Grassland carbon sequestration and emissions following cultivation in a mixed crop rotation

Grasslands are potential carbon sinks to reduce unprecedented increase in atmospheric CO2. Effect of age (1 to 4-yr-old) and management (slurry, grazing multispecies mixture) of a grass phase mixed crop rotation on carbon sequestration and emissions upon cultivation was compared with 17-yr-old grassland and a pea field as reference. Aboveground and root biomass were determined and soils were incubated to study CO2 emissions after soil disturbance. Aboveground biomass was highest in 1-yr-old grassland with slurry application and lowest in 4-yr-old grassland without slurry application. Root biomass was highest in 4-yr-old grassland, but all 1 to 4-yr-old grasslands were in between the pea field (0.81±0.094 g kg-1 soil) and the 17-yr-old grassland (3.17±0.22 g kg-1 soil). Grazed grasslands had significantly higher root biomass than cut grasslands. There was no significant difference in the CO2 emissions within 1 to 4-yr-old grasslands. Only the 17-yr-old grassland showed markedly higher CO2 emissions (4.9 ± 1.1 g CO2 kg-1 soil). Differences in aboveground and root biomass did not affect CO2 emissions, and slurry application did not either. The substantial increase in root biomass with age but indifference in CO2 emissions across the age and management in temporary grasslands, thus, indicates potential for long-term sequestration of soil C

Productivity and forage quality of a phytodiverse semi-natural grassland under various management regimes

Grassland management experiment (GrassMan) was set up in 2008 on a permanent semi-natural grassland in the Solling uplands, Germany. The main research focus is on the ecosystem functioning of the phytodiverse grassland (e.g. productivity and forage quality, water and nutrient fluxes). The aim of our study was to analyse the effects of vegetation composition and functional diversity on productivity and forage quality of the semi-natural permanent grassland. Variation in sward composition was achieved by herbicide application and resulted in three sward types: control sward type (without herbicide application), monocot-reduced and dicot-reduced. Further management factors included different nutrient input levels (without fertilizer and 180-30-100 kg/ha of N-P-K per year) and use intensity (cut once or three times a year). Functional diversity was determined by estimation of the yield shares for each species in the species composition and their specific functional characteristics. Forage quality was analysed by near infrared spectroscopy (NIRS). While sward type influenced the forage quality, yield variation was explained mainly by the management regime

The ten-ecosystem study investigation plan

With the continental United States divided into ten forest and grassland ecosystems, the Ten Ecosystem Study (TES) is designed to investigate the feasibility and applicability of state-of-the-art automatic data processing remote sensing technology to inventory forest, grassland, and water resources by using Land Satellite data. The study will serve as a prelude to a possible future nationwide remote sensing application to inventory forest and rangeland renewable resources. This plan describes project design and phases, the ten ecosystem, data utilization and output, personnel organization, resource requirements, and schedules and milestones

Lack of increased availability of root-derived C may explain the low N2O emission from low N-urine patches

Urine deposition on grassland causes significant N2O losses, which in some cases may result from increased denitrification stimulated by labile compounds released from scorched plant roots. Two 12-day experiments were conducted in 13C-labelled grassland monoliths to investigate the link between N2O production and carbon mineralization following application of low rates of urine-N. Measurements of N2O and CO2 emissions from the monoliths as well as δ13C signal of evolved CO2 were done on day -4, -1, 0, 1, 2, 4, 5, 6 and 7 after application of urine corresponding to 3.1 and 5.5 g N m-2 in the first and second experiment, respectively. The δ13C signal was also determined for soil organic matter, dissolved organic C and CO2 evolved by microbial respiration. In addition, denitrifying enzyme activity (DEA) and nitrifying enzyme activity (NEA) were measured on day -1, 2 and 7 after the first urine application event. Urine did not affect DEA, whereas NEA was enhanced 2 days after urine application. In the first experiment, urine had no significant effect on the N2O flux, which was generally low (-8 to 14 μg N2O-N m-2 h-1). After the second application event, the N2O emission increased significantly to 87 μg N2O-N m-2 h-1 and the N2O emission factor for the added urine-N was 0.18 %. However, the associated 13C signal of soil respiration was unaffected by urine. Consequently, the increased N2O emission from the simulated low N-urine patches was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots

