treatments were studied with some possible combinations among the used fertilizers. The obtained results of the present study could be summarized as follow: Number of storage - roots/plant was significantly affected by fertilizers treatments in both seasons. The highest numbers of roots were produced from plants fertilized with compost only in the first season, while from the combined application of compost + half rate of the recommended NPK fertilizers + bio-fertilizers in the second season. The highest values of average root fresh weight were obtained from plants fertilized with half recommended rate of dose NPK + compost in the first season and the half recommended rate of the chemical NPK fertilizer in the second season. Data declared that the highest values of root dry weight per plant were obtained from plants fertilized with compost + bio-fertilizers in the first season and compost only in the second season . Significant effect on total dry weight per plant in both seasons was detected. The highest value in the first season was obtained from plants fertilized by half NPK + compost, while plants fertilized with the bio-fertilizers only gave the highest value, in the second season. Highest value of harvest index in the first season, was given with using the bio-fertilizers only, while half rate of NPK only produced the highest value in the second season. In general , the effects of organic and bio-fertilizers on most of the studied yield characters indicate the possibility of replacing or reducing the amount of the chemical NPK fertilizers required for sweet potato ( c.v. Mabrouka) production. Furthermore, Compost + bio-fertilizers treatments exceeded the recommended NPK treatment of some economically important studied characters such as number of storage roots / plant and average root fresh weight/ Plant.