Comparative growth responses of perennial forage legumes in hill‐land ultisols and their relationship to soil acidity‐related factors

Abstract

As soils of humid, temperate hill-lands are typically highly weathered, mineral, and acidic, forage legumes for these conditions need to be evaluated, and limiting soil acidity-related factors determined. Two ultisol topsoils (0-15 cm) from Appalachian hill-lands of the Lily series (Typic Hapludults) were utilized 1n a growth chamber experiment. Both soils were of similar pH and low 1n fertility but different in % base saturation due to different management histories (abandoned versus poorly-managed pasture). Treatments to provide a range of soil pH values (aluminum, nil, calcium) were applied to ascertain their effect on various growth response traits of alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), white clover (Trifolium repens L.), birdsfoot trefoil (Lotus corniculatus L.), big flower vetch (Vicia grandiflora Scop.), and flatpea (Lathyrus sylvestris L.). Averaging over all soils and treatments, shoot production Increased 1n the order-alfalfa < red clover, white clover, 245 246 STALEY, WRIGHT AND HERN trefoil, flatpea < vetch, while root production increased in the order-alfalfa < red clover, white clover < trefoil, vetch < flatpea. Main effects for soil source were significant (p 0.05) for shoot N uptake for red clover, trefoil and flatpea only, but not for root production for any of the species with the exception of alfalfa. Alfalfa shoot and root production, and N uptake, were significantly (p 0.05) reduced by low-level (1.5 cmol•kg -1 soil) Al treatment compared to the untreated (nil) soils, whereas the same traits for white clover were significantly (P 0.05) increased. These traits were generally unaffected by Al treatment for red clover, trefoil, vetch and flatpea. Low-level (1.5 Mg•ha -1 ) Ca amendment also had generally little effect on any of the response traits for any of the species examined. Shoot N uptake appeared to be the most sensitive plant response trait to the resulting subtle soil chemical changes. These results indicate that all of the perennial legumes examined, with the exception of alfalfa, were able to establish and obtain acceptable production levels in acidic (~ pH 5.2) ultisols with at least some history of pasture management. INTRODUCTIONThe Appalachian Region comprises approximately one-tenth the land area of the contiguous US, or about 51 million hectares, and consists of mountains and high plateaus (46%), hills and low plateaus (38%) and plains and low-lands (16%; 5). Although the soils of this Region are varied, ultisols predominate, especially Typic Hapludults (7). These soils are typically highly-weathered, mineral, and addle, and often contain growth-limiting levels of aluminum (Table 1). Because of these limitations, and shallow soil depth and low fertility, coupled with steep slopes and Irregular terrain, agricultural endeavors 1n these hill-lands will most certainly depend on legume-based hay and pasture production systems. Downloaded by [JAMES COOK UNIVERSITY] at 20:53 15 March 2015