Sward Height Research Articles

Spatial ecology of host–parasitoid interactions: a threatened butterfly and its specialised parasitoid

Habitat conservation for threatened temperate insect species is often guided by one of two paradigms: a metapopulation approach focusing on patch area, isolation and number; or a habitat approach focusing on maintaining high quality habitat for the focal species. Recent research has identified the additive and interacting importance of both approaches for maintaining populations of threatened butterflies. For specialised host-parasitoid interactions, understanding the consequences of habitat characteristics for the interacting species is important, because (1) specialised parasitoids are particularly vulnerable to the consequences of fragmentation, and (2) altered interaction frequencies resulting from changes to habitat management or the spatial configuration of habitat are likely to have consequences for host dynamics. The spatial ecology of Cotesia bignellii, a specialist parasitoid of the threatened butterfly Euphydryas aurinia, was investigated at two spatial scales: within habitat patches (at the scale of individual aggregations of larvae, or ‘webs’) and among habitat patches (the scale of local populations). Parasitism rates were investigated in relation to larval web size, vegetation sward height and host density. Within patches, the probability of a larval webs being parasitized increased significantly with increasing number of larvae in the web, and parasitism rates increased significantly with increasing web isolation. The proportion of webs parasitized was significantly and negatively correlated with cluster density. Among habitat patches the proportion of parasitized webs decreased as cluster density increased. Clusters with a high proportion of larval webs parasitized tended to have lower parasitism rates per larval web. These results support the call for relatively large and continuous habitat patches to maintain stable parasitoid and host populations. Conservation efforts directed towards maintenance of high host plant density could allow E. aurinia to reduce parasitism risk, while providing C. bignellii with sufficient larval webs to allow population persistence.

Habitat relationships of great gray owl prey in meadows of the Sierra Nevada Mountains

ABSTRACTAnnual productivity of great gray owls (Strix nebulosa) in California, USA, is thought to be largely dependent on vole (Microtus spp.) and pocket gopher (Thomomys spp.; hereafter, gopher) abundance, yet factors influencing these prey populations have not been thoroughly investigated. The abundance of voles and gophers has been influenced by vegetation and cattle grazing in other regions; and many meadows are grazed within the breeding range of great gray owls in the Sierra Nevada Mountains of California. We evaluated the influence of vegetation and cattle grazing on great gray owl foraging habitat by quantifying vole abundance, gopher abundance, and vegetation features in grazed and ungrazed meadows in 2010 and 2011. We found that vole presence was positively associated with sward height and corn lily (Veratrum californicum) dominance; vole abundance was weakly negatively associated with cattle grazing. Gopher abundance was negatively associated with site wetness, and weakly positively associated with stem density, the frequency of forb presence, cattle grazing, and the dominance of corn lily. To efficiently manage vegetation and cattle grazing to benefit great gray owl prey, we suggest prioritizing habitat for voles in wet meadows because gophers were not likely to be abundant in wet sites. Particularly in areas with moist soils, we recommend maintaining sward height commensurate with the habitat relationships of voles found in this study; >290 mm where corn lily is not dominant and 125 mm where it is. Sustaining sward height for voles should benefit great gray owls and other meadow or forest edge carnivores. © 2014 The Wildlife Society.

Use of faecal components as markers to estimate intake and digestibility of grazing sheep

This research was carried out to evaluate the use of faecal components as markers to estimate intake and digestibility of Italian Ryegrass (Lolium multiflorum Lam.) of grazing sheep. The research had two phases. In Phase 1 seven indoor experiments were carried out using individual metabolic cages with 16 lambs in each experiment (four treatments with four animals each). Three phenological stages of the pasture (vegetative, pre-flowering and flowering) were evaluated and four different allowances of Italian Ryegrass, collected by grab sampling daily, of 1.5, 2.0, 2.5kg of dry matter/100kg of live weight and ad libitum. The indoor experimental design was completely randomized and the experiments were grouped according to the phenological stages. Organic matter intake (OMI, g/day), total daily production of faeces, faecal crude protein amount (fCP, g/day), faecal crude protein concentration (fCPc, g/kg of organic matter), faecal acid detergent fibre amount (fADF, g/day), faecal acid detergent concentration (fADFc, g/kg of organic matter) and organic matter digestibility (OMD) were assessed in the indoor experiment. In Phase 2, male sheep were used in two grazing experiments to graze Italian Ryegrass under different management conditions, which were herbage allowance, pasture phenological stage and rotational or continuous system. This phase was designed to validate the equations previously obtained. The stocking rate was controlled according the treatment defined, and the herbage mass, sward height, herbage and faecal chemical composition, OMI and OMD were measured. In Phase 1 significant linear regression equations were found between OMI and fCP in each phenological stage (P<0.05). The intake equations were compared by contrasts analysis and found to be different (P<0.001) between phenological stages, confirming the need to use the data separately by maturity stage. Two equations (simple and multiple hyperbolic) were tested for the relationship between OMD and fCPc, and the multiple hyperbolic, which includes fCPc and fADFc showed best accuracy. In Phase 2 the regression between the actual and estimated had a correlation coefficient of 0.94 and relative prediction error of 9.28%, showing the feasibility of using the generated equations.

