Non-growing Periods Research Articles

Analyses of the Effectiveness of Different Media Depths and Plant Treatments on Green Roof Rainfall Retention Capability under Various Rainfall Patterns

Green roofs have been used to reduce rainfall runoff by altering hydrological processes through plant interception and retention as well as detention within the green roof system. Green roof media depth, substrate type, plant type and density, regional climatic conditions, rainfall patterns, and roof slope all impact runoff retention. To better understand the impacts of media depth (10, 15, and 20 cm), plant (planted and non-planted), and rainfall pattern (low, medium, and high) on rainfall retention, we analyzed data collected between September 2005 and June 2008 from 24 green roof models (61 cm × 61 cm) for growing and non-growing seasons. Our results showed that a planted green roof has greater rainfall retention capability than a non-planted green roof for all media depths. Interestingly, a non-planted green roof system with a 10 cm media depth retained greater rainfall than a planted green roof during both growing and non-growing periods. Retention capability decreased with increasing rainfall amounts for both planted and non-planted green roofs and seasons (growing and non-growing). The 15 cm media depth green roof retained significantly greater rainfall depth than the 20 cm models during medium (0.64 to 2.54 cm) and high (>2.54 cm) rainfall events for the growing season but not during the non-growing season. The study provides insight into the interactive effects of media depth, rainfall amount, plant presence, and seasons on green roof performance. The results will be helpful for designing economical and effective green roof systems.

Mesoscale numerical modeling of the boundary layer of the atmosphere adapted to the Northwestern Black Sea region. Part 2. Finite-difference solution and adaptation to real physical and geographical conditions of the area

The article describes the finite-difference solution of the system of differential equations of the atmospheric boundary layer hydrothermodynamics adapted to the Northwestern Black Sea region. The research presents the description of the sequence of calculations schematically shown on the flowchart. The applied mathematical model was adapted in relation to five aspects: coast geomorphology (coastline shape), land geomorphology (actual terrain of the studied territory), thermal and physical characteristics of soil (density, specific gravity, porosity, thermal conductivity factor), roughness (roughness parameter) and optical characteristics (albedo) of the underlying surface. The coastline shape was described with consideration of water proportion available in the current cell of the spatial grid. If the proportion exceeded 50 %, it was assumed that such cell includes land, and vice versa. The terrain matrix was formed by removing the elevation values at each point of the calculated area from official electronic elevation maps. The thermal and physical characteristics of the soil were set depending on a type of soil observed at the current calculated point. The method of roughness elements double recording during growing and non-growing periods of the year was used to consider the roughness of the underlying surface. This method consists in the fact that, depending on the agricultural zoning and its subject content, there is a certain background weighted average value of roughness elements ensemble elevation that transforms into a roughness parameter through the proportionality factor. In such a case, the proportionality factor is linked to a type of a real roughness element at a specific point. Thus, a comprehensive assessment of roughness features of the territory under study was obtained. The albedo of the underlying surface was taken for three various periods of the year: growing period (April-September), post-growing period – months before winter and the first month of spring (October-November, March) and winter period (December-February). Nature of the external coating of the underlying surface related to optical properties should be also taken into account.

A new framework to map fine resolution cropping intensity across the globe: Algorithm, validation, and implication

Accurate estimation of cropping intensity (CI), an indicator of food production, is well aligned with the ongoing efforts to achieve sustainable development goals (SDGs) under diminishing natural resources. The advancement in satellite remote sensing provides unprecedented opportunities for capturing CI information in a spatially continuous manner. However, challenges remain due to the lack of generalizable algorithms for accurately and efficiently mapping global CI with a fine spatial resolution. In this study, we developed a 30-m planetary-scale CI mapping framework with the reconstructed time series of Normalized Difference Vegetation Index (NDVI) from multiple satellite images. Using a binary crop phenophase profile indicating growing and non-growing periods, we estimated pixel-by-pixel CI by enumerating the total number of valid cropping cycles during the study years. Based on the Google Earth Engine cloud computing platform, we implemented the framework to estimate CI during 2016–2018 in eight geographic regions across continents that are representative of global cropping system diversity. Comparison with PhenoCam network data in four cropland sites suggests that the proposed framework is capable of capturing the seasonal dynamics of cropping practices. Spatially, overall accuracies based on validation samples range from 80.0% to 98.9% across different regions worldwide. Regarding the CI classes, single cropping systems are associated with more robust and less biased estimations than multiple cropping systems. Finally, our CI estimates reveal high agreement with two widely used land surface phenology products, including Vegetation Index and Phenology V004 (VIP4) and Moderate Resolution Imaging Spectroradiometer Land Cover Dynamics (MCD12Q2), meanwhile providing much more spatial details. Due to its robustness, the developed CI framework can be potentially generalized to produce global fine resolution CI products for food security and other applications.

