ANNUAL REPORT, 1943-44 13 



two and one-half times increase in yield from a practically pure stand of timothy. 

 The average increase in yield from applied nitrogen for the nineteen different 

 seedings was about 50 percent. 



For the second harvest, on June 29, yields of the nitrogen half of the plots 

 varied from a 22 percent decrease for the redtop-ladino clover plot to a 78 per- 

 cent increase for a practically pure timothy stand. The average increase for all 

 plots was 5.4 percent. The decrease in yield in the case of redtop is explained 

 by the fact that the clover population was greatly reduced in the fertilized half 

 of the plot. In the no-treatment half of the plot, where there was a fairly good 

 stand of clover, yields were well maintained throughout the season. The results 

 obtained at the time of the third harvest, on July 30, were similar to those ob- 

 tained for the second. Of the increase in yield from additional nitrogen during 

 the season, .94 percent was obtained at the first harvest date in May. 



Response of Different Grasses : Timothy gave the greatest response to nitrogen 

 fertilization, followed in turn by smooth brome grass, Kentucky bluegrass, red- 

 top, meadow fescue, perennial rye grass, and orchard grass. The average in- 

 crease in yield for four different strains of timothy (fairly pure stands) was 82.6 

 percent for the first harvest, 28.1 percent for the second, and 4.9 percent for the 

 third. 



Effect of Nitrogen on the Clover Population: The effect of nitrogen on the clover 

 population varied greatly with different grasses. When redtop was present to 

 an appreciable extent, additional nitrogen tended to strongly suppress the clover. 

 For example, a redtop-ladino clover plot was made up of 80 percent redtop and 

 20 percent clover in the spring. By fall the nitrogen half of the plot had only 10 

 percent clover, while the untreated half contained 60 percent clover. Kentucky 

 bluegrass reacted similarly to redtop. 



Tall fescue and orchard grass had already crowded out much of the ladino 

 clover before nitrogen was applied, and additional nitrogen merely resulted in 

 the elimination of what little clover was left. Brome grass in the pastured plots 

 gave good results, and additional nitrogen, though it increased yields appreciably, 

 had no deleterious effect on the stand of clover. 



Time-of-Planting Trials with Smooth Brome Grass. (W. G. Colby.) Suc- 

 cessive summer seedings of smooth brome grass (Canadian strain) and ladino 

 clover, both with and without a light seeding of oats, wheat, or rye, showed 

 that early seedings were much better than late ones. Seedings made on August 

 19, 1942, resulted in an excellent stand of both brome grass and clover by the 

 summer of 1943. Seedings made on September 2 resulted in a fair stand of 

 brome grass but no ladino clover. Later seedings resulted in very poor stands 

 of brome grass. A light seeding of oats had an injurious effect on the August 

 seeding but was of some benefit to later seedings. Late seedings with wheat or 

 rye showed some benefit from the companion crop. 



These results indicate that summer seedings of smooth brome grass should 

 be made early - — probably not later than is safe for the summer seeding of alfalfa 

 or ladino clover — and without a companion crop of oats, wheat, or rye. 



Winter Hardiness of Orchard Grass Strains. (W. G. Colby.) The winter 

 of 1943-44 was a severe one from the standpoint of winter injury to vegetation. 

 Observations on winterkilling in a three-year-old nursery of orchard grass strains 

 showed the following results: 



1. Strains showing no apparent injury: Commercial, Scandia II, Tammisto. 



2. Strains showing some injury: Brage, Tardus II, O. A. C. No. 1. 



3. Strains showing severe injury: S26, S37, S143, Akaroa, New Zealand. 



