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In complex landscapes with multiple land uses, it is often difficult to identify the source of contaminant loadings. The objective of this study was to compare nutrient runoff as affected by grazing animal depositions vs. poultry litter application. Simulated rainfall was applied twice to 1.5 by 6.0 m runoff plots of tall fescue (Festuca arundinacea Schreb.) with treatments of no waste (CT), dairy calf feces and urine (DFU), poultry litter (PL), and dairy calf feces and urine with poultry litter (DFU + PL). Chemical properties of the runoff samples including pH, electrical conductivity (EC), C, soluble reactive phosphorus (SRP), total nitrogen (TN), NH4‐N, NO3‐N, K, Mg, S, B, Cu, Fe, Mn, Mo, Na, and Zn were determined. Plots receiving poultry litter had significantly greater losses of most nutrient parameters for both rainfall simulations. For the nutrient parameters of primary interest with regard to water quality, 5.0, 29.5, and 21.9% of the TN, NH4‐N, and SRP applied in the PL treatment were transported in runoff during the first rainfall simulation as compared to 3.9, 5.0, and 15.3%, respectively, for the DFU treatment. Comparable percentages of the applied nutrients were lost from the PL and DFU treatments even though the PL treatment, with the exception of NH4‐N, provided at least six times the amount of each nutrient. A severe rainfall event shortly after poultry litter application produces significantly greater nutrient losses as compared to similar application of grazing animal depositions at the rates used in the experiment.

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Optimal utilization of the N2‐fixation capability of legumes improves forage productivity and quality and reduces the need for N fertilizer. This research assessed N2 fixation in binary mixtures of white clover (Trifolium repens L.) (WC), red clover (Trifolium pratense L.) (RC), or bitdsfoot trefoil (Lotus corniculatus L.) (BT) with tall fescue (Festuca arundinacea Schreb.) (TF) at four legume proportions. Two identical experiments were established in Uruguay, one in 1983 (Exp. 1) and one in 1984 (Exp. 2) that were evaluated for 2 yr. The soil of the area was a fine, montmorillonitic, mesic, Typic Argiudoll. Symbiotically fixed N was estimated by 15N isotope dilution by using TF pure stands as nonfixing reference. The proportion of legume N derived from air (%Ndfa) was larger in winter and spring harvests (82‐95%) than in other harvests, and differences among legumes were minimal. In first harvests after seeding, %Ndfa was 58% for BT and 74% for WC or RC, whereas in summer, WC showed the least %Ndfa. Total fixed‐N yield over 2 yr was greatest for RC‐TF (390 and 330 kg ha−1 for Exp. 1 and Exp. 2) because of both large %Ndfa and legume yield. As legume proportion increased %Ndfa decreased linearly, usually with similar slopes for all legumes. Fixed‐N yield increased linearly as legume proportion increased for RC‐TF and BT‐TF mixtures. For WC‐TF, there were optimal WC proportions between 50 and 70% in seeding years. We conclude that %Ndfa was negatively and linearly related to legume proportion for the three mixtures and that legume‐dominant swards were required to maximize fixed N yields for RC‐TF and BT‐TF but not for WC‐TF. Red clover fixed the greatest amount of N2 under the conditions of this study.

Choosing the provenance of seed used in ecological restoration could entail its success. An alternative approach to examine local adaptation in seed sourcing is the assessment of genetic structure and diversity based on molecular markers. These types of analyses focus on the genetics of the target plant itself and eliminate the genetic influence of associated organisms, such as Epichloe¨/Neotyphodium endophytes in grasses. By impacting the fitness of their host, such symbionts may influence population genetic structure and diversity. Therefore, seed sourcing for grasses must consider the influence of their endophytes to increase seed translocation success and minimize the risks associated with this practice. To delineate seed zones for restoration of the alpine fescue Festuca eskia Ramond ex. DC. (Poaceae), we assessed population genetic differentiation and diversity patterns in the species including endophyte occurrence along altitudinal and longitudinal gradients in the Pyrenees Mountains. Twenty-three populations were analysed for endophyte status, and three STS and one SSR marker were used to examine genetic differentiation and diversity patterns. Results showed that F. eskia hosts an asexual form of Epichloe¨and infection frequency within populations decreased from East to West (100 vs. 8-25%). Molecular markers separated F. eskia into two East and West groups, and endophyte infection and genetic patterns were congruent with molecular data. Little evidence for genetic differentiation or difference in endophyte occurrence associated with altitude was detected. Little variation was found in within population diversity, regardless of provenance altitude and site, and/or endophyte infection frequency. The results of this study suggested the establishment of two distinct management units for F. eskia seed sourcing restoration.