Measurement of N2O emissions over the whole year is necessary for estimating reliable emission factors

Nitrous oxide emission factors (N2O-EF, percentage of N2O–N emissions arising from applied fertilizer N) for cropland emission inventories can vary with agricultural management, soil properties and climate conditions. Establishing a regionally-specific EF usually requires the measurement of a whole year of N2O emissions, whereas most studies measure N2O emissions only during the crop growing season, neglecting emissions during non-growing periods. However, the difference in N2O-EF (ΔEF) estimated using measurements over a whole year (EFwy) and those based on measurement only during the crop-growing season (EFgs) has received little attention. Here, we selected 21 studies including both the whole-year and growing-season N2O emissions under control and fertilizer treatments, to obtain 123 ΔEFs from various agroecosystems globally. Using these data, we conducted a meta-analysis of the ΔEFs by bootstrapping resampling to assess the magnitude of differences in response to management-related and environmental factors. The results revealed that, as expected, the EFwy was significantly greater than the EFgs for most crop types. Vegetables showed the largest ΔEF (0.19%) among all crops (0.07%), followed by paddy rice (0.11%). A higher ΔEF was also identified in areas with rainfall ≥600 mm yr−1, soil with organic carbon ≥1.3% and acidic soils. Moreover, fertilizer type, residue management, irrigation regime and duration of the non-growing season were other crucial factors controlling the magnitude of the ΔEFs. We also found that neglecting emissions from the non-growing season may underestimate the N2O-EF by 30% for paddy fields, almost three times that for non-vegetable upland crops. This study highlights the importance of the inclusion of the non-growing season in the measurements of N2O fluxes, the compilation of national inventories and the design of mitigation strategies.

Effects of pesticide exposure on reproductivity of male groundnut farmers in Kyauk Kan village, Nyaung-U, Mandalay region, Myanmar.

IntroductionKyauk Kan village of Nyaung-U, Mandalay region, Myanmar is one of the most famous groundnut-growing zones and has been exposed to pesticides.MethodsThis study design provided evaluation of within-person changes in the season across growing and nongrowing periods. A cross-sectional study was performed to identify health problems related to organophosphate pesticide (OP) exposure, to explore the protected use of this pesticide among 400 participants in the community by face-to-face interviews, and to determine the reproductive effects of OP exposure by using biomarkers of 100 male groundnut farmers aged 18–49 years.ResultsThe mean age of the participants was 37.5±9.45 years. Analysis revealed statistically significant differences in seminal parameters (P<0.05 for pH, viscosity, motility, morphology, and sperm count) and in a reproductive hormonal assay (P<0.05 in follicle-stimulating hormone and testosterone) between the growing and nongrowing periods. Blood-cholinesterase levels of plasma cholinesterase in the growing period were significantly higher than those in the nongrowing period (P<0.05).ConclusionOur results suggest that chronic exposure related to OP dose may reduce potential male reproductivity.

