32 BULLETIN 61, HAWAII EXPERIMENT STATION 
in rows at right angles may be easily cultivated and irrigated when 
necessary. This arrangement is also convenient in picking the fruit. 
During the first year the plants may be watered In depressions 
about the base of the trunk. These depressions should be filled and 
firmed down previous to the occurrence of the heavy rains and winds 
of the wet season to prevent the plants from being blown down. 
After the first year the cultivation should be carried on above the 
feeding roots which will then have extended out in the soil in all 
directions several feet from the trunk. Water should then be ap- 
plied above the feeding roots in a moatlike basin several feet from 
the base of the trunk. Plants which are allowed to stand in large 
basins for several years invariably go down in windy weather, 
particularly when they are loaded with fruit. The moat about a 
plant need not be large. A shallow trench 2 or 3 inches deep and 
12 or 18 inches wide, circling the base of the trunk at a distance of 
2 or 3 feet from it, depending on the size of the plant, will do. Com- 
mercial orchards should be discontinued in three or four years after 
they have begun to fruit. The best and largest amount of fruit is 
obtained from young plants 2 to 4 years of age. 
IRRIGATION 
The papaya responds to irrigation much as it does to natural 
rainfall. Under the widely varying conditions existing in Hawaii, 
it is impossible to give any definite rule governing the amount of 
irrigation to be used. With a uniform supply, which may vary 
from 25 to 50 inches of rainfall evenly distributed weekly throughout 
the year, the plants naturally fruit abundantly and continuously for 
possibly three to five years or more. Irrigating, when practiced, 
should be done with considerable care in order that fruit of the best 
quality may be produced. Insect enemies, particularly red spiders, 
are more likely to attack the foliage during irrigation periods than 
at other times. It has beeen found that in general the amount of 
water required is not nearly so great for the papaya as for most 
other orchard crops. In many groves on dry, leeward lowlands, 
water should be applied liberally about once a week in shallow 
basins or furrows between the rows. The hillside groves should be 
watered in somewhat the same manner, but the plant rows are ar- 
ranged along contour lines to accommodate both irrigation and 
cultivation. 
FERTILIZING 
The addition of barnyard manure to the soil in which the papaya 
is growing has been found to be beneficial at the station. In addi- 
tion to the light application incorporated at the time of planting, 5 
to 10 pounds have been worked into the surface soil around each 
plant about twice a year. This form of fertilizer adds plant food, 
improves the water-holding capacity of the soil, and encourages 
beneficial bacterial action. Good results have followed the use of a 
fairly complete chemical fertilizer having the following formula : 
Pounds 
Superphosphate (acid phosphate) 800 
Sulphate of potash (high grade) 315 
Nitrate of soda 250 
Sulphate of ammonia 190 
Black volcanic sand 445 
