Retention of Meltwater

the reduction by agricultural practices of meltwater runoff. It is particularly important in regions where moisture is insufficient or uneven. The runoff of meltwater results in an annual loss for agriculture of, for example, 50–100 mm of annual precipitation in the central chernozem regions of the USSR and 20–60 mm in the Volga Region. The runoff washes away soil particles, causing erosion, and also removes organic matter and the mineral elements of plant nutrition.

The principal means of retaining meltwater is the use of proper methods of cultivation, employing a combination of special techniques. Deep fall plowing across a slope or con-tour plowing is used mainly for slopes of up to 2°. On slopes of 2°–4°, fall plowing is combined with embankment; ridges 15–20 cm high are made every 140 (175) cm across the slope with an elongated moldboard set on the base of a tractor plow. On slopes of 5° or more, the ridges are made across and along the plowed portions [140(175) × 230(250) cm] using a plow with an elongated moldboard and a special ridger. On steep slopes, good results are achieved by making holes in a late-fall plowed field (diamond-shaped holes are made on the soil surface with a dibbler); by chiseling a late-fall plowed field (deep cultivation across the slopes in strips); by cultivating without a moldboard; by plowing with subsoiling and mole plowing; and by terraced plowing. Before the snow starts to melt, snow barriers are erected across the slopes, the snow is packed in strips, and so forth. Snow retention facilitates the accumulation of meltwater.