MULCHED-BASIN SYSTEM OF IRRIGATED CITRUS CULTURE. Q21 
TapLE 1X.—Relative yields of oranges with different mulching materials in 
the basins. 
Yield in 1916. 
Corrected 
Percent- 
hi . Number | Average | on basis 
Mulching material. of trees. | number | of pre- apere! 
of vious ield 
oranges | perform- 
per tree. | ance of BGG 
pAfabfash ay 2222-22 ~ Soe 2s 2 ce ce Seca Ra Tha 5A ee 12 550 532 150 
TEC EDY Ty co Set seat eee Gr ape Ure eee Beene 9 463 460 130 
INGLE ONO RG he Serene Crest ean ae cae SOU ree eae a ee eae are 9 358 358 101 
Bem Gy Weinvaausssnoeessnns veeest os se nese aeuseeeuceResueEsceecene 10 280 313 89 
SIVOC ER CLOWIC Tiss iey st eaten ee ae ee aera Ee i eae 9 314 305 86 
TBSGUE. GUO AEN asap eB AI ee a ee 5 302 300 85 
HEPAT SIT EVAN See ape ee eee eet a eas meee yor iss a Sees ap site s Epele 6 224 217 61 
It is evident from Table IX that the mulching materials tested 
differ greatly in value. The highest yield of fruit was obtained when 
alfalfa was used as a mulch, while the bean straw and manure rank 
next. The quantity of bean straw used, however, was not sufficient 
to make an effective mulch, and it seems probable that alfalfa and 
bean straw are of approximately equal value for mulching purposes. 
The other legumes were much less beneficial than alfalfa and bean 
straw. The lowest yield was obtained where pine shavings were 
employed asa mulch. This material effectively protected the basins 
from evaporation, so that the beneficial action of the other mulching 
material is clearly attributable to the organic products from the de- 
composing mulch which are carried into the soil with the irrigation 
water. 
The average number of oranges on the trees basined and mulched 
with alfalfa hay was 8 per cent greater than the average yield from 
these same trees during the preceding six years under furrow irriga- 
tion and clean cultivation. The other treatments all show a falling 
off in yield compared with the average yield of the preceding six 
years. Up to the time the basins were established, the trees had been 
irrigated by means of furrows between the ree rows. When the 
basins were established under the trees, the irrigation between the 
tree rows was discontinued. The excavations of the basins to a 
depth of 6 to 8 inches necessarily destroyed some of the small feed- 
ing roots, and this fact, combined with the discontinuance of the 
irrigation between the tree rows, forced the trees to establish a new 
root system during the time that the fruit buds of the 1916 crop were 
being developed. A decrease in yield accompanied in most instances 
the redistribution of the root system, and this fact emphasizes the 
desirability of a gradual transition to the basin system if the entire 
surface is not basined. Irrigation and cultivation between the basins 
for the first year following the installation of the basins would help 
