12 ORCHARD GREEN-MANURE CROPS IN CALIFORNIA. 
SEEDING. 
The most successful growers of green-manure crops sow vetch and 
bur clover in the first half of September, and peas during the latter 
half of the same month. Early seeding is being much more generally 
practiced now than it was a few years ago, when the greater part of 
the crop was sown in October. The time of irrigation of an orchard 
determines to some extent when a green-manure crop shall be sown, 
as water is not always available at the time desired. However, 
when water is available the time mentioned is that most generally 
favored for irrigation. 
The seed is sown either drilled or broadcast and harrowed in. 
IRRIGATION. 
After the seed is sown and before it germinates, the land is prepared 
for fall or winter irrigation if necessary. The furrow method is the 
one most commonly used. This consists in making a number of 
shallow furrows between the rows in the direction the water is to 
flow, the method varying in different sections and with the lay of the 
land. 
The basin method is used to quite an extent in the walnut orchards 
of the southern part of the State and in the orchards of the Santa 
Clara Valley.¢ 
Nothing further is done, with the exception of irrigating if neces- 
sary, until the crop is ready to turn under. When a crop is sown in 
September it can be plowed under during February. 
TURNING UNDER A GREEN-MANURE CROP. 
In turning under a green-manure crop the common moldboard 
plow (see fig. 1), the disk plow, or the disk harrow is used. In using 
the first a sharp colter is attached, and where the vine growth is 
heavy a chain is also used. Sometimes the land is run over once 
with a disk harrow before plowing. This enables a heavy growth to 
be more completely turned under. During the past few years the 
disk plow has been very generally used, and for turning under a heavy 
vine growth it works more satisfactorily than the moldboard plow. 
After plowing under a green-manure crop the land is harrowed, 
and as the crop decays cultivation is given. This at first is shallow, 
so as not to bring the vines to the surface, but later a deeper cultiva- 
tion is given. 
In sections having a very open soil or a sandy loam the disk harrow 
has been used very successfully in turning under a green-manure 
crop. The use of this harrow has been taken up with the idea that 
fewer surface-feeding roots of the trees are disturbed by its use than 
@See Bulletin 145, Office of Experiment Stations, pp. 46-50. 
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