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.

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Are you being a sustainable tourist in a luxury resort? | WURcast
Kok, K. - \ 2017
Wageningen :
water use - tourism impact - tourism - sustainable tourism
Water use in a heavily urbanized delta : scenarios and adaptation options for sectorial water use in the Pearl River Basin, China
Yao, Mingtian - \ 2017
Wageningen University. Promotor(en): Pavel Kabat, co-promotor(en): Saskia Werners; Ronald Hutjes; Huang Heqing. - Wageningen : Wageningen University - ISBN 9789463438230 - 175
water use - water management - water resources - socioeconomics - salt water intrusion - water deficit - china - watergebruik - waterbeheer - watervoorraden - sociale economie - zoutwaterindringing - watertekort

Water use is increasing globally to meet the growing demand for food and industrial products, and the rising living standard. Water scarcity has been reported in many regions, questioning the long-term sustainability of water use. The objective of this thesis is to better understand sectorial water use development in an urbanizing river delta, and to explore the potential of water use management as an adaptation option to reduce water shortage. The Pearl River Basin in Southern China is taken as study area. The upstream part of the basin is one of the poorer regions of China, whereas the Pearl River Delta (PRD) is the world’s largest urban region in both population and area. This study presents the first consistent analysis of sectorial water use in the PRD. Results show that during the period of 2000-2010, the PRD managed to stabilize its annual total water use. Nevertheless, severe salt intrusion induced water shortages occur. Assessment of water use at a monthly resolution shows that water use contributes to salt intrusion by further reducing the already low dry season river discharge.

To investigate the possible future development of water use, this study proposed a method to derive region specific water use scenarios from a global assessment of water use. Scenarios based on regionalised assumptions project substantially lower water use than those based on national assumptions. Nevertheless, hydrological challenges remain for the PRD. The total water use of the PRD may still increase by up to 54% in 2030 in the regionalized scenarios. Also, water use in the upstream regions increases with socio-economic development. To address water shortage, four extreme water allocation strategies were analysed against water use and water availability scenarios under climate change. None of these strategies proved to be sufficient to fully avoid water scarcity in the Pearl River Basin.

This study obtains a better understanding of the sectorial water use development and its impact on salt intrusion induced water shortage in a heavily urbanized river delta. The water use framework and methods used to derive regional water use scenarios are transferable to other regions, provided that data is available. Water use scenarios are crucial to sustainably manage water resources in a changing world.

The Mekong’s future flows : quantifying hydrological changes and developing adaptation options
Hoang, Long Phi - \ 2017
Wageningen University. Promotor(en): Pavel Kabat; Rik Leemans, co-promotor(en): Fulco Ludwig; Michelle van Vliet. - Wageningen : Wageningen University - ISBN 9789463431088 - 159
hydrology - mekong river - modeling - climatic change - socioeconomics - water resources - water use - south east asia - hydrologie - mekong - modelleren - klimaatverandering - sociale economie - watervoorraden - watergebruik - zuidoost-azië

This multidisciplinary study focuses on projecting and adapting to future hydrological changes in the Mekong – an international river of global significance in terms of rapidly increasing human pressures and climate-change vulnerability. A modelling framework was developed to project future changes in both the river flow regime and hydrological extremes (i.e. high/low flows and floods), under multiple scenarios of climate change, irrigation and hydropower developments. Furthermore, we developed a combined quantitative-qualitative approach to develop suitable adaptation measures and strategies to future floods in the Mekong Delta being a key vulnerability hotspot.

