— 127 — It is not advocated that watering should be given with such regularity as has been maintained through this experiment, for the amount of water required obviously varies with climatic conditions. Actually, 400 cubic metres every fifteen days is rather in excess of the water supplied to the main crop in general practice.

Conclusions.—(a) The seasons 1914 and 1915 afford effective contrasts, for in 1914 a pronounced water shortage was experienced, while in 1915 climatic conditions were exceptionally favourable.

(6) Heavy watering retards the development of buds, but increases vegetative growth, i.e., cotton tends to become weedy. The actual yield is as a rule high.

This retardation of the crop is not due to any increase in the maturation period of the bolls in suitable climatic conditions but entirely to an actual delay in the formation of the bolls.

(o) Water shortage hastens maturity, but causes a depreciation in the quality and quantity of the lint which becomes more pronounced as the season advances. The quantities of water necessary in the Sudan to obviate an early senescence are relatively large.

(d) Fine quality lint was produced by the plots receiving a medium quantity of water, i.e., 400 cubic metres every fifteen days.

(e) Length and strength are greatly influenced by the water supply, and it is possible to maintain them at a maximum by suitable waterings.

(/) Seed weight is increased by heavier waterings, but ginning percentage is less influenced than the other three features. The ginning percentage seems to be determined by the date of the maturation of the boll.

(g) These fluctuations, though small in range, are appreciable in the mass and recognised by spinners.

The Influence of Manures on the Cotton Crop.—The soil analyses, earlier tabulated, would seem to indicate an urgent need for an increased nitrogen supply, while other food materials would seem to be present in abundance.

The principal manures employed in the experimental work on the farm have been :— .

(a) Stable manure.

(&) Nitrate of soda.

(c) Superphosphate of lime.

Combinations of these have been made in varying proportions and applied to the west half of feddan plots, the second east half of the feddan being employed as a control in every case. Uniformity in conditions other than manuring has been maintained as far as possible. The same system of observations has been used as in the experiments previously described, by which a weekly record has been obtained of all measurable factors.