scholarly journals Impacts of fertilization on grassland productivity and water quality across the European Alps under current and warming climate: insights from a mechanistic model

2021 ◽  
Vol 18 (6) ◽  
pp. 1917-1939
Author(s):  
Martina Botter ◽  
Matthias Zeeman ◽  
Paolo Burlando ◽  
Simone Fatichi

Abstract. Alpine grasslands sustain local economy by providing fodder for livestock. Intensive fertilization is common to enhance their yields, thus creating negative externalities on water quality that are difficult to evaluate without reliable estimates of nutrient fluxes. We apply a mechanistic ecosystem model, seamlessly integrating land-surface energy balance, soil hydrology, vegetation dynamics, and soil biogeochemistry, aiming at assessing the grassland response to fertilization. We simulate the major water, carbon, nutrient, and energy fluxes of nine grassland plots across the broad European Alpine region. We provide an interdisciplinary model evaluation by confirming its performance against observed variables from different datasets. Subsequently, we apply the model to test the influence of fertilization practices on grassland yields and nitrate (NO3-) losses through leaching under both current and modified climate scenarios. Despite the generally low NO3- concentration in groundwater recharge, the variability across sites is remarkable, which is mostly (but not exclusively) dictated by elevation. In high-Alpine sites, short growing seasons lead to less efficient nitrogen (N) uptake for biomass production. This combined with lower evapotranspiration rates results in higher amounts of drainage and NO3- leaching to groundwater. Scenarios with increased temperature lead to a longer growing season characterized by higher biomass production and, consequently, to a reduction of water leakage and N leaching. While the intersite variability is maintained, climate change impacts are stronger on sites at higher elevations. The local soil hydrology has a crucial role in driving the NO3- use efficiency. The commonly applied fixed threshold limit on fertilizer N input is suboptimal. We suggest that major hydrological and soil property differences across sites should be considered in the delineation of best practices or regulations for management. Using distributed maps informed with key soil and climatic attributes or systematically implementing integrated ecosystem models as shown here can contribute to achieving more sustainable practices.

2020 ◽  
Author(s):  
Martina Botter ◽  
Matthias Zeeman ◽  
Paolo Burlando ◽  
Simone Fatichi

Abstract. Alpine grasslands sustain local economy providing fodder for livestock. Intensive fertilization is common to enhance their yields, thus creating negative externalities on water quality that are difficult to evaluate without reliable estimates of nutrient fluxes. We apply a 1-D mechanistic ecosystem model, seamlessly integrating land-surface energy balance, soil hydrology, vegetation dynamics, and soil biogeochemistry aiming at assessing the grassland response to fertilization. We simulate the major water, carbon, nutrient, and energy fluxes of nine grassland plots across the broad European Alpine region. We provide an unprecedent interdisciplinary model evaluation confirming its performance against observed variables from different datasets. Subsequently, we apply the model to test the influence of fertilization practices on grassland yields and nitrate (NO3) losses through leaching. Despite the generally low NO3 concentration in groundwater recharge, the variability across sites is remarkable, mostly, but not exclusively, dictated by elevation. In high-Alpine sites short growing seasons lead to less efficient nitrogen (N) uptake for biomass production. This combined with lower evapotranspiration rates results in higher amounts of drainage and NO3 leaching to groundwater. The local soil hydrology has a crucial role in driving the NO3 use efficiency. The commonly applied fixed-threshold limit on fertilizer N input is suboptimal. We suggest that major hydrological and soil property differences across sites should be considered in the delineation of best practices or regulations for management. Using distributed maps informed with key soil and climatic attributes or systematically implementing integrated ecosystem models as shown here can contribute to achieving more sustainable practices.


2002 ◽  
Vol 12 (2) ◽  
pp. 250-256 ◽  
Author(s):  
Hudson Minshew ◽  
John Selker ◽  
Delbert Hemphill ◽  
Richard P. Dick

