الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
It was established that mineral fertilizer is one of the most pollutants that affect environment and public health concern in numerous areas of the world and hence a field experiment was carried out at a private farm (Monshat El-Badawi, Talkha, Dakahlia Governorate, (North Nile delta region) during the winter seasons 2004/2005 and 2005/2006 to evaluate some composts on potato fertilization in a clayey soil. Each of organic fertilizers used was applied individually (depth 20 cm subsurface) as follows: 1: NPK as recommended only, 2: Farmyard manure compost, 3: Sheep manure compost and 4: Chicken manure compost. A randomized complete block design was used and all solid treatments were added at 20 cm subsurface, the soil was prepared and ploughed and tunnels were made. The manures were applied and recovered by the same soil before cultivating the crop. All agricultural practices were done as followed by farmers in this region. The obtained results of the present study could by summarized as follows: 1:The addition of organic fertilizer into the soil increased both of total and available nitrogen, phosphorus and potassium in the soil. 2: Applying the organic fertilizers at the depth of 20 cm subsurface resulted in increasing the tested parameters. 3: Organic fertilizers increased tubers fresh yield, tubers humidity, tuber starch, specific gravity. And 4: Also, N, P and K concentration in tubers increased sharply and this increase was highly significant. Thus, it can be concluded that adding organic fertilizers to soils may play important roles in improving the physico-chemical properties of the studied soil which reflected on the plants growth parameters, and yield quality.