Effects of the vertical and horizontal availability of food resources: the diet selection of sheep grazing on natural grassland

SUMMARYThe relationship between sheep diet selection and the vertical/horizontal availability of plant species on complex natural Leymus chinensis grassland was investigated. Two plots (low and high stocking rate plots) with different vegetation availabilities, created by adjusting sheep numbers, were studied for 3 months (June, July and August). In each month, the sheep's diet composition was estimated using n-alkanes in combination with long-chain alcohols and/or fatty acid markers. Vertical (sward surface height) and horizontal food availability (proportion cover of individual plant species) were determined simultaneously. The results revealed that sheep diet composition varied greatly according to seasonal variations in vegetation availability, and that sheep diet selection was related to the vertical and horizontal availability of plant species on both plots. Horizontal availability, which turned out to be the main influencing factor, was strongly and positively correlated with sheep diet composition in each month on both plots. On the low stocking rate plot, vertical availability affected sheep consumption in June, July and August. In contrast, a significant correlation between diet composition and vertical availability was only observed in July on the high stocking rate plot. These results suggest that the relative importance of vertical and horizontal availability differed between plots depending on vegetation availability. Horizontal availability played a more important role than vertical availability when sheep grazed freely on natural L. chinensis grassland. Finally, the changing selectivity index for each plant species in each grazing period on both plots indicated different grazing impacts on vegetation communities when vegetation availability differed.

Biological control of Rumex obtusifolius and Rumex crispus by goat grazing

Rumex obtusifolius and Rumex crispus are problematic grassland weedy species, particularly under conditions of organic farming. They are avoided by cattle and horses, but they can be grazed by goats. The aim of this study was to investigate the effectiveness of continuous goat grazing of moderate intensity on R. obtusifolius and R. crispus control. In 2008, 40 seedlings of each species were transplanted into pasture that was grazed by goats (crossbreed Czech white × Czech brown) on the target sward height of 7–10 cm. The number of leaves, proportion of grazed leaves and mortality of plants were monitored over the following 4 years. The number of leaves per plant was higher for R. obtusifolius than for R. crispus. The maximal number of leaves per plant of R. obtusifolius and R. crispus was 10 and 5, respectively. The proportion of grazed leaves was generally higher for R. obtusifolius than for R. crispus and ranged from 10% to 80%. No fertile plant was recorded during the experiment, as goat grazing totally prevented the flowering of both species. The level of mortality of the plants at the start of the fourth grazing season was 70% and 87% for R. obtusifolius and R. crispus, respectively, and no plant survived the fourth grazing season. It was concluded that continuous goat grazing of a moderate intensity that is carried out over 4 years seems to be an effective method for the non‐chemical control of R. obtusifolius and R. crispus in grassland.

Grazing intensity affects insect diversity via sward structure and heterogeneity in a long‐term experiment

