Ground Cover Types Research Articles

Nitrogen losses in vineyards under different types of soil groundcover. A field runoff simulator approach in central Spain

The soils of Mediterranean vineyards are usually managed with continuous tillage, resulting in bare soil, low infiltration and high soil erosion rates. Soil nutrients, such as nitrogen, could be lost dissolved in the runoff, causing a decrease in soil fertility on such degraded soils and producing eutrophication downstream. The influences of groundcover on the soil erosion processes and sediment yields in Mediterranean vineyards have been widely addressed. However, the runoff process itself, excluding the effect of raindrop impacts, has barely been studied. Thus, a field runoff simulator was built to assess runoff and nutrient losses under different soil management strategies in Central Spain. In the winter of the 2012–2013, four vineyards were selected, and two types of groundcover were established to compare with conventional tillage (T): spontaneous vegetation (CS) and seeded Brachypodium distachyon (CB). In 2014 and 2015, 72 runoff simulations were performed to assess the influence of the two different types of groundcover on the dissolved mineral nitrogen losses in runoff. The results showed that spontaneous vegetation cover was the most effective management choice to reduce runoff and nitrogen loss by producing 3 times less runoff than conventional tillage and 6 times less nitrate loss. Conventional tillage resulted in higher mineral nitrogen loss because it produced more runoff and higher runoff nitrate concentrations. The vegetation cover had a strong influence on runoff and nitrogen losses, while the slope angle and rock fragment cover showed a negligible impact.

Variation in the urban vegetation, surface temperature, air temperature nexus.

Our study examines the urban vegetation - air temperature (Ta) - land surface temperature (LST) nexus at micro- and regional-scales to better understand urban climate dynamics and the uncertainty in using satellite-based LST for characterizing Ta. While vegetated cooling has been repeatedly linked to reductions in urban LST, the effects of vegetation on Ta, the quantity often used to characterize urban heat islands and global warming, and on the interactions between LST and Ta are less well characterized. To address this need we quantified summer temporal and spatial variation in Ta through a network of 300 air temperature sensors in three sub-regions of greater Los Angeles, CA, which spans a coastal to desert climate gradient. Additional sensors were placed within the inland sub-region at two heights (0.1m and 2m) within three groundcover types: bare soil, irrigated grass, and underneath citrus canopy. For the entire study region, we acquired new imagery data, which allowed calculation of the normalized difference vegetation index (NDVI) and LST. At the microscale, daytime Ta measured along a vertical gradient, ranged from 6 to 3°C cooler at 0.1 and 2m, underneath tall canopy compared to bare ground respectively. At the regional scale NDVI and LST were negatively correlated (p<0.001). Relationships between diel variation in Ta and daytime LST at the regional scale were progressively weaker moving away from the coast and were generally limited to evening and nighttime hours. Relationships between NDVI and Ta were stronger during nighttime hours, yet effectiveness of mid-day vegetated cooling increased substantially at the most arid region. The effectiveness of vegetated Ta cooling increased during heat waves throughout the region. Our findings suggest an important but complex role of vegetation on LST and Ta and that vegetation may provide a negative feedback to urban climate warming.

Quantifying eroding head cut detachment through flume experiments and hydraulic thresholds analysis

