22 BOAED OF AGRICULTURE. 



Ill tlio experiments of Prof. Sanborn, previously referred 

 to (Bulletin No. 5), when samples of soil were taken near 

 the close of a hot clay, the first 3 inches of tilled soil con- 

 tained a trifle less moisture than the first 3 inches of untilled 

 soil, but the second 3 in(;hes of tilled soil contained very 

 much more than the second 3 of the untilled ; and in all 

 cases, day or night, when samples were taken to a depth of 

 6 inches, those from the tilled soil held more moisture than 

 those from the untilled. 



If then, light dry soil obtained by tillage is a good 

 mulch, which will check the evaporation and serve to retain 

 the moisture of the soil for our crops, it is certainly a cheap 

 and always available means of accomplishing this end, and , 

 is within the reach of every one, and the farmer Avho neg- 

 lects such ,an available means of protecting his crops from 

 drought, which is almost as sure to come as the seasons, has 

 no reason to complain if his more enterprising neighbor's 

 crops grow when his own fail. 



To recapitulate : I have attempted to show that our crops 

 require a large amount of water, but that our annual rainfall 

 is always much greater than the needed amount, provided it 

 could be made available at all times ; that all soils have the 

 power to absorb a large amount of water and hold it until 

 carried ofi" by evaporation ; that all that is needed on good 

 soils to protect our crops from injury by drought, is to in- 

 crease their absorptive power by the addition of vegetable 

 matter or clay, and by mulching to check the excessive 

 evaporation ; and that a mulch of loose, dry soil, to be 

 obtained by frequent tillage, is a good and practicable means 

 of obtaining it. 



In the practical application of these principles, we should 

 select the most retentive soils, and if their natural drainage 

 is imperfect, secure good drainage of surplus water by arti- 

 ficial means. On such soils, to hasten their drying in 

 spring, we should start the plough as early as it can be used 

 without making the soil lumpy ; for by ploughing the moist 

 soil in early spring, we break the connection with the cap- 

 illary tubes which bring the water up so rapidly from the 

 subsoil, and by admitting tbe air we dry the surface and 

 lower the evaporating point. After we have planted the 



