Forage Vegetation Research Articles

Vegetation diversity based on peat hydrological units for supporting cattle production in West Kalimantan, Indonesia

Abstract. Setiawan D, Jayanegara A, Nahrowi, Kumalasari NR. 2024. Vegetation diversity based on peat hydrological units for supporting cattle production in West Kalimantan, Indonesia. Biodiversitas 25: 2011-2019. This study determined the characteristics of forage supply, composition, and diversity in various West Kalimantan Peat Hydrological Units (PHU) and the capacity for livestock development. The methods used were a combination of surveys, direct observations, and measurements of samples of peat hydrological units commonly used as pasture by farmers. The results showed that the pattern of providing forage for livestock is that the majority of farmers are in the productive age category (41-60 years), the education level was only elementary school, livestock farming was only a side business (78.33-81.67%), and the mowing capacity was still above livestock feed requirements. Important Value Index (IVI) in Mempawah Ageratum conyzoides (32.34%), Pontianak IVI Digitaria sanguinalis (27.17%), Kubu Raya IVI Cyperus brevifolius (22.43%). The forage species diversity index (H) of the three districts in West Kalimantan was classified as moderate or high. The species Richness Indices (R') for Mempawah, Pontianak, and Kubu Raya were 5.01, 6.22, and 6.41, respectively. The carrying capacity index in Kubu Raya (2.01) and Mempawah (5.19) was included in the safety criteria because it has a CCI above 2. In conclusion, The West Kalimantan livestock population can be increased by utilizing land in rice fields, dry fields, community forests, and plantations as a source of diverse forage vegetation.

A Case for Adaptive Management of Rangelands’ Wicked Problems

Sagebrush-steppe restoration has long been seen as a wicked problem—each case has multifaceted problems with no universal solutions—and thus managers have had to adopt adaptive management techniques to meet ever-changing landscape demands. In this study, we characterize the efficacy of an adaptive management plan in a severely degraded sagebrush-steppe winter range habitat for mule deer for 8 yr by monitoring the plant community. During this time, managers have actively managed juniper encroachment through felling and responded to a 2014 wildfire by applying herbicide and seeding for native and forage vegetation. We found that the adaptive management practices reduced annual invasive grasses by about half post fire and nearly doubled preferred herbaceous plants’ cover and biomass. However, these successes were only recorded in plots that received repeated treatments, whereas in plots that only received a single treatment post fire, invasive annual grasses returned to prefire cover. Despite these successes in recovering desired herbaceous composition, shrub regeneration was nearly nonexistent during the study period despite repeated attempts to seed.

Эколого-биологические аспекты кустарниковой мелиорации деградированных пастбищ на бугристо-увалистых комплексах песчаных земель Прикаспия

The article presents the results of studies of the effectiveness of shrub reclamation on pastures of the Caspian Sea. Introduction. As a result of the outbreak of deflationary desertification of lands that occurred on the territory of the Russian Caspian Sea in the 70-80-ies of the XX century, it became necessary to develop methods for large-scale shrub reclamation of degraded lands. One of the problematic areas where these works were carried out is pastures on light soils of the Astrakhan Volga region. Materials and methods. The study is based on biomonitoring materials and field experiments using standard methods of forest taxation, soil science and geo-botany. Results and discussion. Thanks to the microclimate, the best conditions for the growth of herbaceous vegetation are formed in the spaces between pasture-protective strips with a width of 30 m. The yield of herbage phyto mass on them, both in spring and autumn, is higher by 0.06–0.13 t/ha. With severe damage or destruction of shrub plantations, areas with productive herbage degrade. Reclamation and forage plantations, depending on the age, increase the yield of pastures by 41–85%. The productivity of herbage is everywhere higher on pastures with a complex of pasture-protective and reclamation-forage plantations with teresken at the age of 20-25 years. Сonclusion. It has been established that pasture protection strips from haloxylon, reclamation and fodder plantations from krascheninnikovia and calligonum in the Astrakhan Volga region have been functioning for more than 45 years. It was determined that in forested areas, depending on age, the preservation of saxaul is 14–45% with an average plant height of 2.0–3.2 m. It is shown that the plantings of krascheninnikovia and calligonum on hollow-bumpy and withered plains with light soils at the age of 30–40 years have a safety of 45–70%, have a positive effect on the restorative succession of herbage between rows of shrubs and in the wind-shade zones of strip and backstage plantings. It was revealed that the addition to the pasture forage in the form of an available twig-leaf mass of shrubs in May – August can reach 0.5–4.0 t/ha in dry form. The hay yield of natural forage vegetation under the protection of shrub plantations on improved pastures is 1.2–1.5 times higher compared to unprotected lands and amounts to 0.70–1.60 t/ha. The results of the research can be useful in the phyto-melioration of degraded pastures located on bumpy sandy lands. Suggestions for practical application and direction of future research. The results of the research can be useful in the phytomelioration of degraded pastures located on bumpy sandy lands. An urgent problem remains the development of a system of measures for the care, repair and reconstruction of shrub plantations that can increase their productivity and durability on functioning pastures.

