mineral composition" of crops 13 



improved health of the cattle could usually be obtained by dressing 

 pastures with superphosphate, blood, bones, and guano. Heavy 

 applications of superphosphate to soils with a low content of available 

 iron were reported to be sometimes successful in combatting the dis- 

 ease, and the use of iron salts as a drench in advanced cases was some- 

 times satisfactory (477). 



More recent investigations of the soils associated with bush sickness 

 showed that most of them were well leached and that they did not 

 contain any appreciable amounts of calcium and manganese likely to 

 be antagonistic toward the availability of iron. Taylor (549) believed 

 that leaching was primarily the reason why certain Mairoa farms were 

 unsound for stock. He inspected 12 farms with a definite history of 

 abnormality and found that 



The predominating structure in each case was volcanic ash upon porous sand- 

 stones or loose sands. In the neighboring healthy areas the sands were practically- 

 absent, and the ash was underlain by limestone with its attendant residual clay, 

 or by Jurassic mudstones. 



Grange et al. {218) later claimed that profiles of six typically " bush- 

 sick" soils showed evidence of distinct podzolization. They were all 

 coarse-textured soils containing only small percentages of clay. The 

 chemical analyses of the soils showed that some contained a moderate 

 supply of available phosphorus and potash, while others were definitely 

 low in both of these constituents. However, normal volcanic soils 

 were also found to be low in these constituents, and they were often 

 of coarse texture. Texture, in fact, does not seem to be an important 

 factor, for Aston (31) states that certain coarse sandy soils near 

 Rotorua are recognized locally as "hospital" lands and supply a nutri- 

 tious food for animals. 



In their study of bush sickness at Glenhope, Nelson, New Zealand, 

 in 1932, Askew and Bigg (26) reported that the deficient soils were well 

 leached and occurred mostly over granitic formations. Evidence that 

 a deficiency of iron in these soils was a factor in the disease was not 

 demonstrated (487). 



Dawson (144) seems to have been the first to associate " salt-sick," 

 an anemic condition of cattle, to certain characteristics of some of the 

 soils of Florida when in 1906 he stated: "The disease is usually con- 

 fined to regions where the predominating soil is light, sandy, and more 

 or less unproductive of nutritious grasses." He believed the disease 

 to be comparable to that occurring on Cape Cod Peninsula and in 

 certain counties in southern Texas. He observed that salt-sick occurs 

 in nearlv all parts of Florida. 



In 1931 Becker, Neal, and Shealy (51, 429) found that "'salt-sick' is 

 a naturally occurring nutritional anemia in cattle, the feed of which 

 has been restricted largely to grass forage grown on certain white and 

 gray sandy soils, residual muck and peat soils not subject to overflow 

 from more fertile watersheds." No trouble was experienced on clay 

 soils. 



More detailed soil work by Bryan and Becker (94) in 1935 showed 

 that soils from healthy areas contained over twice as much silt and 

 clay in the first foot and over three times as much in the second foot 

 as did those soils in the salt-sick area. Their survey revealed that for 

 many years cattlemen "have found it necessary to transfer ' salt-sick' 

 animals to healthy ranges, sometimes known locally as 'hospital' 