Forage herbs improve mineral composition of grassland herbage

Provision of an adequate mineral supply in the diets of ruminants fed mainly on grassland herbage can present a challenge if mineral concentrations are suboptimal for animal nutrition. Forage herbs may be included in grassland seed mixtures to improve herbage mineral content, although there is limited information about mineral concentrations in forage herbs. To determine whether herbs have greater macro- and micromineral concentrations than forage legumes and grasses, we conducted a 2-year experiment on a loamy-sand site in Denmark sown with a multi-species mixture comprised of three functional groups (grasses, legumes and herbs). Herb species included chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.), caraway (Carum carvi L.) and salad burnet (Sanguisorba minor L.). We also investigated the effect of slurry application on the macro- and micromineral concentration of grasses, legumes and herbs. In general, herbs had greater concentrations of the macrominerals P, Mg, K and S and the microminerals Zn and B than grasses and legumes. Slurry application indirectly decreased Ca, S, Cu and B concentrations of total herbage because of an increase in the proportion of mineral-poor grasses. Our study indicates that including herbs in forage mixtures is an effective way of increasing mineral concentrations in herbage

Grassland futures in Great Britain – Productivity assessment and scenarios for land use change opportunities

This is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).To optimise trade-offs provided by future changes in grassland use intensity, spatially and temporally explicit estimates of respective grassland productivities are required at the systems level. Here, we benchmark the potential national availability of grassland biomass, identify optimal strategies for its management, and investigate the relative importance of intensification over reversion (prioritising productivity versus environmental ecosystem services). Process-conservative meta-models for different grasslands were used to calculate the baseline dry matter yields (DMY; 1961–1990) at 1 km2 resolution for the whole UK. The effects of climate change, rising atmospheric [CO2] and technological progress on baseline DMYs were used to estimate future grassland productivities (up to 2050) for low and medium CO2 emission scenarios of UKCP09. UK benchmark productivities of 12.5, 8.7 and 2.8 t/ha on temporary, permanent and rough-grazing grassland, respectively, accounted for productivity gains by 2010. By 2050, productivities under medium emission scenario are predicted to increase to 15.5 and 9.8 t/ha on temporary and permanent grassland, respectively, but not on rough grassland. Based on surveyed grassland distributions for Great Britain in 2010 the annual availability of grassland biomass is likely to rise from 64 to 72 million tonnes by 2050. Assuming optimal N application could close existing productivity gaps of ca. 40% a range of management options could deliver additional 21 ∗ 106 tonnes of biomass available for bioenergy. Scenarios of changes in grassland use intensity demonstrated considerable scope for maintaining or further increasing grassland production and sparing some grassland for the provision of environmental ecosystem services.Peer reviewedFinal Published versio

Herbs in high producing organic grasslands – effect of management

In many organic grasslands herbs are established due to their expected beneficial properties for nutritive value and biodiversity. However, knowledge about grassland herbs is limited. Three mixtures were therefore established at different grazing/cutting and fertilization managements to examine the growth potential and feeding value. The competitiveness of the different species varied greatly. Chicory, plantain and caraway were competitive in mixtures with traditional grassland species. Lotus and salad burnet were weak competitors and chervil and sainfoin were very weak. The feeding value was also highly variable. Caraway had high digestibility of organic matter, also compared with the traditional grassland species, whereas plantain and salad burnet had lowest digestibility. The management, grazing, cutting, slurry and sward age, affected the proportion of the herb species. The proportion of caraway increased at cutting, slurry application and sward age. The proportion of plantain also increased at cutting but decreased at slurry application and sward age. The proportion of chicory increased with slurry application and decreased with sward age independently of cutting/grazing. The experiment showed that inclusion of herbs in the sward increased the biodiversity, made the herbage mass more diverse without affecting the dry matter yield

