Living Ground Cover Research Articles

Spatial distribution of biological soil crusts on the slope of the Chinese Loess Plateau based on canonical correspondence analysis

Biological soil crusts (BSCs) are a living ground cover widely distributed in arid and semi-arid regions, and providing important ecological functions in arid and semi-arid ecosystems. An understanding of the spatial distribution patterns of BSCs is foundational for the scientific management of this resource. In this study, a typical slope was selected from a small watershed, Liudaogou, in the wind–water erosion crisscross region of the Loess Plateau in northwest China. The spatial distribution characteristics of BSCs and associated influencing factors were investigated at the slope scale via a comprehensive survey and statistical analysis using GS+ and CANOCO statistical software. The results showed that the distribution of BSCs was clearly spatially differentiated, with the majority of BSCs widely and continuously distributed in sandy areas at a mean coverage of greater than 30%. Sporadic distribution of BSCs was observed in loess areas mainly at the edges of slopes with a mean coverage of generally less than 20%. The thickness and shear strength of the BSCs did not present significant spatial variation, indicating that these two BSC indices were primarily associated with the age and developmental stage of the BSC which was relatively constant throughout the study area. A canonical correspondence analysis revealed that the spatial distribution of BSCs was closely correlated with soil type, vegetation, surface soil moisture content, slope and aspect. Among these factors, soil type had the most significant impact on BSC distribution and explained 20% of the spatial variation of BSCs. The vegetation community type and topographic wetness index were the secondary influencing factors, and sagebrush (Artemisia desertorum) shrubland and aspen (Populus simonii) woodland provided the most ideal growth environments for BSCs. Other factors such as slope, aspect and solar radiation also affected BSC distribution to a certain degree. Overall, BSCs were clearly selective for topography, soil type and vegetation community and preferentially grew in humid areas with psammophytic plant communities.

Water Stress Tolerance of Six Rangeland Grasses in the Kenyan Semi-arid Rangelands

This study evaluated six grass species in terms of water stress responses by visual quality and living ground cover attributes and the recovery responses post water stress grown at 80, 50, 30% field capacity soil moisture contents. The grass species evaluated were Chloris roxburghiana, Eragrostis superba, Enteropogon macrostachyus, Cenchrus ciliaris, Chloris gayana, and Sorghum sudanense. The grasses demonstrated varied levels of water stress tolerance as evaluated by quality ratings based on colour (greenness) and uniformity of colour, leaf firing, living matter and wilting signs. All species declined in visual quality rating with prolonged water stress treatment with exception of Sorghum sudanense and Cenchrus ciliaris that had better quality ratings of six after 42 days water stress period. Sorghum sudanense, Chloris gayana and Cenchrus ciliaris had accelerated recovery in quality, attaining a visual rating of eight at 21 days of water stress period. The three soil moisture content treatments had higher quality ratings than rainfed conditions which represented water deficit. Sorghum sudanense and Chloris gayana had higher quality ratings and water use efficiency under rainfed compared to the other species. All the grasses showed higher living ground cover greater than 40% at recovery period of 28 days, when irrigation was resumed at the prescribed level, and attained living cover of over 60% by day 42. Sorghum sudanense, Chloris gayana and Cenchrus ciliaris were able to withstand water stress longer and had also a quick recovery among the six grasses. These three species are recommended for pasture establishment in semi-arid lands where water supply uncertainties exist, owing to their high tolerance to water stress.

Postfire recovery of the ground cover in pine forests of the Lower Angara region

This paper traces the dynamics of the living ground cover at the initial stage of pyrogenic succession (1–9 years) after different-intensity surface fires in the pine forests of the Lower Angara region. Depending on their intensities, fires have reduced the foliage cover and ground-cover biomass. The greatest changes occur in case of medium-intensity and high-intensity fires that change the horizontal structure of plant microgroups and lead to the death of moss-lichen layers.