Gully erosion is known as one of the most important environmental earth hazards in the world and especially in Iran where it is controlled by both environmental and human factors. This research has attempted to assess the effects of land use (LU) on gully hydraulic flow condition of head cut initiation under similar soil conditions through an experimental field base plot (15 × 0.4 m). Results reveal that critical shear stresses (τ cr) for head cut initiation in abandoned, dry farming and rangeland, land are 174, 43 and 192 dyne/cm2, respectively, the remarkable differences being the consequence of soil surface condition (e.g., vegetation cover and micro-relief). Moreover, the flow turbulence and response of soil to an increase in flow condition (rate and depth) indicated a complicated behavior which can be addressed to the influences of surface micro-relief features and LU effects. Although a simple linear equation between τ cr and K c can be used to estimate the parameter, significant differences of regression coefficients decrease the general equation for whole data sets. The main explanation for dramatic (3–4 times) variations of τ cr is the vegetation cover and soil surface conditions. In fact, the significant decrease in τ cr under dry farming can be linked to the effect of tillage operation on aggregate strength and soil susceptibility. Findings showed that a boundary shear stress of 35 dyne/cm2 used in some physically based models for predicting erosion is subjected to high uncertainty and not appropriate for estimation of gully development. In addition, the duration of land abandonment has a crucial influence on soil erodibility, a factor given little consideration in erosion models. For the prediction of gully erosion rate, it is recommended that a single erodibility parameter is created from the functional relationship between τ cr and K c. Due to the interaction of slope, flow regime, shear stress and type of ground cover, the relationship between head cut initiation and surface roughness varies. In addition, the Reynolds number is not a reliable parameter for estimation of surface roughness during head cut initiation. Therefore, for gully erosion modeling other hydraulic parameters should be used to produce a reliable model. For prediction of gully erosion rates a single erodibility parameter from the functional relationship between τ cr and K c could be used.

Comparison of Methods for Estimating Fractional Cover of Photosynthetic and Non-Photosynthetic Vegetation in the Otindag Sandy Land Using GF-1 Wide-Field View Data

Photosynthetic vegetation (PV) and non-photosynthetic vegetation (NPV) are important ground cover types for desertification monitoring and land management. Hyperspectral remote sensing has been proven effective for separating NPV from bare soil, but few studies determined fractional cover of PV (fpv) and NPV (fnpv) using multispectral information. The purpose of this study is to evaluate several spectral unmixing approaches for retrieval of fpv and fnpv in the Otindag Sandy Land using GF-1 wide-field view (WFV) data. To deal with endmember variability, pixel-invariant (Spectral Mixture Analysis, SMA) and pixel-variable (Multi-Endmember Spectral Mixture Analysis, MESMA, and Automated Monte Carlo Unmixing Analysis, AutoMCU) endmember selection approaches were applied. Observed fractional cover data from 104 field sites were used for comparison. For fpv, all methods show statistically significant correlations with observed data, among which AutoMCU had the highest performance (R2 = 0.49, RMSE = 0.17), followed by MESMA (R2 = 0.48, RMSE = 0.21), and SMA (R2 = 0.47, RMSE = 0.27). For fnpv, MESMA had the lowest performance (R2 = 0.11, RMSE = 0.24) because of coupling effects of the NPV and bare soil endmembers, SMA overestimates fnpv (R2 = 0.41, RMSE = 0.20), but is significantly correlated with observed data, and AutoMCU provides the most accurate predictions of fnpv (R2 = 0.49, RMSE = 0.09). Thus, the AutoMCU approach is proven to be more effective than SMA and MESMA, and GF-1 WFV data are capable of distinguishing NPV from bare soil in the Otindag Sandy Land.

Assessing post-fire ground cover in Mediterranean shrublands with field spectrometry and digital photography

Fire severity can be assessed by identifying and quantifying the fractional abundance of post-fire ground cover types, an approach with great capacity to predict ecosystem response. Focused on shrubland formations of Mediterranean-type ecosystems, three burned areas (Ibieca and Zuera wildfires and Peñaflor experimental fire) were sampled in the summers of 2006 and 2007. Two different ground measurements were made for each of the 356 plots: (i) 3-band high spatial resolution photography (HSRP) and (ii) the hemispherical-conical reflectance factor (HCRF) in the visible to near-infrared spectral range (VNIR, 400–900nm). Stepwise multiple lineal regression (SMLR) models were fitted to spectral variables (HCRF, first derivative spectra or FDS, and four absorption indices) to estimate the fractional cover of seven post-fire ground cover types (vegetation and soil – unburned and charred components – and ash – char and ash, individually and as a combined category). Models were developed and validated at the Peñaflor site (training, n=217; validation, n=88) and applied to the samples from the Ibieca and Zuera sites (n=51). The best results were observed for the abundance estimations of green vegetation (Radj.2 0.70–0.90), unburned soil (Radj.2 0.40–0.75), and the combination of ashes (Radj.2 0.65–0.80). In comparison of spectral data, FDS outperforms reflectance or absorption data because of its higher accuracy levels and, importantly, its greater capacity to yield generalizable models. Future efforts should be made to improve the estimation of intermediate severity levels and upscaling the developed models. In the context of fire severity assessment, our study demonstrates the potential of hyperspectral data to estimate in a quick and objective manner post-fire ground cover fractions and thus provide valuable information to guide management responses.

