20 ORANGE CULTURE IN CALIFORNIA. 



appearance of the trees. Close investigation has demonstrated 

 that the orange and the lemon tree, in particular, are very sen- 

 sitive to their soil surroundings. If an orange tree is growing, 

 for instance, in a warm, rich, friable soil, that is well under- 

 drained and that will not toughen by continued rain or by arti- 

 ficial irrigation, its vigor and healthy appearance are marked in 

 great contrast to those of its associates but a few rods distant 

 which may be struggling in a cold, clayey soil, both receiving 

 the same surface care and treatment in the meantime. 



This question has received and is still receiving the closest 

 attention that science and skill can bestow upon it in the Old 

 World. But it is, if possible, more important to us of Southern 

 California, especially those of us who are endeavoring to put 

 into the soil trees that inherit a vigor and tendency to outlive a 

 thousand generations. To reduce this to a practical propo- 

 sition, will it pay to risk the citrus family in any soils but those 

 which already give evidence of adaptability to their natural de- 

 mands? The pear, plum and apple, at least, thrive better in the 

 colder and stiffer soils, and will they not pay? The question 

 may arise in the minds of some, why is it that there is so great 

 a difference between the clayey and the sandy soils in their 

 effect on the growth of the trees already mentioned? It is quite 

 clear to my mind, from the fact that the one family requires 

 continued heat and moisture, and especially the heat, to such a 

 degree beyond the wants and necessities of the other. If you 

 expose, for instance, a given quantity of clayey loam under test 

 conditions to a moist atmosphere for a given time, it will absorb 

 about one-quarter more water than the same quantity of sandy 

 loam under the same conditions, and seventy-five per cent, 

 more than a calcareous sand. Pure clay will absorb still more 

 than clayey loam. Now why is it that clayey soil is so objec- 

 tionable, particularly in our warm and dry climate, if it can ab- 

 sorb and retain so much more moisture than the sandy and 

 friable soils? Simply because in giving off this water it carries 

 away the heat so absolutely essential to the well-being of the 

 citrus family. If, for instance, only sufficient water were applied 

 to supply the needs of the orange tree, and the soil in which it 

 grew could be kept in a friable condition by mechanical means, 