Summary In the past, insect diversity in grasslands showed a severe decline due to management intensification or abandonment. In this study, we investigate the long‐term influence of grazing and the potential for spatial patterns created by different grazing intensities to enhance insect diversity. In a long‐term experiment (2002–2011), three grazing intensities were applied to 1‐ha paddocks in a triplicate block design: moderate grazing (MC), lenient grazing (LC) and very lenient grazing (VLC, since 2005). The experiment was conducted in a moderately species‐rich grassland at the edge of the Solling Uplands in Lower Saxony, Germany. Orthoptera (grasshoppers) and Lepidoptera (butterflies) on three 50‐m transects per paddock were counted in 2002–2004 and again in 2010 and 2011. Statistics were performed using linear mixed modelling. Grasshopper diversity measures (species richness and abundance) were significantly affected by grazing intensity; abundance increased from 2002 to 2011 more strongly in the LC than in the MC treatment. Butterfly species richness response to grazing intensity varied among years. Data from 2010 and 2011 did not reveal any advantage of the lowest grazing intensity (VLC) compared to the intermediate grazing intensity treatment (LC) in either insect group. Multiple regressions were used to investigate diversity patterns. Along with compressed sward height, spatial patchiness was important for grasshopper species richness and abundance as well as for butterfly species numbers. Butterfly abundance was mainly influenced by vertical sward height heterogeneity in addition to the significant effects of thistle abundance and number of nectar plant species. Synthesis and applications. Cattle grazing intensity affects the proportions and spatial heterogeneity of short and tall sward patches on pastures. The less mobile grasshoppers particularly benefitted from the structural modifications created by cattle at lenient grazing levels (stocking rate 1·14 SLU ha−1, standard livestock unit (SLU) = 500 kg). In the final study years, areas with intermediate grazing intensity revealed high diversity indices and the most distinct patchiness, therefore a further reduction in grazing intensity is not recommended. This indicates that commercial livestock production may be compatible with conservation targets.

Black Oat+Annual Ryegrass Biomass Production and Decomposition Managed at Different Sward Heights on Rotational Grazing

Black Oat+Annual Ryegrass Biomass Production and Decomposition Managed at Different Sward Heights on Rotational Grazing

Características produtivas e morfológicas do capim Tanzânia em diferentes intensidades de pastejo

The objective of this study was to determine the best height of the Tanzania grass under grazing, assessing morphological and productive characteristics of the sward. This experiment was conducted in Cidade Gaucha, Parana, where he was rated the accumulation rate and morphological characteristics of Tanzania grass pastures grazed at 20, 40, 60 and 80 cm grazing under continuous stocking with variable stocking rate for beef cattle. The experimental area was 12 hectare divided in paddocks of one hectare each. For each paddock were allocated two grazing exclusion cage for estimating herbage accumulation, and eight samples were taken every 28 days throughout the year 2010. The completely randomized design. The herbage mass of the morphological structures showed a linear positive function of sward heights. The height of defoliation did not influence the rate of herbage accumulation for any of the morphological structures: green leaf, stem + sheaths and senescent material. There were also no differences in leaf: stem ratio. All heights within the range studied provided adequate number of green leaves per tiller. Tanzania grass pastures grazed under continuous stocking between 40 and 60 cm, for providing a good association between accumulation and mass of green leaf blades, and acceptable values of the mass of stem + sheaths and senescent material. Pasture of Tanzania grass under 60 and 80 cm allow of leaves satisfactory accumulation in the autumn.

Short-term response in milk production, dry matter intake, and grazing behavior of dairy cows to changes in postgrazing sward height

Postgrazing sward height (PGSH) can be altered to adjust the allowance of grass in the dairy cow’s diet. This study aimed to investigate the short-term dairy cow response to a change in postgrazing height in early lactation. Ninety Holstein Friesian spring-calving cows were randomly assigned across 3 postgrazing height treatments (n=30): 2.7cm (severe), 3.5cm (low), and 4.2cm (moderate) from February 14 to April 24, 2011. From April 25, animals were rerandomized within each treatment to graze across 2 postgrazing heights: 3.5cm (low) or 4.5cm (high). Animal production measurements were taken from April 4 to 24 (measurement period 1; M1) and from April 25 to May 15 (measurement period 2; M2). The 6 treatments (n=15) of M2 were severe-low, severe-high, low-low, low-high, moderate-low, and moderate-high. During M1, increasing postgrazing height from severe to low to moderate linearly increased daily milk yield (21.5, 24.6 and 25.8kg/cow per day) and grass dry matter intake (GDMI; 13.2, 14.9, and 15.8kg of DM/cow per day). Milk solids yield was reduced in the severe (−1,518g/cow per day) treatment when compared with the low and moderate cows (1,866g/cow per day, on average). The milk yield (MY) response to change in PGSH between M1 and M2 (VM1−M2) was established using VM1−M2 MY=−1.27−1.89 × PGSHM1 + 1.51 × PGSHM2 (R2=0.64). The MY response associated with each treatment between M1 and M2 (3 wk) were −1.03kg/cow for severe-low, 0.68kg/cow for severe-high, −2.56kg/cow for low-low, −1.11kg/cow for low-high, −4.17kg/cow for moderate-low, and −2.39kg/cow for moderate-high. The large increase in energy intake in severe-high between M1 and M2 was achieved through higher GDMI per minute and GDMI per bite, which supported the positive change in MY. Treatments low-high, moderate-low, and moderate-high recorded the highest overall cumulative milk yield (74kg of milk solids/cow) over the 6-wk period, whereas severe-low and severe-high had the lowest (65kg of MS/cow). From the animal responses observed in the present study, imposing a postgrazing height of 3.5cm in early spring provides the opportunity to increase postgrazing height thereafter; the cow increases GDMI accordingly and converts the additional energy intake into milk output. The equations established in this paper provide a decision tool for dairy farmers to anticipate the animal response when postgrazing height is altered or maintained around the tenth week of lactation.

