ANNUAL REPORT, 1941 11 



determined as much by the farming system followed and the kind of crops grjwri 

 as they are by the tj'pe of soil being farmed." 



Since that time these plots have been used for experiments with fruit trees, 

 following the original system of fertilization. The fruit trees have now baen 

 removed, leaving a field with limed and unlimed portions of plots which for the 

 past fifty years have had applications of nitrogen, potash, and phosphoric acid, 

 singly and in various combinations. The check plots have been left unfertilized 

 during the entire period. Preliminary observations during the past year hive 

 shown that the fertility level of all the plots is much higher on the limed than on 

 the unlimed portions. The unlimed portions of the check plots showed crop 

 failures and indications of nutrient deficiences. 



It is the intention to continue this study with the view of observing m )re 

 carefully the various nutrient deficiencies singly and in combination as they 

 appear in the various crops to be grown on this area. 



Potato Variety Trials. (Ralph W. Donaldson, Walter S. Eisenmenger, and 

 Karol J. Kucinski.) Based on yields of marketable size, the ranking of potato 

 varieties grown in plots at the college during the season of 1941 were Sequsia, 

 Earlaine No. 2, Green Mountain, Russet Rural, Katahdin, Houma, Irish Cobbler, 

 Red Warba, Sebago, and Chippewa. 



Soil Nitrates Lower pH Reactions. (Ralph W. Donaldson, Walter S. Eisen- 

 menger, and Hrant M. Yegian.) A marked depression of pH reactions which 

 occurred in potted soil as nitrates formed and accumulated was mentioned last 

 year in reporting "the effect of fineness of limestone on soil reaction." 



Results of a similar trial in progress now, covering a 12-month period, sub- 

 stantiate the previous findings. In this later trial oats were successively grown 

 on a duplicate series of limed and unlimed soil, in an attempt to remove by plant as- 

 similation the nitrates which develop. Both the cropped and the uncropped soil 

 of any given treatment first exhibited similar reactions except for slight varia- 

 tions dependent upon ammonia development. When nitrates developed, how- 

 ever, the uncropped soils dropped about .7 of a pH below corresponding cropped 

 soils, depending upon the relative amounts of nitrates present. This situation 

 prevailed within limed and unlimed treatments. 



Since the product of organic matter decomposition is ultimately nitrates, 

 whirh under seme conditions may accumulate in the soil solution and cause a 

 lowered pH reading, this factor may be important when recommending lime 

 for sensitive crops like potatoes and tobacco. A field sample which shows high 

 nitrates after harvest may give a pH reading about .5 lower than a sample taken 

 during the active growing period of the crop when nitrates are being absorbed. 

 For example, it is conceivable that a potato soil during the active growing period 

 of the crop may show low nitrates in the soil solution and test pH 5.5; yet when 

 tested after harvest, with nitrate accumulated, it may test pH 5.0, for which a 

 light lime application might (wrongly) be suggested. Whether such differences 

 occur under field conditions at least merits consideration. 



Borax Trials on Several Crops. (Ralph W. Donaldson, Walter S. Eisenmenger, 

 and W. G. Colby.) Applications of borax to established stands of alfalfa have 

 been continued on more than 20 farms in the State. Both spring and fall applica- 

 tions at 25 and 50 pound rates have been compared, with no evidence at all of in- 

 jury from the higher rates. In fields where alfalfa "yellows" appeared this season, 

 borax applied prior to this spring effected marked control. This was evident also 

 in single treatments of 25 pounds per acre applied in the fall of 1939, indicating, 

 thus far at least, a two-season carry-over from treatment. The effect of borax 

 applied in the spring was less marked in controlling yellows on the crop which 



