8 MASS. EXPERIMENT STATION BULLETIN 417 



The Absorption by Food Plants of Chemical Elements Important in Human 

 Nutrition. (Walter S. Eisenmenger and Karol J. Kucinski.) When the indi- 

 vidual ions were applied to the soil at the rate of 200 p. p.m., the percentage in- 

 take b}' plants was greater for magnesium, sodium, and potassium than for cal- 

 cium. Chlorine, bromine, and iodine intake was higher than the intake of phos- 

 phorus or sulfur when equal parts per million were added to the soil. 



The place of the plant in the evolutionary scale, as well as the individual ion, 

 is a factor in the increased intake. A more highly developed plant — lettuce — 

 did not increase its content of calcium, magnesium, sodium, and potassium as 

 much as did those lower in the evolutionary scale — celery, beets, cabbage, and 

 beans — when the respective ions were added equally to the soil. 



The Intake by Plants of Elements Applied to the Soil in Pairs Compared to 

 the Intake of the Same Elements Applied Singly. (Walter S. Eisenmenger and 

 Karol J. Kucinski.) In nearly all cases when two cations were added to a plot, 

 each at the rate of 250 p. p.m., the intake of the ions was depressed in comparison 

 with the intake when each was added singly at the same rate. The intake of 

 two ions added in pairs complicates the interpretation. It is probable that, 

 when there is relative abundance of one ion and little of another, the plant takes 

 more of the abundant ion than is necessary for metabolism. It has even been 

 suggested that one element may regulate the semi-permeable membrane of the 

 plant. 



From a practical point of view, it has been observed that liberal potassium 

 applications may lead to magnesium deficiency in plants. 



Magnesium Requirements of Plants. (Walter S. Eisenmenger and Karol J. 

 Kucinski.) Numerous plants of different botanical families have been grown on 

 a plot, part of which is low in magnesium. Enough magnesium is present in the 

 so-called magnesium-deficient soil to produce normal growth of some plants, but 

 not of others. 



Preliminary work suggests that the less evolutionally developed flowering 

 plants need more magnesium in their growing medium than do the plants in the 

 higher orders. No plants of the families Compositae, Chenopodiaceae, Amaran- 

 thaceae, or Labiatae and only one member of the family Gramineae have shown 

 deficiency. All of the lower families have shown deficiency to a marked degree, 

 among these being Ranunculaceae, Magnoliaceae, Ulmaceae, Malvaceae, Ger- 

 aniaceae, Rosaceae, and others. 



It would seem that, as far as needs for normal growth are concerned, mag- 

 nesium is an older element than calcium. 



Long-Time Field Fertility Tests. (Walter S. Eisenmenger and Karol J. 

 Kucinski.) About fifty-five years ago a series of so-called soil test plots was 

 inaugurated to study the effects on the soil and crops of a long-time fertilizer 

 program. Various types of crops have been grown on these plots but the original 

 system of fertilization has always been followed, including check plots which have 

 been left unfertilized during the entire period. Recent results, with hay as an 

 indicator crop, showed that the fertility level of all the plots was much higher 

 on the limed than on the unlimed portions. The unlimed portions of the check 

 plots showed crop failure and indications of nutrient deficiencies. On the com- 

 plete fertilizer plot (N.P.K.), the limed area yielded about 200 percent more hay 

 than the unlimed area. On the limed areas, the complete-fertilizer plot yielded 

 about 50 percent more hay than the no-fertilizer plots. On the unlimed area, 

 the plots receiving nitrogen, nitrogen plus phosphorus, and nitrogen plus potash 

 showed an increase of about 350 percent in yield of hay over the no-fertilizer plots. 