Mass to height relationships in annual pastures and prediction of sheep growth rates

The relationship between pasture height and mass influences the availability of pasture for grazing, and is important for predicting intake of pasture and liveweight change by sheep. The relationship between pasture mass and structure and sheep production is poorly defined for low-mass, clumpy pastures in low-rainfall regions. Between 2001 and 2004, 480 quadrats of pastures were measured in 23 paddocks throughout the Victorian Mallee. Pasture height was related to live mass for medic (linear; r2 = 0.70; P < 0.001) and grassy medic (asymptotic; r2 = 0.64; P < 0.001) pastures, and prediction of grassy medic pasture height was improved by inclusion of proportion live groundcover. During 2004, pasture dry matter accumulation and liveweight changes in sheep grazing annual pastures were measured and compared with predicted outputs from GrazFeed, a software model used to estimate feed intake and liveweight change in sheep. Improved predictions of liveweight gain in grazing sheep were obtained using measured height rather than the GrazFeed default height. The results show that the height to mass relationship of annual pastures in the Victorian Mallee differs between pasture types, between years, and may differ from other published relationships. This study provides information that may assist in the development of models of grazing systems.

Almond orchards with living ground cover host more wild insect pollinators

Wild pollinators are becoming more valuable to global agriculture as the commercial honeybee industry is increasingly affected by disease and other stressors. Perennial tree crops are particularly reliant on insect pollination, and are often pollen limited. Research on how different tree crop production systems influence the richness and abundance of wild pollinators is, however, limited. We investigated, for the first time, the richness and abundance of potential wild pollinators in commercial temperate almond orchards in Australia, and compared them to potential pollinator communities in proximate native vegetation. We quantified ground cover variables at each site and assessed the value of ground cover on the richness and abundance of potential wild pollinators in commercial almond systems focussing on three common taxa: bees, wasps and flies. More insects were caught in orchards with living ground cover than in native vegetation or orchards without ground cover, although overall species richness was highest in native vegetation. Percent ground cover was positively associated with wasp richness and abundance, and native bee richness, but flies showed no association with ground cover. The strongest positive relationship was between native bee abundance and the richness of ground cover plants. Our results suggest that maintaining living ground cover within commercial almond orchards could provide habitat and resources for potential wild pollinators, particularly native bees. These insects have the potential to provide a valuable ecosystem service to pollinator-dependent crops such as almond.

Significance of litter layer in enhancing mesofaunal abundance and microbial biomass nitrogen in sweet corn-white clover living mulch systems

Living mulch is a type of sustainable farming system that consists of cover crops planted either before or with a main crop; a living mulch is maintained as a living ground cover throughout the growing season of the main crop. Microbial biomass and abundance of mesofauna (microarthropods and enchytraeids) are important soil biological parameters in relation to soil function, plant productivity, and nutrient cycling; however, the effects of living mulch on these parameters are not fully understood. In this study we examined the effects of living mulch treatment with nitrogen fertilizer (0, 40, 160, or 200 kg ha−1) on the abundance of soil microarthropods (Oribatida, Mesostigmata, Prostigmata, and Collembola) and the effects of living mulch treatment on the dynamics of the soil biota (mesofauna, microarthropods, enchytraeids, and microbial biomass nitrogen) from spring to autumn. Our results showed that living mulch treatment significantly (p < 0.05) increased the grain weight of the main crop in both experiments. Generally, living mulch treatment had a positive effect on the abundance of mesofauna and microbial biomass nitrogen, despite pesticide usage. Nitrogen levels did not affect the number of microarthropods. The litter layer in living mulch significantly (p < 0.05) enhanced microbial biomass nitrogen and the abundance of Oribatida, Prostigmata, and Collembola. We conclude that living mulch enhances mesofaunal abundance and microbial biomass nitrogen and that the production of a litter layer by living mulch is one of the major mechanisms for this enhancement.