Эффективные технологии восстановления деградированных земель и создания высококачественных сенокосов в бассейне реки Дон

Abstract. Scientific novelty and practical significance. The increasing rates of soil degradation processes in the southern regions of Russia make it urgent to increase the productivity of agricultural land, stabilize ecosystems and restore potentially valuable forage vegetation. Phytomeliorative reconstruction of low-productive lands is of great practical importance for ensuring sustainable development of the region and national food security. The purpose of the research. The purpose of the research is to identify the effectiveness of the conducted phytomeliorative works aimed at increasing productivity and preserving the native biodiversity of hayfields in the conditions of the dry steppe of the Don river basin. Methods. Phytomeliorative reconstruction of hayfields was carried out in the autumn of 2021. (Volgograd region, Ilovlinskiy district) by sowing a grass mixture of Agropyron elongatum + Agropyron cristatum L + Bromus inermis on two plots with an area of 40 and 30 hectares. The abundance of plants was determined by the Drude rating scale. The similarity index of the species composition of phytocenoses is calculated according to the Zhakkar formula. Productivity was determined by the sloping method. Results. 36 species of herbs from 18 families were identified on the phytomeliorated hayfields of plot No. 1, 34 species from 18 families were identified on plot No. 2, 35 species from 17 families were identified on natural hayfields. The Zhakkar index shows the similarity of phytocenoses by 30–33 %. The largest share in the number of species (pieces) in the phytocenosis was occupied by species of the Asteraceae (30–33 %) and Poaceae (17–18 %) families. But phytomeliorants had the greatest influence on the formation of the crop. The proportion of phytomeliorants in the total phytomass in different seasons was not the same. The main phytomass was Agropyron elongatum: in May its share in the phytocenosis reached 53–71 %, in September – 65–68 %. Phytomeliorated areas turned out to be 1.7–1.8 times more productive than natural ones in spring, 1.5 times more productive in summer, and 1.8–2.2 times more productive in autumn. On average, the yield of phytomeliorated plots increased by 1,6–1,9 times compared to last year and amounted to 305–317 g/m2.

Kudurs (mineral licks) on ultrabasic rocks in the Altai Mountains, Russia

In the present study, the mineral and chemical compositions of kudurits consumed by wild ungulates and the chemical composition of forage vegetation near the water‑divide of the Abakan Range, Mountain Altai, Russia, were studied. It was found that the kudurits are represented by smectite‑vermiculite mineral associations with chlorite‑the products of hydrothermal transformation of metamorphosed ultrabasic rocks (serpentinites) following the intrusion of neighboring gabbroid dikes. Acid extracts (hydrogen chloride, pH 1.0) from kudurits most actively extract Ca, K, Mg, Fe and Na. In the composition of trace elements, Ba, Sr, Ni, Cu, Cr, Co, V, Zn and Li are most mobile. The comparison of the chemical composition of a kudurit and coprolite of red deer indicates that when mineral earth materials pass through the digestive tract out of all trace elements only about 0.4 g/kg of Na is reliably assimilated in the body, while kudurits simultaneously sorb and remove P, K, Mg and Ca. Chemical analyses of vegetation in places from which animals most often come to kudurs revealed high concentrations of rare earth elements. A rare‑earth‑sodium hypothesis of the cause of geophagy is developed, which may explain the majority of cases of regular consumption of earthy substances by animals and humans.

