Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Optimum strip width increases dry matter, nutrient accumulation, and seed yield of intercrops under the relay intercropping system
    Raza, Muhammad Ali ; Feng, Ling Yang ; Werf, Wopke van der; Iqbal, Nasir ; Khan, Imran ; Khan, Ahsin ; Din, Atta Mohi Ud ; Naeem, Muhammd ; Meraj, Tehseen Ahmad ; Hassan, Muhammad Jawad ; Khan, Aaqil ; Lu, Feng Zhi ; Liu, Xin ; Ahmed, Mukhtar ; Yang, Feng ; Yang, Wenyu - \ 2020
    Food and Energy Security 9 (2020)2. - ISSN 2048-3694
    competition ratio - growing space - maize - relay intercropping - soybean

    Strip width management is a critical factor for producing higher crop yields in relay intercropping systems. A 2-year field experiment was carried out during 2012 and 2013 to evaluate the effects of different strip width treatments on dry-matter production, major-nutrient (nitrogen, phosphorus, and potassium) uptake, and competition parameters of soybean and maize in relay intercropping system. The strip width (SW) treatments were 0.40, 0.40, and 0.40 m (SW1); 0.40, 0.40, and 0.50 m (SW2); 0.40, 0.40, and 0.60 m (SW3); and 0.40, 0.40, and 0.70 m (SW4) for soybean row spacing, maize row spacing, and spacing between soybean and maize rows, respectively. As compared to sole maize (SM) and sole soybean (SS), relay-intercropped maize and soybean accumulated lower quantities of nitrogen, phosphorus, and potassium in all treatments. However, maize in SW1 accumulated higher nitrogen, phosphorus, and potassium than SW4 (9%, 9%, and 8% for nitrogen, phosphorus, and potassium, respectively). Soybean in SW3 accumulated 25% higher nitrogen, 33% higher phosphorus, and 24% higher potassium than in SW1. The improved nutrient accumulation in SW3 significantly increased the soybean dry matter by 19%, but slightly decreased the maize dry matter by 6% compared to SW1. Similarly, SW3 increased the competition ratio value of soybean (by 151%), but it reduced the competition ratio value of maize (by 171%) compared to SW1. On average, in SW3, relay-cropped soybean produced 84% of SS seed yield and maize produced 98% of SM seed yield and achieved the land equivalent ratio of 1.8, demonstrating the highest level in the world. Overall, these results suggested that by selecting the appropriate strip width (SW3; 0.40 m for soybean row spacing, 0.40 m maize row spacing, and 0.60 m spacing between soybean and maize rows), we can increase the nutrient uptake (especially nitrogen, phosphorus, and potassium), dry-matter accumulation, and seed yields of relay-intercrop species under relay intercropping systems.

    A treasure from the past: Modelling former sperm whale distribution with historical whaling data
    Sahri, Achmad ; Iqbal Herwata Putra, Muhammad ; Mustika, Putu Liza Kusuma ; Murk, A.J. - \ 2020
    In: Wias Annual Conference 2020. - WIAS - p. 50 - 50.
    Knowledge on the presence and habitat preference of cetaceans is important for conservation management in Indonesia. However, the records of current species occurrence covering all the country’s waters are lacking. A potential treasure trove in terms of whale presence is historical whaling data for sperm whale (data from 1761-1920, Charles HaskinsTownsend). Sperm whale is one of the most important species, and ubiquitous around equatorial Indonesia. A critical gap, however, is information about whale distribution, as historic data only depicts whaling points. First, we linked sperm whale historical whaling data to nine submerged topographic variables (bathy metry, slope, distance to- coast,-1000 m & -5000 m isobaths, seamount, shelf, trench, and trough) to determine habitat preference of sperm whale. Then, this relation was projected onto the study area. Both stepswere performed using habitat models, Maxent and Generalized Additive Model (GAM),providing whale distribution over seasons. Our results showed that Maxent predicted a wider area of distribution than GAM, and its distributions agreed best with the historical whaling data. Four areas in the eastern Indonesia were always identified as important habitats for sperm whales at any season, while in some locations at certain seasons, sperm whales did not occur. Conservation management e.g. marine protected areas and marine spatial planning in Indonesia should take into account this seasonal variability. Modern habitat models applied to historical whaling data can unveil historical sperm whale distribution and its seasonal differences. Our information can provide a baseline to assess presents perm whale distribution, prioritise current research and monitoring (future data collection),and contribute with recommendations to marine mammal conservation management in Indonesia.
    Optimum leaf defoliation: A new agronomic approach for increasing nutrient uptake and land equivalent ratio of maize soybean relay intercropping system
    Raza, Muhammad Ali ; Feng, Ling Yang ; Werf, Wopke van der; Iqbal, Nasir ; Khan, Imran ; Hassan, Muhammad Jawad ; Ansar, Muhammad ; Chen, Yuan Kai ; Xi, Zeng Jin ; Shi, Jian Yi ; Ahmed, Mukhtar ; Yang, Feng ; Yang, Wenyu - \ 2019
    Field Crops Research 244 (2019). - ISSN 0378-4290
    Defoliation - Economics - LER - Nutrient - Relay-intercropping

