36 FUNDAMENTALS OF FRUIT PRODUCTION 



the result of seepage from the hill at the bottom of which the orchard is 

 located, supplying so much water that moisture is eliminated as a limiting 

 factor. Many orchards in the eastern United States are in just such 

 locations. 



Some Kentucky and Kansas Records. — Some of the findings of the 

 United States Bureau of Soils on soil moisture conditions in grass land 

 and in cultivated soil may be summarized here. Records were made 

 during the months of May, June and July, 1895, of the water content of 

 soils at a number of places in the United States and under different 

 tillage conditions.^-^ These records bring out a great difference between 

 soils in the way this moisture content is influenced by treatment. For 

 instance, at Greendale, Ky., during the last half of May, the moisture 

 contents of uncultivated, bare land and of bluegrass sod were pract- 

 ically the same (about 18 per cent.) ; during June, however, the moisture 

 content under the bluegrass gradually decreased to about 10 per cent, 

 while that of the uncultivated bare land remained about 17 per cent, 

 except for a period of about 5 days at the end of the month when it 

 dropped practically to the figure shown by the sod land. During July 

 the bare, uncultivated land averaged 2 to 3 per cent, higher in moisture 

 content than the grass land. At Lexington, Ky., a similar series of 

 records showed an average moisture content about 5 per cent, higher dur- 

 ing May, 8 to 10 per cent, during June, and 1 to 5 per cent, during July, 

 in the bare, uncultivated land compared with that under bluegrass sod. 

 During June the bluegrass made its very heavy draft upon the moisture 

 supply of the soil, lowering it to the point where little water was available 

 for plant growth and cultivated crops consequently suffered. 



This suggests that if the sod-mulch system of orchard culture checks 

 tree growth materially during the early part of the season or again after 

 mid-season it is not on account of its lowering the water content of the 

 soil, at least in those sections favored with summer rains. On the other 

 hand, orchards in sections likely to have little rain between the middle 

 of June and early fall probably would suffer materially from drought during 

 that period. In any case, the growth of grass mulching material would 

 take large amounts of water during June; during that month the itrees, 

 may or may not be able to spare it. The question of the practicablity, 

 desirability or efficiency of the grass mulch method of culture so far as it 

 concerns soil moisture therefore depends on what precipitation can be 

 expected reasonably during July, August and September or what can be 

 applied by irrigation — for orchards under these two methods of soil 

 management are very likely to enter this period with material differences 

 in the amount of available soil moisture. In Scott, Kan., on the other 

 hand, the moisture content of prairie sod land has been found to average 

 only about 8 per cent, during the last half of May, while cultivated land 

 averaged about 17 per cent. Rains late in May and scattered through 



