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This article identifies the quality themes of distance learning that arose from the learners' perspective as reflected in the literature. The paper reviews literature through the four themes of 1) Course design, 2) Interaction, 3) Learner support and 4) Technology Use. Key quality indicators in distance learning that appear repeatedly in research on students' point of view are also examined. It is argued that distance learning quality standards must first be focused on the students' perspective in order to develop comprehensive and efficient standards for evaluating distance learning. This review serves as a starting point for distance learning providers specifically and accreditation organizations generally to better inform current quality practices regarding distance learning environments in higher education.

Perennial groundcover (PGC) has promise as a scalable approach to generating natural resource benefits and sustainable biofuel feedstock while preserving the high yields of annual row crop production. Partnering row crops with temporally and spatially complementary low-growing, shallow-rooted perennials, such as Kentucky bluegrass (KBG) (Poa pratensis L.), is one example of an emerging PGC system. PGC's ecosystem benefits can only be fully realized if commercial-scale adoption occurs, which hinges on its economic feasibility. This paper utilizes an enterprise budget framework to detail and compare the expected cost and revenue of establishing and maintaining PGC in row crop systems with standard continuous corn (SCC) (Zea mays L.) production, including stover harvest, but excluding economic incentives for ecosystem services. Optimistic and pessimistic assumptions were used, along with Monte Carlo simulation, to characterize the uncertainty in results. In the optimistic stover market scenario, Year 1 net returns for PGC averaged USD 84/ac less than for SCC; Year 2+ net returns averaged USD 83/ac more, meaning that cost parity with SCC occurs by the second PGC system year. Without stover revenue, parity is achieved after five years. These results affirm that PGC's economic viability is critically impacted by a groundcover's lifespan, the yield parity with SCC, and the availability of a stover market. [ABSTRACT FROM AUTHOR]

Seed quality of maize (Zea mays L.) can be negatively impacted by a fall frost event. It is important for the seed industry to detect frost damage early and to make marketing decisions before the seed lots are conditioned for sale. This study compared several seed quality tests (standard germination [WG], accelerated aging [AA], saturated cold [SC], and soak tests) for their ability to quantify frost damage. Additionally, these tests were used to predict field emergence under poor and average to good field conditions. Two genotypes (B73 x IRF311 and Mo17 x IRF311) were harvested at three moisture contents (300-350, 400-450, and 500-550 g [H.sub.2]O [kg.sup.-1] fresh weight). An artificial frost treatment was applied to the seed and damage was determined by testing seed after approximately 0, 1.5, 3, 4.5, and 6 mo of storage. The artificial frost treatment significantly decreased viability and vigor of all the seed lots except Mo17 x IRF311 harvested at 300 to 350 g [H.sub.2]O [kg.sup.-1] fresh weight. As seeds matured, the damage associated with frost treatment decreased. Laboratory tests did not accurately predict field emergence of frost-damaged seed under poor field conditions; however, AA at 0 mo, SC at approximately 0, 1.5, and 3 mo, and soak at approximately 0, 1.5, and 3 mo had strong relationships to field emergence under average to good field conditions. These results indicate that frost damage in seed lots is quantifiable using the SC and soak tests during approximately the first 3 mo of storage and both tests accurately predict field emergence.

Pasturelands are inherently variable. It is this variability that makes sampling as well as characterizing an entire pasture difficult. Measurement of plant canopy reflectance with a ground-based radiometer offers an indirect, rapid, and noninvasive characterization of pasture productivity and composition. The objectives of this study were (i) to determine the relationships between easily collected canopy reflectance data and pasture biomass and species composition and (ii) to determine if the use of pasture reflectance data as a covariate improved mapping accuracy of biomass, percentage of grass cover, and percentage of legume cover across three sampling schemes in a central Iowa pasture. Reflectance values for wavebands most highly correlated with biomass, percentage of grass cover, and percentage of legume cover were used as covariates. Cokriging was compared with kriging as a method for estimating these parameters for unsampled sites. The use of canopy reflectance as a covariate improved prediction of grass and legume percentage of cover in all three sampling schemes studied. The prediction of above-ground biomass was not as consistent given that improvement with cokriging was observed with only one of the sampling schemes because of the low amount of spatial continuity of biomass values. An overall improvement in root mean square error (RMSE) for predicting values for unsampled sites was observed when cokriging was implemented. Use of rapid and indirect methods for quantifying pasture variability could provide useful and convenient information for more accurate characterization of time consuming parameters, such as pasture composition., SAMPLING IS THE researcher's best way to learn about a population. When a pasture is considered to be a population, the task is to determine where to sample and how [...]

Seed dormancy is a main factor limiting the use of eastern gamagrass (Tripsacum dactyloides L.) for forage and conservation purposes; however, there is little available information on the seed bank dynamics of eastern gamagrass plantings. Knowledge of the degree and rate of seed dormancy loss would improve decisions concerning eastern gamagrass plantings and provide a better understanding of the seed bank longevity for this species. In this study, cold, moist stratified seed or unstratified seed was planted at 2.5- and 5.0-cm depths on 16 Aug. 1999, 1 Nov. 1999, 14 April 2000, 15 May 2000, and 16 June 2000 for the first year of the study and 15 Aug. 2000, 31 Oct. 2000, 17 April 2001, 15 May 2001, and 15 June 2001 in the second year. Plants and seeds were retrieved at 3, 6, 9, and 12 mo after planting of 50 seeds for each seed treatment and planting depth combination. Intact seeds were germinated for 28 d and the viability of ungerminated seeds was determined with a tetrazolium test. Seed dormancy of both stratified and unstratified eastern gamagrass seed was lost mostly between mid-September and mid-November. No more than 12% dormant seed remained after mid-December and dormancy was completely lost by April and May. Seed dormancy in eastern gamagrass was substantially reduced with several weeks of soil temperatures below 15°C and adequate soil moisture., EASTERN GAMAGRASS is a warm-season, perennial, bunch grass found growing naturally from the northeastern and north central USA and south into Mexico, Central America, the Caribbean, and into Bolivia and [...]

The productivity of grasslands depends in part on their diversity of species and functional composition. Our objective was to examine the effects of three landscape positions (summit, backslope, and toeslope) and three stocking systems (continuous, rotational, and nongrazed) on species diversity and percentage of cover of grass, legume, and weed species functional types in southeastern Iowa pastures. Data were collected in 0.2-[m.sup.2] plots randomly distributed throughout each of four replicate pastures in spring and summer 2000 and 2001. Backslope landscape positions within pastures managed with either continuous or rotational stocking contained the greatest overall diversity of species. Across years, overall species richness under grazing averaged 4.8 on backslopes, 3.5 on summits, and 2.9 on toeslopes. Legume cover was greatest within the rotational stocking system, averaging 21% on backslopes, 10% on summits, and 3% on toeslopes across years. Cool-season grasses dominated summits and toeslopes, consisting of 88 to 94% of the cover. Weed species diversity and cover were greatest on backslopes within the continuous stocking system. Our results showed that rotational stocking had more desirable effects through greater legume cover and less weed cover on backslopes than continuous stocking. This research suggested that spatial components of pastures should be considered to optimize the production and quality of forage for grazing livestock., THE PRODUCTIVITY AND STABILITY of aboveground biomass in grassland ecosystems depends inpart on the functional composition and diversity of plant species. Recent experiments showed that species-rich grasslands have greater productivity [...]