Effects of Natrustoll (Solonetz) Soil Horizons and Nitrogen on Growth of Tall Wheatgrass

McGinnies, William J.; Ludwig, Jim R.

Effects of Natrustoll (Solonetz) Soil Horizons and Nitrogen on Growth of Tall Wheatgrass

1977

McGinnies, William J. | Ludwig, Jim R.

Vast hectarages of potentially valuable pasture land in Colorado and Wyoming are dominated by saltgrass (Distichlis stricta (Torr.) Rydb.), an undesirable pasture component. Saltgrass meadows could possibly be revegetated with a more valuable forage species such as tall wheatgrass (Agropyron elongatum (Host) (Beauv.). A greenhouse study was conducted to evaluate the effects of the A, B, and C horizons of a solonetz soil on herbage yield of tall wheatgrass; the effect of N application was also investigated. Yields of plants grown in soils from the A horizon were highest, those from the B horizon where somewhat lower, and those from the C horizon were very low. Mixtures of A and B horizons usually produced higher yields than the A or B alone. Plants grown in any soil mixture which included the C horizon showed reduced yields. The deleterious effect of the C horizon was attributed to its high Na-salt content. Nitrogen, applied at rates equivalent to 56 to 448 kg N/ha, significantly increased herbage yield. Compared to no N application, the highest rate resulted in a three-fold increase in yield. The highest N efficiences in terms of total biomass produced per unit of N applied were obtained from rates of 112 and 224 kg N/ha which produced 39 and 37 kg of additional biomass per kg of N applied, respectively.

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