TY  - BOOK
ED  - Department of Agriculture, U. S.
TI  - Maintaining drainage system
U1  - 631.6 MAI 1952 
PY  - 1952///
CY  - Washington
PB  - Department of Agriculture, U. S.
KW  - Drainage
N1  - Bedding and Ridging; Land grading or smoothing……; Preparing and cultivating land to help maintainance; Selecting best method of maintainance
ER  -