    Upper canopy leaves of maize decrease the light-transmittance at middle-strata-leaves of maize and soybean canopy in maize-soybean relay-intercropping systems (MS). This affects the uptake of nutrients and distribution patterns in various plant organs of intercrop species in MS. Judicious defoliation of maize plants in MS could help to alleviate this problem and improve nutrient uptake and intercrop yields. In a two-year field experiment with MS, including the measurements of biomass production, nutrients uptake, and distribution at the organ level, and grain yields of intercrop species, maize plants were subjected to four-leaf defoliation treatments to improve the light-transmittance of maize and soybean plants. Defoliation of the topmost two-leaves (T2), four-leaves (T4), six-leaves (T6) was compared to no defoliation (T0). Compared to T0, treatment T2 improved the uptake of nitrogen (N), phosphorus (P), and potassium (K) in each plant part of maize by 23, 12, and 11% (grain), 22, 19, and 13% (straw), and 28, 14, and 18% (root), respectively. Defoliation also enhanced the uptake of N, P, and K in each plant part of soybean by 5, 5, and 10% (grain), 10, 17, and 13% (straw), and 14, 11, and 11% (root), respectively. The improved nutrient uptake in T2 increased the total biomass and its distribution in the root, straw, and grain of soybean and maize by 15 and 13%, and 21 and 15%, 20 and 14%, 7 and 10%, respectively compared to T0. On average, over two years, under T2, relay-cropped maize obtained 107% of the sole-yield, and relay-cropped soybean obtained 65% of the sole-yield. The T2 defoliation treatment also achieved the highest land equivalent ratio of 1.69 and 1.77, with a net profit of 1301.6 $ ha−1 and 1293.4 $ ha−1 in 2017 and 2018, respectively. Following the optimum defoliation treatment of maize in maize-soybean intercrops, i.e., defoliation of the topmost two-leaves, the nutrient uptake can be increased, and the nutrient partitioning over plant organs be better balanced. Optimum defoliation, therefore, enhances the productivity of maize-soybean intercropping systems.

    Prospects of bioenergy cropping systems for a more social‐ecologically sound bioeconomy
    Cossel, Moritz Von ; Wagner, Moritz ; Lask, Jan ; Magenau, Elena ; Bauerle, Andrea ; Cossel, Viktoria Von ; Warrach‐Sagi, Kirsten ; Elbersen, Berien ; Staritsky, Igor ; Eupen, Michiel van; Iqbal, Yasir ; Jablonowski, Nicolai David ; Happe, Stefan ; Fernando, Ana Luisa ; Scordia, Danilo ; Cosentino, Salvatore Luciano ; Wulfmeyer, Volker ; Lewandowski, Iris ; Winkler, Bastian - \ 2019
    Agronomy 9 (2019)10. - ISSN 2073-4395
    Biodiversity - Bioeconomy - Bioenergy crop - Biomass - Carbon capture - Climate change adaptation - Cropping system - Industrial crop - Marginal land - Resilience

    The growing bioeconomy will require a greater supply of biomass in the future for both bioenergy and bio‐based products. Today, many bioenergy cropping systems (BCS) are suboptimal due to either social‐ecological threats or technical limitations. In addition, the competition for land between bioenergy‐crop cultivation, food‐crop cultivation, and biodiversity conservation is expected to increase as a result of both continuous world population growth and expected severe climate change effects. This study investigates how BCS can become more social‐ecologically sustainable in future. It brings together expert opinions from the fields of agronomy, economics, meteorology, and geography. Potential solutions to the following five main requirements for a more holistically sustainable supply of biomass are summarized: (i) bioenergy‐crop cultivation should provide a beneficial social‐ecological contribution, such as an increase in both biodiversity and landscape aesthetics, (ii) bioenergy crops should be cultivated on marginal agricultural land so as not to compete with food‐crop production, (iii) BCS need to be resilient in the face of projected severe climate change effects, (iv) BCS should foster rural development and support the vast number of small‐scale family farmers, managing about 80% of agricultural land and natural resources globally, and (v) bioenergy‐crop cultivation must be planned and implemented systematically, using holistic approaches. Further research activities and policy incentives should not only consider the economic potential of bioenergy‐crop cultivation, but also aspects of biodiversity, soil fertility, and climate change adaptation specific to site conditions and the given social context. This will help to adapt existing agricultural systems in a changing world and foster the development of a more social‐ecologically sustainable bioeconomy.

    Maize leaf-removal: A new agronomic approach to increase dry matter, flower number and seed-yield of soybean in maize soybean relay intercropping system
    Raza, Muhammad Ali ; Feng, Ling Yang ; Werf, Wopke van der; Iqbal, Nasir ; Khalid, Muhammad Hayder Bin ; Chen, Yuan Kai ; Wasaya, Allah ; Ahmed, Shoaib ; Ud Din, Atta Mohi ; Khan, Ahsin ; Ahmed, Saeed ; Yang, Feng ; Yang, Wenyu - \ 2019
    Scientific Reports 9 (2019)1. - ISSN 2045-2322 - 1 p.

    Shading conditions adversely affect flower-number and pod-number of soybeans under maize-soybean relay-intercropping (MSR). Here we reveal that leaf-removal from maize-canopy improves the photosynthetically active radiation (PAR) transmittance and dry-matter production (DMP) of soybean (especially during the co-growth phase), and compensates the maize seed-yield loss by considerably increasing soybean seed-yield. In a two-year experiment with MSR, maize-plants were subjected to different leaf-removal treatments to increase the PAR-transmittance of soybean; removal of the topmost two-leaves (R2), four-leaves (R4), six-leaves (R6), with no-removal of leaves (R0). Leaf-removal treatments improved the PAR-transmittance, photosynthetic-rate, and morphological-characteristics of soybean under MSR. At 90 days after sowing, the dry-matter of pods, and seeds was increased by 25%, and 32%, respectively under R6 than R0. Importantly, enhanced PAR-transmittance and DMP under R6 enabled soybean to initiate a greater number of flowers 182.2 plant-1 compared to 142.7 plant-1 under R0, and it also decreased the flower-abscission (by 13%, from 54.9% under R0 to 47.6% under R6). These positive responses increased the pod-number by 49% and seed-number by 28% under R6 than R0. Overall, under R6, relay-intercropped soybean produced 78% of sole-soybean seed-yield, and relay-intercropped maize produced 81% of sole-maize seed-yield and achieved the land equivalent ratio of 1.59.

