Soils infested with weed seeds are considered hostile lands for crop production. In this context, great wild oat (Avena sp.) in winter seasons and redroot pigweed (Amaranthus sp.) in summer seasons represent problematic weeds in cropland fields. In a series of laboratory trials, we estimated the effects of gibberellic acid (GA3) and potassium nitrate (KNO3) on germination and seedling growth of Avena sterilis L. and Amaranthus retroflexus L. Different concentrations of GA3 and KNO3 were evaluated in randomized complete block design with four replicates. Findings revealed that GA3 at a rate of 200 mg L−1 along each of 150 and 250 mg L−1 treatment showed the maximum increases in germination percentage, radicle length, plumule length and seedling dry weight of A. sterilis L. All applied concentrations of KNO3 were similar (p ≥ 0.05) in enhancing seed germination of A. sterilis L. exceeding the control treatment. Application of GA3 at rates of 250, 500 and 750 mg L−1 surpassed the treatments of 0 and 1000 mg L−1 GA3 for activating A. retroflexus L. seeds germination. Addition of 250 and 500 mg L−1 KNO3 were the potent treatments for stimulating the radicle length of A. retroflexus L. It could be concluded that for breaking dormancy efficiently, addition of gibberellic acid or potassium nitrate with Avena sterilis L. as well as gibberellic acid with Amaranthus retroflexus L. is recommended. Such chemicals could be involved in weed management programs, since distinctive promotion of seed germination for the target weeds was achieved. This undoubtedly will keep the soil and crops healthy.

The present investigation was carried out at the Experimental Farm of the Faculty of Agriculture at Fayoum, Cario University at Dalla, Fayoum Governorate during the two seasons 2000/2001 and 2001/2002. The aim of this investigation was to study the effect of organic manure and number of berseem cuts on cotton yield and its components and fiber traits. The obtained results indicate that only plant height at harvest, number of fruiting branches / plant and the height of the 1 st fruiting branch were significantly affected by organic manure (O.M.) application. On the other hand, organic manure did not affect significantly the seed cotton yield, yield components and fiber quality traits. Cotton planting dates affected significantly all studied vegetative growth, seed cotton yield, yield components and fiber quality traits. Early planting date (1 st week of March) showed significant superiority over the other two planting dates (1 st week of April & May) in number of fruiting branches/ plant, number of days to 1 st flower appearance and 1 st boll opening, number and weight of open bolls/ plant in the 1 st & 2 nd pickings, seed cotton yield, lint percentages and studied fiber quality traits. The decreases in the total seed cotton yield attributed to the late planting dates (1 st week of April & May) amounted 26.4 and 84.8% and 30.6 and 84.1% of March planting with the treatments of 10 and 20 m 3 / fad organic manure, respectively.

A laboratory experiment was carried out to study the early growth response of 22 sugar beet (Beta vulgaris, L.) varieties to four salt concentrations of seawater i.e. 2000, 4000, 8000 and 16000 ppm. Germination and seedling growth traits (germination percentage (%), germination rate, seedling length (cm), seedling fresh weight (mg) and seedling vigor) were determined at the end of the experiment after 30 days from planting. The results showed that increasing the salinity level decreased the germination %, germination rate, seedling length, seedling fresh weight and seedling vigor of all sugar beet varieties under investigation to different extents. The results also clearly revealed that the response of the investigated varieties to salt concentrations was not the same, some varieties approved to be highly salt tolerant i.e. Soultan, Kawmira and Desprez; others were very sensitivity tolerant i.e. Helsiniki and LP16. However most of the investigated varieties were moderately salt tolerant. Results revealed clearly that the interaction effect between sugar beet varieties and salt concentrations was significant. This significant effect means that the tested varieties do not behave the same under the different levels of salinity stress.