To study the integrated impacts of halotolerant N2 fixers and humic acid application on N – availability and nutrient contents of wheat crop (Triticum Aestivum L). CV Sakha 93 in asalt affected soil, two successive field experiments were conducted in El-Matarya District near Al Manzala Lake, Dakahlia Governorate during the winter of 2009-2010 and 2010-2011 seasons. Eighteen treatments were arranged in asplit-split block design, which were the simple possible combination between two treatments of humic acid (with (50 L fed-1. & without) as the main plots, three treatments of bio inoculation (Non-inoculation, Azotobacter+ Azospirillum and Nostoc + Anabaena) as the sub plots and three levels of nitrogen fertilization (control, 40 and 80 Kg N fed-1) as sub- sub plots. Each treatment was replicated three times. Thus, the total number of plots used for each season were 54 plots.
The results of this investigation revealed that:
With adding humic acid, the mean values No. of grains spike-1, spike length (cm), weight of 1000 seeds (g), grain yield (ardab fed-1), straw yield (ton fed-1), N, P and K-uptake (kg fed-1) of grain, straw and whole plant at harvesting stage were significantly increased due to addition of humic acid.
This investigation also indicated that an application of Azotobacter+ Azospirillum was more effective for increasing the No. of grains spike-1, spike length (cm), weight of 1000 seeds (g), grain yield (ardab fed-1), straw yield (ton fed-1), N, P and K-uptake (kg fed-1) of grain, straw and whole plant at harvesting stage than the other halotolerant N2 fixers and this effect was significance during both seasons of the experimentation.
Concerning the effect of N-fertilization the average values of No. of grains spike-1, spike length (cm), weight of 1000 grains (g), grain yield (ardab fed-1), straw yield (ton fed-1), N, P and K-uptake (kg fed-1) of grain, straw and whole plant at harvesting stage for wheat plant treated with 80 kg N fed-1 doses of N-fertilization was more increased significantly than that treated with the untreated plant.
With respect to the interactive effect between adding humic acid, halotolerant N2 fixers and nitrogen application found that with adding 4080 kg N fed-1 of nitrogen fertilization mixed with Azt+Azs in presence of humic acid gave the highest value of No. of grains spike-1, spike length (cm), weight of 1000 seeds (g), grain yield (ardab fed-1), straw yield (ton fed-1), N, P and K-uptakes (kg fed-1) of grain, straw and whole plant at harvesting stage for wheat plant.