Does post‐grazing sward height influence sward characteristics, seasonal herbage dry‐matter production and herbage quality?

AbstractExtending the grazing season through the production and utilization of high‐quality forage is a key objective in grassland‐based dairy production systems. Grazing swards to a low post‐grazing sward height (PGSH) is a strategy for improving grass utilization. A grazing experiment conducted in Ireland investigated immediate and subsequent effects of PGSH on sward production, utilization and structural characteristics. Swards were grazed to 2·7 cm (severe; S1) or 3·5 cm (moderate; M1) from 10 February to 18 April 2010 (Period 1; P1). From 19 April, each P1 paddock was halved and grazed to either 3·8 cm (S2) or 4·8 cm (M2), until 30 October (Period 2; P2). The first grazing rotation was +7 d on S1 swards compared with M1 swards (45 d), due to greater herbage utilization (+0·22). Herbage production during P1 was not affected by PGSH but a severe PGSH during this period reduced subsequent herbage production: 13·9 (S1) vs. 15·5 t dry matter (DM) ha−1 (M1) by the end of the study. Leaf proportion was increased (+0·10) on S2 swards compared with M2 swards, but M2 swards produced 1·2 t DM ha−1 more herbage during P2. Despite the relatively lower level of sward utilization obtained from moderate grazing in P1 (3·5 cm) and P2 (4·5–5·0 cm), such levels of PGSH increased DM production while maintaining sward quality, compared with severe grazing (2·7 cm in P1 and 3·5–4·0 cm in P2).

Ewe lamb diet selection on plantain (Plantago lanceolata) and on a herb and legume mix, including plantain, chicory (Cichorium intybus), red clover (Trifolium pratense) and white clover (Trifolium repens)

The objective of Experiment 1 was to examine the diet selection and grazing preference of ewe lambs for plantain (Plantago lanceolata), chicory (Cichorium intybus), red clover (Trifolium pratense) and white clover (Trifolium repens). This was examined in a herb and legume sward mix containing plantain, chicory, red clover and white clover between seasons under both hard- and lax-grazing. During early spring, the sward predominately comprised plantain (63%) and chicory (21%) and ewe lambs grazed a greater proportion (P &lt; 0.05) of these species and displayed greater (P &lt; 0.05) grazing preference for plantain and chicory ahead of red and white clover. From late spring onward, ewe lambs had a greater (P &lt; 0.05) defoliation rate and a greater (P &lt; 0.05) grazing preference for red clover than for all other species. This greater selection of red clover was particularly evident in summer and autumn when red clover made a greater (P &lt; 0.05) contribution to the sward composition (8–9%) and the overall sward nutritive value dropped. This supports previous evidence, suggesting that diet selection is intrinsically affected by availability, access and palatability. The objective of Experiment 2 was to determine whether ewe lamb grazing behaviour during late summer was affected by time since a pure plantain sward was previously grazed. Ewe lambs were observed while grazing plantain of varying weeks since previous grazing (3, 6,10 or 16 weeks). Experiment 2 found no difference (P &gt; 0.05) in the average number of ewe lambs grazing each sward of varying weeks since previous grazing. However, ewe lambs grazed the 3-week-old plantain growth to a lower (P &lt; 0.05) post-grazing sward height than the height of the swards of greater number of weeks since previous grazing. Organic matter digestibility and metabolisable energy content did not differ (P &gt; 0.05) among all swards, regardless of weeks since previous grazing. This suggests that the palatability of plantain is not affected by the time since it was last grazed.

