Implications of humic, fulvic and K-humate extracted from each of compost and biogas manure as well as their teas on faba bean plants grown on Typic Torripsamments and emissions of soil CO2

The current study assumed that foliar application of organic extracts might be as beneficial in improving plant growth as amending soils with organic amendments. Moreover,the foliar application of these extracts can minimize, to some extent, the emissions of CO2 which is an obligatory option to attain desirable environmental conditions. To investigate this assumption, (1) different organic extracts i.e. humic acid, fulvic acid and K-humate prepared from each of a biogas manure and a mature compost (consisting of composted rice straw and farmyard manure) and (2) a tea of each of the aforementioned manures (TEA) prepared by soaking the latter organic materials in distilled water, were studied for their effects on dry matter yield of faba bean plants grown on a Typic Torripsamment soil sampled from Meet Kenana village, Qalubia, Egypt under greenhouse conditions. Each of these extracts and TEAs was applied either solely or in different combinations with each other, foliarly or through soil applications, at two different rates i.e. 48 and 96 L ha-1. Results revealed that the applications of the investigated organic extracts as well as the compost/biogas tea increased significantly NPK uptake by the grown plants and consequently improved the dry matter yield of faba bean plants especially with increasing the rate of the applied organic extract or tea. Mixed type extracts seemed to be more efficient in this concern than the single type extracts. It seemed preferable to use the single type extracts foliarly; whereas, the mixed type ones seemed more preferably to be used through soil applications. Results also revealed that the investigated organic amendments stimulated both the number and dry weights of nodules with significant effects on reducing the emissions of CO2 especially when added as foliar applications. In conclusion, the foliar application of the liquid organic amendments (as extracts or teas) is recommended to improve the plant growth on one hand, and decrease the emissions of CO2 on the other hand to attain more desirable environmental conditions.