الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 135 |  |  |
| | | from | 135 | | |
Abstract
A pot experiment was carried out during the winter season of 2014 under alluvial soil at the green house of Soils Dept. Faculty of Agriculture, Mansoura University The experiment treatments included four different application rates of humic and fulvic acid (0, 7, 10 and 13 kg fed-1) using three methods of application (soil, fertigation and foliar applications). The used experimental design was a completely randomized design with three replicates for each treatment .The effects of soil applications, fertigation and foliar of humic substances on the plant growth and some nutrient elements uptake of lettuce (Lactuca sativa L.) grown under different rates were examined. The results of the present study showed that the significant effects of different application rates of humic substances on fresh and dry weights, plant height, N%, P % and K% . The results indicated that the highest values of fresh and dry weight of shoot as well as plant height (cm) were at foliar addition of fulvic acid at 13 kg fed-1 treatment. Also, the nutrient content (N, P, and K) of lettuce was significantly increased with raising of application rates of humic substances. Aim of the work :
This research aimed to study the response of lettuce plant to different levels of humic substances (humic and fulvic acids)under analluvial soil conditions as well as to study their effects on some soil properties , plant growth, yield and chemical composition of lettuce plant. Conclusion : Based on the obtained results of this study it could be concluded that the addition of humic substances (humic and fulvic acid) significantly increase the plant growth and mineral contents of lettuce plant especially when increasing of application dose but the positive effect of fulvic acid is greater than the positive effect of humic acid. foliar application of humic substances induced positive effect tgreater than soil application and fertigation.