SITUATIONS FOR THE ORANGE 



435 



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 trees 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 natur- 

 ally 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 dan- 

 gerous 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 

 air can be dammed and held back; consequently the low land of 

 a small valley may be worse than lower land in the main valley, 

 because in the latter there are air currents which prevent accumu- 

 lation of cold air in particular places. These air movements make 

 some plantings on the upper plains of the main valley safe, though 

 the whole region may seem to the eye rather flat and low, but, of 

 course, broad sinks of the main valley may also be dangerous. Too 

 great elevations are to be guarded against. Where one approaches 

 the reach-down of mountain temperatures and loses the warming 

 influences of the valley mesas, the danger line is at hand. 



An ample water supply is essential. Small waterings which may 

 bring satisfactory growth to a young tree are no measure of the 

 needs of a bearing tree. The orange is using water all the year, 

 as discussed in the chapter on Irrigation. Its crop requires nearly 

 a year to reach maturity. Both in leaf growth and fruit growth it 

 nearly doubles the activity of the decidous tree and all the time it 

 is pumping water with its roots and pouring forth water into the 

 air through its exposed surfaces. No investment in orange planting 

 can be profitable without assurance of adequate water supply. 



PROPAGATION OF THE ORANGE 



The orange is grown from cuttings, layers, and seeels. Growth 

 from the seed is the method almost exclusively followed, and by 

 far the best, but the others will be mentioneel briefly. 



Growth from Cuttings. This method of propagation is de- 

 scribed in the chapter on Propagation. 



* "Marly Subsoils and Chlorosis of Citrus Trees," by E. W. Htlgard. Circular 27, 

 University Experiment Station, Berkeley. 



