Two field experiments were carried out during 1999 and 2000 seasons at the Agric. Res. and Exp. Center of the Fac. of Agric. Moshtohor to study the effect of different practices of seedbed preparation including chisel plowing alone "once or twice" and in combination with moldborad plowing, water stress during the different stages of growth (vegetative or flowering) and hand hoeing (once or twice) on maize yield, weed density, water relations and some soil properties. Results could be summarized as follows:
Moldboard plowing followed by chisel plowing reduced the bulk density whereas, porosity percentage of the soil increased. Moldboarding + chisel plowing followed by chisel plowing (twice) was good procedure to depress weeds in maize. Skipping one irrigation at two stages of growth (vegetative or flowering) were superior to control (without skipping) in depressing weeds. Two hand hoeings significantly depressed weed infestation. Plant height, leaf area, number of kernels/row, car weight, weight of grains/car and grain yield/fed, were markedly affected by tillage systems in 1999 and 2000. Weight of 100-kerrtcls was affected only in 2000. Moldboard plowing + chisel plowing was the best treatment. Exposing plants to water stress during vegetative stage decreased significantly plant height and leaf area while, grain yield of maize per feddan and its components decreased by exposing plants to water stress at flowering stage in both seasons. All studied traits of maize except car length, number of rows per ear and shelling percentage were affected by hand hoeing treatments in 1999 and 2000. The best treatment was that of two hand hoeings. The maximum value of seasonal consumptive use (CU) of maize was recorded by no-till treatment while, the minimum (CU) obtained by moldboarding + chisel plowing. Water use efficiency (WUE) of maize increased by moldboarding + chisel plowing. Also, the highest (CU) value was obtained from control (7 irrigations) while, the lowest value was recorded from skipping one irrigation at flowering stage. The highest (WUE) value was obtained from skipping one irrigation at vegetative stage. The maximum net farm return was achieved by moldboarding + chisel plowing with applying 7 irrigation-s and two hand hoeines in 1999 and 2000. |