Results show that the Mekong’s future flow regime is subjected to substantial changes under climate change and human developments. Climate change will intensify the hydrological cycle, resulting in increasing average river flows (between +5 % and +16%, annually), and more frequent and extreme high flows during the wet season. Flow regime shows substantial alterations in the seasonal flow distributions under the combined impacts of climate change, irrigation expansions and hydropower developments. While dry season flows increase strongly (monthly changes up to +150%), wet season flows show contrasting changes with reductions during June - October (up to -25%) and substantial increases during November – December (up to 36%). A follow-up modelling assessment for the Mekong Delta shows substantial increases in flood hazards under climate change and sea level rise, shown by higher flood frequencies and flood depths across the whole delta. Increasing flood hazards therefore represents a key issue to be addressed in terms of future adaptation. The adaptation appraisal study further shows that effective adaptation requires looking beyond sole infrastructural investments. Instead, technological innovations for flood risk management combined with improved governance and institutional capacities offer ample opportunities to adapt to future hydrological changes.

This study projects substantial future hydrological changes under future climate change and accelerating socioeconomic developments and shows potentially serious consequences for water related safety and sustainable water resources uses and allocations. Furthermore, this study demonstrates amble opportunities to manage future changes through strategic development planning and through adaptive interventions. Insights from this study address the needs for quantified future hydrological changes and emphasize adequate adaptation to the associated risks in an important international river experiencing climate change and rapid socioeconomic developments.

Steering with high EC improves taste and quality of fruits : search for less water, fertilisers and discharge
Beerling, Ellen - \ 2017
horticulture - greenhouse horticulture - tomatoes - water use - water use efficiency - fertilizers - emission reduction - drainage - rockwool - irrigation systems - crop quality - cultural methods
With a little more effort you can improve even more. This is the approach behind new trials aimed at optimizing water and fertiliser use with the specific aim of reducing fertiliser emission to the environment. It sounds rather demanding until you realise that the quality of the end product can also improve, while maintaining or even increasing yield. Excess drain as an insurance policy for the cultivation is an out-dated idea.
Kokos als volvelds groeimedium geeft beste resultaten bij lisianthus
Raaphorst, Marcel - \ 2016
horticulture - greenhouse horticulture - cut flowers - eustoma grandiflorum - substrates - cultural methods - copra - agricultural research - growing media - energy saving - environmental protection - fertilizer application - water use
Beprijzen van water voor de landbouw - geactualiseerde versie
Linderhof, Vincent ; Snellen, W.B. ; Schipper, P.N.M. ; Hattum, T. van; Veraart, J.A. - \ 2016
Stowa (Deltafactsheet ) - 6 p.
landbouw - beregening - oppervlaktewater - watergebruik - kosten - marktregulaties - agriculture - overhead irrigation - surface water - water use - costs - market regulations
Deze deltafact behandelt de achtergronden en mogelijkheden om water te beprijzen dat door de landbouw wordt gebruikt voor beregening. De nadruk hierbij ligt op het gebruik van oppervlaktewater en de haalbaarheid om water te beprijzen in tijden van watertekorten.
Crop intensification options and trade-offs with the water balance in the Central Rift Valley of Ethiopia
Debas, Mezegebu - \ 2016
Wageningen University. Promotor(en): Martin van Ittersum, co-promotor(en): Huib Hengsdijk; Katrien Descheemaeker. - Wageningen : Wageningen University - ISBN 9789462578616 - 178
cropping systems - intensification - water balance - crop production - land use - climatic change - crop yield - water use - irrigation - ethiopia - teeltsystemen - intensivering - waterbalans - gewasproductie - landgebruik - klimaatverandering - gewasopbrengst - watergebruik - irrigatie - ethiopië

The Central Rift Valley (CRV) of Ethiopia is a closed basin for which claims on land and water have strongly increased over the past decade resulting in over-exploitation of the resources. A clear symptom is the declining trend in the water level of the terminal Lake Abyata. The actual productivity of most cereals in the CRV is less than 2 t ha-1 associated with low input use and poor crop management. Consequently, there are two major development objectives in the CRV, i.e. producing sufficient food for the increasing population, while at the same time ensuring efficient use of limited water and land resources under variable and changing climate conditions. The low productive cereal systems and a declining resource base call for options to increase crop productivity and improve resource use efficiency in order to meet the growing demand for food.

