CULTIVATION 289 



Soil. — The citrus fruits are very cosmopolitan with regard 

 to soil. In California as well as in Florida and other citrus 

 regions the citrus fruits are grown on a great variety of 

 soils, ranging from light sandy soil through loams to black, 

 heavy, adobe soils. There are probably no other fruit trees 

 which are so plastic and which will adapt themselves with 

 such ease as to grow on almost any type of soil. The 

 determining factor in the soil seems to be its physical con- 

 dition and where this is good the citrus fruit is almost sure 

 to grow on any soil. From the stand-point of cultivation 

 and ease of handling the soft sandy loams should be pre- 

 ferred over the sticky, heavier soils. 



The subsoil perhaps influences the growth of the citrus 

 fruits to a greater extent than does the top soil. In many 

 cases the layer of soil just below the top soil varies in thick- 

 ness from a few inches to several feet. Sometimes this sub- 

 soil is so hard and so firm as to be impervious to water. 

 Not only does it prevent the water from soaking away or 

 rising from lower levels, but it is so hard that the roots of 

 the plants cannot penetrate it. On such a soil the root 

 development of the tree is greatly restricted. 



Sometimes the subsoil is too loose and open and unretentive 

 of moisture. This condition gives a deficiency of plant 

 food and a lack of water. 



A good soil then for the citrus tree may be of any type, 

 but preferably a sandy loam which should be at least 4 or 

 5 feet deep. It must be well trained and the subsoil should 

 neither be hard nor very loose. 



Cultivation. — Good preparation of the soil is essential if 

 profitable crops are to be grown. The soil should be thor- 

 oughly plowed and worked into a very fine state before 

 any trees are planted. After the trees are set, the soil 

 should be plowed thoroughly once a year and preferably in 

 March or April. At this time the cover crop should be 

 turned under. The plowing should be completed before the 

 tree comes into full bloom, in order to avoid the cutting 

 of the roots at this critical time. The depth of plowing 

 should vary with each year so as to- prevent any hard layer 

 from forming by the pressure of the plow, 

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