Field experiments were conducted to study the differential responses of a wheat crop to water stress during different stages of its growth. Evidence was produced to show that both the flowering phase and the stage of grain filling and maturation were more sensitive to drought than the vegetative period of growth. Yield of wheat was not reduced when the crop suffered from cycles of water stress induced during the vegetative period, if the crop received favourable water regimes thereafter. Efficiency of water utilization from different water treatments was assessed. There was no relation between the protein and starch contents of the grain and the type of water treatment.

The effects of different water treatments on crop development and on components of yield were studied.

Equal volumes of irrigation water, applied in different ways to a crop of haricot beans in two seasons, showed that the best practice was 60 mm. irrigation every ten days.

The effects of three irrigation regimes on growth, yield and quality of cotton were investigated for two seasons in relation to earliness, quality and water-use efficiency, expressed as m. of water/kg. cotton produced. Light irrigations of cotton, at 75 mm. per irrigation every ten days, were economically better than the traditionally-accepted practice of irrigating every 14 days, and markedly better than prolonging the irrigation cycle to 20 days, mainly due to increased market value of the crop. The results also showed that irrigation intervals of 20 days, besides depressing yield, had a deleterious effect on fibre strength, though the different water regimes did not seem to affect other quality tests.

A simple but reliable type of drainage lysimeter was used to measure evaporation rates from lucerne and wheat and these were compared with calculated estimates of evaporation. Plant height was found to have an important effect on the amount of water lost from a plant cover, which also varied between two different species of crop of similar heights. Using two different soil types, maintained at a high moisture status, the rate of water loss was not influenced by the type of soil in which the plants were grown.

Four sesame varieties were tested at three plant populations to study varietal and population effects on some attributes of vegetative growth. Significant differences between varieties were detected and planting density was found to modify both areas and dry weights of leaves.

Experiments were made in glasshouses, growth cabinets and growth rooms to study the differential responses of the broad bean to water stress during the vegetative and flowering phases of growth. Plants in the flowering phase proved to be more sensitive to drought than in the vegetative period, and there were different responses (Relative Growth Rate) to temperature at different stages of plant growth. Day length and temperature influenced the position of the earliest flower initials on the stem, and intensity of flower shedding was aggravated by high temperature.

Four local sesame varieties were tested at three plant populations. Increase in plant density increased seed yield, which was positively related to number of pods per plant, seeds per pod, 1000-seed weight, heights of main stems and numbers of nodes per plant. Changes in soil moisture did not affect relative turgidity, whereas stomatal openness decreased as the irrigation interval became longer.

A crop of broad beans was subjected to different water treatments with a view to finding the most economical irrigation policy. Increments in yield were obtained from the sixth to ninth irrigation, but the relative significance of each irrigation after the sixth was dependent upon whether irrigation water was saved during the vegetative and early flowering phase, or during the phase of pod development. The influence of the different water regimes on yield components and on some attributes of growth was studied.