In this thesis, the recent impacts were quantified of climate change, land use change and irrigation water abstraction on water availability of Lake Abyata of the CRV. The trends in lake levels, river discharges, basin rainfall, temperature and irrigation development (ca. 1975-2008) were analysed and the additional evapotranspiration loss resulting from temperature change and irrigated land were computed. We also analysed land use change (1990-2007) and the associated changes in runoff. Results showed that temperature has increased over 34 years (p<0.001) whereas annual rainfall has not changed significantly. Consequently, increased evapotranspiration consumed 62 and 145 Mm3 of additional water from lakes and land surface, respectively, during 1990-2007. Furthermore, an estimated 285 Mm3yr-1 of water was abstracted for irrigation in 2009 of which approximately 170 Mm3yr-1 is irrecoverable evapotranspiration loss. In addition, surface runoff has increased in the upper, and decreased in lower sub-basins of the CRV associated with extensive land use change (1990-2007).

We analysed a large number of data from farmers’ fields (>10,000) and experimental data across the CRV from 2004-2009 to quantify the gaps (Yg) between actual (farm) and experimental (water-limited potential - Yw) yields of maize and wheat in homogenous farming zones. We found that the average (2004-2009) yield gap of maize and wheat ranged between 4.2-9.2 t ha-1, and 2.5-4.7 t ha-1, respectively, across farming zones. The actual N and P application in farmers’ fields was low, as about 46% of maize and 27% of wheat fields did not receive fertilisers. We calibrated, validated and used the Agricultural Production System Simulator (APSIM) model to explore intensification options and their trade-offs with water losses through evapotranspiration. Variety selection and N fertilization were more important for yield gap closure than crop residue management and planting density, and the magnitude of their effect depended on soil type and climate. There was a trade-off between intensification and water use through evapotranspiration, as increasing yield comes at the cost of increased transpiration. However, this trade-off can be minimized by choosing location-specific N levels at which both water use efficiency (WUE) and gross margin are maximised. These application rates varied between 75 and 250 kg N ha-1 across locations and soils, and allowed producing 80% of Yw of maize and wheat. Climate change was projected to lower Yw of maize and wheat by ca. 15-25% and 2-30%, respectively, compared to current climate conditions.

An automated gridded simulation framework was developed to scale up the promising intensification options from field scale to basin scale. We then aggregated basin scale production and identified trade-offs between production and water use for different land use scenarios. This procedure allowed designing land use scenarios based on a spatially explicit optimization of WUE and gross margin per grid cell. Consequences of land use scenarios for food production and water use at basin level were evaluated. Results of the different land use scenarios demonstrated that crop intensification options for which WUE and gross margin are maximised can meet the projected food demand (year 2050) of the growing population in the CRV while at the same time saving large areas of the currently cultivated land. In the intensification scenarios total water loss through evapotranspiration from agricultural land is reduced compared with water loss from current cultivated land and low crop productivity levels.

It is concluded that the current land use together with climate change and water abstraction for irrigation negatively affected the basin level water balance in CRV over the past decade. Furthermore, the scope for further expansion of farmland to increase food production is very limited. The focus should, therefore, be towards intensification also because the existing yield gaps are huge and hence the scope for intensification is large. Model-based exploration of intensification options can be used to prioritize promising options, to close the yield gap and for quantifying trade-offs. Scaling up of promising options allows to assess whether the food demand of the growing population can be met while at the same time saving the less productive land and water per unit agricultural product.