Local incidence angle referenced classification on polarimetric synthetic aperture radar images in mountain glacier areas

The incidence angle is a crucial parameter for synthetic aperture radar (SAR). The local incidence angle differs greatly in mountainous areas, and it may lead to quite different backscatter properties for the same ground targets for different incidence angles. As a result, it has to be taken into consideration in image classification. This work demonstrates the importance of the local incidence angle and the necessity of considering this angle in SAR image classification in mountainous areas. A local incidence angle referenced method based on support vector machines is developed to perform classification. In this method, the datasets are divided into different zones according to local incidence angle, and the training and predicting are performed within these zones to eliminate the influence of the local incidence angles. The experiments are performed around the Dongkemadi Glacier in the central Qinghai-Tibetan plateau using two RADARSAT-2 polarimetric SAR images. This paper concentrates on the effect of the local incidence angles in SAR image classification. Compared to the method using only backscatter coefficients, the proposed method improves the overall classification accuracy by 6 to 8%. More important, it is verified that this method is more helpful for the ground cover types where the terrain changes sharply.

Phenology and species determine growing-season albedo increase at the altitudinal limit of shrub growth in the sub-Arctic.

Arctic warming is resulting in reduced snow cover and increased shrub growth, both of which have been associated with altered land surface-atmospheric feedback processes involving sensible heat flux, ground heat flux and biogeochemical cycling. Using field measurements, we show that two common Arctic shrub species (Betula glandulosa and Salix pulchra), which are largely responsible for shrub encroachment in tundra, differed markedly in albedo and that albedo of both species increased as growing season progressed when measured at their altitudinal limit. A moveable apparatus was used to repeatedly measure albedo at six precise spots during the summer of 2012, and resampled in 2013. Contrary to the generally accepted view of shrub-covered areas having low albedo in tundra, full-canopy prostrate B. glandulosa had almost the highest albedo of all surfaces measured during the peak of the growing season. The higher midsummer albedo is also evident in localized MODIS albedo aggregated from 2000 to 2013, which displays a similar increase in growing-season albedo. Using our field measurements, we show the ensemble summer increase in tundra albedo counteracts the generalized effect of earlier spring snow melt on surface energy balance by approximately 40%. This summer increase in albedo, when viewed in absolute values, is as large as the difference between the forest and tundra transition. These results indicate that near future (<50years) changes in growing-season albedo related to Arctic vegetation change are unlikely to be particularly large and might constitute a negative feedback to climate warming in certain circumstances. Future efforts to calculate energy budgets and a sensible heating feedback in the Arctic will require more detailed information about the relative abundance of different ground cover types, particularly shrub species and their respective growth forms and phenology.