Behavioural mechanisms of intake rate by heifers grazing swards of contrasting structures

The relationship between herbage intake by herbivores and herbage available depends on the interaction between sward structure and animal behaviour. This relationship is a crucial component determining the stability, function and productivity of grazing systems. The present study aims at quantifying the mechanisms by which intake rate is determined in swards of contrasting structure and forage species, and it reveals the importance of animal choice in the interaction between animal and sward. We hypothesised that as sward height and herbage mass increased, bite mass and intake rate would increase. The relationship between intake rate and bite mass should exhibit a higher asymptote for the more succulent, less fibrous Avena than for Cynodon due to differences in chewing requirements per unit dry mass of intake. In four different experiments, Cynodon sp. cv. Tifton 85 and Avena strigosa cv. Iapar 61 swards of different heights were obtained by various durations of short time high-intensity grazing or by different growth periods. Bite mass and intake rate were estimated by the double-weighing technique with correction for insensible losses. Number and timing of jaw movements and bites were measured with behaviour recorders. Bite mass was the main variable determining intake rate. Contrary to expectations, bite mass first increased and then decreased with increasing sward height, a result that seems due to animal choice and not from restrictions imposed by the swards. As expected, Cynodon sp. swards required more chewing per unit DM intake due to their higher DM content (39.5 vs. 22.6, P<0.0001) and higher fibre (67.8 vs. 51.3, P<0.0001) content than A. strigosa. Harvesting and chewing jaw movements, the components of total jaw movements and time per bite, had different time costs, and values were remarkably similar to previously published values. On average, each harvesting jaw movement took 1s and a chewing jaw movement took 0.68s. The reduction in bite mass with increasing sward height in tall swards is discussed as a destabilising mechanism that generates spatial heterogeneity in sward height and mass.

Rising plate meters and a capacitance probe estimate the biomass of chicory and plantain monocultures with similar accuracy as for ryegrass-based pasture

Abstract It is useful to gain an estimate of herbage biomass when feed budgeting. However, none of the tools that are available to estimate biomass (e.g., the rising plate meter (RPM) or capacitance probe (CP)) have been tested on popular forage herbs, such as chicory or plantain. We tested the hypothesis that RPM and CP could be used to estimate biomass of first year pure chicory and plantain swards with accuracy at least as great as for ryegrassbased pasture. In two summer experiments at different locations in the Waikato, RPM, CP and uncompressed sward height (SH) readings were taken throughout regrowth within 0.2 m² quadrats in chicory and plantain swards, and ryegrass-based pasture. The herbage was then cut to ground level and oven-dried to estimate biomass. Linear equations relating biomass to mean readings were generated for each method, both within each experiment and as pooled datasets. In ryegrassbased pasture, the correlation coefficients (R²) were 0.73, 0.43 and 0.51 for RPM, CP and SH, respectively. For chicory swards, the pooled correlation coefficients (R²) were 0.73, 0.73 and 0.81 for RPM, CP and SH, respectively, while for plantain swards the R2 were 0.70, 0.59 and 0.68 for RPM, CP and SH, respectively. This led to the conclusion that the RPM was a suitable tool for the estimation of biomass in pure chicory or plantain swards as it had similar accuracy to calibration equations for ryegrass-based pasture. Farmers, at least in the Waikato, can estimate first year chicory or plantain biomass through the summer and autumn period using the following equations: Chicory biomass (kg DM/ha) = 86 × RPM reading + 235, or = 0.64 × CP reading + 437, or = 94 × SH - 190. Plantain biomass (kg DM/ha) = 94 × RPM reading + 455. Keywords: rising plate meter (RPM), capacitance probe (CP), chicory, plantain

Effects of restricted time allocation to pasture on feeding behaviour, intake and milk production of dairy sheep rotationally grazing Italian ryegrass (Lolium multiflorum Lam) in spring