    Narrow-wide-row planting pattern increases the radiation use efficiency and seed yield of intercrop species in relay-intercropping system
    Raza, Muhammad Ali ; Feng, Ling Yang ; Werf, Wopke van der; Cai, Gao Ren ; Khalid, Muhammad Hayder Bin ; Iqbal, Nasir ; Hassan, Muhammad Jawad ; Meraj, Tehseen Ahmad ; Naeem, Muhammd ; Khan, Imran ; Ur Rehman, Sana ; Ansar, Muhammad ; Ahmed, Mukhtar ; Yang, Feng ; Yang, Wenyu - \ 2019
    Food and Energy Security 8 (2019)3. - ISSN 2048-3694
    competition - intercropping - land equivalent ratio - radiation use efficiency

    Planting arrangements affect radiation use efficiency (RUE) and competitiveness of intercrop species in intercropping systems. Here, we reveal that narrow-wide-row planting arrangement in maize-soybean relay-intercropping system increases the dry matter and competitiveness of soybean, increased the RUE of maize and soybean, and compensates the yield loss of maize by substantially increasing the yield of soybean. In this field study, maize was planted with soybean in different planting arrangements (P1, 20:180, P2, 40:160; P3, 60:140, and P4, 80:120) of relay intercropping, all the relay-intercropping treatments were compared with sole crops of maize (SM) and soybean (SS). Results showed that P1 improved the total RUE 3.26 g/MJ (maize RUE + soybean RUE) of maize and soybean in relay-intercropping system. Compared to P4, treatment P1 increased the soybean competition ratio (CR) values (by 55%) but reduced the maize CR values (by 29%), which in turn significantly improved the yield of soybean by maintaining the maize yield. Generally, in P1, soybean produced 82% of SS yield, and maize produced 88% of SM yield, and it achieved the land equivalent ratio of 1.7. These results suggest that by maintaining the appropriate planting distances between maize and soybean we can improve the competitiveness and yield of intercrop species in relay-intercropping system.

    Marginal agricultural land low-input systems for biomass production
    Cossel, Moritz Von ; Lewandowski, Iris ; Elbersen, Berien ; Staritsky, Igor ; Eupen, Michiel Van; Iqbal, Yasir ; Mantel, Stefan ; Scordia, Danilo ; Testa, Giorgio ; Cosentino, Salvatore Luciano ; Maliarenko, Oksana ; Eleftheriadis, Ioannis ; Zanetti, Federica ; Monti, Andrea ; Lazdina, Dagnija ; Neimane, Santa ; Lamy, Isabelle ; Ciadamidaro, Lisa ; Sanz, Marina ; Carrasco, Juan Esteban ; Ciria, Pilar ; McCallum, Ian ; Trindade, Luisa M. ; Loo, Eibertus N. Van; Elbersen, Wolter ; Fernando, Ana Luisa ; Papazoglou, Eleni G. ; Alexopoulou, Efthymia - \ 2019
    Energies 12 (2019)16. - ISSN 1996-1073
    Bio-based industry - Bioeconomy - Bioenergy - Biomass - Industrial crop - Low-input agriculture - MALLIS - Marginal land - Perennial crop - Sustainable agriculture

    This study deals with approaches for a social-ecological friendly European bioeconomy based on biomass from industrial crops cultivated on marginal agricultural land. The selected crops to be investigated are: Biomass sorghum, camelina, cardoon, castor, crambe, Ethiopian mustard, giant reed, hemp, lupin, miscanthus, pennycress, poplar, reed canary grass, safflower, Siberian elm, switchgrass, tall wheatgrass, wild sugarcane, and willow. The research question focused on the overall crop growth suitability under low-input management. The study assessed: (i) How the growth suitability of industrial crops can be defined under the given natural constraints of European marginal agricultural lands; and (ii) which agricultural practices are required for marginal agricultural land low-input systems (MALLIS). For the growth-suitability analysis, available thresholds and growth requirements of the selected industrial crops were defined. The marginal agricultural land was categorized according to the agro-ecological zone (AEZ) concept in combination with the marginality constraints, so-called 'marginal agro-ecological zones' (M-AEZ). It was found that both large marginal agricultural areas and numerous agricultural practices are available for industrial crop cultivation on European marginal agricultural lands. These results help to further describe the suitability of industrial crops for the development of social-ecologically friendly MALLIS in Europe.

    The impact of socio-economic development and climate change on E. coli loads and concentrations in Kabul River, Pakistan
    Iqbal, Muhammad Shahid ; Islam, M.M.M. ; Hofstra, Nynke - \ 2019
    Science of the Total Environment 650 (2019). - ISSN 0048-9697 - p. 1935 - 1943.
    Bacterial modelling - Escherichia coli - Global change - Hydrological modelling - Scenario analysis

    Microbial pollution is a major problem worldwide. High concentrations of Escherichia coli have been found in Kabul River in Pakistan. E. coli concentrations vary under different socio-economic conditions, such as population and livestock densities, urbanisation, sanitation and treatment of wastewater and manure, and climate-change aspects, such as floods and droughts. In this paper, we assess potential future E. coli loads and concentrations in the Kabul River using the Soil and Water Assessment Tool with scenarios that are based on the most recent Shared Socio-economic Pathways and Representative Concentration Pathways (SSPs and RCPs) developed for the Intergovernmental Panel on Climate Change (IPCC). Scenario_1 considers moderate population and livestock density growth, planned urbanisation and strongly improved wastewater and manure treatment (based on SSP1, “Sustainability”), and moderate climate change (RCP4.5, moderate greenhouse gas (GHG) emissions). Scenario_2 considers strong population and livestock density growth, moderate urbanisation, slightly improved wastewater treatment, no manure treatment (based on SSP3, “Regional rivalry”) and strong climate change (RCP8.5, high GHG emissions). Simulated E. coli responses to Scenario_2 suggest a mid-century increase in loads by 111% and a late century increase of 201% compared to baseline loads. Similarly, simulated E. coli loads are reduced by 60% for the mid-century and 78% for the late century compared to the baseline loads. When additional treatment is simulated in Scenario_1, the loads are reduced even further by 94%, 92% and 99.3% compared to the baseline concentrations when additional tertiary treatment, manure treatment or both have been applied respectively. This study is one of the first to apply combined socio-economic development and climate change scenario analysis with an E. coli concentration model to better understand how these concentrations may change in the future. The scenario analysis shows that reducing E. coli concentrations in Pakistan's rivers is possible, but requires strongly improved waste water treatment and manure management measures.