Predicting leaching of residual soil nitrate-nitrogen (NO3-N) in wet climates is important for reducing risks of groundwater contamination and conserving soil N. The goal of this research was to determine the potential to use easily measurable or readily available soilclimatic-plant data that could be put into simple computer models and used to predict NO3 leaching under various management systems. Two computer programs were compared for their potential to predict monthly NO3-N leaching losses in western Oregon vegetable systems with or without cover crops. The models were a statistical multiple linear regression (MLR) model and the commercially available Nitrate Leaching and Economical Analysis Package model (NLEAP 1.13). The best MLR model found using stepwise regression to predict annual leachate NO3-N had four independent variables (log transformed fall soil NO3-N, leachate volume, summer crop N uptake, and N fertilizer rate) (P < 0.001, R2 = 0.57). Comparisons were made between NLEAP and field data for mass of NO3-N leached between the months of September and May from 1992 to 1997. Predictions with NLEAP showed greater correlation to observed data during high-rainfall years compared to dry or averagerainfall years. The model was found to be sensitive to yield estimates, but vegetation management choices were limiting for vegetable crops and for systems that included a cover crop.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1482
Author(s):  
Silvia Pampana ◽  
Alessandro Rossi ◽  
Iduna Arduini

Winter cereals are excellent candidates for biosolid application because their nitrogen (N) requirement is high, they are broadly cultivated, and their deep root system efficiently takes up mineral N. However, potential N leaching from BS application can occur in Mediterranean soils. A two-year study was conducted to determine how biosolids affect biomass and grain yield as well as N uptake and N leaching in barley (Hordeum vulgare L.), common wheat (Triticum aestivum L.), durum wheat (Triticum turgidum L. var. durum), and oat (Avena byzantina C. Koch). Cereals were fertilized at rates of 5, 10, and 15 Mg ha−1 dry weight (called B5, B10, and B15, respectively) of biosolids (BS). Mineral-fertilized (MF) and unfertilized (C) controls were included. Overall, results highlight that BS are valuable fertilizers for winter cereals as these showed higher yields with BS as compared to control. Nevertheless, whether 5 Mg ha−1 of biosolids could replace mineral fertilization still depended on the particular cereal due to the different yield physiology of the crops. Moreover, nitrate leaching from B5 was comparable to MF, and B15 increased the risk by less than 30 N-NO3 kg ha−1. We therefore concluded that with specific rate settings, biosolid application can sustain yields of winter cereals without significant additional N leaching as compared to MF.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. W. McDowell ◽  
Z. P. Simpson ◽  
A. G. Ausseil ◽  
Z. Etheridge ◽  
R. Law

AbstractUnderstanding the lag time between land management and impacts on riverine nitrate–nitrogen (N) loads is critical to understand when action to mitigate nitrate–N leaching losses from the soil profile may start improving water quality. These lags occur due to leaching of nitrate–N through the subsurface (soil and groundwater). Actions to mitigate nitrate–N losses have been mandated in New Zealand policy to start showing improvements in water quality within five years. We estimated annual rates of nitrate–N leaching and annual nitrate–N loads for 77 river catchments from 1990 to 2018. Lag times between these losses and riverine loads were determined for 34 catchments but could not be determined in other catchments because they exhibited little change in nitrate–N leaching losses or loads. Lag times varied from 1 to 12 years according to factors like catchment size (Strahler stream order and altitude) and slope. For eight catchments where additional isotope and modelling data were available, the mean transit time for surface water at baseflow to pass through the catchment was on average 2.1 years less than, and never greater than, the mean lag time for nitrate–N, inferring our lag time estimates were robust. The median lag time for nitrate–N across the 34 catchments was 4.5 years, meaning that nearly half of these catchments wouldn’t exhibit decreases in nitrate–N because of practice change within the five years outlined in policy.


Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 515
Author(s):  
Ying Ouyang ◽  
Gary Feng ◽  
Heidi Renninger ◽  
Theodor D. Leininger ◽  
Prem Parajuli ◽  
...  

Eucalyptus is one of the fastest growing hardwoods for bioenergy production. Currently, few modeling tools exist to simultaneously estimate soil hydrological processes, nitrogen (N) uptake, and biomass production in a eucalyptus plantation. In this study, a STELLA (Structural Thinking and Experiential Learning Laboratory with Animation)-based model was developed to meet this need. After the model calibration and validation, a simulation scenario was developed to assess eucalyptus (E. grandis × urophylla) annual net primary production (ANPP), woody biomass production (WBP), water use efficiency (WUE), and N use efficiency (NUE) for a simulation period of 20 years. Simulation results showed that a typical annual variation pattern was predicted for water use, N uptake, and ANPP, increasing from spring to fall and decreasing from fall to the following winter. Overall, the average NUE during the growth stage was 700 kg/kg. To produce 1000 kg eucalyptus biomass, it required 114.84 m3 of water and 0.92 kg of N. This study suggests that the STELLA-based model is a useful tool to estimate ANPP, WBP, WUE, and NUE in a eucalyptus plantation.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 740
Author(s):  
Ken Okamoto ◽  
Shinkichi Goto ◽  
Toshihiko Anzai ◽  
Shotaro Ando