The use of Eucalyptus in agroforestry systems of southern Rwanda : to integrate of segregate
Mugunga, C. - \ 2016
Wageningen University. Promotor(en): Frits Mohren; Ken Giller. - Wageningen : Wageningen University - ISBN 9789462577534 - 162 p.
eucalyptus - agroforestry - eucalyptus saligna - zea mays - agroforestry systems - rotations - water use - rwanda - agroforestrysystemen - rotaties - watergebruik
Zelfvoorzienend in zoetwater: zoek de mogelijkheden : kleinschalige oplossingen voor een robuustere regionale zoetwatervoorziening
Jeuken, A. ; Tolk, L. ; Stuyt, L.C.P.M. ; Delsman, J. ; Louw, P. de; Baaren, E. van; Paalman, M. - \ 2015
Amersfoort : Stowa (Rapport / STOWA 2015-30) - ISBN 9789057736940 - 73 p.
watervoorziening - watertekort - zoet water - waterbeheer - watergebruik - zelfvoorziening - klimaatverandering - water supply - water deficit - fresh water - water management - water use - self sufficiency - climatic change
In deze STOWA publicatie ‘Zoek het zelf uit’: Kleinschalige oplossingen voor een robuustere regionale zoetwatervoorziening wordt een overzicht gegeven van de maatregelen die waterbeheerders en watergebruikers in de regio kunnen treffen om de zelfvoorzienendheid op het gebied van zoetwater te vergroten. Dit sluit aan bij de ambities die in het Deltaprogramma zijn geformuleerd om de watertekorten die in de toekomst worden verwacht naast de maatregelen in het hoofdwatersysteem met lokale maatregelen in de regio te ondervangen. Er is een groot aantal van dit soort maatregelen beschikbaar om de neerslag die in een gebied valt beter te benutten, waarmee de zelfvoorzienendheid kan worden vergroot. Een flink aantal pilot studies loopt nog of zijn in het recente verleden afgerond.
Flexibility in land and water use for coping with rainfall variability
Siderius, C. - \ 2015
Wageningen University. Promotor(en): Ekko van Ierland; Pavel Kabat, co-promotor(en): Petra Hellegers. - Wageningen : Wageningen University - ISBN 9789462576063 - 222
rain - land use - water use - climatic change - food production - sustainable agriculture - irrigation - rainfed agriculture - regen - landgebruik - watergebruik - klimaatverandering - voedselproductie - duurzame landbouw - irrigatie - regenafhankelijke landbouw
Water productivity of sunflower under different irrigation regimes on Gezira clay soil, Sudan
Elsheikh, E.R.A. - \ 2015
Wageningen University. Promotor(en): E. Schultz, co-promotor(en): H.S. Adam; A.M. Haile. - Leiden : CRC Press/Balkema - ISBN 9781138029149 - 162
helianthus annuus - zonnebloemen - irrigatie - irrigatiesystemen - watergebruik - waterbeschikbaarheid - sudan - sunflowers - irrigation - irrigation systems - water use - water availability
The urban harvest approach as framework and planning tool for improved water and resource cycles
Leusbrock, I. ; Nanninga, T.A. ; Lieberg, K. ; Agudelo, C. ; Keesman, K.J. ; Zeeman, G. ; Rijnaarts, H. - \ 2015
Water Science and Technology 72 (2015)6. - ISSN 0273-1223 - p. 998 - 1006.
waterbeschikbaarheid - waterbeheer - hulpbronnenbeheer - innovaties - urbanisatie - afvalwater - watergebruik - waterzekerheid - hulpbronnenbehoud - waterbescherming - stedelijke gebieden - water availability - water management - resource management - innovations - urbanization - waste water - water use - water security - resource conservation - water conservation - urban areas
Water and resource availability in sufficient quantity and quality for anthropogenic needs represents one of the main challenges in the coming decades. To prepare for upcoming challenges such as increased urbanization and climate change related consequences, innovative and improved resource management concepts are indispensable. In recent years we have developed and applied the Urban Harvest Approach (UHA). The UHA proposes to model and quantify the urban water cycle on different temporal and spatial scales. This approach allowed us to quantify the impact of the implementation of water saving measures and new water treatment concepts in cities. In this paper we will introduce the UHA and present for urban water cycles. Furthermore, we will show first results for an extension to energy cycles and highlight future research items (e.g., nutrients, water-energy-nexus). Key words | Resource cycles, Water management, Water-Energy Nexus, Decision-Support
Sustainable use of land and water under rainfed and deficit irrigation conditions in Ogun-Osun River Basin, Nigeria
Adeboye, O.B. - \ 2015
Wageningen University. Promotor(en): E. Schultz, co-promotor(en): K.O. Adekalu; K. Prasad. - Leiden : CRC Press/Balkema - ISBN 9789462572782 - 237
landgebruik - watergebruik - duurzaamheid (sustainability) - irrigatie - regenafhankelijke landbouw - watertekort - modellen - bodemwaterbalans - gewasopbrengst - nigeria - land use - water use - sustainability - irrigation - rainfed agriculture - water deficit - models - soil water balance - crop yield
Summary