Method and timing of grassland renovation affects herbage yield, nitrate leaching, and nitrous oxide emission in intensively managed grasslands

Managed grasslands are occasionally ploughed up and reseeded in order to maintain or increase the sward productivity. It has been reported that this renovation of grassland is associated with a flush of soil organic nitrogen (N) mineralization and with a temporary increase in soil mineral N contents. Here, we report on the effects of method and time of grassland renovation on herbage yield, nitrate (NO3 -) leaching and nitrous oxide (N2O) emission. Field experiments were carried out at three sites (two sandy soils and a clay soil) in the Netherlands for three years. Renovation of grassland increased the percentage of Perennial ryegrass from 48–70% up to more than 90%. However, averaged over three years, dry matter yields were higher for the reference (not reseeded) swards (on average 13.6 Mg ha-1 for the highest N application rate) than for the renovated grasslands (12.2–13.1 Mg ha-1 dry matter). Grassland renovation in April did not increase N leaching in comparison to the reference. However, renovation in September increased the risk of leaching, because mineral N contents in the 0–90 cm were in November on average 46–77 kg N ha-1 higher than in the reference. Contents of dissolved organic N (DON) in the soil were not affected by renovation. Renovation increased N2O emissions by a factor of 1.8–3.0 relative to the reference grassland. Emissions of N2O were on average higher after renovation in April (8.2 kg N2O-N ha-1) than in September (5.8 kg N2O-N ha-1). Renovation without ploughing (i.e. only chemically destruction of the sward) resulted in a lower percentage of perennial ryegrass (60–84%) than with ploughing (>90%). Moreover, N2O emissions were higher after renovation without ploughing than with ploughing. Clearly, farmers need better recommendations and tools for determining when grassland renovation has beneficial agronomic effects. Losses of N via leaching and N2O emission after renovation can probably not be avoided, but renovation in spring in stead of autumn in combination with ploughing and proper timing of fertilizer application can minimize N losses

30 years of hay meadow succession without fertilization: how does it affect soil and avifauna groups?

