SUMMARY 
Chelates are relatively new aids in combating plant malnu- 
trition. They are organic chemicals which have the capacity to 
envelop certain elements (nutrient metal ions, in their agricul- 
tural application) and to keep them water-soluble under condi- 
tions in which they would otherwise become insoluble. 
Chelated metal treatments applied to the soil or as foliage 
sprays have proved advantageous in supplying iron and zinc to 
some plants damaged for want of these essential nutrients. 
The Agricultural Research Serviceis among agencies that 
are investigating the role of chelates in plant nutrition and 
their agricultural uses. Current research includes work with 
experimental chelates as well as chelates now on the market. 
Practical chelated metal treatments are necessarily de- 
veloped to suit a specific plant in a specific soil situation. Re- 
cently, for example, a spray treatment employing a chelate 
combined with iron and manganese has been developed which 
improves the greening and fruit yield of pear trees grown on 
clay adobe soils of southern Oregon--where iron deficiency has 
posed a serious problem for pear growers. 
At present costs, chelates are practical primarily for 
treating crop trees, ornamentals, and other high-value plants. 
ARS applied chelate research is focused mainly on crop trees, 
though some work is being done to test the effectiveness of 
these substances for combating nutrient metal deficiencies in 
other plants. 
Information in this report was provided by the Soil and Water Conservation 
Research Division and the Crops Research Division, 
Agricultural Research Service 