    Modeling Escherichia coli fate and transport in the Kabul River Basin using SWAT
    Iqbal, Muhammad Shahid ; Hofstra, Nynke - \ 2019
    Human and Ecological Risk Assessment 25 (2019)5. - ISSN 1080-7039 - p. 1279 - 1297.
    E. coli contamination - fate and transport - Kabul River Basin - SWAT model - water quality modeling

    Access to safe water is the primary goal of all development plans, yet population increase, urbanization lead to contamination of water resources. This paper focuses on microbial contamination and aims to analyze the fate and transport of Escherichia coli in the Kabul River Basin using SWAT model to evaluate the contribution of different sources. The SWAT is calibrated and validated for the monthly time step using observed E. coli concentrations for April 2013–July 2015. The model skill score; coefficients of determination (R2) equal 0.72 and 0.70, Nash–Sutcliffe efficiencies (NSE) equal 0.69 and 0.66, and percentages bias (PBIAS) equal 3.7 and 1.9 respond well for both calibration and validation, respectively. Regional measured and modeled concentrations are very high with peaks of up to 5.2 10log cfu/100 ml in the wet season. Overall, point sources that are comprised of human feces from the big cities and livestock manure from animal sheds, contribute most (44%) to the E. coli concentrations. During peak discharge the non-point sources become the most important contributors due to wash-off from the land and diluted point sources. Allthough such studies are lacking in developing countries, they can be helpful for sanitation management by developing and accessing regional sanitation scenarios.

    Potential for re-emergence of wheat stem rust in the United Kingdom
    Lewis, Clare M. ; Persoons, Antoine ; Bebber, Daniel P. ; Kigathi, Rose N. ; Maintz, Jens ; Findlay, Kim ; Bueno-Sancho, Vanessa ; Corredor-Moreno, Pilar ; Harrington, Sophie A. ; Kangara, Ngonidzashe ; Berlin, Anna ; García, Richard ; Germán, Silvia E. ; Hanzalová, Alena ; Hodson, David P. ; Hovmøller, Mogens S. ; Huerta-Espino, Julio ; Imtiaz, Muhammed ; Mirza, Javed Iqbal ; Justesen, Annemarie F. ; Niks, Rients E. ; Omrani, Ali ; Patpour, Mehran ; Pretorius, Zacharias A. ; Roohparvar, Ramin ; Sela, Hanan ; Singh, Ravi P. ; Steffenson, Brian ; Visser, Botma ; Fenwick, Paul M. ; Thomas, Jane ; Wulff, Brande B.H. ; Saunders, Diane G.O. - \ 2018
    Communications Biology 1 (2018)1. - ISSN 2399-3642

    Wheat stem rust, a devastating disease of wheat and barley caused by the fungal pathogen Puccinia graminis f. sp. tritici, was largely eradicated in Western Europe during the mid-to-late twentieth century. However, isolated outbreaks have occurred in recent years. Here we investigate whether a lack of resistance in modern European varieties, increased presence of its alternate host barberry and changes in climatic conditions could be facilitating its resurgence. We report the first wheat stem rust occurrence in the United Kingdom in nearly 60 years, with only 20% of UK wheat varieties resistant to this strain. Climate changes over the past 25 years also suggest increasingly conducive conditions for infection. Furthermore, we document the first occurrence in decades of P. graminis on barberry in the UK. Our data illustrate that wheat stem rust does occur in the UK and, when climatic conditions are conducive, could severely harm wheat and barley production.

