The impact of sensitivity and uncertainty of soil physical parameters on the terms of the water balance: Some case studies with default R packages. Part I: Theory, methods and case descriptions
Wesseling, Jan ; Kroes, Joop ; Campos Oliveira, Thalita ; Damiano, Francisco - \ 2020
Computers and Electronics in Agriculture 170 (2020). - ISSN 0168-1699
HPC - IRS - LHS - Numerical model - R - Sensitivity - Sobol - SWAP - Uncertainty
These papers (part I and part II) emphasize the need for sensitivity and uncertainty analyses. A number of techniques are applied, e.g. latin hypercube sampling, impact response surfaces and Sobol-analyses. Five examples are presented, four of them concerning the numerical model SWAP. The data generation and analysis is performed with standard R packages. Although the computations can be made on any computer, the most time-consuming examples in this paper have been run on a High Performance Computer Cluster. With the relatively simple Impact Response Surface technique it is shown that variation of the saturated hydraulic conductivity has far less impact than changing the moisture content at saturation. Analyses according to the Sobol-Jansen method show that when the soil physical relationships are described according to Damiano, then the parameter b has a very large influence on the results. If the well-known Mualem - Van Genuchten equations are applied, most variation can be explained by the parameter n.
Intercropping simulation using the SWAP model: Development of a 2x1D algorithm
Pinto, Victor Meriguetti ; Dam, Jos C. van; Jong van Lier, Quirijn de; Reichardt, Klaus - \ 2019
Agriculture 9 (2019)6. - ISSN 2077-0472
Intercropping modeling - Lateral water flux - Radiation sharing - SWAP
Intercropping is a common cultivation system in sustainable agriculture, allowing crop diversity and better soil surface exploitation. Simulation of intercropped plants with integrated soil-plant-atmosphere models is a challenging procedure due to the requirement of a second spatial dimension for calculating the soil water lateral flux. Evaluations of more straightforward approaches for intercrop modeling are, therefore, mandatory. An adaptation of the 1D model Soil, Water, Atmosphere and Plant coupled to the World Food Studies (SWAP/WOFOST) to simulate intercropping (SWAP 2x1D) based on solar radiation and water partitioning between plant strips was developed and the outcomes are presented. An application of SWAP 2x1D to maize-soybean (MS) strip intercropping was evaluated against the monocropping maize (M) and soybean (S) simulated with the 1D model SWAP/WOFOST, and a sensitivity analysis of SWAP 2x1D was carried out for the intercropping MS. SWAP 2x1D was able to simulate the radiation interception by both crops in the intercropping MS and also to determine the effect of the radiation attenuation by maize on soybean plants. Intercropped plants presented higher transpiration and resulted in lower soil evaporation when compared to their equivalent monocropping cultivation. A numerical issue involving model instability caused by the simulated lateral water flux in the soil from one strip to the other was solved. The most sensitive plant parameters were those related to the taller plant strips in the intercropping, and soil retention curve parameters were overall all significantly sensitive for the water balance simulation. This implementation of the SWAP model presents an opportunity to simulate strip intercropping with a limited number of parameters, including the partitioning of radiation by a well-validated radiation sharing model and of soil water by simulating the lateral soil water fluxes between strips in the 2x1D environment.
Agrohydrological analysis of groundwater recharge and land use changes in the Pampas of Argentina
Kroes, Joop ; Dam, Jos van; Supit, Iwan ; Abelleyra, Diego de; Verón, Santiago ; Wit, Allard de; Boogaard, Hendrik ; Angelini, Marcos ; Damiano, Francisco ; Groenendijk, Piet ; Wesseling, Jan ; Veldhuizen, Ab - \ 2019
Agricultural Water Management 213 (2019). - ISSN 0378-3774 - p. 843 - 857.
Argentina - Capillary rise - Groundwater recharge - Land use - Pampas - Soybean - SWAP - WOFOST
This paper studies the changes of groundwater, climate and land use in the Pampas of Argentina. These changes offer opportunities and threats. Lowering groundwater without irrigation causes drought and successive crop and yield damage. Rising groundwater may alleviate drought as capillary rise supports root water uptake and crop growth, thus narrowing the difference between potential and actual yields. However, rising groundwater may also limit soil water storage, cause flooding in metropolitan areas and have a negative impact on crop yields. Changing land use from continuous soy bean into crop rotations or natural vegetation may decrease groundwater recharge and thus decrease groundwater levels. In case of crop rotation however, leaching of nutrients like nitrate may increase. We quantified these impacts using integrated dynamic crop growth and soil hydrology modelling. The models were tested at field scale using a local dataset from Argentina. We applied distributed modelling at regional scale to evaluate the impacts on groundwater recharge and crop yields using long term weather data. The experiments showed that threats arise from continuous monotone land use. Opportunities are created when a proper balance is found between supply and demand of soil water using a larger differentiation of land use. Increasing the areas of land use types with higher evapotranspiration, like permanent grassland and trees, will contribute to a more stable hydrologic system with more water storage capacities in the soil system and lower groundwater levels. Modelling tools clearly support the evaluation of the impact of land use and climate change on groundwater levels and crop yields.
