Definition from Wiktionary, the free dictionary
echard (plural echards)
- (dated) The portion of water in a sample of soil that is not available to vegetation
1951, John Smith, Distribution of Tree Species in the Sudan in Relation to Rainfall and Soil Texture:
- Grasses sprout on the sands long before the early rains have restored the echard of adjoining clays and given a surplus as chresard which can initiate grass growth.