1917] FIELD CROPS. 639 



tion was reached, while in the remaining tests the minimum amount of leaf 

 water occurred at the time of maximum evaporation. 



On a wet basis the maximum and minimum percentages of water in the 

 leaves showed an average variation during the day of 3.5 for corn, 3.2 for 

 Kafir corn, and 4.5 for milo maize. The average variation between the mini- 

 mum percentage of water during the day and the maximum during the night 

 was 5.4, 5.9, and 6, respectively. On a dry basis the average difference between 

 the minimum and maximum percentages of water during the day was 39.5 

 for corn, 31.1 for Kafir corn, and 35.9 for milo maize. The average range 

 between maximum and minimum water content during the night was 37.5, 

 47.5, and 40 per cent, respectively, while the average range between the mini- 

 mum percentage of water during the day and the maximum percentage during 

 the night was 67.8, 67.2, and 51.2, respectively. 



The average dry weight of a square meter of leaf for all observations was 

 48.2 gm. for corn, 52.5 for Kafir corn, and 56.2 for milo maize. The average 

 difference between the minimum and maximum amounts of dry matter in the 

 leaves for each square meter during the day was 4, 4.8, and 8 gm. for corn, 

 Kafir corn, and milo maize, respectively. The increase in dry matter began 

 at daybreak and usually reached a maximum between 2 and 5 p. m., the rate 

 of increase during that portion of the day when the climatic conditions were 

 severe being higher for milo maize than for either corn or Kafir corn. 



The results are held to indicate that the sorghums, more particularly milo 

 maize, can absorb water from the soil and transport it to leaves more rapidly 

 in proportion to the loss of water from the plant than can corn. As a result 

 of this the sorghums are enabled to produce more dry matter per unit of leaf 

 area under severe climatic conditions than can the corn plant. 



Experiments with legume crops under irrigation, J. S. Welch (Idaho Sta. 

 Bui. 94 (1911), pp. 14y flus. 5). — Field tests and observations with various 

 legumes under irrigation at the Gooding substation in southern Idaho are noted 

 and briefly discussed. 



Rate-of-seeding tests with alfalfa during the period of 1910-1912, inclusive, 

 gave average yields of 4.021, 3.726, 4.364, 3.855, and 3.702 tons per acre, with 

 20-, 16-, 12-, 8-, and 4-lb. rates, respectively. 



A comparison of the corrugation method with the flooding method for irrigat- 

 ing alfalfa showed the former to be far superior for the first season of growth, 

 after wliich it failed to show any advantage over the latter method. A com- 

 parison of different sized sti'eams for the application of irrigation water during 

 3915-16 gave average yields of cured hay of 4.246, 2.842, and 2.291 tons per 

 acre for streams of 0.3, 0.65, and 1.2 cu. ft. per second, respectively. Tests 

 on the duty of water for alfalfa hay during 1911-1914, inclusive, indicated that 

 for three crops of hay an application of about 2.75 acre-feet per acre gave best 

 results. 



For alfalfa-seed production light, frequent applications of water suflScient to 

 maintain a uniform but not excessive soil moisture content were deemed best. 



Field tests with red clover indicate that the common is the most important 

 strain, and that grown for hay it requires practically the same treatment as 

 alfalfa. The heaviest yields of seed were obtained from plats clipped late in 

 May. Increased yields of barley, wheat, and oats estimated at 17.57, 10.74, and 

 9.47 bu. per acre, respectively, were attributed to the plowing under of a red 

 clover crop as a green manure. 



Alsike and white clovers are deemed valuable as pasture mixtures, while 

 crimson clover has not proved to be sufficiently hardy for Idaho conditions. 



22397°— 17— No. 7 4 