In the present study we investigated the effects of hay meadow succession in the brook valley system of the Drentse A Nature Reserve, in the NE of the Netherlands. In particular, we compared the plant and soil fauna composition in five grasslands that differed in the stage of vegetation succession in two well-studied chronosequences, dry and wet respectively. The sampled meadows include a control site (still fertilized meadow), a 5, 15, 25 and 32 years stage of vegetation succession after the cessation of fertilizer application. At all sites, vegetation and earthworm composition was studied in replicate subplots of 4 m2 respectively 0.04 m² each. Moreover, the breeding birds have been monitored in the area over the last 28 years by mapping territories overlapping the meadows of the chronosequences. Concerning the plants we found that diversity was increasing with time of succession. In the wet meadow series the plant species richness increased from ca. 13 species per site (40 m2) to a maximum of ca. 49 species per site in the latest successional stage. In the drier parts the increase in species was less and reached an over all maximum of 27 species in the intermediate (15 years old) stage of the succession in 40 m2, but still increased to a mean of 15 species at the scale of 4 m2 plots in the oldest stage. The diversity and abundance of earthworms dropped significantly over time of succession. The species all belonged to 4 genera with Allolobophora being the most abundant. Soil pH dropped significantly during the succession even below 3.8 in the dry series. This largely explains the unfavourable conditions for the earthworms to survive in the oldest stages of the dry succession. The earthworm biomass dropped in nearly all sites below 25 g/m2 during the summer period, indicating unfavourable conditions for a suit of grassland breeding waders.The abundance of breeding birds in general was low due to the rather small area covered in this study. Anyhow we could find obvious changes in the breeding bird community. In particular waders such as Lapwing (Vanellus vanellus) and Black-tailed Godwit (Limosa limosa) disappeared completely from the area and were followed up by Curlew (Numenius arquata) and Snipe (Gallinago gallinago) being currently also rare in the area. Probably due to changes in grassland vegetation (increase of amongst others Cirsium palustre) and insect abundance the Stonechat (Saxicola torquata) has entered the area as a breeding bird. The same happens to a set of bird species typical for developing carr woodlands such as Lesser Spotted Woodpecker (Dendrocopos minor) and Golden Oriole (Oriolus oriolus).Die vorliegende Studie thematisiert am Beispiel der Fließgewässerniederung der Drentse A, einem großflächigen Schutzgebiet im Nordosten der Niederlande, die Folgen einer langjährigen Heuwiesennutzung ohne Düngung. Im Einzelnen wurde von uns die Zusammensetzung der Vegetation und Bodenfauna auf fünf Grünlandflächen untersucht, die sich in der Dauer der Ausmagerung unterschieden. Getrennt betrachtet wurden dabei die bachnahen, moorigen Niederungsbereichen und die angrenzenden sandigen Geestbereiche. Die ausgewählten Grünlandflächen waren zum Zeitpunkt der Aufnahmen seit 5, 15, 25, und 32 Jahren gemäht aber nicht mehr gedüngt worden. Eine weitere, nach wie vor konventionell bewirtschaftete Wiesenfläche (incl. Düngung) diente als Kontrolle. Auf allen Flächen wurde die Vegetation und Regenwurmfauna in 10 Plots mit einer Größe von jeweils 4 m² bzw. 0.04 m² untersucht. Darüber hinaus wurden über 28 Jahre hinweg die Brutvögel des Gebietes mittels Revierkartierung erfasst. Die Pflanzenartendiversität hat sich mit Dauer der Ausmagerung signifikant erhöht. Sie stieg in den bachnahen Bereichen von 13 Arten in der Kontrollfläche (40 m²) auf 49 Arten in der am längsten ausgemagerten Grünlandfläche an. In den trockenen Geestbereichen war der Anstieg deutlich schwächer. Bezogen auf die Gesamtfläche von 40 m² wurden die meisten Arten hier in der 15 Jahre lang ausgemagerten Grünlandfläche gefunden, während bei Betrachtung der 4 m² großen Aufnahmepunkte die höchste Artenzahl ebenfalls in der ältesten Untersuchungsfläche lag. Die Diversität und Abundanz der Regenwürmer nahm mit Dauer der Ausmagerung ab. Die festgestellten Arten gehörten zu 4 Gattungen, wobei die Gattung Allolobophora am individuenreichsten vertreten war. Mit Dauer der Ausmagerung sank besonders im trockenen bachfernen Geestbereich der Boden-pH-Wert auf unter 3,8 ab. Die damit einhergehenden pessimalen Lebensbedingungen erklären hinreichend die geringe Diversität und Dichte von Regenwürmern in diesen Bereichen. An fast allen Standorten sank die Biomasse der Regenwürmer zum Sommer hin auf Werte unter 25 g/m², so dass für viele Limikolen zu dieser Zeit pessimale Ernährungsbedingungen bestehen. Die Zahl der Brutvogelarten war aufgrund des recht kleinen Untersuchungsgebietes insgesamt gering. Dennoch konnten auffallende Veränderungen in der Brutvogelgemeinschaft beobachtet werden. Während Limikolen wie Kiebitz (Vanellus vanellus) und Uferschnepfe (Limosa limosa) vollständig aus dem Gebiet verschwanden, wanderten der Große Brachvogel und die Bekassine ein. Allerdings sind auch sie aktuell nur noch selten im Gebiet vertreten. Dafür hat sich inzwischen das Schwarzkehlchen (Saxicola torquata) als Brutvogel eingestellt – möglicherweise eine Folge der sich ändernden Grünlandvegetation (hier: Zunahme von Pflanzenarten, die als Ansitzwarten fungieren können wie etwa Cirsium palustre) in Kombination mit einem verbesserten Nahrungsangebot an Makroinvertebraten. Eingewandert sind zwischenzeitlich auch eine Reihe weiterer Vogelarten, wie Pirol (Oriolus oriolus) und Kleinspecht (Dendrocopos minor), die charakteristisch für sich entwickelnde Bruchwälder sind. Letztere haben sich, meist kleinflächig, auf ehemaligen Feuchtgrünlandstandorten entwickelt