26 EXPERIMENT STATION BULLETIN 354 



The above data are significant for maintaining hay yields at a high 

 level and indicate the importance of top-dressing. Contrast, for example, 

 the two treatments, 2 and 5. Series 5 was treated annually since the plots 

 were seeded in 1937, whereas in series 2 treatment was applied only in 

 1942 and 1943 to plots which had received no potash during the preceding 

 years in the life of the stand. The yields show that the plots which had been 

 top-dressed each year yielded nearly 800 pounds more of hay than those 

 in which the treatment was omitted during the early years. During these 

 early years, many of the desirable hay plants like clover and timothy dis- 

 appeared because of lack of plant food, and their places are filled by less 

 responsive species which are not high yielding under any system of fer- 

 tilization. 



This point is further emphasized by comparing plot number 7 and 3 

 and 4 which have been treated in equal amounts since 1942, although prior 

 to that and since 1937, plots 3 and 4 had not received a complete fertilizer. 

 The difference in yield between the two series for 1943 is 1711 pounds of 

 cured hay per acre, signifying that by the time heavy top-dressing began on 

 plots treated with 8-16-16 there had been a considerable reduction in de- 

 sirable species. 



Some clover persisted in 1943 in the plots treated with potash, but 

 yield dift'erences are due mainly tq maintaining timothy in the stand. Those 

 that had been fertilized generously over the years have a fairly good per- 

 centage of this specie. 



The Departrrjent of Agricultural and Biological Chemistry, co-opera- 

 ting, continued a greenhouse comparison of metapotassium phosphate with 

 an equivalent amount of potassium chloride and superphosphate. The plots 

 were divided into halves and one-half was treated with nitrate of soda at 

 the rate of 40 pounds of nitrogen per acre. Cornell 29-3 Double Cross 

 Corn was planted. The corn was harvested when tasselled and a compari- 

 son of the dry weights shows that there was no significant difference be- 

 tween treatments. 



The comparison of equivalent amounts of potassium chloride, potas- 

 sium sulphate and potassium metaphosphate on the near virgin soil taken 

 from the farm on the Connecticut River terrace was continued without ad- 

 ditional fertilizer applications. Again potassium sulphate and potassium 

 metaphosphate gave significant increases in dry matter over the check. 

 Another crop of corn is now growing in these same plots and all plants in- 

 dicate a marked deficiency of potassium. 



Some of the plots were sampled last fall by levels for available nu- 

 trients. The results show that there was more available potash present in 

 the plots that still had a good growth of red clover than in the plots where 

 it was absent. 



F. S. Prince, P. T. Blood, G. P. Percival 



Oat Variety Trials in Northern New Hampshire 



This experiment is being conducted in the Colebrook area, and has 

 been in progress three seasons. 



Data secured from the trials were published in Experiment Station 

 Circular 67, February, 1944. Yields of different varieties are tabulated on 

 pages 8 and 9 of that publication. In general, the results indicate a differ- 



