34 THE ESSEX EXPERIMENTS 



with the exception of the two receiving Florida pebble, were much 

 superior to the open hearth fluorspar basic slag. 



Plots C and E unmistakeably show that lime without phosphate 

 has little or no effect in improving this type of pasture. 



It is difficult to interpret the results from Plots B, D, F, G, H 

 and L in terms of the other plots. They were not sown until 1919, 

 and the exceedingly dry season prevented a rapid response. As all 

 the plots were grazed throughout this season, these particular plots 

 would not receive the same benefit from the grazing as those sown 

 the year previously, which, at the beginning of the grazing period, 

 were already covered with a thick and close bottom of wild white 

 clover. 



During the latter part of May, 1920, Plots B, D, F and H, at first 

 backward, made rapid progress, and at harvest time there seemed 

 to be more heads of clover on some of these plots than on the majority 

 of the others. Plate VI illustrates the appearance of Plot H in 

 July, 1920. 



It has been quite obvious during the past two years that the light 

 dressing of superphosphate on Plot 14 has not been effective. The 

 improvement was much less than the weight of hay would appear 

 to indicate, and during the seasons 1919 and 1920 Plot 14 looked 

 very like an untreated plot. The heavy dressing of superphosphate 

 on Plot 13 was much more effective. It was not, however, nearly so 

 good as the high soluble slag plots or the " superphosphate and lime " 

 plot. Even on a soil of this character, very deficient in phosphoric 

 acid and with a small reserve of calcium carbonate, an acid manure 

 like superphosphate is not suitable. On Plot 15 the same dressing 

 of superphosphate as on Plot 13, namely 200 Ibs. P 2 O 5 per acre, plus 

 one ton of lime per acre, were sown together. Under such circum- 

 stances the reversion of the water soluble phosphate in the super- 

 phosphate would be practically instantaneous (22) and the dressing 

 would become a basic one comparable to the application of a dressing 

 of basic superphosphate. It is of interest to note that Plot 15 gives 

 results practically identical with those secured on the plots receiving 

 the most soluble type of basic slag. A close observation was kept 

 on Plots 15 and 17 throughout the 1920 season, and the only notice- 

 able difference was the somewhat earlier start made by Plot 15. The 

 difference in this respect was not great, probably not more than 

 7 to 10 days, and had visits to the plots been less frequent, might 

 have been entirely overlooked. 



During the season of 1919 the long drought lasting from the 