Eastern wild turkey nest site selection in two frequently burned pine savannas

Reproductive success is a critical factor affecting avian demographics and can be influenced by many factors including nesting chronology, predation risk, and fine-scale nest site selection. We modeled the relative influences of habitat-related covariates at six spatial scales (nest site: 15-, 40-, 80-, 120-, 160-, and 200-m radii) on Eastern wild turkey (Meleagris gallopavo silvestris) nest site selection in two pine savannas managed by frequent prescribed fire (≤3 years) in southwestern Georgia during 2011–2013. Nest site (15-m scale) habitat metrics (mean visual obstruction [cm] and canopy closure [%]) had the greatest influence on nest site selection relative to covariates measured at larger spatial scales. Scaled odds ratios suggested that nests were 26.8 % more likely to occur for every 10 cm increase in mean vegetation height with a range of 7.5 to 150.0 cm and 18.5 % less likely to occur for every 10 % increase in canopy closure with a range from 0.0 to 97.8 %. Total ground cover, canopy closure, edge density, and percent land cover type (e.g., mature pine, mixed pine/hardwood, shrub/scrub) had minimal influence on nest site selection. Management of pine savannas for turkey nest sites should focus on creating early-successional vegetation to conceal nests from potential predators. Additionally, we suggest that future studies consider evaluating the influence of spatial scale on turkey nest site selection.

Urban shade as a cryptic habitat: fern distribution in building gaps in Sapporo, northern Japan

Biodiversity conservation and restoration in cities is a global challenge for the 21st century. Unlike other common ecosystems, urban landscapes are predominantly covered by gray, artificial structures (e.g., buildings and roads), and remaining green spaces are scarce. Therefore, to conserve biodiversity in urban areas, understanding the potential conservation value of artificial structures is vital. Here, we examined factors influencing the distribution of ferns in building gaps, one of the more common artificial structures, in urban Sapporo, northern Japan. We observed 29 fern species, which corresponds to 30 % of all fern species previously recorded in Sapporo. The four dominant species were Equisetum arvense, Matteuccia struthiopteris, Dryopteris crassirhizoma, and Athyrium yokoscense. Statistical analyses showed that their distribution patterns in building gaps were associated with both local- and landscape-scale environmental factors. Although ground cover type and distance from continuous forests were the most important determinants, other factors such as the amount of solar radiation, habitat age (years after building development), and urban district type also affected fern distribution. These results suggest that building gaps act as an important habitat for ferns in highly urbanized landscapes. Policy makers and city planners should therefore not overlook these cryptic habitats. Clarifying the ecological functions of artificial structures will both further our understanding of novel ecosystems and develop a new framework for conserving and restoring biodiversity in human-modified landscapes.

Restoration potential of native forests after removal of conifer plantation: A perspective from Australia

This study investigates whether undertaking a rotation of pine plantation on abandoned farmland facilitates the return of native species. Plant functional traits were used as a means of assessing the effects of land-use change on vegetation. We explored the relationships among plant traits, time since harvesting and environmental variables for the vegetation found in Pinus radiata plantations after clear-felling. Vegetation was monitored 1–3years following harvesting and repeated eight years later. We compared species richness, composition and traits to those in reference native forest and abandoned farmland. There was a significant temporal shift in attribute associations of harvested plantations towards those in native forest and a move away from plant attributes common to the pre-plantation use of abandoned farmland. Cluster analysis produced ten emergent groups of plant functional traits for 144 plant species. After harvesting, attribute associations were typical of therophytes and included high specific leaf area (SLA), small stature, arbuscular or non-mycorrhizal associations and small, wind-dispersed seed. These were predominantly introduced species that were dominant in abandoned farmland. The repeat survey identified an obvious decrease in therophytes and an increase in species with low SLA, ant dispersal, large seed and ectomycorrhizal associations. This was largely due to an increase in native Myrmecochorous shrubs. Similar attributes were also shared by Ericoid heaths but these species failed to recolonise harvested sites. Relationships among plant traits of species and environmental variables changed over time with a greater proportion of the variance in attribute associations explained by prevailing site conditions (e.g. type of ground cover, edaphic properties) with increasing time since harvesting. There were no relationships among plant attribute associations and stem density or basal area of planted overstorey species suggesting that planting of tubestock seedlings of native overstorey species does not effectively promote the development of native vegetation. The persistence of introduced grasses in areas of former plantation, recruitment failure of native species and a ready supply of introduced species from surrounding land uses suggest that additional rehabilitation measures will be required to promote the return of a fuller complement of native species.