Human population is increasing faster than ever in the history. There is an urgent need to scale up food production in order to meet up with food demands, especially in Sub-Saharan Africa. In Ogun-Osun River Basin, Nigeria, more than 95% of the crop production is done under rainfed conditions. Fluctuation in rainfall as a result of climate change is a major challenge in the recent times in the basin. Land productivity can be greatly improved by using affordable water conservation practices by peasant farmers who produce crops in the basin. Similarly, water saving measures would have to be adopted by using drip irrigation and application of water at critical stages of growth of crops. Fertility of the soil needs to be maintained by cultivating crops that naturally replenish soil nutrients. Such measures will go a long way in ensuring sustainable use of land and water in Ogun-Osun River Basin.

An indeterminate cultivar of Soybeans TGX 1448 2E was cultivated at the Teaching and Research Farms of Obafemi Awolowo University, Ile-Ife, Nigeria during the rainy seasons from May to September, 2011 and June to October, 2012. Similarly, the crop was drip irrigated for two dry seasons from February to May in 2013 and from November, 2013 to February, 2014. The purpose of conducting the experiments in the rainy and dry seasons was to compare the yields and their components and to evaluate the performances of the crop in terms of water use and productivity. The experimental field during the dry season was located at about 1 km from the field used during the rainy season due to the nearness to the source of water. During the experiments in the four seasons, key biometric data of the crop were taken from emergence to physiological maturity. The crop cycle during the rainfed experiment lasted for 117 and 119 days in 2011 and 2012 respectively, while in the dry season it lasted for 112 days in the first season and 105 days in the second season. The lengths of the crop cycles in the four seasons differed a little bit. This is attributed to environmental factors such as weather conditions, nutrient availability in the soil and period of cultivation. During the rainy seasons, six water conservation treatments were used namely Tied ridge, Mulch, Soil bund, Tied ridge plus Soil bund, Tied ridge plus Mulch, Mulch plus Soil bund and Direct sowing without water conservation measure (conventional practice), which was the control treatment. The treatments were placed in a randomised complete block design with four replicates in an area of 31 by 52 m (1,612 m2) and standard agronomic measures were taken. Soil water balance approach was used in determining evapotranspiration during the rainfed and irrigation seasons. Seasonal evapotranspiration was partitioned into the productive transpiration from the plants and non-productive evaporation from the soil.

Seasonal average canopy extinction coefficients were 0.46 and 0.51 respectively in the rainy seasons of 2011 and 2012, while in the dry seasons of 2013 and 2013/2014 they were 0.43 and 0.49. The plant height ranged from 51.3 cm for Soil bund to 67.8 cm for the conventional practice in 2011 while in 2012, it ranged from 60.3 cm for Tied ridge plus Soil bund to 80.3 cm for Mulch plus Soil bund. The minimum fraction of Intercepted Photosynthetically Active Radiation was 0.13 during establishment for Tied ridge plus Soil bund while the peak fraction was 0.97 during seed filling for Soil bund during the rainy seasons. Similarly, the minimum and peak leaf area indices were 0.13 m2 m-2 for Tied ridge plus Soil bund during establishment in 2011 and 6.61 m2 m-2 for Soil bund during seed filling in 2012. There were strong and significant correlations between the fraction of Intercepted Photosynthetically Active Radiation and the leaf area indices (LAI) (0.70 ≤ r2 ≤ 0.99) in 2011 and (0.93 ≤ r2 ≥ 0.99) in 2012 by using an exponential model. Seasonal rainfall in 2011 and 2012 was 539 and 761 mm respectively. Seasonal water storages in the soil in 2011 ranged from 407 mm for the conventional practice to 476 mm for Tied ridge plus Mulch, while in 2012 it ranged from 543 mm for Tied ridge to 578 mm for Tied ridge plus Soil bund.

