24 Journal of the Department of A(;riculture. 



of brak accompauies the couditiou the result cau be better imagined 

 than described. I have met instances where even the brak bushes 

 have died. 



Wlien the sub-soil water has risen high enough to keep the surface 

 soil permanently moist it will in most cases entail drastic and costly 

 measures to prevent the trouble from spreading. Timely warning of 

 what is happening is of great advantage in such cases. This may be 

 obtained by observing the water-levels in a series of boreholes, which 

 can be very cheaply put down with an ordinary post auger, having 

 extra lengths of rod if necessary. If the water-level in any hole rises 

 the irrigator may know that he is putting more water on the land than 

 the drainage can cope with. 



Every irrigator should have a post auger not only for making 

 holes in which to observe ground water levels, but also to see how deep 

 the water sinks at the spot on which it is applied. This is necessary 

 because the same watering will sink to different depths in different 

 lands. The method of applying water and allowing it to run into a 

 bed until it has reached the lower end may result in too much or too 

 little water being applied. If the soil is porous too much water will 

 sink in at the top end of the bed. while if the soil is stiff too little will 

 penetrate any where. 



The Penetration of Soil by AVater. 



When land is irrigated for the first time it may not take the water 

 so well as it does. on the next occasion. Thereafter there is only too 

 frequently a progressive decline in the rate at which the water 

 penetrates. This applies particularly to soils that could be classed as 

 loams and clays. 



This deterioration in the physical properties of the soil is always 

 greatest in cases where water is used in excess. The desirable crumb- 

 like structure of the soil g-ets destroyed and the soil becomes more or 

 less consolidated. I cannot here enter into the causes save to say that 

 if in the course of irrigation there is a development of sodium 

 carbonate in the soil this may arise through using too much water or 

 it may be added in the water. Unfortunately for us the occurrence of 

 carbonate of soda in the waters available for irrigation is very general, 

 which means that much of the soil that can be irrigated requires very 

 careful and intelligent handling to prevent it from deteriorating. In 

 a case which has recently come under my notice five or six years of 

 irrigation have resulted in the greatest difficulty being experienced in 

 producing what at be^t can be called a poor seed-bed. The following- 

 are the operations necessary to prepare that land for seeding : — 



The land is first watered, it is then disced, rolled, ploughed, 

 disced again, and then harrowed with a zig-zag harrow. 



I was shown some land that had been watered a week previously 

 as the first step in the above operations. The land had a dry skin, 

 but below this it was very wet and pasty to a depth of about six inches : 

 below this depth it was much drier and of apparently good physical 

 condition. It is evident that the water could not penetrate properly. 

 By the time the soil is sufficiently dry to turn over, the surface has 

 dried out to a hard unbreakable mass. This land is yielding about 

 five to six bags of wheat per acre. (3ne can imagine what the yield 

 would be if it were possible to form a good seed bed. 