Dry season forage assessment across senegalese rangelands using earth observation data

Strengthening of feed security in the Sahel is urgently needed given the climate change and growing human population. A prerequisite to this is sustainable use of rangeland forage resources for livestock. Many studies have focused on the assessment of rangeland resources during the rainy season, while only a few have focused on the dry season which is the longest and most demanding period for livestock in Sahelian rangelands. The objective of this study is to develop remote sensing-based models for estimating dry season forage vegetation mass. To that end, 29 vegetation indices calculated from each of the MODIS-MCD43A4 (500 m), Landsat-8 (30 m), and Sentinel-2 (10 m) satellite products were used and tested against in situ data collected during three field-measurement campaigns in 2021 at eleven monitoring sites across Senegalese rangelands. Four statistical models were tested, namely, random forest, gradient boosting machines, and simple linear and multiple linear regressions. The two main vegetation mass variables modeled from remote sensing imagery were the standing herbaceous and litter dry mass (BH) and total forage dry mass (BT) with a dry mass of woody plant leaves added to BH. Overall, Sentinel-2 data provided the best performance for the assessment of BH with multiple linear regression (R2 = 0.74; RMSE = 378 kg DM/ha) using NDI5 (Normalized Difference Index5), GRCI (Green Residue Cover Index), SRI (Simple Ratio Index), TCARI (Transformed Chlorophyll Absorption in Reflectance Index), and DFI (Dead Fuel Index) indices. For BT, the best model was also obtained from Sentinel-2 data, including RVI3 (Ratio Vegetation Index3) (R2 = 0.78; RMSE = 496 kg DM/ha). Results showed the suitability of combining the red, green, blue, NIR, SWIR1, and SWIR2 bands in monitoring forage availability during the dry season. Our study revealed that the spectral richness of the optical sensor systems Sentinel-2, Landsat-8, and MODIS-MCD43A4 allowed for accurate assessments of dry-season forage mass of semi-arid rangelands. Adding to this, the high spatial and temporal resolution of Sentinel-2 satellite imagery makes this a promising data source for timely monitoring. These findings can support the monitoring of the animal feed balance in Sahelian countries and contribute to enhancing the resilience of pastoralism toward feed shortage through early warning systems.

Seeding Rate Effects on Forage Mass and Vegetation Dynamics of Cool-Season Grass Sod Interseeded with Sorghum-Sudangrass

Interseeding annual warm-season grasses into perennial cool-season grasses has the potential to increase summer forage mass and nutritive value. Knowledge of how seeding rate affects annual warm-season grass establishment, forage mass, and vegetation dynamics remains limited. From 2016–2017, we conducted a field experiment evaluating the effects of seeding rates on sorghum-sudangrass (Sorghum bicolor × S. bicolor var. sudanense) density and forage mass and on the frequency of occurrence of plant species in cool-season grass sod in Lincoln, NE. The experiment had a completely randomized design consisting of six replicates of four seeding rates [0, 14, 28, and 35 kg pure live seed (PLS) ha−1] in sod mowed at a 2.5-cm height and one unseeded, non-mowed control treatment. Sorghum-sudangrass establishment increased with seeding rate from an average of 20 to 45 plants m−2 as the seeding rate increased from 14 to 35 kg PLS ha−1. Forage mass depended on a seeding rate × harvest interaction, showing positive linear and cubic responses to seeding rate in consecutive harvests at 45 and 90 d after interseeding. To increase forage mass in perennial cool-season grass sod, producers should interseed sorghum-sudangrass with at least 28 kg PLS ha−1. One-time seedings into cool-season, perennial grass sod have no residual effects on subsequent forage mass and vegetation dynamics.

