PHOSPHATES IN MASSACHUSETTS AGRICULTURE. 151 



It will be noted that with three exceptions the yields are quite uniform. 

 Plots 1 and 10 are considerably above the average in productiveness, while 

 plot 13 is about as much below. 



The crops grown during the experiment in the order of their succes- 

 sion have been as follows: corn, cabbages, corn, oats and Hungarian 

 grass (in 1900), onions, onions, cabbages, corn (ensilage), grasses and 

 clovers seeded in spring (no crop harvested), hay, hay, cabbages, soy 

 beans, potatoes, oats and alfalfa (badly winterkilled, 1911-12), buck- 

 wheat (turned under), corn and corn. 



IMany of the annual crop yields have been published in the reports of 

 the experiment station, and certain averages only will be presented at 

 this time. These wiU include an average for each crop on each of the 

 three classes of phosphates into which those used somewhat naturally fall. 

 The first class includes the natural mineral phosphates: apatite and 

 Arkansas phosphate, ^ South Carohna rock phosphate, Florida soft phos- 

 phate and Navassa and Teimessee phosphates; ^ the second class in- 

 cludes basic slag meal, raw bone meal and steamed bone meal; the third 

 class, dissolved bone black, dissolved bone meal and acid phosphate. 



The yields for the first two years have not been included in figuring these 

 averages, as it is apparent that initial inequaUties in productive capacity 

 exercised a considerable influence in determining yields. It is not unlikely 

 that such inequahties continued for some time (possibly they still con- 

 tinue to exercise some influence), but it is believed that the manner of 

 computing increases due to the several phosphates previously described ' 

 has so reduced the influence of such inequalities that the averages of 

 results extending over so long a term of j^ears present a reliable basis 

 for determining the relative crop-producing value of the different classes 

 of phosphates. 



1 Apatite from 1897-1905; since 1908, Arkansas. 



* Navassa phosphate from 1897-1900; since 1901, Tennessee. 



3 See p. 148. 



