36 SCIENTIFIC SOCIETY OF SAN ANTONIO 



effect of this arrangement of ditches is, that when there 

 is a sufficiently heavy rain, water runs down the hill into 

 the main ditch, and from this into the laterals, as it ar- 

 rives at them, these being deeper than the main. When 

 all the laterals are nearly full, the excess of water runs 

 off through the main without doing any damage, this ditch 

 being well sodded with the native buffalo-grass, or curly 

 mesquite (Buchloe dactyloides) . The water held in the 

 laterals penetrates deeply into the ground. Thus, in some 

 cases, the trees are thoroughly watered when the adjoining 

 land is moistened but a few inches deep. By maintaining 

 a dust-mulch, much of this moisture is conserved, even 

 during a long drought. There seems to be but little danger 

 from excess of water, as the effect of such a condition was 

 noticed but once in the history of the orchard, when one 

 tree was lost from this cause. 



HISTORY OF THE ORCHARD. 



The land was planted to fruit-trees, fifty-five in num- 

 ber, partly in December, 1902, and partly one year later. 

 These trees represented 21 varieties of peaches, 7 of 

 plums, 5 of pears, and 2 of apples. The lana was broken 

 up deeply and the trees planted in holes four feet in diam- 

 eter and over two feet deep. Each year during the period 

 extending from March to October the orchard has been 

 given from four to eight shallow cultivations by plowing, 

 harrowing, hoeing, etc. In this way the weeds have been 

 kept down, and the dust-mulch restored after each heavy 

 rain. 



The years 1903 to 1908 inclusive were favorable as to 

 rainfall, the total for but one of these falling below the 

 average annual precipitation (27 inches) of San Antonio. 

 There were several comparatively short droughts, but the 

 trees did not suffer seriously in consequence. Tests made 

 during the droughts indicate that at no time did the 

 per cent of moisture in the soil, calculated on the basis of 

 the moist soil, fall below 16. This was at the depth of 8 

 inches. Tests of the soil at 18 inches showed a somewhat 