The effects of restricted time allocation (2, 4 or 6 h/day) to pasture and grazing day (Day 1, initial; Day 4, intermediate; Day 7, final) on feeding behaviour, intake and performance were assessed in Sarda dairy ewes, rotationally grazing Italian ryegrass plots for 7 days, with 21 days of regrowth. A randomised block design with two replicates per access time was used with six groups of six ewes each. The ewes were supplemented daily with 400 g/head of a commercial concentrate at milking, 300 g/head of lupin after grazing and 700 g/head of ryegrass hay overnight. Pasture variables, feeding behaviour, herbage and supplement DM intake, and milk yield and composition were measured on 12 days (4 per target grazing day). Plot average data were analysed by a bifactorial model with interaction, which was not significant. Sward height and herbage mass decreased between Day 1 and Day 4 (P &lt; 0.05). Leaf area index dropped from Day 1 to Day 7 (P &lt; 0.05). Eating time, as proportion of access time, and intake rate were higher in 2 h/day groups than in the others (P &lt; 0.05). Nevertheless, herbage and total intake were higher in 6 h/day than in 2 h/day groups, being 4 h/day groups intermediate (P &lt; 0.05). Herbage intake decreased with grazing period (P &lt; 0.05). Fat normalised milk yield was higher in 6 h/day groups than in the others (P &lt; 0.05) and in Day 1 and Day 4 than in Day 7 (P &lt; 0.05). To conclude, time restriction below 6 h/day and pasture depletion, in terms of herbage quality, constrained intake and performance of rotationally grazing dairy ewes.

Nutritional Characteristics of &amp;lt;i&amp;gt;Brachiaria brizantha&amp;lt;/i&amp;gt; Cultivars Subjected to Different Intensities Cutting

This study evaluated the nutritional characteristics of Brachiaria brizantha cultivars subjected to three cutting intensities in the course of one year. The experiment was conducted at the University of Rio Verde. The experiment was performed as a randomized 3 × 3 factorial in complete block design with three replications and repeated measures in the time. Three Brachiaria brizantha cultivars (Marandu palisadegrass, Xaraes palisadegrass, and Piata palisadegrass), were tested at three cutting intensities (10, 20, and 30 cm sward height). The evaluations were conducted on the same plots throughout one year and during all four seasons (autumn, winter, spring, and summer). The results showed that the Piata palisadegrass had the best chemical composition compared to the Marandu palisadegrass and Xaraes palisadegrass. The management of Brachiaria brizantha cultivars at the lowest residual height (10 cm) affected the nutritional value of these feed grasses. Seasonality also influenced the nutritional value of these forages.

Production of Aruana guinea grass subjected to different cutting severities and nitrogen fertilization

Aruana guinea grass (Panicum maximum cv. Aruana) is widely used as pasture for sheep, which are extremely susceptible to infestation by larvae of gastrointestinal parasites in tropical pasture-based systems (Zanini et al. 2012). One way to mitigate this problem, and consequently reduce the need for use of anthelmintics, is to manage pastures with post-grazing height low enough to ensure sunlight reaches the base of tussocks. This will aid in killing larvae and controlling their development, without jeopardizing canopy regrowth and persistence. The pre-grazing sward height recommended for Aruana guinea grass is 30 cm, when the canopy intercepts 95% of the incident light, with post-grazing height at 15 cm (Zanini et al. 2012). As cutting severity and nitrogen (N) fertilization cause morphological and physiological adaptations in individual plants − altering the production of forage grasses − the objective of this study was to evaluate the accumulation of morphological components of Aruana guinea grass subjected to different cutting severities and N fertilization.

Soil carbon indices as affected by 10 years of integrated crop–livestock production with different pasture grazing intensities in Southern Brazil

Brazil has the world's second-largest cattle herd and second-largest no-till grain crop area. However, these activities are not frequently integrated because there is a widespread perception that cattle have a negative effect on cropping, especially when high crop yields are a goal. This misunderstanding of the synergy between pastures, livestock and crops is linked to overgrazing at the pasture rotation phase, which causes a decline in soil quality. Few studies have investigated the effect of pasture grazing intensities on soil carbon (C) balance and soil quality in subtropical environments. This work assessed the effects of different grazing intensities (0.10, 0.20, 0.30 and 0.40m sward height) on soil C indices and animal productivity in a clay Haplorthox. The crop–livestock system model was a soybean/ryegrass plus black oat annual rotation managed for 10 years, using a randomized complete block design with three replications. Grazing intensity affected the quantity and composition of soil C input. Under heavy grazing with limited soil C input, there was a decrease in pasture and an increase in soybean participation in total C input. Soil organic C (0–0.20m) under different grazing intensities had a linear relationship with C stratification ratio, C management index (CMI) and C pool index. Our results suggest that integrated crop–livestock systems could act as atmospheric C sources or sinks, depending on the grazing intensity. Pastures managed at 0.20 and 0.40m height had the best balance between CMI and animal daily gain. The best balance between CMI and live weight gain per unit area occurred in sward height of 0.20m.

