The objective of this study is to evaluate the effect of nine compost types on soil properties and their positive effect on plant growth during two successive seasons. The organic treatments were nine types; poultry manure, sawdust, farmyard manure, town refuse, sewage sludge , cottons stalks , sawdust activated by organic compost, treated sawdust by NaOH, and treated of cotton stalks by NaOH. The experiments were conducted at the experimental farm of Sakha Agric. Res. Station, Kafr EL-sheikh governorate, Egypt. longitude 30o 56- E and latitude 31o 5 N., Wheat, variety (Sakha 94) was planted on November (2011) and followed by maize, variety
( Giza 352) cultivated on May (2012) in the same experimental area. The experiments were conducted in a randomized complete block design with four replicates. 50% of the recommended nitrogen was applied to each treatment.
The obtained results application due to composts could be summarized as follows:
1- Soil organic matter content and ECe values were increased, while pH values showed slight decrease.
2- In the first, season the maximum wheat grain and straw yields (3.09 (Mg/fed and 5.98 Mg/fed., respectively) were obtained when soil was mixed with farmyard manure and sawdust activated by compost combined with urea at rate of 50% of recommended dose. The highest 100 grain weight (4.46gm) was obtained with using composted farmyard manure combined with urea at rate of 50% recommended dose . The corresponding values in the second season under maize crop were 4.21 Mg /fed, 6.63Mg/fed and 32.58 gm for composted sawdust activated by organic compost, sewage sludge compost and farmyard manure combined with urea, respectively.
3- Application of different composted materials were more effective in increasing available N, P and K in soil in the 1st and 2nd seasons.
4- The obtained results indicated a significant increase in NPK content of wheat and maize plants, with composts application.
5- Available and total amounts (mg/kg soil) of Fe, Mn, Cu, Pb, Ni and Cd were increased with composts application. Data showed that the available heavy metal represented only a small percentage of the total content. This indicates that heavy metals applied to soil were strongly sorbed in non exchangeable form. The availability of these metals due to composts application can be arranged descendingly as follows: Fe, Mn, Pb, Ni, Cu and Cd.
6- Application of different composts increased significantly the concentration of heavy metals in grain and straw of wheat and maize plants, these contents were in the order: Fe > Pb > Mn > Cu > Ni > Cd. The results showed that Mn, Ni, Cd and Cu concentrations in the grain and straw of wheat and maize plants (except Cu in wheat straw) being within the normal range. On the other hand Fe and Pb concentration in the grain and straw of wheat and maize plants and Cu in maize straw are being within the critical concentrations range of these elements in plants.
7- Application of different composted improved some soil physical properties such as bulk density and aggregate parameters.
8- Economical evaluation was done by calculating the benefit to cost ratio B/C parameter. The highest profit was obtained when soil was mixed with composted sawdust activated by compost.