Many Iowa farmers are now farming around the hills instead of up and down them. The results of many investigations have justified for some time this practice as a soil- and water-conserving measure, but until comparatively recently there was little contour farming practiced in the state. Since contour farming has been adopted on many Iowa farms in the last few years, its value under real Iowa conditions can be appraised on the basis of actual experience. “The proof of the pudding is in the eating,’’ according to the old English proverb, and so it is with contour farming. Farmers have found it to be a wise and feasible practice as shown by the fact that only a very few of those who have given it a fair trial have abandoned it.
The reasons why contour farming helps to conserve soil and water are obvious. Every row running around the hill acts as a little barrier which checks the velocity of the surface runoff, causing it to unload its silt and to flow more slowly from the land so that more of the water will have time to soak into the soil. Strips of close-growing, soil-binding crops, planted alternately between strips of contour row crops, likewise lessen the amount of the slope exposed by the clean tillage. The close-growing crop will check the velocity of any runoff from the cultivated strip above and cause it to drop its load of silt. The soil covered by the soil-binding crop will be held against erosion, and the continuous extension of rills and gullies through the field will be checked.
Peterson, J. B. and Clapp, L. E.
"Following the contour (How to strip-crop Iowa land),"
Bulletin P: Vol. 2
, Article 1.
Available at: https://lib.dr.iastate.edu/bulletinp/vol2/iss53/1