SOME SUBTROPICAL ORCHARD FRUITS. 199 



feeding-fibres. It must have water and a regular supply 

 of vegetable humus to give the needed green color to the 

 foliage and to carry a full crop of fruit to maturity. 

 Experience has shown also that continued culture and the 

 use of commercial fertilizers soon change the mechanical 

 condition of the soil, and that a given supply of water is 

 sooner evaporated than on soils well supplied with vege- 

 table matter. 



In the fine orange orchards of Eedlands, Riverside, 

 Colton, and other orange centres of south California, many 

 growers are now cultivating and watering in the usual way 

 during the season of growth, but follow it with a cover- 

 crop of the field-pea, cow-pea, or other legume to shade 

 the ground during the period of fruit maturation and to 

 add humus and nitrogen to the soil when plowed under 

 the next spring. In the winter of 1897-98 the writer 

 travelled many miles to observe the effect of this treatment 

 on the color of the foliage and the perfection of the fruit. 

 In all cases the orchards given the cover-crop treatment 

 in connection with fifty pounds of potash and twenty-five 

 pounds of phosphoric acid to the acre annually, were indi- 

 cated afar off by the dark green of the foliage alone. 



On the foot-hill slopes of the Salt River valley in Arizona 

 the observed benefit of this system was still more apparent, 

 as the cover-crop seemed to bring about a ripening of the 

 wood prior to danger from frost that prevented much 

 damage to leaves or points of growth when cultivated 

 orchards were defoliated. 



195. Pruning the Orange. The most approved plan of 

 pruning in European and American orange-growing 

 centres is to form a low head and compact top when the 

 tree is young and up to the first stages of bearing. In 

 transplanting the tree is trimmed to a straight shoot, as 

 practised with the peach in Georgia, and tying to a stake. 



