Effects of fertilization with liquid extracts of biogas residues on the growth and forage yield of alfalfa (medicago sativa l.) under arid zone conditions

In this study liquid extract of biogas residue (LEBR) from date palm waste was used to fertilize soil for alfalfa (Medicago sativa L.) cultivation. The results revealed that LEBR application significantly increased plant height, number of branches per meter and the contents of crude protein and ash over the control. The largest plant height and number of branches per meter and the highest ash and Phosphorus contents in the plant dry matter were obtained at the application of 3 L/m2 of LEBR solution containing 15% extract, to the soil while a solution containing 10% extract gave the highest fresh and dry biomass yields. Soil treated with LEBR had higher EC and higher contents of NH/sub 4/, NO/sub 3/, Na, K, Ca, Mg, Fe, Mn, Zn and Cu than the untreated soil. The pH of the soil decreased with increased amount of LEBR applied. (author)