PASTURE CULTURE 29 



shown that many physiologic disorders or diseases are directly associated with a 

 deficiency in one or more essential nutrient elements. Some of these so-called 

 "deficiency diseases" have been found affecting forage crops in Massachusetts. 

 A characteristic chlorotic condition of the plant leaves has been identified with a 

 deficiency of soil magnesium. More recently, a yellowing of the leaves of alfalfa, 

 particularly in the second crop, has been definitely associated with deficiency of 

 soil boron. 



Winter injury, particularly with some of the leguminous crops, is another 

 important trouble which has long been associated with soil fertility'. In 1888, 

 for example, the Massachusetts Experiment Station reported^"' that the un- 

 fertilized plots of alfalfa, red clover, alsike, perennial rye grass, and meadow 

 fescue showed serious winter injury, whereas fertilized plots did not. It was 

 reported from Rhode Island in ISQSi*'^ that the liberal use of lime had resulted 

 in good crops of red clover on soils where clover had "formerh" winterkilled nearly 

 every year." 



Much evidence has been obtained in Massachusetts recently to show that 

 additional potash applied as top-dressing to fields of alfalfa will greatly reduce 

 winter injury and thereby prolong the life of the stand. '"^ In this case potassium 

 appears to have been the limiting fertility factor to what was otherwise a satisfac- 

 tory level of fertility. Since alfalfa is a heavy feeder on potassium and since 

 Massachusetts soils are naturally low in potassium, this pronounced response 

 to a potash fertilizer is readily conceivable. In Rhode Island, lime or more likely 

 calcium was directly associated with winter injury while in Massachusetts it was 

 potassium. It would seem, therefore, that a deficiency of any important nutrient 

 element might so weaken a plant as to render it susceptible to winter injury. 

 The weakening of a plant by injury from certain disease organisms might also 

 hav^e the same effect. 



Healthy plants are hardy plants and to produce healthy plants the soil must 

 be capable of delivering to the plant an adequate supply of all essential plant 

 nutrients. Plants like animals perform at their best only when given a balanced 

 as well as a plentiful "diet." 



Factors in Soil Fertility Maintenance 



Practically all available evidence indicates that adequate levels of soil fertility 

 are just as important to the pasture crop as they are to any other productive 

 crop. Pastures offer some difficulties in this respect which do not exist with tilled 

 crops. The fundamental principles of fertility maintenance are essentially the 

 same in both cases, but because of differences in cultural procedure, the practical 

 application of these principles is more difficult. 



Fertilizer Materials. — As previously discussed, the soils of Massachusetts 

 are naturally low in available quantities of many essential nutrient elements, 

 including calcium, magnesium, potassium, phosphorus, and nitrogen. Therefore, 

 for these soils to supply the pasture crop with an "adequate and balanced diet," 

 the supplies of these necessary elements must be periodically replenished. 



Lime. — The need for calcium was early recognized and materials supplying 

 this element were among the first soil amendments used in this country. Jared 

 Eliot in 1747 wrote of a type of marl which he tried and "found it equal to good 

 dung."!"^ The use of this material on grasslands was mentioned as early as 



Wllbid.. 36th Annual Report (1888). p. 517. 

 ^"^ibid., 46th Annual Report (1898), p. 189. 

 lO^Mass. Agric. Expt. Sta.. Bui. 355 (1939), p. 19. 

 '"^Field Husbandry, p. 17. 