Radiation Use efficiency was determined by plotting dry above ground biomass measured at intervals of seven days against the Daily Photosynthetically Active Radiation from Solar radiation and the Instantaneous Photosynthetically Active Radiation measured near solar noon for all the treatments. For the Photosynthetically Active Radiation obtained from solar radiation, Radiation Use Efficiency of the crop ranged from 1.18 g MJ-1 for Tied ridge to 1.98 g MJ-1 of Intercepted Photosynthetically Active Radiation for Tied ridge plus Soil bund in 2011, while in 2012 it ranged from 1.45 g MJ-1 for Tied ridge to 1.92 g MJ-1 for Mulch. There was no significant difference in the average seasonal Radiation Use Efficiency in the two seasons. By using instantaneous measurement of the Photosynthetically Active Radiation, Radiation Use Efficiency ranged from 0.80 g MJ-1 of Intercepted Photosynthetically Active Radiation for Tied ridge to 1.65 g MJ-1 for Tied ridge plus Soil bund in 2011, while in 2012 it ranged from 0.94 g MJ-1 for Tied ridge to 1.24 g MJ-1 for Soil bund. The two approaches gave relatively similar values of Radiation Use Efficiency. Positive -correlation coefficients (0.50 ≤ r2 ≤ 0.89) were found among the treatments between the dry above ground biomass simulated by using a light model and those measured in the field in the two seasons.

The seasonal crop water use ranged from 311 mm for Mulch plus Soil bund to 406 mm for Tied ridge plus Soil bund in 2011, while in 2012 it ranged from 533 mm for Mulch plots to 589 mm for Soil bund. Seasonal transpiration ranged from 190 mm for Tied ridge plus Mulch to 204 mm for Soil bund in 2011 while in 2012 it ranged from 164 mm for Tied ridge plus Mulch to 195 mm for Mulch plot. Seasonal evaporation was higher in 2012 ranging from 338 mm for Mulch plots to 408 mm for Soil bund while in 2011 it ranged from 311 mm for Mulch plus Soil bund to 406 mm for Tied ridge plus Soil bund. Water storage in the soil and seasonal crop water use are significantly related. Similarly, the seasonal crop water use, Intercepted Photosynthetically Active Radiation and Radiation Use efficiency were highly related for the crop over the two seasons.

Marketable seed yield ranged from 1.68±0.50 t ha-1 for Tied ridge to 2.95±0.30 t ha-1 for Tied ridge plus Soil bund in 2011, while in 2012 the yield ranged from 1.64±0.50 t ha-1 for the conventional practice to 3.25±0.52 t ha-1 for Mulch plus Soil bund. In 2011, seed yield for Tied ridge plus Soil bund was 15.6, 15.9, 25.4, 28.5, 43.1 and 47.1% higher than seed yield for Mulch plus Soil bund, Soil bund, Mulch, Tied ridge plus Mulch, Tied ridge and conventional practice respectively. In 2012, seed yield for Mulch plus Soil bund was 7.4, 21.8, 32.0, 32.3, 43.7 and 49.5% higher than the seed yields for Soil bund, Tied ridge, Mulch, Tied ridge plus Mulch, Tied ridge plus Soil bunds and Direct sowing respectively. Average seasonal seed yield of the crop was significantly related to the Total Intercepted Photosynthetically Active Radiation but not to the Radiation Use Efficiency. Harvest indices ranged from 47.4±4.5% for Tied ridge to 57.6±1.1% for Tied ridge plus Soil bund in 2011 and 53.1±3.0% for Soil bund to 58.1±2.3% for Tied ridge 2012. The highest harvest indices were obtained in Tied ridge plus Soil bund and Tied ridge in 2011 and 2012 respectively. Harvest index was not significantly related to both Intercepted Photosynthetically Active Radiation and Radiation Use Efficiency of the crop.