Increased fire hazard in human-modified wetlands in Southeast Asia
Taufik, Muh ; Setiawan, Budi I. ; Lanen, Henny A.J. van - \ 2019
Ambio 48 (2019)4. - ISSN 0044-7447 - p. 363 - 373.
Canal water level - Canalization - Fire hazard - SWAP - Water management
Vast areas of wetlands in Southeast Asia are undergoing a transformation process to human-modified ecosystems. Expansion of agricultural cropland and forest plantations changes the landscape of wetlands. Here we present observation-based modelling evidence of increased fire hazard due to canalization in tropical wetland ecosystems. Two wetland conditions were tested in South Sumatra, Indonesia, natural drainage and canal drainage, using a hydrological model and a drought-fire index (modified Keetch–Byram index). Our results show that canalization has amplified fire susceptibility by 4.5 times. Canal drainage triggers the fire season to start earlier than under natural wetland conditions, indicating that the canal water level regime is a key variable controlling fire hazard. Furthermore, the findings derived from the modelling experiment have practical relevance for public and private sectors, as well as for water managers and policy makers, who deal with canalization of tropical wetlands, and suggest that improved water management can reduce fire susceptibility.
Importance of soil-water to the Caatinga biome, Brazil
Alves Rodrigues Pinheiro, Everton ; Metselaar, Klaas ; Jong van Lier, Quirijn de; Araújo, José Carlos de - \ 2016
Ecohydrology 9 (2016)7. - ISSN 1936-0584 - p. 1313 - 1327.
Evaporation - Evapotranspiration - Hot spots - Hydrology - Semi-arid - SWAP - Water balance
Northeastern Brazil is hydrologically characterized by recurrent droughts leading to a highly vulnerable natural water resource system. The region contains the Caatinga biome, covering an area of approximately 800000km2. To increase insight in water balance components for this sparsely studied ecosystem, hydrology simulations were performed with the SWAP (Soil Water Atmosphere Plant) model for a Caatinga basin of 12km2. SWAP model was developed to simulate hydrology under short-cycle crops, and its parameterization and validation to a diverse ecosystem is a novelty. The validation of the simulations was performed using a dataset of daily soil water content measurements taken at 0.2m depth in three sites in the basin in the period from 2004 to 2012. Average Nash-Sutcliffe efficiency coefficient for these simulations was 0.57 and root mean square error of prediction was 4.3%. The results of the simulations suggest that water components do not diverge statistically among different sites of the biome. The Caatinga biome returns 75% (±17%) of the annual precipitation to the atmosphere, whereas the partitioning of total evapotranspiration into its components (transpiration, evaporation and interception) on annual basis accounts for 41% (±7%), 40% (±6%) and 19% (±3%) respectively. Regarding water availability, the surface soil layer (0.0-0.2m) is the most important layer in the rooted profile, supplying up to 90% of atmospheric water demand. According to our analysis performed on daily basis, evapotranspiration and air temperature are most sensitive to soil moisture during the periods June-September and December-January.
Deep drainage modeling for a fertigated coffee plantation in the brazilian savanna
Pinto, Victor Meriguetti ; Reichardt, Klaus ; Dam, Jos van; Lier, Quirijn D.J.V. ; Bruno, Isabeli Pereira ; Durigon, Angelica ; Dourado-Neto, Durval ; Bortolotto, Rafael Pivotto - \ 2015
Agricultural Water Management 148 (2015). - ISSN 0378-3774 - p. 130 - 140.
Brazil - Deep drainage - Savanna - SWAP - Water productivity
Modeling in agriculture represents an important tool to understand processes as water and nutrient losses by drainage, or to test different conditions and scenarios of soil and crop management. Among the existing computational models to describe hydrological processes, SWAP (Soil, Water, Atmosphere and Plant model) has been successfully used under several conditions. This model was originally developed to simulate short cycle crops and its use also to cover longer cycles, e.g. perennial crops, is a new application. This report shows a SWAP application to a mature coffee crop over one-production cycle, focusing on deep drainage losses in a typical soil-plant-atmosphere system of the Brazilian savanna (Cerrado). The estimated annual deep drainage Q=. 1019. mm obtained by SWAP was within 99% of the value determined by the climatologic water balance of 1010. mm. Monthly results of SWAP for Q compared to the estimative using the climatological method presented a determination coefficient of 0.77. A variety of coffee fertigation scenarios were simulated using SWAP and compared to farmer's management scenario, leading to the conclusion that larger irrigation intervals result in lower Q losses, better water productivity and higher crop yield.