Response of snap bean to biogas slurry combined with either rock Phosphate or super phosphate fertilizers

M. Y. Abou-Zeid and El-Sayeda H. M. El-Badawy and A. El. Sherif

Abstract

This research was carried out to study the potential use of by-products of biogas production, i.e. biogas slurry (BS) generated from cattle dung, as nutrient sources in agriculture. The pot trials were conducted under green house conditions on the growth, yield of snap bean and their chemical composition. Some soil enzymes, i.e, nitrogenase and dehydrogenase were determined, also available P. Snap bean was fertilized with various sources of phosphate fertilizers, calcium superphosphate or rock phosphate at the rate of 30 kg P2O5/fed combined with BS. Results showed that vegetative growth parameters significantly increased by using BS and RP or SP for two used varieties, applying of 10 m3BS + 30kg P2O5/fed as SP gave the maximum values of vegetative growth parameters for Paulista variety. For other variety, Xera, 10 m3BS + 30kg P2O5/fed as SP led to the highest plant height. While 2.5 m3BS + 30kg P2O5/fed as RP gave the highest values of plant dry weight and No of branches. With respect to yield and its components, pods weight /plant and pod length of Xera cultivar significantly increased over control, also pods weight /plant for another cultivar significantly increased over control as a result of using BS and various sources of P fertilizer Regarding the leaves chemical composition, using Bs combined with RP or SP caused significant increase of N, P, K as macronutrients, where 10 m3BS + 30kg P2O5/fed as RP gave its highest values for two used varieties. Micronutrients Fe, Mn, Zn and Cu significantly increased over control. Applying of rock phosphate (RP) with BS was more effective on most of these nutrients than super phosphate (SP) + BS for the two cultivars used. For the pod chemical composition which significantly increased, N,.K and total protein of Xera variety reached to the maximum values by using SP + 10 m3BS. While the highest value of T.P% obtained by RP +10 m3BS. Fe, Mn and Zn concentration (ppm) enhanced by using RP +10 m3BS. For Paulista cultivar, T.N, T. protein and Fe increased up to the greatest values by RP +10 m3BS, while T.P and Mn reached to the maximum values by using SP +10 m3BS. With regard to biological activity and available phosphorus, data showed significant increases by the treatment under this study. Clearly applying RP along with 10 m3BS gave the highest values of dehydrogenase, nitrogenase enzyme activity and total count of bacterial more than those obtained by SP +10 m3BS, while the best results for available P were obtained by SP +10 m3BS. Accordingly, this study ensured that the use of rock phosphate with biogas slurry may be recommended as a substitute for super phosphate with biogas slurry in snap bean production.

Key words

biogas slurry, rock phosphate, super phosphate, nitrogenase enzyme, dehydrogenase enzyme, snap bean, N, P, K, Fe, Mn, Zn, Cu.