    Impact of climate change on flood frequency and intensity in the kabul river basin
    Iqbal, Muhammad Shahid ; Dahri, Zakir Hussain ; Querner, Erik P. ; Khan, Asif ; Hofstra, Nynke - \ 2018
    Geosciences 8 (2018)4. - ISSN 2076-3263
    Climate-change - Floods - GCMs - HEC-SSP - Kabul basin - SWAT model
    Devastating floods adversely affect human life and infrastructure. Various regions of the Hindukush-Karakoram-Himalayas receive intense monsoon rainfall, which, together with snow and glacier melt, produce intense floods. The Kabul river basin originates from the Hindukush Mountains and is frequently hit by such floods. We analyses flood frequency and intensity in Kabul basin for a contemporary period (1981-2015) and two future periods (i.e., 2031-2050 and 2081-2100) using the RCP4.5 and RCP8.5 scenarios based on four bias-corrected downscaled climate models (INM-CM4, IPSL-CM5A, EC-EARTH, and MIROC5). Future floods are modelled with the SWAT hydrological model. The model results suggest an increasing trend due to an increasing precipitation and higher temperatures (based on all climate models except INM-CM4), which accelerates snow and glacier-melt. All of the scenario results show that the current flow with a 1 in 50 year return period is likely to occur more frequently (i.e., 1 in every 9-10 years and 2-3 years, respectively) during the near and far future periods. Such increases in intensity and frequency are likely to adversely affect downstream population and infrastructures. This, therefore, urges for appropriate early precautionary mitigation measures. This study can assist water managers and policy makers in their preparation to adequately plan for and manage flood protection. Its findings are also relevant for other basins in the Hindukush-Karakoram-Himalayas region.
    Modelling the impact of future socio-economic and climate change scenarios on river microbial water quality
    Islam, M.M.M. ; Iqbal, Muhammad Shahid ; Leemans, Rik ; Hofstra, Nynke - \ 2018
    International Journal of Hygiene and Environmental Health 221 (2018)2. - ISSN 1438-4639 - p. 283 - 292.
    Climate change - Faecal indicator bacteria - Modelling - RCPs - Socio-economic development - SSPs
    Microbial surface water quality is important, as it is related to health risk when the population is exposed through drinking, recreation or consumption of irrigated vegetables. The microbial surface water quality is expected to change with socio-economic development and climate change. This study explores the combined impacts of future socio-economic and climate change scenarios on microbial water quality using a coupled hydrodynamic and water quality model (MIKE21FM-ECOLab). The model was applied to simulate the baseline (2014-2015) and future (2040s and 2090s) faecal indicator bacteria (FIB: E. coli and enterococci) concentrations in the Betna river in Bangladesh. The scenarios comprise changes in socio-economic variables (e.g. population, urbanization, land use, sanitation and sewage treatment) and climate variables (temperature, precipitation and sea-level rise). Scenarios have been developed building on the most recent Shared Socio-economic Pathways: SSP1 and SSP3 and Representative Concentration Pathways: RCP4.5 and RCP8.5 in a matrix. An uncontrolled future results in a deterioration of the microbial water quality (+75% by the 2090s) due to socio-economic changes, such as higher population growth, and changes in rainfall patterns. However, microbial water quality improves under a sustainable scenario with improved sewage treatment (-98% by the 2090s). Contaminant loads were more influenced by changes in socio-economic factors than by climatic change. To our knowledge, this is the first study that combines climate change and socio-economic development scenarios to simulate the future microbial water quality of a river. This approach can also be used to assess future consequences for health risks.
    The Relationship between Hydro-Climatic Variables and E. coli Concentrations in Surface and Drinking Water of the Kabul River Basin in Pakistan
    Shahid Iqbal, Muhammad ; Nauman Ahmad, Muhammad ; Hofstra, Nynke - \ 2017
    AIMS Environmental Science 4 (2017)5. - ISSN 2372-0344 - p. 690 - 708.
    Microbial water contamination is a risk for human health, as it causes waterborne diseases like diarrhea. E. coli is a faecal indicator microorganism. Climate variables, such as temperature and precipitation, influence E. coli concentrations in surface and drinking water resources. We measure and statistically analyse E. coli concentrations in drinking and surface water in the Kabul River Basin. E. coli concentrations are very high in the basin. Drinking and bathing water standards are violated. Water temperature, surface air temperature, discharge and precipitation were positively correlated with E. coli concentrations. Precipitation induced runoff transports of E. coli from agricultural lands to Kabul River and high temperature coincides with high precipitation and discharge. A linear regression model was developed to assess the net effect of the climate variables on E. coli concentrations. We found that climate variables accounted for more than half of the observed variation in E. coli concentrations in surface (R2 = 0.61) and drinking water (R2 = 0.55). This study indicates that increased precipitation together with higher surface air temperature, as expected in this region with climate change, were significantly correlated with increased E. coli concentrations in the future. Waterborne pathogens are expected to respond similarly to hydro-climatic changes, indicating that disease outbreaks could well become more frequent and severe.
    A light-weight hyperspectral mapping system for unmanned aerial vehicles - The first results
    Suomalainen, Juha ; Anders, Niels ; Iqbal, Shahzad ; Franke, Jappe ; Wenting, Philip ; Bartholomeus, Harm ; Becker, Rolf ; Kooistra, Lammert - \ 2017
    In: 5th Workshop on Hyperspectral Image and Signal Processing. - IEEE computer society - ISBN 9781509011209 - 4 p.
    DSM - Hyperspectral - Orthoimage - UAV
    Research opportunities using UAV remote sensing techniques are limited by the payload of the platform. Therefore small UAV's are typically not suitable for hyperspectral imaging due to the weight of the mapping system. In this research, we are developing a light-weight hyperspectral mapping system (< 2 kg) suitable to be mounted on small UAVs. The system is able to produce georeferenced and georectified hyperspectral data cubes in 400-1000nm spectral range at 10-50cm resolution. The georeferenced reflectance factor spectra cubes are to be used in e.g. precision agriculture and soil erosion research. In this paper we describe prototype of the system, the processing chain, and present preliminary results.
    Quantifying the impact of socioeconomic development and climate change on Escherichia coli concentrations in the Pakistani Kabul River
    Iqbal, Shahid - \ 2017
    Wageningen University. Promotor(en): Rik Leemans, co-promotor(en): Nynke Hofstra. - Wageningen : Wageningen University - ISBN 9789463434478 - 183
    escherichia coli - rivers - climatic change - socioeconomics - water quality - regression analysis - water pollution - health - escherichia coli - rivieren - klimaatverandering - sociale economie - waterkwaliteit - regressieanalyse - waterverontreiniging - gezondheid

    Clean water is indispensable for the sustenance of life and maintenance of health. However, water quality is threatened by changes in socio-economic developments (population growth, urbanisation, livestock increase and sanitation) and climate (surface air temperature and precipitation patterns). Major water quality contaminants include microorganisms, such as fecal coliforms, Escherichia Coli (E.coli) and pathogens. Microbial contamination poses serious health risks in developing countries like Pakistan, where people do not have access to clean water due to lack of waste water treatment and thorough manure management. Therefore, to reduce the present and future health risk, it is important to understand the impacts of socio-economic development and climate-change on microbial fate and transport in surface water resources in the Kabul River Basin in Pakistan.

    The objective of this study is quantifying the impact of socio-economic development and climate change on E.coli concentrations in the Pakistani Kabul River. To reach the objective, I sampled E.coli concentrations at several locations in Kabul River, applied statistical and process based modelling, developed future global change scenarios and analysed the impact of these scenarios on E.coli concentrations. I focus on E.coli rather than pathogens, because sampling of pathogens and its chemical analysis are expensive. Kabul River Basin is a tributary of the Indus river and is located in the Hindukush-Karakoram-Himalayas (HKH) and suffers from floods every year. The population suffers from a high risk of waterborne diseases. The water is contaminated by direct sewage inputs from large cities, like Peshawar, direct manure inputs from animal sheds along the river and indirect manure inputs from the land.