Localized dry spots on golf greens in a moderately continental climate, and its prevention and control

There are clear and commonly accepted design criteria for the construction of golf greens. Accordingly, top layers contain at least 90% sand, which often becomes water repellent. Drought is therefore common on golf greens and it may manifest itself as spots of wilted or dead turfgrass, known as localized dry spots (LDSs). The aims of the current paper are to review soil water repellency and localized dry spots on golf greens; and to study the turfgrass appearance regarding dependence of water repellency under the moderately continental climate in the Moscow region. The study was conducted during the growing seasons of 2007 and 2008 by Moscow State Forest University, Russia, in collaboration with Wageningen University, the Netherlands. Green 4 of the Moscow golf course was intensively studied. The texture of the top layer met the USGA, German and British specifications for golf greens. The organic matter content was also as desired. The low soil water content (down to 0.80%) in top 5–10 cm layer, high reference evapotranspiration and low amount of applied water in May and June of 2007 (2.52 against 1.20 mm/day) and of 2008 (2.41 against 1.73 mm/day), resulted in drought and LDS occurrence. Severe water repellency as determined by water drop penetration time ( WDPT) test was found in the 5–10 cm depth (up to 1536 s). It decreased with depth (at depth 5–10 cm 33.3% of samples were strongly and 66.7% severely water repellent; at depth 20–25 cm 41.6% of samples were strongly and 41.6% slightly water repellent, and 16.8% were wettable). However, samples from the same depth from good areas (GAs) of the turf were also water repellent – at depth 5–10 cm all samples were slightly or strongly water repellent; at depth 20–25 cm 66.7% were non-repellent. In this study, the poorest turfgrass condition was found in plots with LDSs (the scores of turfgrass quality and living ground cover were lower than 5). A negative correlation was found between WDPT and turfgrass parameters (shoot density, living ground cover and turfgrass quality). A positive correlation between water content and shoot density was found. LDSs exhibited low shoot density (which did not exceed 20 per cm 2 whereas in GA it exceeded 32 per cm 2) and low water content (in the range 0.8–6.75% whereas in GA it was in the range 7.8–14.47%). This means that the reason of unacceptable turfgrass condition is related to water deficit and severity of water repellency.

Analysis of the soil organic matter stability in spruce forests of Krkonose in Czechia on the basis of the ROMUL mathematical model

Computational experiments with the ROMUL mathematical model were performed for studying the dynamics of soil organic matter (SOM) in spruce forests of northeastern Czechia that were disturbed because of the atmospheric sulfur deposition in the second half of the 20th century. The effect of the soil acidification on the decomposition dynamics of the forest die-back in the model is of importance. Conditions of the forest productivity were found under which the SOM pool could be preserved. It was shown that, later on, the content of the litter will decrease because of the forest degradation, and the succession changes due to the effect of the contamination will affect the type of vegetation, as well as the type of soil organic matter. The total SOM content will decrease in this case. However, the maintenance of the grass productivity can slow down this process. It was noted that the quantitative prediction of the SOM dynamics requires measurements of the productivity parameters of the forest as a whole and the living ground cover, including the content of root litter, and the hydrothermal regime of the soil determining the transformation of the litter and humus.

Structural and functional organization of a larch phytocenosis in a postfire progressive succession in the north of Central Siberia

The author considers specific features of the postfire formation of a larch (Larix gmelinii) phytocenosis in Central Evenkia, the north of Central Siberia. Morphological parameters of trees, structure, height, growth, and biological productivity of the tree stand, shrub layer, live ground cover, and accumulation of detritus after progressive pyrogene succession are analyzed and discussed.

Habitat Selection by Swainson's Warblers Breeding in Loblolly Pine Plantations in Southeastern Louisiana

Abstract Although Swainson's warbler (Limnothlypis swainsonii) is typically associated with bottomland hardwood forests, they also breed in even-age pine (Pinus spp.) plantations. We used mist nets and point counts from 1998–2000 to survey intensively managed even-age loblolly pine (P. taeda) plantations of different age classes and management histories to determine breeding status and stand structure preferences of Swainson's warbler in southeastern Louisiana, USA. We detected Swainson's warblers in 23 of 124 sampled loblolly pine stands. We also confirmed breeding in 7–24-year-old pine stands. We found Swainson's warblers in pine stands that had well-developed canopy closure, abundant understory vegetation, and sparse live ground cover. Floristic differences between hardwood and pine breeding habitats demonstrate that Swainson's warblers do not require specific vegetation composition, although they discriminate within habitats based on physical structure of vegetation. Although management of Swainson's ...

