MAXIMIZING THE UTILIZATION OF DRAINAGE WATER RE-USE IN IRRIGATION TOMATO PLANT TREATED WITH HUMIC ACID

Abstract

In this study, two field experiments were carried out during the growing seasons of 2011/2012 and 2012/2013, at the experimental farm of the south-west portion on a saline soil at Tina plain region, south Sinai governorate, Egypt. The experiments were carried out in order to investigate the effects of humic acid and salinity and their interactions on vegetative growth, yield and quality of tomato (Lycopersicon esculentum Mill). Seeds of tomato cultivar "Castle-rock". The two fields Soil salinity were moderate and high ranging between 2 to 3 mmohs/cm/25Co and the other field soil salinity ranged between 5 to 8 mmohs/cm/25Co.Potassium humate (86% Humic acid and 6% potassium oxide) was added with different four dozes i.e., (0 kg/fed - control, with distilled water), 0.5, 1 and 2 kg/fed., at two times, the first (50% of the amount) was added after 15 days from transplanting and the second one (50% of the amount) was carried out after one month from the first addition Asplit plot design with three replicates was used where the soil salinity was the main plots and potassium humate treatments were located in the subplots.The results of this experiment can be summarized as follows: 1. Humic acid effect on Soil properties : 1.1. Crop water use efficiency According to the experiment results the addition of humic acid concentration 1kg /fed reduced the effect of soil salinity on the yield therefore this concentration gave the highest yield. However, humic acid with low soil salinity resulted in higher value of Crop water use efficiency in addition to a high amount of seasonal yield compared with high soil salinity, on the other head, improving the crop water use efficiency of tested field. 1.2. Soil salinity as affected by humic acid concentrations. For Moderate Soil Salinity Level the data and the figures revealed that the values of soil salinity EC (dSm/m/25Co) were significantly affected by increasing the rates of humic. This means that, the salts concentration with Moderate Soil Salinity Level decreased with the increase of concentration of humic acid rate. The average electrical conductivity (EC) in (dSm/m/25Co) which was measured with the time (beginning, mid, maturity and end of the growing season) using different humic acid rates for two soil salinity levels (For Moderate and high Soil Salinity Levels) was observed that, soil salinity value decreased with the time for all humic concentrations. Application of humic acid rate led to a reduction of soil salinity because humic acid could improve the soil physical properties (increasing soil porosity). The decomposition of humic acid releases acids forming compounds and active microorganisms, which react with the soluble salts already present in soil either to convert them into soluble salts or at least increase their solubility.