    Kabul River Basin is subjected to hazardous levels of microbiological pollution. The concentration of micro-organisms is influenced by hydro-climatic variables, such as water and surface air temperature, precipitation and discharge. However, the net effect of these variables remains thus far unclear. High concentrations of E.coli were found in the main stream and its tributaries (Chapter 2). Samples were collected along the Kabul river and drinking water samples from the city of Nowshera (April 2013 to July 2015) and all surface water samples violate the bathing water criteria and all drinking water samples violate the drinking water criteria. The correlation between hydro-climatic variables and E.coli concentration was analysed. Water temperature and surface air temperature were positively correlated, most likely because high temperatures coincide with high precipitation and discharge. Precipitation and river discharge data were also positively correlated with E.coli concentrations. This shows that precipitation, which increases the surface runoff, transports E.coli and other waterborne pathogens to the river nearby (correlation with precipitation) and further upstream (correlation with discharge). A regression model was also applied that explained 61% of the E.coli variability in surface water and 55% of E.coli variability in drinking water resources, even when other factors, such as location and land-use variables are ignored (Chapter 2).

    To better understand the hydrology in the basin, the current and future flows of Kabul river were modelled using the Soil and Water Assessment Tool (SWAT), which serves as a basis for the process-based E.coli model. Flash floods occur every year in the basin as a result of increased discharge due to snow and glacier melt together with monsoon precipitation. The Kabul River Basin is one of the most vulnerable regional basin to climate change. The hydrological model was calibrated and validated for the full Kabul River Basin and performed well (NSE equals 0.77 and 0.72 respectively). Flood frequency and expected return period were analysed for a contemporary period (1981-2000) and two future periods (i.e. 2031-2050 and 2081-2100) using the Representative Concentration Pathway (RCP) 4.5 and RCP8.5 scenarios based on four bias-corrected downscaled climate models (Chapter 3). The flood frequency analysis shows that the present day’s one-in-a-fifty year event could occur between once in every 3 year (EC-EARTH and MIROC climate-models) and once in every 24 years (IPSL climate-model). This study presents climate-change impact assessment in the Kabul River Basin. The selected approach is in general well accepted in the scientific community and the results can be useful in flood management in the region. Outcomes of this study can be helpful for regions that have similar hydro-climatological conditions.

    To better understand the fate and transport of bacteria from land to water resources and to assess source contribution, the SWAT model was calibrated and validated for E.coli. Our study is the first bacterial modelling study for the Kabul River Basin (Chapter 4). The simulated concentrations have slightly lower variability than the observed concentrations. The model performance could be improved further by using more input E.coli data, but the current model results agree well enough with our measured E.coli concentrations (NSE equals 0.69 and 0.66 for calibration and validation respectively). Based on the pathogen source estimations, point (direct) sources are identified to be the most important microbial pollution sources. Pollution from upstream areas is also important, while non-point (diffuse) sources play a role mostly during the periods with high discharge. Our study underlines the importance of wastewater treatment and manure management both in and upstream of the study area. Studies like ours were lacking in developing countries like Pakistan and can be used for scenario analyses in the region (Chapter 4). The model can be useful in microbial water quality assessments in other watersheds and for pathogenic microorganisms, such as Cryptosporidium and Rotavirus.

    The calibrated and validated SWAT bacterial model (Chapter 4) was used to assess E.coli concentrations in a comprehensive scenario analysis (Chapter 5). We developed two future scenarios based on state-of-the-art approaches, using the Shared Socio-economic Pathways (SSPs), RCPs and own assumptions in line with the SSP storylines. We took the modelled E.coli concentrations from Chapter 4 as baseline scenarios and defines two future scenarios as Scenario_1 (sustainability scenario) and Scenario_2 (uncontrolled scenario). These scenarios represent different socio-economic development and climate change. The two scenarios were developed by combining SSP1, a sustainable, equitable and environmentally focussed world with RCP4.5 (limed climate change) in Scenario_1, and SSP3 (a divided world, with no interest in the environment) with RCP8.5 (strong climate change) in Scenario_2. Currently, no wastewater treatment plant exists in the basin, because the 2010 floods destroyed the available plants. We assumed excellent and poor wastewater and manure treatment for 2050s and 2100s for Scenario_1 and Scenario_2 respectively, in line with the storylines. Scenario_2 resulted in higher E.coli concentrations compared to the baseline scenarios due to high population growth, poor wastewater and manure treatment and land-use changes. However, microbial water quality was found to improve under Scenario_1. This was achieved by implementing improved and technologically advanced wastewater treatment and manure management. Future concentrations were found to be between 0.6% and 7% of the baseline concentrations depending on the treatment technology used (Chapter 5). This study highlights the need for substantial improvements in wastewater and manure treatment systems in the Kabul River Basin to assure future E.coli concentrations in water sources will be within the limits of WHO and US-EPA regulations for drinking and bathing water quality. The primary treatment facility that is currently installed is a good start, but insufficient to strongly reduce concentrations. Hence major investments are required to install technologically advanced wastewater treatment and manure treatment plants to cut-down the current contamination level of Kabul river.

    My PhD thesis provides a base for devising optimal coping strategies that are essential for the sustainability of hydrological resources under socio-economic developments and climate-change impacts. The results of our research are helpful to further assess alternative water quality management options. The outcomes of this study also increase the knowledge in the field of microbial fate and transport in water resources in a developing country like Pakistan, where such studies are lacking. A limited number of previous studies on global change impacts on microbial contamination of surface water in other areas of the world focused only on the climate-change impacts on microbial water quality. This is the first study to evaluate the influence of combined socio-economic and climate-change impacts on E.coli concentrations in the Kabul River Basin. The developed SWAT model and scenario analysis can be used for other contaminants, such as nutrients, pesticides and heavy metals. Our study can be a first step to improve water quality of the Kabul River Basin by providing tools for water managers and health specialists to improve the water quality and reduce the risks related to the use of contaminated water resources. This study will be useful not only in this region, but also for other regions of the world with similar microbial water contamination issues.

