1817] FIELD CROPS. 39 



of the plant If applied two months after the use of the nitrates. Frequent 

 light rains, together with heavy dews, produce different effects from irrigation. 

 The time of rainfall and weather conditions following are of great but indirect 

 importance, depending upon the development of rust. 



Just before maturity, the plant transfers its substance to the berries and 

 the effect of rust is to inhibit this transfer. Rust causes a marked depression 

 in the protein content of the wheat, even if the crop is well developed at 

 the time of attack. Rust also increases the percentage of crude fiber in the 

 wheat by preventing the filling out of the berries. 



There exists an optimum ratio between nitric nitrogen and available 

 potassium in the soil. If potassium predominates, yellow berry is produced, 

 while, if nitric niti'Ogen predominates, soft, weak plants and small, flinty, 

 and often shrunken berries result. 



In regard to crushing strength, Colorado wheats range from semihard to 

 hard. The general composition of these wheats is above the average but 

 undergoes considerable variation due to soil and other immediate causes, but 

 not as a rule to climatic conditions. 



Nitrogen fixation proceeds rapidly enough, in the soils studied, to furnish 

 an amount of nitrogen sufficient to become an important factor in these 

 problems. Furthermore, nitrification proceeds rapidly enough to more than 

 quintuple in five months the nitrate nitrogen in the soil at harvest time. 



The analytical methods employed by the author are abstracted on page 11. 



Dry-farmed and irrigated wheat, J. S. Jones, C. W. Colvee, Amy Kelly, 

 and Elizabeth Hays (Idaho Sta. Bui. 88 {1916), pp. 18). — This reports analy- 

 tical and baking tests with samples of dry-farmed and irrigated wheat 

 grown in southern Idaho during 1912, 1913, and 1914, for a comparison of 

 the quality of wheat so produced and as supplementary to work previously 

 noted (E. S. R., 27, p. 266). 



From an analysis of the mill products of 79 samples of dry-farmed wheat 

 and 60 samples of irrigated wheat, two things are outstanding in the 

 Bluestem and Turkey Red varieties, the two varieties which seem to be 

 most commonly grown on both dry and irrigated farms. These are (1) 

 the lower yield of flour from the soft wheat, and (2) the lack of any decided 

 difference between dry-farmed and irrigated Bluestem and dry-farmed and 

 irrigated Turkey Red in the percentage of flour obtained. The average gain 

 in milling for all dry-farmed samples was 1.17 per cent and for all irrigated 

 samples 1.12 per cent. 



Additional data are presented showing the weights per bushel and per 

 thousand kernels for all wheat samples, together with the percentages of 

 moisture, ash, ether extract, and protein for all wheat and flour samples 

 and the percentages of gluten (wet and dry) and of gliadin for all flour 

 samples. In a comparison of Bluestem and Turkey Red samples the irrigated 

 samples are slightly heavier in weight per bushel, while in weight per thousand 

 kernels the difference is more pronounced, especially in Turkey Red. The 

 moisture, ash, and ether extract of both wheat and flour show no differences 

 that would serve to identify them with the system of farming under which 

 they were produced. There was an average difference between the flours 

 of dry-farmed and irrigated Bluestem of only 0.38 per cent of protein, 2.35 

 per cent of wet gluten, and 1.06 per cent of dry gluten, while those of the 

 average dry-farmed and irrigated Turkey Red wheats show a difference of 

 2.79 per cent protein, 9 per cent wet gluten, and 2.24 per cent dry gluten, 

 all differences being in favor of the dry-farmed samples. The ratio of wet 

 to dry gluten in both dry-farmed and irrigated Bluestem is 2.9, in dry-farmed 

 Turkey Red 3.2, and in irrigated Turkey Red 3. Since the relative strength 

 102477°— 17 4 