Fostering integrated land and water management approaches: Evaluating the water footprint of a Mediterranean basin under different agricultural land use scenarios

In the Genil River Basin (southern Spain), agriculture is the greatest pressure on freshwater demand. Furthermore, water degradation caused by soil erosion is becoming a key environmental concern. This study aims to assess the water-related impacts of agriculture combining the use of an ecohydrological model (SWAT) with a spatiotemporal water footprint assessment to evaluate the current status of streamflow (blue water), soil water (green water) and the assimilability of sediments by streamflow (grey water footprint). The Common Agricultural Policy (CAP) requires farmers to adopt certain agricultural practices that are beneficial for the environment. Such practices could affect the conditions of available land and water resources. Because of the importance of applying the best land management practices for the maintenance of sustainable water resources, the study also infers probable water availability and water pollution level changes under different post-2013 CAP scenarios. The Genil streamflow is highly regulated, and, as a result, it is hard to discern significant changes (p<0.05) under the proposed scenarios. However, there is a shift with afforestation measures from unproductive (i.e., direct soil evaporation) to productive water (i.e., evapotranspired water from agricultural and natural areas, excluding non-growing periods) consumption. The probability of annual evapotranspiration from natural areas being greater in afforestation scenarios than in the baseline scenario is 0.70 to 0.88, whereas the likelihood of soil water evaporation being lower is 0.60. Evapotranspiration in natural areas increases by about 521% from September to May under afforestation measures compared with the baseline scenario, whereas soil water evaporation decreases by 30% in winter. The grey water footprint and water pollution level decrease by 19% and 9%, respectively, with the highest streamflow conditions under afforestation as opposed to current conditions. However, water pollution levels of suspended solids greater than 1 indicate that the river flow is not capable of assimilating the existing sediment loads. Since land use changes and agricultural practices have a major impact on water resources, the post-2013 CAP reform can provide environmental benefits for water allocation and mitigation of water pollution. However, further efforts are required to better align the policy goals of the CAP and the Water Framework Directive.

Sinorhizobium meliloti Sigma Factors RpoE1 and RpoE4 Are Activated in Stationary Phase in Response to Sulfite

Rhizobia are soil bacteria able to establish a nitrogen-fixing symbiosis with legume plants. Both in soil and in planta, rhizobia spend non-growing periods resembling the stationary phase of in vitro-cultured bacteria. The primary objective of this work was to better characterize gene regulation in this biologically relevant growth stage in Sinorhizobium meliloti. By a tap-tag/mass spectrometry approach, we identified five sigma factors co-purifying with the RNA polymerase in stationary phase: the general stress response regulator RpoE2, the heat shock sigma factor RpoH2, and three extra-cytoplasmic function sigma factors (RpoE1, RpoE3 and RpoE4) belonging to the poorly characterized ECF26 subgroup. We then showed that RpoE1 and RpoE4 i) are activated upon metabolism of sulfite-generating compounds (thiosulfate and taurine), ii) display overlapping regulatory activities, iii) govern a dedicated sulfite response by controlling expression of the sulfite dehydrogenase SorT, iv) are activated in stationary phase, likely as a result of endogenous sulfite generation during bacterial growth. We showed that SorT is required for optimal growth of S. meliloti in the presence of sulfite, suggesting that the response governed by RpoE1 and RpoE4 may be advantageous for bacteria in stationary phase either by providing a sulfite detoxification function or by contributing to energy production through sulfite respiration. This paper therefore reports the first characterization of ECF26 sigma factors, the first description of sigma factors involved in control of sulphur metabolism, and the first indication that endogenous sulfite may act as a signal for regulation of gene expression upon entry of bacteria in stationary phase.

Adsorption characteristics of 3-nitrogen absorbed by the soil-plants in Xiquan lake wetland

Abstract In allusion to water pollution of the Xiquan Lake wetland in Liaohe river basin, the three nitrogen adsorption rules were studied through the adsorption experiments of soil-plants over 3-nitrogen in Xiquan lake. The goal to protect the safety of the Xiquan lake reserve groundwater sources was attained. The native soil and the aboriginal plants named Typha orientalis Presls were used through the study and the contamination adsorption rules of the soil-plants system were analyzed and summed up through testing the removal rate of ammonia nitrogen, nitrate nitrogen, nitrite nitrogen by the soil-plants. The average adsorption and degradation coefficient of the growing period and non-growing period were calculated by the first order reaction ratio equation. The research obtained that it was an adsorption capacity that the soil-plants absorbed contaminations, the adsorption reaction finished when reaching saturation-- a dynamic equilibrium established between the adsorption and desorption. To some extent, soil and plants play a N buffering container role. The adsorption and degradation coefficient of the growing and non-growing periods are 5.64l/d and 4.05l/d respectively. The adsorption features of soil and plants to nitrogen were deeply researched and revealed, so as to the wetlands ecosystem was understood properly and play the ecological function role fully.