    Environmental influences on the growing season duration and ripening of diverse Miscanthus germplasm grown in six countries
    Nunn, Christopher ; Hastings, Astley Francis St John ; Kalinina, Olena ; Özgüven, Mensure ; Schüle, Heinrich ; Tarakanov, Ivan G. ; Weijde, Tim van der; Anisimov, Aleksander A. ; Iqbal, Yasir ; Kiesel, Andreas ; Khokhlov, Nikolay F. ; McCalmont, Jon P. ; Meyer, Heike ; Mos, Michal ; Schwarz, Kai Uwe ; Trindade, Luisa M. ; Lewandowski, Iris ; Clifton-Brown, John - \ 2017
    Frontiers in Plant Science 8 (2017). - ISSN 1664-462X - 14 p.
    Miscanthus - Modeling - Multi-location - Ripening - Senescence

    The development of models to predict yield potential and quality of a Miscanthus crop must consider climatic limitations andthe duration of growing season. As a biomass crop, yield and quality are impacted by the timing of plant developmental transitions such as flowering andsenescence. Growth models are available for the commercially grown clone Miscanthus x giganteus (Mxg), but breeding programs have been working to expand the germplasmavailable, including development of interspecies hybrids. The aimof this study was to assess the performance of diverse germplasmbeyond the range of environments considered suitable for a Miscanthus crop to be grown. To achieve this, six field sites were planted as part of the EU OPTIMISC project in 2012 in a longitudinal gradient from West to East: Wales—Aberystwyth, Netherlands—Wageningen, Stuttgart—Germany, Ukraine—Potash, Turkey—Adana, and Russia—Moscow. Each field trial contained three replicated plots of the same 15 Miscanthus germplasmtypes. Through the 2014 growing season, phenotypic traits were measured to determine the timing of developmental stages key to ripening; the tradeoff between growth (yield) and quality (biomass ash and moisture content). The hottest site (Adana) showed an accelerated growing season, with emergence, flowering and senescence occurring before the other sites. However, the highest yields were produced at Potash, where emergence was delayed by frost and the growing season was shortest. Flowering triggers varied with species and only in Mxg was strongly linked to accumulated thermal time. Our results show that a prolonged growing season is not essential to achieve high yields if climatic conditions are favorable and in regions where the growing season is bordered by frost, delaying harvest can improve quality of the harvested biomass.

    Extending miscanthus cultivation with novel germplasm at six contrasting sites
    Kalinina, Olena ; Nunn, Christopher ; Sanderson, Ruth ; Hastings, Astley F.S. ; Weijde, Tim van der; Özgüven, Mensure ; Tarakanov, Ivan ; Schüle, Heinrich ; Trindade, Luisa M. ; Dolstra, Oene ; Schwarz, Kai Uwe ; Iqbal, Yasir ; Kiesel, Andreas ; Mos, Michal ; Lewandowski, Iris ; Clifton-Brown, John C. - \ 2017
    Frontiers in Plant Science 8 (2017). - ISSN 1664-462X
    Establishment - Marginal land - Miscanthus - Multi-location field trials - Novel hybrids - Productivity

    Miscanthus is a genus of perennial rhizomatous grasses with C4 photosynthesis which is indigenous in a wide geographic range of Asian climates. The sterile clone, Miscanthus × giganteus (M. × giganteus), is a naturally occurring interspecific hybrid that has been used commercially in Europe for biomass production for over a decade. Although, M. × giganteus has many outstanding performance characteristics including high yields and low nutrient offtakes, commercial expansion is limited by cloning rates, slow establishment to a mature yield, frost, and drought resistance. In this paper, we evaluate the performance of 13 novel germplasm types alongside M. × giganteus and horticultural “Goliath” in trials in six sites (in Germany, Russia, The Netherlands, Turkey, UK, and Ukraine). Mean annual yields across all the sites and genotypes increased from 2.3 ± 0.2 t dry matter ha−1 following the first year of growth, to 7.3 ± 0.3, 9.5 ± 0.3, and 10.5 ± 0.2 t dry matter ha−1 following the second, third, and fourth years, respectively. The highest average annual yields across locations and four growth seasons were observed for M. × giganteus (9.9 ± 0.7 t dry matter ha−1) and interspecies hybrid OPM-6 (9.4 ± 0.6 t dry matter ha−1). The best of the new hybrid genotypes yielded similarly to M. × giganteus at most of the locations. Significant effects of the year of growth, location, species, genotype, and interplay between these factors have been observed demonstrating strong genotype × environment interactions. The highest yields were recorded in Ukraine. Time needed for the crop establishment varied depending on climate: in colder climates such as Russia the crop has not achieved its peak yield by the fourth year, whereas in the hot climate of Turkey and under irrigation the yields were already high in the first growing season. We have identified several alternatives to M. × giganteus which have provided stable yields across wide climatic ranges, mostly interspecies hybrids, and also Miscanthus genotypes providing high biomass yields at specific geographic locations. Seed-propagated interspecific and intraspecific hybrids, with high stable yields and cheaper reliable scalable establishment remain a key strategic objective for breeders.

