SOILS FOR THE ORANGE 357 



able citrus climate are limited in area and every citrus climate has 

 numerous places where local meteorological conditions will prove 

 destructive to the profit of the enterprise, if not to the life of the 

 trees. The orange is a hardy tree, judged within its temperature 

 limits, but there is no money in a tree which is subjected to any 

 kind of hardship. For this reason the selection of a good depth of 

 strong, free loam should be made, for such is essential not only 

 to good growth of the young tree, but to its support through the 

 long productive life which the orange enjoys. Depth of good soil 

 is not only a storehouse of plant food, which will postpone the use 

 of purchased fertilizers, but it is a reservoir of water so that irriga- 

 tion can be applied in larger amounts at longer intervals. While 

 it is quite possible to grow an orange tree and to secure good fruit 

 on shallower soils, if conditions are kept just right by frequent use 

 of water and fertilizers in just the right amounts, such conditions 

 impose heavy burdens in their constant requirements of extra care 

 and expenditure, and these are handicaps of no small economic 

 importance. The tree can not live upon climate as a man may, 

 because a tree can not speculate ; it must have a good foundation in 

 the earth as well as a good outlook in the sky. 



Growing orange trees on defective soils has brought disappoint- 

 ment and loss in all parts of California. Ample supplies of irrigation 

 water available have encouraged over-irrigation where trees have 

 been planted above hardpan and drainage is absent. Dying-back 

 and yellow leaf have appeared in some groves and have been 

 accounted for by digging to find the roots bedded in mud and slush. 

 All plantings over clay sub-soils should be guarded against this 

 danger. Digging deep holes and filling them with good soil is 

 setting a trap for the future failure of the tree unless the deep hole 

 is properly drained by the nature of the sub-soil or by artificial 

 provision. On the other hand, planting over a gravelly sub-soil is 

 often disappointing, because the water passes through the sub-soil 

 as through a sieve, and the tree shows distress although generous 

 amounts are applied to the surface. Wide observation through the 

 State teaches that such warnings are needed by the unwary. There 

 has also been injury to the tree from planting over sub-soils carrying 

 excess of lime. 



Local temperature conditions even in sections generally suited 

 to orange culture should be carefully ascertained. Frosty places 

 must be avoided. A few feet difference in elevation may change 

 profit to loss, but one must not therefore draw the hasty conclusion 

 that all small elevations are favorable. The experience of the last 

 few years shows that nothing is, on the whole, more dangerous than 

 the warm bottom land in a small elevated valley which seems 

 naturally protected on all sides. There are many such places which 

 are far more treacherous than the uplands of the broad valleys, 

 which may be considerably lower. The benches around the sides 

 of the small valley may be safe and the bottom of the same valley 

 dangerous because there is no adequate outflow for cold air to the 

 large valley below. Look out for small valleys which have divides 

 of crumpled hills where they debouch into the main valley. Cold 



