Evaluation of Different Weed Control Measures on Some Rhizosphere Microorganisms, Weeds and Productivity of Pea under Bio-Organic Fertilization

The use of some natural and plastic mulches (rice straw, black and white plastic) as well as hand hoeing and butralin herbicide under bio-organic fertilization were evaluated for their effects on some beneficial rhizosphere microorganisms, weeds, growth and yield of pea plants during 1998/1999 and 1999/2000 seasons. Densities of phosphate dissolving bacteria and Pseudomonas spp. in biofertilized rhizosphere were always higher in the presence of farmyard manuring (25 or 50 m3/fed.) compared to chemical fertilizer under weed control treatments. The mulch treatments (rice straw, black and white plastic) recorded a marked positive effect on the counts of tested microorganisms in the rhizosphere as compared to butralin herbicide and unweeded control treatment. Biofertilizers associated with farmyard manure at the rate of 50 m3/fed under hand hoeing treatment, yielded higher fresh weight and number of nodules in pea plants. On the other hand, presence of weeds reduced fresh weight and number of nodules, seed index, number of pods per plant and pod yield per fed. Application of different weed control treatments caused a significant reduction in number and dry weight of weeds. The best weed control was obtained by black plastic mulch, followed by hand hoeing and rice straw mulch treatments. Associating biofertilizer with farmyard manure at rate of 50 m3/fed exhibited the greatest pod yield and significant increase in the fresh and dry weight of seeds when compared with farmyard manure at rate of 25 m3/fed. and chemical fertilizer application under weed control treatments. The highest concentrations of N, P, K, Zn and Mn elements in pea seeds were achieved, due to combined action of biofertilizer and 50 m3/fed. of farmyard manure under controlling weeds by hand hoeing treatment