Climatically induced interannual variability in aboveground production in forest-tundra and northern taiga of central Siberia

To investigate the variability of primary production of boreal forest ecosystems under the current climatic changes, we compared the dynamics of annual increments and productivity of the main components of plant community (trees, shrubs, mosses) at three sites in the north of Siberia (Russia). Annual radial growth of trees and shrubs was mostly defined by summer temperature regime (positive correlation), but climatic response of woody plants was species specific and depends on local conditions. Dynamics of annual increments of mosses were opposite to tree growth. The difference in climatic response of the different vegetation components of the forest ecosystems indicates that these components seem to be adapted to use climatic conditions during the short and severe northern summer, and decreasing in annual production of one component is usually combined with the increase of other component productivity. Average productivity in the northern forest ecosystems varies from 0.05 to 0.14 t ha(-1) year(-1) for trees, from 0.05 to 0.18 t ha(-1) year(-1) for shrubs and from 0.54 to 0.66 t ha(-1) year(-1) for mosses. Higher values of tree productivity combined with lower annual moss productivity were found in sites in northern taiga in comparison with forest-tundra. Different tendencies in the productivity of the dominant species from each vegetation level (trees, shrubs, mosses) were indicated for the last 10 years studied (1990-1999): while productivity of mosses is increasing, productivity of trees is decreasing, but there is no obvious trend in the productivity of shrubs. Our results show that in the long term, the main contribution to changes in annual biomass productivity in forest-tundra and northern taiga ecosystems under the predicted climatic changes will be determined by living ground cover.

Orchard Floor and Nitrogen Management Influences Soil and Water Quality and Tart Cherry Yields

Designing and implementing more productive, nutrient-efficient, and environmentally sound orchard management systems requires a better understanding of plant and soil responses to more biologically driven management practices. This study explored the effect of orchard floor and N management on soil organic C and N, populations of nematodes, NO3 leaching, and yields in tart cherry (Prunus cerasus L. `Montmorency') production. A baseline conventional orchard system consisting of an herbicide-treated tree row and a full rate of N fertilizer was compared to two modified-conventional and ten alternative orchard floor and N management systems. Living ground cover and the use of mulch with or without composted manure increased total C and the active C and N pools in the soil. For instance, supplemental mulch or mulch applied using a side-delivery mower increased soil C by &gt;20% above the conventional baseline. The size of the active C pool increased 45% and 60% with the use of the species mix 2 ground cover and compost, respectively. Increases in the active N pool ranged from a low of 25% in the soils using mulch or a ground cover mix to a high of 60% when compost was used. As a result, the ability of these soils to provide N to growing plants was enhanced. Total soil N increased in the treatment using natural weeds as ground cover and the full rate of N fertilizer. It is likely that weeds were able to convert significant amounts of fertilizer N into organic forms. Increasing the active C and N pools stimulates microbial activity, and may favor populations of nonplant parasitic nematodes over plant parasitic species. Using a trunk-to-trunk cover crop mix under the cherry trees reduced NO3 leaching by &gt;90% compared to a conventional, herbicide treated soil, even when N fertilizer was used at full rate. Nitrate leaching also dramatically diminished when N fertilizer was fertigated at a reduced rate or when compost was used as N source. Alternative orchard floor and N management did not reduce yields when compared to the baseline conventional treatment.

PerennialArachisspp. as a Multipurpose Living Mulch, Ground Cover and Forage

ABSTRACT From 1997 to 1999, 16 cultivars/accessions of perennial forage Arachis sp. were evaluated at the Tropical Research and Education Center. IFAS, Homestead, FL. Evaluation focused on adaptability to soil and climatic conditions of south Florida and included criteria deemed desirable for a multipurpose cover crop that might be used as a living mulch in no-till vegetable production fields and orchards, forage for animal feeding, and ornamental ground cover along highway ramps and sidewalks. Four cultivars/accessions of Pinto's peanut, A. pintoi Krapov. & W.C. Gregory, plus IRFL 6968 grew well in the low-fertility calcareous soils with minimal fertilizer, minimal irrigation and no pesticide. They were compared with ‘Florigraze’ rhizoma peanut (A. glabrata Benth.) in all the evaluation criteria used. The stands had become well established 31 months after planting. Biomass yields for the selected accessions at 31 months ranged from 12.0 to 21.5 mt ha−1. Nitrogen content in the dry biomass of plant parts ...