Vegetation diversity of feeding plant of Tapanuli Orangutan (Pongo tapanuliensis) in the land of other uses around the Batang Toru Forest Area, North Sumatera

The Tapanuli orangutan (Pongo tapanuliensis) is an endemic species found in the Batang Toru ecosystem. The population of Tapanuli orangutan is divided into two main regions (west and east blocks), and also a small population in the natural reserve. Its status based on the IUCN red list is classified as “Critically Endangered”. It is necessary to identify the diversity and abundance of forage vegetation for Tapanuli orangutan using vegetation analysis especially in other zones of Batang Toru forest area. All is related to the importance and urgency of Orangutan habitat protection. This research aimed to estimate the availability of forage sources of Orangutans particularly outside the protection area. It shows a total diversity index (H’) of 4.62, which means that the level of diversity is high. Consequently, protection efforts outside the conservation area are really needed to support Batang Toru ecosystem from land conversion threat that may cause negative impact on the sustainability of Orangutan habitat itself.

Physiology of Leymus chinensis under seasonal grazing: Implications for the development of sustainable grazing in a temperate grassland of Inner Mongolia

Plants have different physiological characteristics as the season changes, grazing management in compliance with plant growth and development characteristics may provide new ideas for sustainable livestock development. However, there has been little research on seasonal grazing and plants physiological responses under it. Here, we studied a typical steppe ecosystem of Inner Mongolia, with Leymus chinensis as the dominant species, in five grazing treatments: continuous grazing, seasonal grazing (which started in spring or in early and late summer), and no grazing (the control). We analyzed growth and resistance of L. chinensis in the five treatments by measuring annual primary productivity, morphological traits and various physiological processes. Compared with continuous grazing, seasonal grazing significantly alleviated grassland degradation. The plants were less affected by stress under spring grazing, with net photosynthesis and non-photochemical quenching closer to the control values and with a lower malondialdehyde content. The annual primary production of plants under grazing started in the early and late summer were 3–4 times the value under continuous grazing. Regrowth under early-summer grazing was greatly improved, and stress resistance was stronger with a higher proline content and high antioxidant enzyme activity. And nutrient accumulation at the end of the growing season such as abundant soluble sugars were transferred from aboveground tissue to the roots in September under late-summer grazing, which benefited regrowth the next year. All these physiological processes were regulated by hormonal changes. Our results highlight how plants response grazing stress in different growing seasons and suggest that seasonal grazing can improve the stress resistance and regrowth capacity of forage vegetation, and applying this knowledge can promote more sustainable grazing practices.

Locally produced chicken eggs-a source of dietary lead for an Australian community living with an active lead smelter?

The South Australian regional city of Port Pirie has a long history of environmental lead contamination caused by smelting operations that have resulted in elevated blood lead levels in local children. This study examines the potential exposure of children to lead as a result of consuming eggs produced by domestic chickens kept in a lead-contaminated environment. Lead concentrations were measured in eggs, chicken enclosure soil, chicken feed and forage vegetation collected from a domestic site in Port Pirie. Eggs produced in the vicinity of the operating smelter had higher whole-egg lead concentrations (median: 0.09 mg/kg; range: 0.03-0.19 mg/kg) than control eggs (median: 0.002 mg/kg; range: 0.002-0.005 mg/kg). Soil and forage vegetation were identified as potential lead sources for the chickens in this study. The impact of remediating potential lead sources accessed by the chickens was examined and remedial actions were found to be only partly effective with a three-fold reduction in lead concentrations in eggs. Estimated lead intake for a 2-year-old child consuming these eggs indicated that a diet rich in eggs could more than double the child's daily lead exposure from dietary sources. Eggs produced by chickens housed in residential backyards are a readily avoidable additional source of lead exposure for children living in this industrial community, where all environmental lead sources contribute to an unacceptable daily intake.

