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EDITORIAL. 
THE EFFECTS OF ALKALI ON CITRUS TREES... 
In a bulletin issued by the California Experimental Station the 
authors report the result of a survey of several citrus groves in dif- 
ferent localities of Southern California, to determine the effects’ of 
alkali, preliminary to a study of methods of combating alkali. “The 
results of this survey are discussed and related studies briefly reviewed. 
Tn lieu of more definite information some general suggestions are given 
for the treatment of injured groves. Severe alkali injury was observed 
_ in a number of citrus_groves in several districts, and a large percentage 
of this injury was due to irrigation water. Chlorides were the most 
injurious constituents of the waters, although in certain localities some 
of the waters also contained injurious amounts of sulphates and car- | 
bonates. The irrigation supplies rarely contained enough alkali to 
harm citrus trees directly, but the injury was due to the concentration 
of salts after a variable period of years, depending on the nature of the 
soil, the amounts of alkali in the water and soil, rate of evaporation, 
&e. Alkali injury was also brought about in an experimental plot ‘at 
the citrus sub-station by repeated large applications of nitrate of soda. 
Examination of the nature of alkali injury showed that an excess of 
chlorides causes the tips and margins of citrus leaves to become yellow 
or brown, followed byXdefoliation. Sometimes a large portion of the 
leaves fall, and the young, tender shoots may be killed. An excess of 
sulphates and bicarbonates, on the other hand, is more likely to stunt 
the growth of the trees and cause the leaves to become chlorotic. More 
or less mottle leaf may also occur. Lemon trees are apparently injured 
by lesser amounts of alkali than oranges. The effects of alkali are 
intensified by the puddling effect of continued irrigation with waters 
containing sodium salts, particularly those containing sodium carbonate 
and sodium bicarbonate. Under such conditions the alkali’ cannot 
leach down beyond the citrus roots. It is especially important to keep 
the soil open and porous where nitrate. of soda or saline irrigation 
water 1s used in regions of light rainfall. To accomplish this, the use 
of deep-rooted cover crops and ploughing under organic materials such 
as manure or bean straw is recommended. When saline water is the 
only source of irrigation, the use of the basin or flooding systems instead 
of the furrow system of irrigating may afford temporary relief .from 
alkali injury in case the subsoil drainage is satisfactory. By increasing 
the ulkaline content of the drainage water, however, the ground water 
may ultimately become heavily changed with salts. Observations made 
in one district showed the most effective treatment for injured groves 
to consist of thorough tillage, ploughing down manure, and the applica- 
tion of irrigation water free from alkali. ; 
MANURING FOR MILK. 
Experiments extending. over several years, conducted at the Clona- 
kilty Agricultural School in Ireland, in which cows were tested on 
manured and unmanured pastures, are reported in the Hxperiment 
Station. Record. The experiment consisted in the estimation of the 
improvement in pasture following the application of basic slag and 
other fertilizers, in terms of milk yield, the results being obtained by 
grazing milch cows, and comparing the yield of milk produced with that 
ees on rats, 
