438 EXPERIMENT STATION EECORD. [Vol.35 



breeding with reference to spacing plants in experimental and practical plant 

 breeding, giving special attention to the recommendation of Mitscherlich that 

 each plant be given sufficient space to enable a person to walk around it and 

 to treat it frequently with nutrient solution. The author concludes that this 

 plan does not meet practical requirements and expresses the belief that the 

 practical plant breeder should be advised to adhere to the customary spacing 

 in pedigree and selection work. 



Rotations and tillage methods in western Nebraska, W. P. Snydeb and 

 W. M. OsBORN (Nebraska Sta. Bui. 155 (1916), pp. 6-48, figs. 6; pop. ed. (1915), 

 pp. 21, fig. 1). — This bulletin is a report on plat experiments begun in 1906 at 

 the North Platte Substation in cooperation with the Bureau of Plant Industry 

 of the U. S. Department of Agriculture for the purpose of testing various 

 rotations, crop sequences, and methods of tillage in the production of corn, 

 spring wheat, oats, barley, and sorghum hay. The deductions presented are 

 based on the average results of eight years' work. 



The weather conditions of the season are recognized as the greatest factor in 

 controlling yields. The seasonal precipitation was found to have a much 

 greater influence on the crop production than methods of seed-bed preparation, 

 crop sequence, or the use of manure. During favorable seasons profitable 

 crops were produced by all methods under test and during unfavorable seasons 

 profitable crops were not produced by any method. The system of alternate 

 cropping and summer tillage failed to overcome severe drought conditions, 

 and was less profitable in the production of corn and spring grain than ordinary 

 methods of production. In some unfavorable years, however, this method gave 

 a large increase in yields over common practices. 



In considering the average yearly profit or loss per acre for the eight 

 years, it is shown that corn grown on summer-tilled land gave a loss of 

 3 cts. as against a profit of $3.65 for corn grown continuously. Spring wheat 

 gave a profit of $2.11 when grown on sumraei'-tilled land and a profit of $2.28 

 or $3.06 on land growing wheat continuously. Oats gave a loss of $2.29 per 

 acre on summer-tiled land while on land continuously cropped the loss was 

 small. Barley gave a loss of $2.08 per acre on summer-tilled land and a small 

 profit on land continuously cropped. 



The results of the eight years further indicated that from the standpoint of 

 yield or profit it mattered but little whether the land was spring plowed or 

 fall plowed for fall or spring grains. The difference in the yield of spring 

 wheat on land that grew spring grain or corn the previous year was not 

 marked during any season. Almost every year corn following corn yielded 

 more than corn following small grain. The average annual difference for the 

 eight years is reported at 5 bu. per acre in favor of land growing corn the 

 preceding season. The yields of spring wheat and oats following sorghum 

 grown for forage were not much different from the yields of the same crops 

 following corn or spring grain. In most years spring wheat yielded more 

 when following corn and spring grain than when following sorghum, but in 

 some seasons the reverse was true. 



The use of barnyard manure gave no appreciable beneficial effect on the 

 yields of the succeeding crop. Rye and field peas plowed under as green 

 manure proved to be more expensive and less profitable than alternate cropping 

 and summer tillage. Nearly all rotations giving a loss were designed to main- 

 tain the soil fertility through barnyard manure, a green manure crop, or a 

 grass crop. Corn grown on summer-tilled land, oats grown continuously on 

 spring plowed or on summer-tilled land, and barley on summer-tilled land 

 were also unprofitable. Considering the comparative ineffectiveness of barn- 

 yard manure, the most profitable rotation of the series was sorghum, corn, 