Case Study: Using Soil Survey to Help Predict Sonoran Desert Tortoise Population Distribution and Densities

On the Ground Soils properties can affect the ability of an animal to dig burrows for habitat and survival purposes. The Sonoran (Gopherus morafkai) and Mojave Desert Tortoise (Gopherus agassizii) require burrows that are at least 20 inches deep to help them thermoregulate during the cold of winter and heat of summer. Soils that have characteristics that restrict their “digability” would be expected to limit the population density and distribution of animals such as the Sonoran or the Mojave Desert Tortoise regardless of the amount of forage vegetation being produced. The Sonoran Desert Tortoise in Mohave County, Arizona, and possibly throughout its range may seek “habitats of opportunity” within boulder piles, under exposed bedrock, and in caliche caves due to the limited “digability” of the soils endemic to this part of the Sonoran Desert. The natural availability of thermoregulating burrowing habitat and temperature/precipitation records should be considered when interpreting any fluctuations in Sonora...

Forage availability to saigas (Saiga tatarica) and their state on steppe pastures with a different ratio of graminoid plants and forbs

An interfaced analysis of change of forage vegetation, nutrition of saigas (Saiga tatarica), and their state in tne steppe regions of Russia is performed. It is noted that the percent of graminoids has increased considerably and the proportion of forbs has decreased in the vegetation of current pastures, which has had a negative impact on the nutrition and state of saigas. It is shown that the lower nutritional value of graminoids has caused a decrease in the digestibility of forage used by saigas and does not provide the physiological requirements of the animals. It is established that modern steppe pastures, where gramineous communities prevail, are of little use or absolutely unsuitable for the stable existence of saiga populations. Only separate dwelling places with an abundance of forbs continue to provide adequate nutrition for saigas and well-being for their local groupings.

Water retention and s index of an oxisol subjected to weed control methods in a coffee crop

Weed control in different crops affects the chemical, physical, and biological properties of the soil and consequently its structural quality. The objective of this study was to evaluate, using water retention characteristics and the S index, the physical quality of an Oxisol (Red-Yellow Latosol), subjected to weed control during the cultivation of coffee. The following weed control methods were evaluated: harrowing, brushcutting, residue crushing, manual weeding, post-emergence herbicide application, pre-emergence herbicide application, and maintenance of soil cover with peanut forage, Brachiaria grass, and spontaneous vegetation (no weed treatment). The following properties were determined for physical characterization of the soil: bulk density, total porosity, macroporosity, microporosity, water retention, and the S index. The weed control method significantly affected the physical properties and water retention in the subsurface layer of the Oxisol. Soil bulk density, total porosity, macroporosity, and microporosity were significantly correlated with the S index. According to the S index, the physical quality of the soil was classified as very good for the various weed control methods investigated.

Quality control by leaf-cutting ants: evidence from communities of endophytic fungi in foraged and rejected vegetation

Leaf-cutting ants of the genera Acromyrmex and Atta forage vegetation for incorporation into their mutualistic fungal gardens. However, the presence of certain endophytic fungi in this predominantly leaf-based material could affect the fungal garden and thus the choice of material by the ants. The present study was conducted to document the endophytic fungal communities occurring in the vegetation being transported by workers of Atta laevigata into their nests and to compare this community structure with that of the vegetative material subsequently rejected from the nests. We found considerable diversity in the fungi isolated. Acremonium, Cylindrocladium, Drechslera, Epicoccum, Fusarium, Trichoderma, Ulocladium and two unidentified morphospecies were significantly more common in rejected compared with foraged material, and some of these genera include mycoparasites, which could represent a threat to the fungal gardens. Conversely, Colletotrichum, Pestalotiopsis, Phomopsis, Xylaria and an unidentified morphospecies were more common in carried compared with rejected material. The possibility that ants have a ‘quality-control’ mechanism based on the presence of antagonistic fungal endophytes is discussed, as is the potential use of these fungi as biocontrol agents against Attini pests.