Northern flicker mates foraging on renewing patches within home ranges avoid competition not by separate niches but by segregation

Foraging with others can reduce predation risk but may increase competition for resources. Species, sex, or age classes may use different niches to reduce competition for food, which may be enforced by social dominance or may lead to ecological specialization. An alternate hypothesis is that individuals using resource patches that renew over time intentionally avoid recently depleted patches by avoiding each other. We tested these hypotheses by simultaneously radio-tracking northern flicker (Colaptes auratus) mates. Members of a pair rarely foraged in the same patch, spending over 90 % of the time >50 m apart. Counter to the ecological specialization hypothesis, the types of ground cover used for foraging and the distance of foraging patches from cover and edge did not differ between males and females. Mates were more spatially segregated on the home range than random and males foraged closer to the nest than females, but we never saw agonistic behaviors counter to the dominance hypothesis. Both sexes avoided returning to the same foraging location repeatedly, perhaps because of prey depletion. We suggest that members of a pair avoided foraging close to each other to reduce encounters with depleted prey patches. We emphasize the importance of simultaneous tracking of mates to identify foraging strategies and potential niche segregation at the home range scale.

Correlação entre condição da superfície do solo agrícola e o coeficiente de absorção acústica

This work applied acoustic technique to relate the response of a signal sound to different surfaces, measured in equivalent sound pressure level, with the factors governing soil loss. Four erosion plots in reduced scale (2.0 x 12.5 m) were built on the field. One plot contained barren soil while the others contained forage grass (Brachiaria), corn and temporary crop soybean/wheat, following the seasonal agricultural practices implemented in the watershed where the study was conducted. Pink noise was used in the measurements of the acoustic system to collect information regarding the equivalent sound pressure level (LEQ) of incident and reflected waves. The results of the noise tests indicated that there was no differentiation between the type of ground cover and the acoustic absorption coefficient measured in LEQ.

Effect of ground‐cover type on surface runoff and subsequent soil erosion in Champagne vineyards in France

AbstractThis study was conducted in Champagne vineyards in France, and the objectives were to compare the main cultivation practices in Champagne vineyards and to specify the conditions required for the optimum effect of inter‐row grass cover on runoff and erosion in experimental plots of 0.25 m² under simulated rainfall. Three types of ground cover were studied. In the bark‐and‐vine‐prunings plots, the runoff coefficient (RC) ranged from 1.3 to 4.0% and soil losses were &lt;1 g/m2/h. In the bare soil (BS) plot, the highest RC of the study was found (80.0%) and soil losses reached 7.4 g/m2/h. In the grass cover plots, the RC and amount of eroded soil were highly variable: the RCs ranged from 0.4 to 77.0%, and soil losses were between less than 1 and 13.4 g/m2/h. Soil type, soil moisture, slope and agricultural practices did not account for the variability. In fact, the density of grass cover in the wheel tracks explained a portion of this variability. The lack of grass in the centre of the inter‐row allowed for a preferential flow and created an erosion line in the wheel tracks where the soil was compacted. This study showed that grass cover in a vineyard was not necessarily sufficient to reduce surface runoff and prevent soil erosion. To be effective, the grass cover must be dense enough in the wheel tracks of agricultural machinery to avoid RCs close to the RC achieved with BS.

