A field experiment was carried out in plastic greenhouses at Sakha Agricultural Research Station to study the effect of different cultivation media, irrigation water sources and compost levels on fresh yield of tomato and NPK contents of leaves and C/N ratio of rice straw bales. Split plot design with four replicates was used. The obtained results could be summarized as follows:
1) Fresh yield of tomato grown on clay soil was higher than that grown on rice straw bales.
2) Fresh yield of tomato was decreased significantly with irrigation by well water or blended fresh with well water compared to fresh water.
3) Addition of 20 ton of compost/fed. gave the highest fresh yield of tomato, while zero level leads to achieve the lowest yield.
4) N and P contents in tomato leaves were higher under cultivation on clay soil than rice straw bales, while K took the opposite trend. Concerning the irrigation water sources, the contents of these elements were higher with fresh water than blended and well water, as well as, addition of 20 ton compost /fed. achieve the highest values of NPK content compared with other levels.
5) The C/N ratio of rice straw bales is decreased after tomato harvesting comparing to that before the experiment. Using fresh water or blended water gave the lowest value of C/N ratio with tomato plants. Whereas, well water tend to decrease the rate of decomposition. The increase of compost application level up to 20 ton/fed. leads to consequently increase the decomposition of rice straw and clearly decrease C/N ratio.
Generally, it could be concluded that compost application at the rate of 20 ton/fed. to rice straw bales as a growing media was the recommended treatment which produced the highest total tomato yield and quality fruits under greenhouse in Egypt. Thus, these treatments can replace completely or partially instead of mineral fertilizers, which protect the environment chemical pollution and its harmful effect on human and animal health besides reducing the production costs.