ORANGE CULTURE IN CALIFORNIA. 51 



irrigations are probably best, while on soils with good natural 

 under -drainage, or disposed to be 'leachy,' irrigation may, 

 and probably should be, heavy heavy in contradistinction to 

 an irrigation which simply wets the surface of the soil a few 

 inches in depth. Water should, in all cases, be applied in suffi- 

 cient quantity so that the moisture therefrom will fully meet the 

 moisture from below, otherwise the effect will be to produce an 

 undue amount of surface roots a thing to be carefully avoided. 



"As to the frequency with which orchards should be irrigated, 

 much depends, as referred to above, on the thrift of the trees, 

 whether they be fruiting or not, and perhaps still more on the 

 character of the soil for retaining moisture. The practice of 

 some, of allowing their trees to show signs of distress before 

 irrigating them, is a vicious one. As well may a man fast until 

 emaciation before eating, without injury to himself, as that trees 

 be allowed to show signs of withering before supplying them 

 with their needed moisture. Perhaps perfection in irrigation 

 would be to keep the soil at all times, to the very farthest point 

 to which the roots extend, in a state of what may be called 

 'growing moisture.' There need be no fears, as are entertained 

 by some, that by so doing trees will be unduly stimulated and 

 induced to make an unnatural and unhealthy growth. They are 

 governed by fixed laws in their growth, and under no circum- 

 stances will they take up more food from the soil than they can 

 assimilate and appropriate to their legitimate use. 



"The practice of mulching the ground around the trees merits 

 a passing notice in this connection. The advantages of this are 

 obvious in the case of small trees or those newly planted. A 

 mulching of rotted straw or coarse manure retains the moisture, 

 by preventing rapid evaporation, and in our cool nights retains 

 the warmth generated in the soil by day, thus equalizing its 

 temperature and thereby favoring growth, and by shading the 

 ground from the direct rays of the sun, enhances its fertility in 

 addition to that derived from the decay of the mulch. 



"The necessity of thorough cultivation, stirring and pulver- 

 izing the soil after each irrigation, would seem so self-evident 

 as to require no mention here were it not so often neglected. 

 This negligent habit of leaving the ground undisturbed after 