    Site-specific management of miscanthus genotypes for combustion and anaerobic digestion : A comparison of energy yields
    Kiesel, Andreas ; Nunn, Christopher ; Iqbal, Yasir ; Weijde, Tim Van der; Wagner, Moritz ; Özgüven, Mensure ; Tarakanov, Ivan ; Kalinina, Olena ; Trindade, Luisa M. ; Clifton-Brown, John ; Lewandowski, Iris - \ 2017
    Frontiers in Plant Science 8 (2017). - ISSN 1664-462X
    Biogas - Biomass - Energy yield - Harvest time - Moisture content - Substrate-specific methane yield - Yield
    In Europe, the perennial C4 grass miscanthus is currently mainly cultivated for energy generation via combustion. In recent years, anaerobic digestion has been identified as a promising alternative utilization pathway. Anaerobic digestion produces a higher-value intermediate (biogas), which can be upgraded to biomethane, stored in the existing natural gas infrastructure and further utilized as a transport fuel or in combined heat and power plants. However, the upgrading of the solid biomass into gaseous fuel leads to conversion-related energy losses, the level of which depends on the cultivation parameters genotype, location, and harvest date. Thus, site-specific crop management needs to be adapted to the intended utilization pathway. The objectives of this paper are to quantify (i) the impact of genotype, location and harvest date on energy yields of anaerobic digestion and combustion and (ii) the conversion losses of upgrading solid biomass into biogas. For this purpose, five miscanthus genotypes (OPM 3, 6, 9, 11, 14), three cultivation locations (Adana, Moscow, Stuttgart), and up to six harvest dates (August-March) were assessed. Anaerobic digestion yielded, on average, 35% less energy than combustion. Genotype, location, and harvest date all had significant impacts on the energy yield. For both, this is determined by dry matter yield and ash content and additionally by substrate-specific methane yield for anaerobic digestion and moisture content for combustion. Averaged over all locations and genotypes, an early harvest in August led to 25%and a late harvest to 45%conversion losses. However, each utilization option has its own optimal harvest date, determined by biomass yield, biomass quality, and cutting tolerance. By applying an autumn green harvest for anaerobic digestion and a delayed harvest for combustion, the conversion-related energy loss was reduced to an average of 18%. This clearly shows that the delayed harvest required tomaintain biomass quality for combustion is accompanied by high energy losses through yield reduction over winter. The pre-winter harvest applied in the biogas utilization pathway avoids these yield losses and largely compensates for the conversion-related energy losses of anaerobic digestion.
    Evaluation of Miscanthus sinensis biomass quality as feedstock for conversion into different bioenergy products
    Weijde, Tim van der; Kiesel, Andreas ; Iqbal, Yasir ; Muylle, Hilde ; Dolstra, Oene ; Visser, Richard G.F. ; Lewandowski, Iris ; Trindade, Luisa M. - \ 2017
    Global change biology Bioenergy 9 (2017)1. - ISSN 1757-1693 - p. 176 - 190.
    Miscanthus sinensis - Anaerobic digestion - Bioethanol - Biogas - Biomass quality - Cell wall composition - Combustion - Enzymatic saccharification - Lignin

    Miscanthus is a promising fiber crop with high potential for sustainable biomass production for a biobased economy. The effect of biomass composition on the processing efficiency of miscanthus biomass for different biorefinery value chains was evaluated, including combustion, anaerobic digestion and enzymatic saccharification for the production of bioethanol. Biomass quality and composition was analyzed in detail using stem and leaf fractions of summer (July) and winter (March) harvested biomass of eight compositionally diverse Miscanthus sinensis genotypes. Genotype performance in tests for enzymatic saccharification, anaerobic digestion and combustion differed extensively. The variation between the best and the worst performing genotype was 18% for biogas yield (ml g-1 dm) and 42% for saccharification efficiency (glucose release as %dm). The ash content of the best performing genotype was 62% lower than that of the genotype with the highest ash content and showed a considerably high ash melting temperature during combustion. Variation between genotypes in biomass quality for the different thermochemical bioconversion processes was shown to be strongly correlated to differences in biomass composition. The most important traits that contributed favorably to biogas yields and saccharification efficiency were a high content of trans-ferulic acid, a high ratio of para-coumaric acid to lignin and a low lignin content. Additionally, a high content of hemicellulosic polysaccharides positively affected saccharification efficiency. Low contents of ash and inorganic elements positively affect biomass quality for combustion and low potassium and chloride contents contributed to a higher ash melting temperature. These results demonstrate the potential for optimizing and exploiting M. sinensis as a multipurpose lignocellulosic feedstock, particularly for bioenergy applications.

    Biomonitoring of fluoride pollution with gladiolus in the vicinity of a brick kiln field in Lahore, Pakistan
    Ullah, Kifayat ; Saeed Ahmad, S. ; Nauman Ahmad, M. ; Khan, Sardar ; Urooj, Rabail ; Shahid Iqbal, M. ; Zia, Afia ; Ahmad Khan, N. - \ 2016
    Fluoride 49 (2016)3. - ISSN 0015-4725 - p. 245 - 252.
    Biomonitoring - Brick kilns - Fluoride - Gladiolus - Pakistan - South Asia

    Although there are thousands of small-scale, poorly regulated brick kilns in rural areas of South Asia their impact on local agricultural crops is largely unknown. The impact of fluoride on crops in a brick kiln area in the Northern Punjab Region of Pakistan was investigated. Fluoride accumulation, leaf necrosis, and reduced corm diameter and weight were found in the brick kiln area in two cultivars of Gladiolus that have been widely used as biomonitors in Europe. The rate of increase in leaf injury of the sensitive Gladiolus cultivar was greatest at all sites when the temperature was lower and there was a high relative humidity of 60–75%. The necrotic leaf tip lengths of the indicator plants correlated very well with their fluoride concentrations. The fluoride accumulation was directly proportional to the Fluoride Injury Index, although a higher injury index was observed with the fluoride-sensitive cultivar Lavendell Puff compared to the fluoride-tolerant cultivar Flower Song. These results suggest that injury to sensitive crops from fluoride may occur in other brick kiln areas in South Asia, and that Gladiolus plants could be used as a cost-effective biomonitor for further investigation in this region.

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