The Steinach Grassland Experiment: Soil chemical properties, sward height and plant species composition in three cut alluvial meadow after decades-long fertilizer application

The Steinach Grassland Experiment (SGE) is probably the oldest still-running grassland fertilizer experiment in Continental Europe. It was established on an alluvial Alopecurus pratensis meadow in southeast Germany in 1933. The aim of this study was to provide detailed information on this experiment concerning the effects of decades-long nitrogen, phosphorus, potassium, and calcium application (46 treatments in total) on (1) soil chemical properties, (2) sward height, (3) plant species composition, and (4) species richness of vascular plants derived from a field survey in spring 2008.(1) A steep gradient of soil properties was recorded, namely plant-available (Mehlich III) P (14–161mgkg−1), K (82–1018mgkg−1) and Ca (532–3336mgkg−1) concentrations, C:N ratio (6.9–10.4) and pH (H2O) (4.7–7.0).(2) Compressed sward height in the third week of May 2008 ranged from 11cm in the control to 47cm in the limed plot with high N, P, and K application.(3) Although fertilizer application altered the plant species composition, diversification of plant communities was not as high as in the case of fertilizer application on low productive soils in other experiments. This was caused by sufficient nutrients enabling the survival of species adapted to high nutrient availability, even in the unfertilized control. The species composition in productive alluvial grasslands is substantially less affected by fertilizer application than in low productive grasslands.(4) Long-term fertilizer application negatively affected the species richness of vascular plants directly by soil acidification and indirectly by an increase in sward height. The extent to which N application negatively affected species richness was dependent on whether N was applied alone or in combination with other nutrients and whether N application acidified the soil.

The effect of light availability on leaf area index, biomass production and plant species composition of park grasslands in Warsaw

How light conditions affect development of park grasslands is a question that has not been satisfactory addressed. The aim of this study was therefore determination of the level to which unfavorable light conditions influence grassy parks area and relationships between parameters which determine state of turf grasses. Researches were conducted in two parks in Warsaw, in various light conditions and included measurement of: leaf density, sward height, leaf area index (LAI), and botanical composition of the communities. The leaf density of shaded areas did not exceed 70%. LAI value varied from 0.5 to 0.9-fold lower than in the areas in half-shade and in sun. The participation of basic lawn species at Skaryszewski Park was higher under shade, while at Łazienki Kr&amp;oacute;lewskie was higher in full-sunlight areas. The state of tested grassy areas in limited solar radiation does not satisfy the requirements of recreational and representational functions. The development processes of vegetation coverage were inhibited at the sites of lower solar radiation. LAI was influenced by both leaf coverage and sward height. Agrostis stolonifera and Poa trivialis may be recommended to create grass areas under limited solar radiation.

Clipping management and its effect on the composition and height of low-input turf

The effect of mulching and moving management on the height and the composition of low-input turf was studied in Vatin research station of fodder crops regularly in May, during years 2007–2012. The experiment was established in 2006 with using a clover-grass lawn mixture (95% grasses, 5% clover crops). The experimental plots were not fertilized and the patches were mown or mulched five times a year to a sward height of 40 mm.The achieved results show that mulching affected the composition of the low-input turf very significantly. On the average of six-year monitoring, the representation of grasses in the sward of the mulched variant was 66.9%, which was a significantly higher share of grasses than in the mown variant (52.3%). By contrast, the share of clover crops in the mown variant (36.6%) was significantly higher than in the mulched variant (21.3%). Mulching significantly affected neither the infestation by weeds nor the total sward cover.Mean height of the cut sward was non-significantly higher by 10.1% in the mulched variant with the sward heights being 210.9mm in the mown variant and 232.3mm in the mulched variant.