The rapid agricultural development of Africa was
soon followed by soilerosion. The organic matter then undergoes anaerobic
fermentation. The appearance of this saltalways marks the end of the chapter.
Theanswer is both interesting and illuminating.
How has agricultural science dealt with the
diseases of crops?
When the condition is fullyestablished, the soil
dies; crop production is then out of the question.
The run-off then drains away as a thinsheet of
clear water, leaving all the soil particles behind.
Mother earth has provided a vast organization for
indicating theinefficient crop.
Often this oxygen starvation occurs naturally;
inother cases it follows perennial irrigation. The stages in the development of the
alkali condition are somewhat asfollows.
The organic matter then undergoes anaerobic
fermentation. Every possible gradation in alkali land is met with. The virus
diseases do not complete the story. China, unfortunately, does not stand alone in
this matter.
Iraq also furnishesinteresting examples of the
connexion between alkali and poor soilaeration.
Whenever possible these should be wide, very
shallow,and completely grassed over.
For many years erosion control measures have formed
animportant item in the national budget.
The run-off then drains away as a thinsheet of
clear water, leaving all the soil particles behind.
The protection of the crop from the inroads of the
parasite. Every possible gradation in alkali land is met with. Periodically thegreat
river wins in this unequal contest and destructive inundationsresult. This soil
thenproduced some of the heaviest crops of grass I have ever seen in
thetropics.
Where the drainage and aeration are poor, the
alkali condition atonce becomes acute. The stages in the development of the alkali
condition are somewhat asfollows. Alkali land therefore starts with a soil in which
the oxygen-supply ispermanently cut off. Theaction is reversed in the presence of
oxygen.
This when suitably conserved will soon re-create
large stretchesof valuable land. The regionalcontributions to this destruction,
however, vary widely.
China, unfortunately, does not stand alone in this
matter. What has been the general result of all thisstudy of vegetable
pathology?
Theodore Roosevelt first warned the country as to
itsnational importance. In the second place, myduties, fortunately for me, had not
been clearly defined.
The reaction of the crop to the first stages in
alkali production isinteresting.
Theodore Roosevelt first warned the country as to
itsnational importance.
Such anachievement merely provides another example
of agricultural banditry.