Average seasonal transpiration efficiencies - the ratio of the dry above ground biomass at harvest to the seasonal transpiration - for all the treatments were 7.0 kg ha-1 mm-1 in 2011 and 14.9 kg ha-1 mm-1 in 2012. Transpiration efficiency of the crop was strongly related to Intercepted Photosynthetically Active Radiation but not to Radiation Use Efficiency under field conditions in the rainy seasons. The peak water productivity for seed was 7.99 kg-1 ha-1 mm-1 in 2011 and 5.76 kg-1 ha-1 mm-1 for Mulch plus Soil bund in 2012. Water productivity for seed was strongly and significantly related to Intercepted Photosynthetically Active Radiation. However, it was not significantly related to Radiation Use Efficiency. These findings will provide information to the crop yield modellers during the simulation of yields of Soybeans under water conservation practices.

The construction of ridges and Soil bund especially for Tied ridge, Mulch plus Soil bund and Tied ridge plus Soil bund increased the average seasonal cost of production by 28.9% compared with Mulch and conventional practice and by 10.1% compared with Soil bund. In addition, economic water productivity was 3.90 US$ ha-1 mm-1 for Mulch plus Soil bund while for Soil bund and conventional practice, it was 3.30 and 2.27 US$ ha-1 mm-1 respectively.

Due to increase in demand for food, there is the need to produce more crop per drop of water under rainfed conditions and to manage water for agriculture at basin scale. The key priority in the study area was to increase the seed yields, water and economic productivity and the financial benefits at the end of a cropping season. The results show that the use of Mulch plus Soil bund had the average maximum transpiration efficiency, seed yield, water and economic productivity, and revenue of 1,630 US$ per ha. By comparing the average seasonal transpiration efficiency, crop water use, yield, water productivity and costs of production for the six conservation practices with those of the conventional practice in the two rainy seasons, Mulch plus Soil bund had the maximum average seed yield, water and economic productivity. Mulch plus Soil bund is hereby recommended for the cultivation of the crop in the study area. Other conservation practices, such as Soil bund, also performed satisfactorily in terms of seed yield and water productivity, although with a slight reduction in revenue. The use of these water conservation practices will not only increase the yields of the crop, but reduce depletion of water in the soil, which could initiate or increase land degradation in the study area to the barest minimum. Hence, sustainability of land and water in Ogun-Osun River Basin can be ensured. These findings demonstrate that land and water productivity of Soybean under rainfed conditions can be significantly improved with water conservation practices under the current fluctuations of rainfall and competition for land resources between agriculture and urban land use in Ogun-Osun River Basin.

Field trials were also conducted for two irrigation seasons from February to May, 2013 and November, 2013 to February, 2014. The crop was planted in a Randomized Complete Block Design with three replicates and in-line drip irrigation was applied to supply water to the crops. Five treatments were selected and these are: (i) full irrigation, skipping of irrigation every other week during (ii) flowering; (iii) pod initiation; (iv) seed filling and (v) commencement of maturity. Biometric data, which are number of leaves, plant height, leaf area indices and dry above ground biomass, were taken and recorded every week from sowing until maturity in the two irrigation seasons. Soil moisture contents were taken at the root zone of the plants prior to irrigation in order to determine the net irrigation water requirements at each stage of growth. Harvest indices were determined for each treatment. Number of pods per plant, number of seeds per pod and yields under each treatment were determined after physiological maturity in each season. Regression equations were generated for: (i) yield; (ii) number of pods per plant; (iii) number of seeds per pod; (iv) number of leaves; (v) seasonal transpiration and leaf area indices. Similarly, regression equations were generated for: (i) plant heights; (ii) seasonal transpiration; (iii) number of pods per plant; (iv) number of seeds per pod; (v) dry above ground biomass. Linear regressions were also fitted to the yield, dry above ground biomass and seasonal crop water use. The crop response factor was determined. Water productivity and Irrigation water productivity were computed and compared for each treatment. Linear models were fitted to the water productivity, irrigation water productivity and harvest index.