Evaluating shredded rubber tires and sewer sludge as surface mine spoil amendments

ABSTRACT Shredded rubber tires and composted sewer sludge were evaluated and compared as spoil amendments on an abandoned mine site in western Kentucky. Percent ground cover was measured in early spring and early summer of the third year to determine treatment effects. Significant treatment effects did not appear until the summer measurement, and the combination of rubber tire mulch and incorporated sewer sludge was found to be the most effective in promoting site revegetation. There was a significant decline in percent live grass ground cover as the growing season progressed, indicating that early season measurements may not be adequate for estimating revegetation effectiveness.

Establishment of Asparagus with Living Mulch

Experiments were begun in 1990 to determine the efficacy of using grassy and leguminous living mulches for asparagus (Asparagus officinalis L.) establishment and production. Ten-week-old seedlings of hybrid asparagus, cv. Syn4-56 were planted in loamy sand in the irrigated Central Sands of Wisconsin. Treatments were unsuppressed living mulches of perennial ryegrass (Lolium perenne L.), Dutch white clover (Trifolium repens L.), a mixture of ryegrass and clover, and a cultivated no-mulch control. A second variable, ammonium nitrate, banded at 40 and 80 lb N/acre, with a control of 0 lb N/acre, was factorially combined with mulch treatments. Asparagus fern growth with living mulches in year 1 was half that of asparagus grown with no mulch. Asparagus fern growth with clover and mixed mulches in year 2 averaged 75% of that grown without mulch. Fern growth with ryegrass mulch in year 2 was 50% of that grown with no mulch. Asparagus N uptake in clover and mixed mulch plots was as great as that grown with no mulch at each level of applied N. Weeds were controlled better by clover and mixed mulches than by ryegrass mulch or by cultivation in the no-mulch plots

Effect of litter layer on natural regeneration of companion tree species in the Korean pine forest

As an integrated part of the research on ‘The Structure and Dynamics of the Korean Pine Forest’ in the Lesser Khingan Mountain (Xiao Xingan Ling), 325 plots were set, treated, sown and periodically observed from 1963 to 1965 to study the effect of removing the litter layer and/or living ground cover on seed germination and seedling survival of aspen, birch, spruce, larch and linden. An inverse relation was found between litter layer and seed germination and seedling survival in all species except linden. Some birch seeds were inhibited from germinating but remained alive for 2–3 years. The adaptability of seeds to germinated and survive on a litter layer was correlated to seed size. The relation between adaptability of seeds to germinate and survive on litter layer and seedling tolerance to shade is discussed.

A survey and assessment of grasshoppers as herbivores in the South Island alpine tussock grasslands of New Zealand

Abstract A detailed assessment of grasshopper grazing pressures has been made for 10 alpine tussock grassland sites throughout the South Island of New Zealand. All sites were selected as reputedly high-density sites based on questionnaire returns from 61 observers, and a capture-recapture census of adult grasshoppers was made at each site. Standardised census procedures and timing permitted sites to be compared with a reference site where species biologies and population behaviour had been investigated in detail over a 4-year period. The comparisons were made using a behavioural grazing model that had been developed for populations at the reference site, given five major variables between survey sites: population density, consumption level of the population members, vegetation composition, percentage living ground cover, and site aspect. Variations in grazing pressure of up to 25-fold were demonstrated between sites, and these reflected the combined impact of all five variables rather than any particular one. All comparisons were necessarily calculated in relative terms, because appropriate data on vegetation productivity and the available crop are at present unavailable for any alpine tussock grasslands. However, evidence is given of the cumulative vegetation damage of low-volume grazing by grasshoppers, and this is shown to be serious in some grasslands. A general assessment of the importance of grasshoppers as herbivores is given for four classes of tussock grassland throughout the South Island.