Detecting continuous lichen abundance for mapping winter caribou forage at landscape spatial scales

Spatial variation of available food resources can be difficult to accurately quantify for wide ranging organisms at landscape scales. Lichens with usnic acid, a yellowish pigment, constitute a large portion of caribou winter diet across much of their range. We take a new approach of modeling lichen abundances by capitalizing on unique spectral characteristics of usnic acid lichens. We utilize a recently completed ground reference vegetation data set extending over 12,000km2 in Denali National Park and Preserve, Alaska to model the abundance of usnic lichen and other forage vegetation groups. Spectral signatures were obtained for more than 700 vegetation monitoring plots in Denali from Landsat 7 ETM+ imagery. We fit models of the absolute percent cover of vegetation groups corresponding to caribou diet items, with a focus on lichens. We used non-parametric multiplicative regression to capture the non-linear relationships between vegetation cover and spectral and environmental data. Different groupings of lichen cover were tried as response variables in addition to usnic lichens to see if other lichen color groups were more detectable. The best fitting lichen model was for usnic acid lichens, which explained 37% of the variation using only three predictors (elevation, bands 1 and 7). Elevation had a non-linear, double-humped shaped relationship to usnic lichen abundance while bands 1 and 7 were positively correlated with usnic lichen cover. These results support previous spectroradiometric ground measurements that indicated usnic lichens were distinctive at those wavelengths. Other vegetation groups had models that explained between 31% and 51% of the variation in cover. Maps of estimated abundance of usnic lichens and other vegetation groups covering the northern half of Denali were generated using our models. These maps enable the study of the role of food resources as a continuous resource in winter habitat selection by caribou, rather than assuming food as a coarser, categorical or thematic variable assigned to discrete areas of the landscape as has been done in most previous studies.

Avian Foods, Foraging and Habitat Conservation in World Rice Fields

Abstract. Worldwide, rice (Oryza sativa) agriculture typically involves seasonal flooding and soil tillage, which provides a variety of microhabitats and potential food for birds. Water management in rice fields creates conditions ranging from saturated mud flats to shallow (<30 cm) water, thereby attracting different guilds of birds. Grain not collected during harvest (i.e. waste rice) is typically the most abundant potential food of birds in rice fields, with estimates of seed mass from North America ranging from 66–672 kg/ha. Although initially abundant after harvest, waste rice availability can be temporally limited. Few abundance estimates for other foods, such as vertebrate prey or forage vegetation, exist for rice fields. Outside North America, Europe and Japan, little is known about abundance and importance of any avian food in rice fields. Currently, flooding rice fields after harvest is the best known management practice to attract and benefit birds. Studies from North America indicate specific ...

The effect of quantitative variables of forage vegetation on the structure of ruminant guilds

An interrelation between the structure of ruminant guilds and forage species structure depend on food consumption/supply proportion. The success in competition is determined not only by adaptive advantages of consumer species but also by their specific food benefits, which root in habitat vegetation structure. It is proposed that consumer coexistence in the chronologically former guilds is rather neutral for lack of considerable benefits and advantages. Inversely, some species of further guilds are able to dominate others using adaptive advantages more than food benefits of pastures. Resource shortage and competition in consumer guilds may be an indicator of community transformation or at least feature of guild novelty.

