Concern over nonpoint-source phosphorus (P) losses from agricultural lands to surface waters has resulted in scrutiny of factors affecting P loss potential. A rainfall simulation study was conducted to quantify the effects of alternative P sources (dairy manure, poultry manure, swine slurry, and diammonium phosphate), application methods, and initial soil P concentrations on runoff P losses from three acidic soils (Buchanan-Hartleton, Hagerstown, and Lewbeach). Low P (12 to 26 mg kg(-1) Mehlich-3 P) and high P (396 to 415 mg kg(-1) Mehlich-3 P) members of each soil were amended with 100 kg total P ha(-1) from each of the four P sources either by surface application or mixing, and subjected to simulated rainfall (70 mm h(-1) to produce 30 min runoff). Phosphorus losses from fertilizer and manure applied to the soil surface differed significantly by source, with dissolved reactive phosphorus (DRP) accounting for 64% of total phosphorus (TP) (versus 9% for the unamended soils). For manure amended soils, these losses were linearly related to water-soluble P concentration of manure (r2 = 0.86 for DRP, r2 = 0.78 for TP). Mixing the P sources into the soil significantly decreased P losses relative to surface P application, such that DRP losses from amended, mixed soils were not significantly different from the unamended soil. Results of this study can be applied to site assessment indices to quantify the potential for P loss from recently manured soils.

Cold-acclimated plants acquire an additional 3-5 degrees C increase in freezing tolerance when exposed to -3 degrees C for 12-18 h before a freezing test (LT50) is applied. The -3 degrees C treatment replicates soil freezing that can occur in the days or weeks leading to overwintering by freezing-tolerant plants. This additional freezing tolerance is called subzero acclimation (SZA) to differentiate it from cold acclimation (CA) that is acquired at above-freezing temperatures. Using wheat as a model, results have been obtained indicating that SZA is accompanied by changes in physiology, cellular structure, the transcriptome, and the proteome. Using a variety of assays, including DNA arrays, reverse transcription-polymerase chain reaction (RT-PCR), 2D gels with mass spectroscopic identification of proteins, and electron microscopy, changes were observed to occur as a consequence of SZA and the acquisition of added freezing tolerance. In contrast to CA, SZA induced the movement of intracellular water to the extracellular space. Many unknown and stress-related genes were upregulated by SZA including some with obvious roles in SZA. Many genes related to photosynthesis and plastids were downregulated. Changes resulting from SZA often appeared to be a loss of rather than an appearance of new proteins. From a cytological perspective, SZA resulted in alterations of organelle structure including the Golgi. The results indicate that the enhanced freezing tolerance of SZA is correlated with a wide diversity of changes, indicating that the additional freezing tolerance is the result of complex biological processes.

No abstract

ball et al., 1997). The ecology of natural populations of plantain and its biology as a weed have been investigated Graziers in the northeast USA often face forage shortages in mid- (Bassett, 1973; Kuiper and Bos, 1992). Apart from older summer. Chicory (Cichorium intybus L.) and English plantain (Plantago lanceolata L.) have been introduced in the USA as sumer-active reports in the scientific literature, the forage value of perennial herbs for pastures. We conducted two experiments at Rock plantain is relatively unknown. We have investigated Springs, PA, to evaluate chicory and plantain for yield and persistence the seedling development and establishment of plantain under clipping. 'Grasslands Puna', 'Lacerta', and 'Forage Feast' chicand found that it establishes easily from seed (Sanderson ory, and 'Ceres Tonic' and 'Grasslands Lancelot' plantain were sown and Elwinger, 2000a,b). There are some reports of mein field plots in May 1997 (Exp. 1) and 1999 (Exp. 2). Plots were cut dicinal attributes for plantain, such as anthelmintic every 3 or 5 wk in 1998 and 1999 in Exp. 1 and every 4 wk during properties, but the research is not conclusive (Knight 2000 and 2001 in Exp. 2. Dry matter yield was determined at each et al., 1996; Gustine et al., 2001). harvest. Stand densities were determined in each experiment. Forage Establishing complex pasture plant communities has Feast chicory yielded 25% less than Puna (6000 vs. 8100 kg dry matter received renewed attention (Sanderson et al., 2001). In ha Ϫ1 ; P Ͻ 0.05) in 1998, whereas yields of both cultivars were similar (P Ͼ 0.05) in 1999 and 2000. Lacerta chicory yielded 9 to 16% less New Zealand, pastures seeded with a mixture of 18 to than Puna and Forage Feast in Exp. 2. Forage Feast and Puna chicory 26 species consisting of cool-season grasses and legumes had 20 to 50% stand loss in Exp. 1 and 40 to 60% stand loss in Exp. along with several pasture herbs, including chicory and 2. Lacerta chicory lost 80% of the stand during Exp. 2. The plantain plantain, yielded more dry matter under sheep grazing cultivars yielded 6 to 14% less dry matter than Puna chicory in 1998 than did perennial ryegrass (Lolium perenne L.)-white and 33 to 39% less in 2000. Both plantain cultivars, however, suffered clover (Trifolium repens L.) mixtures (Ruz-Jerez et al., a nearly complete loss of plants during the second winter after estab-1991; Daly et al., 1996). The increased production relishment in both experiments. Ceres Tonic and Lancelot plantain are sulted from greater forage growth during the summer, not suited for the northeastern USA.contributed mainly by the forb component (mostly chicory). In Scotland, trials with several mixtures of forbs, grasses, and white clover under low-input management

plant (Ivins, 1952; Foster, 1988). The nutritive value of plantain is relatively unknown. We have investigated Forage production in midsummer is a challenge for graziers in the seedling development and establishment of plantain the northeastern USA. Domesticated cultivars of chicory (Cichorium intybus L.) and English plantain (Plantago lanceolata L.) are avail-and found that it establishes easily from seed (Sanderson able in the USA as perennial herbs for pastures. These species have and Elwinger, 2000a, b). Plantain also contains a number been touted as having good summer production and relatively high of biologically active compounds, such as the iridoid nutritive value. We conducted two field-plot experiments at Rock glycosides acubin and catapol, which have chemical de-