Effect of bio-organic fertilizers, hoeing and polyethylene mulch on weeds, the citrus nematode (Tylenchulus semipenetrans) and yield ofmandarin trees in Egypt

摘要

Combined safety methods and bio-organic fertilizers for controlling weeds and the citrus nematode, Tylenchulus semipenetrans were designed to producing healthy food free from the biomagnified agrochemical residues in fruit yield of mandarin trees in Egypt. A field experiment was carried out to study the effect of hoeing, black and white polyethylene sheets 80μm and different composted plant wastes such as rice straw, maize stalks or crop weeds in the presence or absence of multi-biofertilizers and their interactions on controlling weeds, citrus nematode and fruit yield parameters of mandarin trees cv. Balady. The results revealed that Cynodon dactylon, Echinochloa colonum, Amaranthus retroflexus, Portulaca oleracea, Panicum repens and Cyperus rotundus were the dominant weeds in the citrus grove. Covering the soil with black plastic sustained the lowest weed density and reduced the number of citrus nematode and consequently produced the highest fruit yield/tree, followed by white plastic, then hoeing treatments. The use of either composted weeds under white plastic or composted chicken manure under black plastic in the presence of biofertilizer attained twice superiority for controlling the citrus nematode comparing to without biofertilizer application, while rice straw compost treatment under hoeing and at black plastic surpassed the others in one period for controlling the citrus nematode. Application of the biofertilizer with the different organic composts caused increase in the number and yield of fruits per tree. Generally, the association action between composted plant wastes and biofertilizer application increase the number and fruits yield under weed control treatments. Also, composted crop weeds recorded the greatest fruits yield under black plastic. The treatments of chicken manure and composted rice straw without addition of biofertilizer surpassed the chemical treatment in fruit yield by 34.9% and 14.0%, respectively. While application of maize stalks compost caused a reduction of the fruit yield by 8.1%, compared to inorganic treatment. The highest value of total soluble solids in fruits was observed with rice straw compost and biofertilizer under the white plastic. The most promising interaction treatment producing the highest safety fruits production of Balady mandarin was the associating weeds composted with biofertilizer or chicken manure under black plastic treatment.