24 THE MONTHLY BULLETIN. 



properly sustain them. A similar purpose attaches to irrigation in 

 deep furrows. By means of the latter but little of the irrigation water 

 wets the surface, most of its descending into the greater depths of the 

 soil in which in turn it is more adequately distributed in all directions. 

 By thus insuring better water as well as air conditions in the deeper 

 soil and a relative lack of water at the surface a double encouragement 

 will be offered the root to ramify deeply and widely in the soil, thus 

 insuring to the plant a better, larger and more lasting source of food 

 and water for vigorous growth. 



No fears need be entertained as to the effects of subsoiling or deep 

 plowing on trees growing in soils which have always been plowed shal- 

 low. The writer's experience in the field has taught him that trees do 

 not even suffer a temporary setback as a result of subf-oiling, and thus 

 the alarming condition usually predicted when the fibrous roots are 

 cut is a specious one. 



Deep Incorporation of Manures and Fertilizers. 



With respect to manures and fertilizers which are the carriers of 

 plant foods to the roots, the same rule holds as for the air and water 

 supply above discussed. In fact, their fate is dependent in so large a 

 measure on the fate of the soil water that it is difficult to consider the 

 two apart. It must of course follow to the reasonably minded that if it 

 is desirable to encourage the distribution of most of the soil water 

 considerably below the surface of the soil, the fertilizers must be placed 

 in its vicinity in order to insure their decay, transformation and avail- 

 ability. We are constrained, therefore, to recommend consistently that 

 manures and fertilizers be deeply incorporated in the soil. The pres- 

 ence of this plant food in the greater soil depths will thus be another 

 incentive to deep root penetration, the importance of which has been 

 emphasized above. 



Frequent Summer Cultivation and the Conservation of Soil Moisture. 



One of the most valuable precepts for agricultural practice flowing 

 from the development of that interesting branch of soil science called 

 soil physics is the conservation of soil moisture by means of mulching. 

 Perhaps nothing else in our farm practice can be said to be attended 

 with such striking results as the mulching of soil for the purpose of 

 moisture conservation. Among the numerous investigations on the 

 subject those of King for Eastern conditions and Hilgard and Lough- 

 ridge for California conditions have clearly shown why mulches are 

 effective, to what extent they are so, and have worked out the best 

 methods of their application. The principle of the mulch of course 

 consists merely in having something on the surface of the soil which 

 will act as a blanket and prevent the dissipation of soil moisture as it 

 is brought to the surface by a combination of physical forces, the exact 

 nature of which we do not as yet understand. It follows, therefore, 

 that the best mulch must be the one which is cheapest and the most 

 feasible to employ in soil management, and at the same time one which 

 is very efficient in moisture conservation. There are only two materials 

 which could possibly answer to such description under ranch condi- 

 tions. They are the straw^ mulch and the dust mulch. By the first we 

 mean mulching with a thin layer of straw on the surface soil, and by 

 the second the covering of soil by a thin layer of air dry soil thoroughly 