Diferentes métodos de controle de plantas indesejáveis em pastagem nativa

O experimento foi desenvolvido em área de pastagem nativa representativa da transição entre a Serra do Sudeste e a Depressão Central do Rio Grande do Sul, onde as espécies indesejáveis foram representadas especialmente por carqueja (Baccharis trimera (Less.) DC.), caraguatá (Eryngium horridum (Spreng.) Less.) e alecrim (Vernonia nudiflora Less.). Foram avaliados os efeitos iniciais de dois métodos de controle de espécies indesejáveis (até 60 dias após aplicação) sobre a produção de forragem, a dinâmica da vegetação e a eficiência de controle: sem-controle; controle mecânico; e controle químico (herbicida comercial à base de Picloram [64 g/L] + 2,4-D [240 g/L], na dosagem de 5 L do produto comercial/ha). Os tratamentos foram arranjados em um delineamento em blocos ao acaso, com quatro repetições. A massa gramíneas verdes secas e a massa total de MS não diferiram entre os métodos de controle. Foram obtidos valores de 587,9; 472,0 e 0 kg de MS com o controle mecânico, o controle químico e sem-controle, respectivamente, o que comprova influência do método de controle sobre a massa de forragem de leguminosas. A eficiência de controle das espécies indesejáveis, em comparação à ausência de controle, foi de 76,2% para o controle químico e 27,9% para o controle mecânico. A eficiência de controle de espécies, sob aspectos de freqüência dos componentes da pastagem, evidenciou que o controle mecânico não foi eficiente aos 60 dias após aplicação no controle de plantas de alecrim no segundo toque (-27,7%) e plantas de caraguatá no primeiro toque (-30,0%).

An Ecological Risk Assessment Framework for Effects of Onsite Wastewater Treatment Systems and Other Localized Sources of Nutrients on Aquatic Ecosystems

ABSTRACT An ecological risk assessment framework for onsite wastewater treatment systems and other localized sources of nutrients is presented, including problem formulation, characterization of exposure, characterization of effects, and risk characterization. The framework is most pertinent to the spatial scale of residential treatment systems located adjacent to small ponds, streams, or lagoons and some parts of shallow estuaries. Freshwater and estuarine ecosystems are distinguished based on differences in nutrient dynamics. Phosphorus exposure is the major determinant of phytoplankton production in most North American lakes. Nitrate can be directly toxic to aquatic biota such as amphibians. In shallow estuaries or lagoons, nitrogen is the primary stressor, which can be directly toxic to vegetation or can interact with biota to produce secondary stressors (limited light penetration, oxygen limitation, reduction in habitat, or reduction in forage vegetation or prey). Algal production, macrophyte production, fish community abundance and production, benthic community abundance and production, and amphibian community abundance and production are examples of risk assessment endpoint properties. Models and measurement methods for the characterization of exposure and effects are discussed, as well as sources and quantification of uncertainty. Example weight-of-evidence tables are presented for failure scenarios involving traditional and emerging onsite wastewater system technologies.

Crop content in nutrient-restricted versus non-restricted organic laying hens with access to different forage vegetations

1. The purpose of this study was to evaluate how feed intake of organic layers varies according to type of forage vegetation available when hens are fed a normal concentrate for organic layers or a nutrient-restricted diet with whole wheat and oyster shells, assuming that the nutrient-restricted diet would reflect the capacity of the hens to forage. 2. Two 23-d experiments were arranged with chicken runs in a 2 × 2 factorial design with two types of complementary feed (concentrate with 184 g/kg dry matter (DM) crude protein vs whole wheat with 120 g/kg DM crude protein) and two types of forage vegetation (grass/clover vs a mixture of forbs in experiment 1 and grass/clover vs chicory in experiment 2): each experiment was carried out in three replications. 3. Twice during each experiment two hens from each run were slaughtered—two in the evening and two the following morning. Subsequently, the birds’ crops were removed. Crop content was separated into 8 fractions. 4. For most feed items crop content was found to be significantly higher in the evening than in the morning. 5. Complementary feed significantly influenced the content of several feed items in the crop. In both experiments wheat-fed hens had a significantly higher amount of soil in the crops and a significantly lower amount of weed seeds compared to the concentrate-fed hens. Plant material and grit stone were significantly more abundant in wheat-fed hens only in experiment 2 and numerically more abundant in experiment 1, whereas the amount of oyster shells was significantly higher in wheat-fed hens in experiment 1 and numerically higher in experiment 2. 6. Type of forage itself only significantly influenced the amount of soil in the crops in experiment 1 and amount of seeds in experiment 2, since more soil was found in hens foraging on the mixed forbs and more seeds were found in the hens foraging on the chicory plots, respectively.