共 79 条
[51]
REDMANN RE, 1968, THESIS U ILLINOIS
[52]
REED MJ, 1961, 1252 US DEP AGR FOR
[54]
ROGLER GA, 1947, J AM SOC AGRON, V39, P378
[55]
SHIVELY SB, 1939, 21 U NEBR CONS SURV
[56]
SMOLIAK S., 1956, Journal of Range Management, V9, P89, DOI 10.2307/3894557
[57]
Soil Survey Staff, 1960, SOIL CLASSIFICATION
[59]
STEEL R. G. D., 1960, PRINCIPLES PROCEDURE
[60]
Stevens O. A., 1950, HDB N DAKOTA PLANTS