Characterizing soil surface structure in a temperate tree-based intercropping system using X-ray computed tomography

The objective of this work was to characterize differences in the soil surface (top 3.5 cm) microstructure, as influenced by four tree species, within a temperate tree based intercropping (TBI) system. Soils adjacent to walnut (Juglans nigra), poplar (Populus spp.), red oak (Quercus rubra), Norway spruce (Picea abies), as well as three types of ground cover [row crop, willow (Salix spp.), and perennial grass tree rows] were analyzed. X-ray computed micro –tomography (µCT) was employed to evaluate soil void phase characteristics, as well as heterogeneity of soil matrix radiodensity. X-ray µCT identified void phase parameters were not affected by tree species due to confounding effects caused by perennial vegetation and mixed leaf litter inputs.. A positive correlation was found between traditionally measured soil bulk density and bulk X-ray radiodensity (rs = 0.53, p < 0.01) and a negative correlation between mean intra-aggregate X-ray radiodensity and soil organic carbon (rs = −0.48, p = 0.03). It was determined, through the use of geostatistics, that there were no distinct or consistent anisotropic structures, in directional semivariograms, evident for the various species. However, the semivariograms revealed greater variability, correlated with less directional anisotropy within the tree row as compared to cropping alley soils. It was interpreted that processes within soils in the tree rows were leading to a homogenous type of structure, and that soils under row crops exhibited a greater tendency for destruction of surface structure, leading to more directional anisotropy (trends).

Regeneration of Abies cephalonica Loudon after a Large Fire in Central Greece

Background and Purpose: Abies cephalonica Loudon (Greek fir) is a dominant tree species of the mountainous Greece that forms productive forests. Wildfires in fir forests were not considered a major threat but in recent decades, fir ecosystems in Greece have experienced large crown fires with subsequent ecological and economical losses. Materials and Methods: This study was designed to aid our understanding of Greek fir recovery after fire. In Central Greece, 12 years after a large fire, fir regeneration and site factors were studied in 143 sampling plots located in 10 transects. Results: Fir regeneration density decreased abruptly with distance from the remnant stands and followed the negative exponential curve with decreasing regeneration abundance from the border of the unburned zone. Abiotic factors such as elevation, aspect, slope steepness and ground cover type could not significantly explain any variability in fir regeneration density. Conclusions: Our results showed that distance from a seed source was the most important variable in explaining fir regeneration. Moreover, the density of fir regeneration seemed adequate to provide stocking for a future fir forest.

Investigation of potential integration of spectroradiometer data with GIS technology: The Spectro-GIS tools

The Earth's surface consists of different ground cover types. The spectral signature of these ground cover targets is unique and can be determined in the field through quantitative measurement of radiance and reflectance response by portable spectroradiometers. In this study, a field portable spectroradiometer, the GER 1500, covering the Ultraviolet, Visible and Near-infrared wavelengths from 350 nm to 1050 nm was used to record the spectral response reading of different ground cover types. The measurements were made at the time when the Sun was at several instant positions to find out the influences and impacts on the spectroradiometer observations. These instant positions of the Sun were determined via spherical computation. The outcome from the measurements made against selected target features by the spectroradiometer is an output file containing signature plot data that was generated in .sig and/or ASCII format. The attempt of the study was to convert that spectroradiometer data into a GIS-enable format. The development of a Spectro-GIS tool was customized using Visual Basic. Net programming language that enables the tools to run independently and automate the process of the conversion and generation of spectral library of the surface targets is highlighted. The results of this study will be benefited to the earth observation community in a way of providing alternative automation of spatial data archiving as well as the data integration and fusion of the land spectral signatures.

Bioclimatic conditions under different ground cover types in the greater Athens area, Greece

This research aims to investigate the bioclimatic conditions in different ground cover types in the greater Athens area, Greece: a major street with heavy traffic (MS), an adjacent pedestrian street (PS) with irrigated plants and an urban park. Four sites were selected: one in each of the streets, and two in the park (one of which is covered by irrigated plants (IPS) while the other is covered by non-irrigated plants (NIPS). Air temperature and relative humidity were monitored in each site during the periods of July-August and September-October of the years 2009 and 2010. These parameters were used for the calculation of the thermohygrometric index based on which bioclimatic conditions were evaluated. The “Hot” class prevailed at all sites during the July-August period while similar bioclimatic conditions detected at all environments with irrigated plants at the aforementioned period. During autumn, the “Comfortable” class prevailed at the PS and the urban park compared to the MS. The findings of our study could provide useful information for the design of outdoor spaces with irrigated vegetation as well as for the plantation and irrigation of plant species on city roads with heavy traffic.

