20 BULLETIN 490, U. S. DEPARTMENT OF AGRICULTURE. 



60 square feet in area) and were mulched with a mixture of hay of 

 different kinds. The trees improved in appearance, but on August 

 12, 1916, when the counts were made, they were still far from being in 

 as good condition as the trees in row No. 3. On that date the average 

 number of oranges per tree in row No. 2 was 182. 



At the time that row No. 3 was basined and mulched the rest of 

 the grove was treated likewise, except that smaller basins, 70 to 80 

 square feet in area, were installed. These trees improved greatly as 

 compared with trees in certain other adjoining rows which were 

 furrow irrigated in the usual way, but they have not yet come up to 

 row No. 3 either in the appearance of the foliage or in fruit bearing, 

 showing that the larger basins are much more effective. 



EUREKA TRACT. 



A test of the relative value of different mulching materials was 

 begun in this tract in October, 1915, on a block of 60 navel-orange 

 trees. The mulching material used included alfalfa, bean straw, bur 

 clover, sweet clover, barley hay, stable manure, and pine shavings. 

 The basins were about 10 by 12 feet in dimensions. Approximately 

 125 pounds of mulching material was applied to each basin, except in 

 the case of bean straw, which on account of its scarcity at the time 

 was applied at the rate of 75 pounds per basin. The manure was 

 applied at the rate of about 15 cubic feet per basin. Various com- 

 mercial fertilizers were also applied to some of the trees, but the effect 

 of these substances was not in evidence at the time the oranges were 

 counted. 



In August, 1916, 10 months after the mulch was applied, the 

 number of oranges on each tree was determined by counting. Eecords 

 of the yields of the individual trees in this block had also been kept 

 for the preceding six years by the Office of Horticultural and Pomo- 

 logical Investigations of the Bureau of Plant Industry, which 

 afforded an excellent basis for establishing the relative productive- 

 ness of the different trees under the same treatment. To make the 

 results of the mulching experiments directly comparable, the mean 

 yield of each group of trees in 1916 was corrected by dividing the 

 observed count by the ratio of the average productiveness of that 

 group during the preceding six years to that of the whole block for 

 the same period. This eliminates the influence of high or low per- 

 formance trees. The results of the counts are given in Table IX, 

 together with the relative yield under the various mulching treat- 

 ments. 





