الفهرس 
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Abstract
’Fertile soil is the most important resources of food production. Shortage in agricultural area or deficiency in its productivity of crop plants is a great threat to food security in any nation. Subsequently, the nation had to depend on foreign sources to satisfy its food requirement. The agricultural area in Egypt is limited to 6 million faddans . This limited area has derived many fanners to use several types of chemical fertilizers, e.g. ) nitrogenous and phosphorous fertilizers , to enhance the fertility of the land and hence the productivity. Excessive application rates of chemical fertilizers would lead to that residual amounts of these fertilizers will be left in the soil. These residuals would build up because they are superfluous. They are waste of money and are one of the causes of soil pollution . Ultimately , they would adversely affect the ecological system in the soil and surrounding environment, especial1y water bodies. The government has decided to recycle some of the domestic soJid wastes by building 5 compost plants. In this way, garbage as one of the hazardous components of domestic solid wastes wil1 be disposed off with the production of compost. This compost is sought to be llsed as a soil conditioner to improve the soil characteristics and therefore, its productivity. other words, composting of organic solid wastes will address some of the problems of solid waste disposed and give a beneiicial product, which may replace the expensive chemical rertj]izer . Consequently, the environmental hazards of both solid wastes and chemical fertilizers win be abated. Other organic compostable solid wastes could be utilized to produce this compost. Agricultural residues are cheap raw materials for such compost and are available in vast quantities as well. Crop residues , mixed with manure, may be co-composted to give a soil conditioner. Agricultural residues , about 106 mil1ion tons/year, may produce about 55 mil1ion tons/year of compost. The aim of this work was to study the applicability of the co composting of agricultural residues on the fann. This co-compost was’ applied to soil to grow wheat and maize. Comparison with nitrogenous chemical fertilizers and Abis compost were undertaken. Five experiments were carried out at the Experiment Station of Faculty of Agriculture in Abis . These included three experiments of co-composting (aerobic and anaerobic) of agricultural residues and two experiments of wheat and maize grown with different treatments and rates of co-compost, Abis compost, and nitrogenous chemical fertilizers. The development of the co-composting processes shown by the temperature, moisture content, and chemical composition was studied. The effects of the different treatments on the wheat and maize were detected. Aerobic co-composting of Winter crop residues A pile of wheat straw, barley straw, broad bean stalks, clover stalks, and manure of 200 kg each was constructed. Water was added to raise the moisture content to about 500/0 . This experiment started in June, 1993 and last 149 days. Five samples of the raw materials and 11 samples from the pile were analysed for moisture, ash, volatile solids, and C/N ratio. The I st and last samples from the pile were analysed for macronutrients (P , K , Ca , Mg , Na , and Mn) , microl1utrients (Zn , Cu , and Ni) , and toxic metals (Pb and Cd) . The highest recorded temperature in the pile was 62.1°C on the 651lLday , and the moisture reached 39.5°,10 on the 63rd day. At the end (I 49th day) , the temperature dropped to 29.7°C and moisture was 570/0 . Volatile solids and C/N ratio diminished to 33.4 and 15.1 °,10 , respectively. Most of macronutrients and micronutrients increased. On the contrary, toxic heavy metals were not affected. The final co-compost product was about 530/0 of the raw materials. Anaerobic co-composting of Winter crop residues A pit measuring 2*2*1 m was excavated where the wheat straw, broad bean stalks, and manure were mixed together, each of 500 kg . Water was added and the pit was completely covered with earth and left to undergo anaerobic co-composting for 333 days.