Submitted to: Soil Use and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 17, 1996
Publication Date: N/A
Interpretive Summary: Plant establishment and/or growth can be inhibited in soil by excessive chemical additions or adverse physical conditions. A soil can exhibit a low pH, high salt content, or high concentrations of toxic metals. Soils may also be dense and compact at the surface, with openings or pores sufficiently small to hinder rainfall or irrigation water from entering. Cheese whey, the liquid byproduct of cheese production, in some areas is a disposal problem but, if land applied, may help to open soil pores. In the spring and summer of 1993, either 0, 200, 400, or 800 Mg/ha of whey were flood applied to bermed plots of a Portneuf silt loam near Kimberly, ID. In August and September of 1993, a tension infiltrometer was used to measure unconfined (three-dimensional) infiltration rates into the bottom of irrigation furrows in each plot. This device, which held water at a slight tension as it infiltrated into the soil, allowed us to measure infiltration through the fine pores in the soil while excluding water flow through the largest pores in the soil. These infiltration rates decreased as whey applications increased, probably because milk solids in the whey or microbiological growth clogged pores at or near the soil surface. We concluded that up to 400 Mg/ha of cheese whey could be added without incorporation to soil surfaces without adversely affecting soil hydraulic properties. This maximum annual whey loading rate for land applications during the summer can be used to safely dispose of whey on furrow-irrigated, winter wheat cropland in southern Idaho.
Technical Abstract: Whey, the liquid byproduct of cheese production, can improve the physical condition of sodic soils or those susceptible to erosion by increasing their aggregate stability. Whey effects on soil hydraulic properties, however, are not known. In this experiment, we determined whey effects on infiltration rates (at water potentials of -30 mm or less) and unsaturated hydraulic conductivities of Ap horizons of a Portneuf silt loam (coarse-silty, mixed, mesic Durixerollic Calciorthid) after a winter wheat (Triticum aestivum L. 'Malcolm') growing season. We studied four liquid whey application rates, each totaling either 0, 200, 400, or 800 Mg/ha (control, low, medium, and high, respectively). In September 1992, our site near Kimberly, ID, USA, was leveled, subsoiled, then roller-harrowed twice. After planting wheat on 15 September, all plots were furrowed and a berm was constructed around each to retain all precipitation, irrigation water, and whey. At 3-week intervals beginning on 19 May 1993, either zero, one, two, or four flood applications of 200 Mg/ha of whey were made to each plot, without subsequent tillage. After the August 1993 wheat harvest, we used a tension infiltrometer to measure vadose zone, unsaturated flow characteristics in the bottom of undisturbed furrows, where the most whey had infiltrated. Infiltration rates at potentials of -60 and -150 mm decreased linearly, but slowly as whey applications increased from 200 to 800 Mg/ha. At a potential of -60 mm, hydraulic conductivity increased but then decreased with whey additions. In short, soil hydraulic properties were little affected by surface whey additions of 400 Mg/ha or less.