Abstract: This research paper deals with one of clay soils considering the benefits of using bio dissolving microorganisms of phosphor. Also these microorganisms could improve plant assimilation through releasing some sort of growth regulators. This research has been carried out through two different field experiments during 2005 and 2006 seasons. Traditional phosphate system fertilization was applied using super calcium phosphate with unincoulated squash seeds compared with using rock phosphate mixed with bio dissolving microorganism and inoculated squash seeds with P. polymyxa and micrrohiza G. mosseae or bio dissolving phosphor bacteria B. megaterium (Bio phos-phor®). The previous treatments combined with boron foliar spray to study their effects on morphological and physiological parameters and quality and productivity of squash, also to study the microbial activity and phosphor availability in the soil. Results showed that double inoculation with / or both inoculation with foliar spray of boron improved vegetative growth as stem length, stem thickness, leaf number, leaf area and plant dry weight compared with uninoculated plants. Plant pigments as chlorophyll A and B and carotenoids increased with biofertilizer treatments, also the same positive trend noticed with chemical contents of plant including N, P,K, Mg, B, total protein, total soluble sugars / fresh weight and total carbohydrates / dry weight increased compared with uninoculated plants. Double inoculation with P. polymyxa and B. megaterium with foliar spray with boron led to an enhancement of internal level of growth promoters including GA, IAA and cytokinines combined with decreasing of ABA inhibitor. Double inoculation especially with micrrohiza with boron spray improved sex ratio and early production of fruits with high yield. Results indicated obvious positive and significant microbial activity in soil rhizosphere expressing by activity of 3 3 dehydrogenase, phosphatase and nitrogenase enzymes, also nitrogen phases as NH and NO , available 2 5 phosphor and P O reached to their highest values with double inoculation and boron application during the two seasons. The present research results that using rock phosphate mixed with bio dissolving microorganism and treating seeds before sowing with BDM combined with boron foliar spray significantly improved growth and productivity and quality of squash plant cultivated in clay soils.
Key words: Biofertilizers, mycorrhizae, P. polymyxa, B. megaterium var phosphaticum (Bio phos-phor®) boron, squash, chlorophyll, endogenous hormones, sex ratio, early yield, fruit quality |
