INFLUENCE OF SOIL MOISTURE UPON YIELD. 



29 



the plot receiving only nitrogenous fertilizer with that receiving the 

 complete fertilizer it will be seen that the former has a higher percent- 

 age of nitrogen, but this is evidently due to the poorly developed ker- 

 nels which weigh less per bushel than the grain on the completely 

 fertilized plot. 



Von Gohren's results show plainly that the kernels on the manured 

 land developed better than on the unmanured, and with this better 

 development there was an increase in the percentage of starch and a 

 decrease in the nitrogen. 



In Lawes and Gilbert's second experiment the percentage of nitro- 

 gen in the wheat on the soil manured with ammonium salts was less 

 than that in the wheat on the unmanured soil, but the weight of grain 

 per bushel shows that the higher- nitrogen content was due, in part at 

 least, to incomplete maturation. The higher percentage of nitrogen 

 in the wheat on the soil receiving only nitrogenous manures as com- 

 pared with that receiving complete manures can be traced to the same 

 condition of the grain. 



INFLUENCE OF SOIL MOISTURE UPON COMPOSITION AND YIELD. 



Experiments were conducted by D. Prianishinkov a in w^hich wheat 

 was raised with different degrees of moisture, but in the same soil and 

 under the same conditions of light and temperature. With a larger 

 amount of moisture in the soil there was a lower nitrogen content in 

 the grain. It was also stated that the duration of the period of vege- 

 tation was somewhat shorter when the moisture supply was greater. 



Traphagen 6 reports marked changes in the composition of wheat 

 grown with and without irrigation at the Montana Experiment 

 Station. A wheat grown under irrigation on the station farm was 

 planted the following year on land not irrigated. Presumably the 

 land was of similar character. The two crops of grain were analyzed 

 and the percentages stated below were found. 



No records of yields or of weights of kernels are given, but it is fair 

 to suppose that the unirrigated wheat possessed the light, shrunken 

 kernel which is characteristic of wheat raised without sufficient 

 moisture. 



" Abstract, Experiment Station Record, 13, p. 631, from Zhur. Gpuitn. Agron., 1 (1900), 

 No. 1, pp. 13-20. 

 ^Montana Experiment Station Report (1902), pp. 59-60. 