Synergistic effects of ground cover and adjacent vegetation on natural enemies of olive insect pests

The use of pesticides in conventional agriculture poses several risks to humans and to the environment, and may turn out to be inefficient in the long-term as pests can develop resistance to pesticides. Non-chemical control methods can be preferable to prevent pest damage. One way to achieve this involves the establishment of ground cover or the restoration of vegetation adjacent to the crop. Either of these methods can effectively increase the abundance of natural enemies, particularly in perennial crops, but their interaction has been typically neglected. In this study we used maximum likelihood methods to analyse the synergistic effects of ground cover and different types of adjacent vegetation (herbaceous, woody) on the abundance of the main natural enemy groups of insect pests in olive groves. A Gaussian function was used to predict their abundance as a response of time, ground cover, different types of adjacent vegetation and year (2010, 2011). We examined 40 different alternative models for each group of natural enemies: spiders, ants, predatory Heteroptera, and parasitoids. Spiders, parasitoids, and one species of predatory Heteroptera (Deraeocoris punctum), showed a greater abundance in ground cover plots. Overall, herbaceous and large woody vegetation adjacent to the crop influenced the abundance of natural enemies more than small woody vegetation. However, this effect was modulated by ground cover. When both structures were present in the crop, the abundance of some groups of natural enemies (spider and parasitoids) was positively influenced by adjacent vegetation, whereas this effect was lower or even reversed in bare soil crops. We thus encourage olive farmers to use both habitat management approaches simultaneously, since the interaction of these ecological infrastructures produce an effect that maximises the abundance of natural enemies.

Nitrogen topdressing on common bean cropped in winter-spring in three cropping systems.

The aim of this study was to evaluate the nitrogen topdressing influence in common bean irrigated (winter-spring), in the first year of no tillage implementation. The experimental design was split-plot with three replications in randomized blocks. The plots were formed by three types of ground cover, corn-grain, corn-grain intercropped with Brachiaria ruziziensis and only B. ruziziensis . The subplots were formed by five doses of nitrogen topdressing (0, 40, 80, 120 and 160 kg ha-1), using urea as nitrogen source. It was determined the dry mass of residue present as ground cover, the full flowering time, the leaf nitrogen content, the 100 grains mass, the grain yield, the processing income, the chemical soil properties and economic analysis of common bean grain yield. It was found the common bean grain productivity in succession to corn-grain was positively influenced by nitrogen fertilization, showing it is economically viable only when given 160 kg ha-1 of nitrogen and the intercropping corn-grain and B. ruziziensis use is the best option when the common bean is sown in succession.

Adubação nitrogenada de cobertura no feijoeiro de invernoprimavera em três sistemas de cultivo

The aim of this study was to evaluate the nitrogen topdressing influence in common bean irrigated (winter-spring), in the first year of no tillage implementation. The experimental design was split-plot with three replications in randomized blocks. The plots were formed by three types of ground cover, corn-grain, corn-grain intercropped with Brachiaria ruziziensis and only B. ruziziensis . The subplots were formed by five doses of nitrogen topdressing (0, 40, 80, 120 and 160 kg ha-1), using urea as nitrogen source. It was determined the dry mass of residue present as ground cover, the full flowering time, the leaf nitrogen content, the 100 grains mass, the grain yield, the processing income, the chemical soil properties and economic analysis of common bean grain yield. It was found the common bean grain productivity in succession to corn-grain was positively influenced by nitrogen fertilization, showing it is economically viable only when given 160 kg ha-1 of nitrogen and the intercropping corn-grain and B. ruziziensis use is the best option when the common bean is sown in succession.