KESULTS OF TESTS WITH VARIOUS LEGUMES. 25 



RESULTS OF GREEN MANURING IN CALIFORNIA. 



There have been no definite tests made in Cahfornia to determine 

 the results in an increased yield of fruit or improved quality of the 

 same from the use of green manures. The only evidence available 

 is that of general observation and the experience of the orchardists. 



While orchardists differ to some extent in conclusions, they gener- 

 ally are favorable to the practice, as its continued and growing use 

 attests. Careful observations also show the beneficial results of 

 green-manure crops in a more thrifty appearance of the trees, an 

 improved condition of the soil, and a better quality of the fruit. 

 The belief is quite general that the yield, also, is increased. Orchards 

 in which a few years ago there were unthrifty trees with yellowish- 

 colored leaves now, after several years' use of green-manure crops, 

 show a decided improvement in color and general appearance. The 

 work of the California experiment station has demonstrated that 

 gummosis of citrus trees is brought on by unfavorable soil conditions 

 and that in remedying such conditions green manures serve a very 

 useful purpose.*^ Orchards in w^hich green manures have been used 

 for a long time are but little affected by this disease. 



The improved condition of the soil when green manures have been 

 used for some time has been readily noticeable to those handling an 

 orchard. The heavier soils have become quite open and friable and 

 the sandier soils more loamy. Beneficial results in the conserving 

 of rainfall and the prevention of washing of the soil have also been 

 very apparent. Most soils that wash badly do so because they are 

 deficient in organic matter. Green manuring, by the improvement 

 of the mechanical condition of the soil, not only prevents washing, 

 but the presence of the growing crop on the land prevents gullying 

 during the rainy season. This is of particular importance on sloping 

 lands. 



RESULTS OF TESTS WITH VARIOUS LEGUMES. 



From the fact that the addition of humus to the soil is one of the 

 main objects in using a green manure, it necessarily follows that, 

 other things being equal, the crop producing the heaviest vegetative 

 growth is the most desirable. To determine the comparative 

 amount of vegetative growth made by various crops the green weight 

 per acre has been determined, as shown in Tables I, II, and III. 

 However, these figures can be taken only as indicating in a general 

 way the amount of organic matter returned to the soil, as no correc- 

 tions were made for the varying moisture content of the different 

 crops. 



a Bulletin 200, California Agricultural Experiment Station. 1908. 

 190 



