Field experiments were conducted in 1997-1998 and 1998- 1999 successive seasons; to study the effect of soil management system on the vegetative growth, yield and fruit quality of apple trees (uniform 6 years old) under drip irrigation system.
Experiments involved six treatments as Control (without weed control). Hand hoeing, mulching and chemical (Herbicides) weed control treatments. The applied herbicides were Round up2%, Gesaprem 2% and Diuron 0.35%. Water as spray on the soil surface two times on the mid of May and August during the two seasons.
Regarding the vegetative growth of the growing weeds under different applied treatments; mulching by polyethylene sheets was more effective for controlling either broad leaved or grassy weeds when compared with the other used soil management systems. The same trend was also existed in case of the number of shoots per branch of Anna apple trees as well as most of the other studied characteristics including mineral contents.
Meanwhile, the highest percentages of fruit set and hence fruit yield were obtained by Diuron 0.35%, yet, mulching treatment gave the highest reduction of fruit drop percentage. In addition mulching treatment preceded all other treatments regarding both total sugars and total soluble solids in fruits of the treated trees. Concerning the herbicide residues in fruits; Diuron 0.35% had a detectable amount of 0.013-0.022 ppm but Round up and Gesaprem did not.
Of the new findings of this study is that hand hoeing gave the highest costs but the lowest costs were existed in case of Gesaprem herbicide. Yet, mulching showed intermediate cost but on the long term it gave the lowest costs when compared with the other applied treatments.
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