414 DRY LAND FARMING 



and where the humidity is marked trees will eventually 

 take possession and crowd out the grasses. In arid 

 areas under such conditions the weed growth would be 

 much less strong. The possession of the soil by grasses 

 would be much less complete, and forest trees would 

 not grow at all. In humid areas germination from 

 good seed is sure, but in dry areas such is not always 

 true. Even though crops should be grown specially 

 to increase the supply of humus, dry conditions may 

 prevail to such an extent that they may not furnish very 

 much vegetation. 



Fortunately humus is not lost so readily in dry 

 areas as in moist areas of equal temperature. Organic 

 matter buried in the soil does not decay in the absence 

 of moisture. Should a heavy coating of stubble be 

 buried in the soil in dry areas, say in the spring season, 

 and a crop be sown on the land, the crop will fail be- 

 cause the undecayed stubble cuts off the moisture sup- 

 ply from below. Should dry weather prevail through 

 the entire season, the stubble will be turned up by the 

 plow in a condititon showing but little decay, whereas 

 had rain fallen copiously the stubble would have been 

 all decayed. This explains why the effects of farmyard 

 manure are discernible for a period much longer than in 

 humid areas. This fact tends much to even up, as it 

 were, the difference resulting from the different quanti- 

 ties of humus possessed by soils in dry and humid areas 

 respectively. It is less needed in dry soils to keep them 

 in mechanical condition, and because of their dryness. 

 Moreover it is claimed that humus in dry areas contains 

 much more nitrogen than in humid areas. But because 

 of the greatly increased power which humus gives to the 

 soil to hold moisture when judiciously supplied to it 

 in dry areas, the aim should be to maintain at all times 

 an adequate supply in the same. 



