Productivity of maize (Zea mays L.) and nitrogen use efficiency (NUE) as affected by nitrogen application levels and timing were studied. The experimental design was a three-replication randomized complete block design (RCBD). The first factor was nitrogen levels (122, 240, 288 and 336 kg N/ha) and the second factor was nitrogen timing (50% of N at sowing and 50% of N before the first irrigation; T1, 50% of N at sowing and 50% of N before the second irrigation; T2 and 50% of N before the first irrigation and 50% of N before the second irrigation; T3). Results indicated that plant height, ear length, kernel weight, number of grains/rows, number of grains/ear and grain yields all increased significantly as nitrogen levels increased and the level of 336 kg N/ha significantly exhibiting the highest values in both seasons. In terms of nitrogen application time, maize yield parameters such as plant height, ear length, kernel weight/ear, number of grains/rows, number of grains/ear and grain yield were significantly affected by nitrogen timing, with the highest values obtained at T3 while the lowest values obtained at T1 in both seasons. The interaction had a significant impact on plant height and grain yield/ha, with the tallest plants, the highest yields and its components observed at 336 kg N/ha, with 50% of N applied during the first irrigation and 50% of N applied during the second. Furthermore, under the study conditions, NUE decreased dramatically as nitrogen levels increased and increased significantly as nitrogen application time changed.

Two field experiments were carried out at Gemiza (ARS), during 2012, 2013. The aim of the study was to evaluate the performance of S.C.167 and T.W.C. 253 maize under the use of different rates of NPK. Fertilizer were tested cross (Cs) , soil application (SA) and foliar one (FA). All the agriculture treatments were used as usual. A split split plot design was used. five traits were studied. Such traits were distributed at ear length, ear diameter, ear height, cob. Weight, and shilling percentage. The obtained results could be summarized as follows :-Crosses, soil application and foliar application of NPK signifcantly affected most studied traites except ear height, cob. weight, and shilling percentage .-Significancey was completely absent as respect to first and second order interaction with all studied trait but the superior vlues were produced from combination (T.W.C. 253 × 80% NPK (S.A.)), (T.W.C. 253 × 80% NPK (F.A.)) and (80% NPK (S.A.

The present study entitled “effect of weed control on weeds, grain yield and its components of maize (Zea mays L.) cv. Single cross-10 was carried out at the Agricultural and Experiments Research Station at Giza, Faculty of Agriculture, Cairo University, Egypt. The experiment was conducted in the summer 2017 and was repeated in 2018 on the same piece of land to conform previous findings. The experiment design was Randomized Complete Block design (RCBD) having three replications. Six treatments include atrazine (1.0 kg/ha), glyphosate (0.8 kg/ha). atrazine + glyphosate, one hand hoeing after three weeks, hand hoeing twice after three and five weeks from sowing and weedy chick as control were used. Results indicated that glyphosate was found superior to atrazine for all studied characters. Moreover, lower weed dry matter accumulation and higher weed control % as well as higher values of ear characters ( ear length, ear diameter, grain weight/ear and shilling %) and grain yield per unit area were recorded in tank mix application of atrazine + glyphosate followed by hand hoeing twice.

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To achieve larger production per unit area, sciences and farmers face a great defiance in improving cropping practices and elicitation new top yielding wheat varieties and also to establish the effects of these factors on the spike characters. Two years experiment were conducted to evaluate the effect of three nitrogen fertilizer levels (recommend rate 80 kg N/fed and 25% lower and higher than the recommended, i.e. 60 and 100 kg N/ fed, three seeding rates (40, 60 and 80 kg grains/fed) and there varieties (Giza-171, Gemmiza-12 and Shandawil-1), on spike characters of wheat at the Agricultural and experimental Research Station, Faculty of Agriculture, Cairo University, Giza, Egypt during 2018/2019 and 2019/2020 seasons.The experimental design was a split- split plot in randomized complete block arrangement with three replications. Nitrogen levels were allocated to the main plots, while the sub plots were assigned for seeding rates. 2 Wheat varieties were distributed at random in the sub-sub plots.Each sub-sub plots area 4 m (2 x 2m).Generally,results indicated that significant effect on spike length and number of grains/ spike in both seasons and on weight of grains/ spike and 1000-grain weight in one season,where the tallest and heaviest spike as well as the heaviest 1000-grain weight were produced at the 100 kg N/fed in both seasons but the highest number of grains/spike was obtained at 80 kg N/fed in one season. It could be concluded that application nitrogen at the rate of 100 kg/fed proceed the favorable effect on spike characters under the environmental conditions of the experimental site and the similar conditions. Seeding rates caused a significant effect on all studied traits in one season,so the highest values were at 80 kg grains/fed,but this effect on 1000-grain weight was true in both seasons,where the highest value was at 60 kg grains/fed.Moreover,varieties were significantly differed in all spike character in both seasons except number and weight of grains/spike in one season where Giza-12 variety surpassed others.Al studied interactions had significant effect on all studied traits either in one or two season.Planting Giza-171 with 80 kg grains/fed and application of 100 kg N/fed was the pest treatmnt.