MULCHED-BASIN SYSTEM OF IRRIGATED CITRUS CULTURE. 15 



mulched, (2) surface soil left undisturbed, (3) seeded to barley, 

 (4) covered with about 2 inches of alfalfa mulch. The soil con- 

 tained 19.2 per cent of moisture when the cans were, filled. The cans 

 were weighed from time to time to determine the moisture loss, hut 

 only the final results need be given here. On August 3, 38 days 

 after the initial weighing, the moisture content of the soil in the 

 different cans was as follows: (1) Surface soil mulched, 14 per 

 cent; (2) surface left undisturbed, 10.1 per cent; (3) seeded to 

 barley, 3.1 per cent; (4) mulched with alfalfa, 18 per cent. The 

 soil seeded to barley had reached the wilting coefficient by July 10, 

 21 days after the seed was planted. 



These results show the relative effectiveness of a soil mulch and 

 an alfalfa mulch in retaining moisture. The soil under the alfalfa 

 mulch had lost but 1.2 per cent of moisture, while the soil under the 

 dust mulch had lost 4 per cent, or over three times as much as the 

 alfalfa-covered soil. The soil mulch in this test was, furthermore, 

 kept in a much more effective condition than is practicable in a 

 grove. 



EFFECT OF BASINING ON TREE GROWTH. 



THE SUNNY MOUNTAIN GROVE. 



On the light soil of the Sunny Mountain experimental grove it 

 was nearly a year before any very noticeable change occurred in the 

 appearance of the mulched trees, but during the autumn of 1914 there 

 was a distinct advance in the new growth on the trees in the basins as 

 compared with the check trees. 



The grove was badly infested with scale, for which it was fumi- 

 gated in the fall of 1914, at a time when the new growth on the 

 basined trees was well advanced. The basined trees, on account of the 

 larger amount of new growth, were injured more by the fumigation 

 than the check trees, but the trees soon recovered and again grew 

 faster than the check trees. The beneficial effect of the mulched-basin 

 treatment was also plainly in evidence on the untreated rows of trees 

 immediately adjoining the experimental tract, showing that the root 

 systems extend laterally to adjoining tree rows when conditions are 

 favorable. 



THE VICTORIA GROVE. 



The portion of the grove used for these experiments had been pre- 

 viously used as an experimental plat and had received sodium nitrate 

 only as a fertilizer for four years. This experiment was terminated 

 in 1913, and the plat was manured in 1914. The trees were in an un- 

 thrifty condition in 1914 and 67 per cent of the leaves were mottled. 

 The trees were heavily pruned in the winter of 1914-15, so that the 