Nitrate isotopes unveil distinct seasonal N-sources and the critical role of crop residues in groundwater contamination

Summary Globally, fertilizers are identified as principle sources of nitrate in waters of intensely cultivated areas. Here this general concept is appraised on a seasonal basis over a two year period, under temperate climatic conditions. Water (δ2H and δ18O) and nitrate (δ15N and δ18O) isotopes in surface water and groundwater suggest that freshwater is acting as a transport vector conducting nitrate from agricultural soils to groundwater and ultimately to surface water. Measured nitrate isotopes of organic and inorganic fertilizers and of nitrate in groundwater are used to constrain a conceptual apportionment model quantifying the relative seasonal N contributions in an area of intense potato production. Source inputs differ strongly between the growing (summer and fall) and non-growing (winter and spring) periods. Chemical fertilizers and soil organic matter equally dominate and contribute to the growing period load, whereas soil organic matter dominates the non-growing period load, and accounts for over half of the overall annual nitrogen charge. These findings reveal the magnitude of nitrogen cycling by soil organic matter, and point to the benefits of controlling the timing of its nitrate release from this organic material. We conclude that strategies to attenuate contamination by nitrate in waters of temperate climate row-cropping regions must consider nitrogen cycling by soil organic matter, including the crucial role of crop residues throughout both the growing and non-growing seasons.

Regional assessment on influence of landscape configuration and connectivity on range size of white-tailed deer

Variation in the size of home range of white-tailed deer (Odocoileus virginianus) has broad implications for managing populations, agricultural damage, and disease spread and transmission. Size of home range of deer also varies seasonally because plant phenology dictates the vegetation types that are used as foraging or resting sites. Knowledge of the landscape configuration and connectivity that contributes to variation in size of home range of deer for the region is needed to fully understand differences and similarities of deer ecology throughout the Midwest. We developed a research team from four Midwestern states to investigate how size of home range of deer in agro-forested landscapes is influenced by variations in landscape characteristics that provide essential habitat components. We found that for resident female deer, annual size of home range in Illinois (mean = 0.99 km2), Michigan (mean = 1.34 km2), Nebraska (mean = 1.20 km2), and Wisconsin (mean = 1.47 km2) did not differ across the region (F 3,175 = 0.42, P = 0.737), but differences between agricultural growing and nongrowing periods were apparent. Variables influencing size of home range included: distance to forests, roads, and urban development from the centroid of deer home range, and percent of crop as well as four landscape pattern indices (contrast-weighted edge density, mean nearest neighbor, area-weighted mean shape index, and patch size coefficient of variation). We also identified differences in model selection for four landscapes created hierarchically to reflect levels of landscape connectivity determined from perceived ability of deer to traverse the landscape. Connectivity of selected forested regions within agro-forested ecosystems across the Midwest plays a greater role in understanding the size of home ranges than traditional definitions of deer habitat conditions and landscape configuration.

Actual and Reference Evaporative Losses and Surface Coefficients of a Maize Field during Nongrowing (Dormant) Periods

Effective water resources planning, allocation, management, and use in agroecosystems require accurate quantification of actual evapotranspiration ( ETc ) during growing and nongrowing (dormant) pe...

Productivity studies on heath vegetation in southern Australia the use of fertilizer in studies of production processes

An experiment, in which fertilizer was used for accelerating growth for studies on production processes, is described. In this Australian heathland—a community common on soils very deficient in phosphorus and other nutrients—responses to fertilizer consisted in increases in leaf area index and standing biomass above ground. Fertilizer had no effect on growth below ground. These results were derived in the second growing season after treatment; no statistically significant effect could be shown in the non-growing periods up to two years after treatment. Discussion is centred on the limitations to be expected of such natural communities used as experimental material on which fertilizer has been imposed as a major treatment.