Fertilizer application during sugarcane cultivation is a main source of nitrogen (N) loads to groundwater on small islands in southwestern Japan. The aim of this study was to quantify the effect of reducing the N fertilizer application rate on sugarcane yield, N leaching, and N balance. We conducted a sugarcane cultivation experiment with drainage lysimeters and different N application rates in three cropping seasons (three years). N loads were reduced by reducing the first N application rate in all cropping seasons. The sugarcane yields of the treatment to which the first N application was halved (T2 = 195 kg ha−1 N) were slightly lower than those of the conventional application (T1 = 230 kg ha−1 N) in the first and third seasons (T1 = 91 or 93 tons ha−1, T2 = 89 or 87 tons ha−1). N uptake in T1 and T2 was almost the same in seasons 1 (186–188 kg ha−1) and 3 (147–151 kg ha−1). Based on the responses of sugarcane yield and N uptake to fertilizer reduction in two of the three years, T2 is considered to represent a feasible fertilization practice for farmers. The reduction of the first N fertilizer application reduced the underground amounts of N loads (0–19 kg ha−1). However, application of 0 N in the first fertilization would lead to a substantial reduction in yield in all seasons. Reducing the amount of N in the first application (i.e., replacing T1 with T2) improved N recovery by 9.7–11.9% and reduced N leaching by 13 kg ha−1. These results suggest that halving the amount of N used in the first application can improve N fertilizer use efficiency and reduce N loss to groundwater.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Sara Bonetti ◽  
Zhongwang Wei ◽  
Dani Or

AbstractEarth system models use soil information to parameterize hard-to-measure soil hydraulic properties based on pedotransfer functions. However, current parameterizations rely on sample-scale information which often does not account for biologically-promoted soil structure and heterogeneities in natural landscapes, which may significantly alter infiltration-runoff and other exchange processes at larger scales. Here we propose a systematic framework to incorporate soil structure corrections into pedotransfer functions, informed by remote-sensing vegetation metrics and local soil texture, and use numerical simulations to investigate their effects on spatially distributed and areal averaged infiltration-runoff partitioning. We demonstrate that small scale soil structure features prominently alter the hydrologic response emerging at larger scales and that upscaled parameterizations must consider spatial correlations between vegetation and soil texture. The proposed framework allows the incorporation of hydrological effects of soil structure with appropriate scale considerations into contemporary pedotransfer functions used for land surface parameterization.


2001 ◽  
Vol 1 ◽  
pp. 10-16 ◽  
Author(s):  
James L. Baker

The primary mode of nitrogen (N) loss from tile-drained row-cropped land is generally nitrate-nitrogen (NO3-N) leaching. Although cropping, tillage, and N management practices can be altered to reduce the amount of leaching, there are limits as to how much can be done. Data are given to illustrate the potential reductions for individual practices such as rate, method, and timing of N applications. However, most effects are multiplicative and not additive; thus it is probably not realistic to hope to get overall reductions greater than 25 to 30% with in-field practices alone. If this level of reduction is insufficient to meet water quality goals, additional off-site landscape modifications may be necessary.


2019 ◽  
Vol 42 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Igor Gopchak ◽  
Tetiana Basiuk ◽  
Ihor Bialyk ◽  
Oleg Pinchuk ◽  
Ievgenii Gerasimov

Abstract The environmental assessment of the surface water quality of the Western Bug River has been made using the system of classification quality of land surface water of Ukraine in accordance with the approved methodology, which allows comparing water quality of separate areas of water objects of different regions. The calculation of the environmental assessment of water quality has been carried according to three blocks: block of salt composition, block of trophic and saprobic (ecological and sanitary) indicators and block of indicators of content of specific toxic substances. The results are presented in the form of a combined environmental assessment, based on the final conclusions of the three blocks and consists in calculating the integral ecological index. Comprehensive studies of changes in the water quality of the Western Bug River have been conducted within the territory of Ukraine for a long-term period. The water quality of the river on the final values of the integral indicators of the ecological condition corresponded mainly to 4nd category of the 3rd class – the water is “satisfactory” by condition and “little polluted” by degree of purity (except for points of observation that located within the Volyn region, where the water quality corresponded to 3rd category and the 2nd class. It is “good” by condition and “fairly clean” by the degree of purity). Visualization and part of the analysis are performed using GIS technologies in the software of the ArcGIS 10.3.


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