Rainfall contribution to the crop water use was 262 and 50 mm for 2013 and 2013/2014 irrigation seasons respectively. Maximum Leaf Area Index in the 2013 irrigation season was 7.10 m2 m-2 for full irrigation during seed filling, while in the 2013/2014 irrigation season, it was 3.44 m2 m-2 for full irrigation during flowering. The dry above ground biomass after maturity ranged from 359 g m-2 where irrigation was skipped every other week at the commencement of maturity to 578 g m-2 for full irrigation. The seed yields ranged from 1.81 t ha-1 when irrigation was skipped every other week during seed filling to 3.11 t ha-1 for full irrigation. Average seasonal seed yield for full irrigation was 18.8, 21.8, 24.4 and 47.9% higher than yields for treatments where irrigation was skipped every other week during flowering, pod initiation, commencement of maturity and seed filling respectively. Seasonal transpiration ranged from 217 mm when irrigation was skipped every other week during seed filling to 409 mm for full irrigation in the 2013 irrigation season, while in the 2013/2014 irrigation season it ranged from 28 mm for the treatment where irrigation was skipped every other week during seed filling to 223 mm for full irrigation. Seasonal crop water use ranged from 463 mm when irrigation was skipped every other week during flowering to 523 mm for full irrigation in the 2013 irrigation season, while in the 2013/2014 irrigation season it ranged from 364 mm when irrigation was skipped every other week during seed filling to 507 mm for full irrigation. Harvest indices ranged from 56.0% when irrigation was skipped during seed filling to 65.9% when irrigation was skipped during flowering in the 2013 irrigation season, while in the 2013/2014 irrigation season, it ranged from 43.2% when irrigation was skipped during seed filling to 63.9% for full irrigation. Water productivity for seed production ranged from 3.89 kg ha mm-1 when irrigation was skipped during seed filling to 5.95 kg ha-1 mm-1 for full irrigation in the 2013 irrigation season while in the 2013/2014 irrigation season, it ranged from 1.93 kg ha mm-1 when irrigation was skipped during seed filling to 3.00 kg ha-1 mm-1 for full irrigation. Irrigation water productivity ranged from 8.90 kg ha mm-1 when irrigation was skipped during seed filling to 14.0 kg ha-1 mm-1 when irrigation was skipped during flowering in 2013, while in the 2013/2014 irrigation season, it ranged from 2.24 kg ha-1 mm-1 when irrigation was skipped during seed filling to 3.32 kg ha-1 mm-1 for full irrigation. Leaf area indices and yield, number of leaves, number of pods per plant, number of seeds per pod and seasonal transpiration were significantly correlated. Similarly, dry above ground biomass and seasonal transpiration, number of pods per plant, number of seeds per pod were significantly correlated. The crop response factor (Ky), a measure of the relative decrease in seed yield due to relative decrease in evapotranspiration, was 2.24. It indicates that the deficit irrigation imposed on the crop was high and that relative decrease in yields due to deficit irrigation was higher than relative decrease in evapotranspiration.

Results show that skipping of irrigation at any growth stage of the crop led to reduction in the leaf area indices, dry above ground biomass and seasonal crop water use. Deficit irrigation had significant effects on both the dry matter and yields. The effect of deficit irrigation was more pronounced on seed yields than on dry matter. Severity of the effects of deficit irrigation depended on the stage of growth and its duration. Deficit irrigation reduced significantly dry matter at flowering and pod initiation. However, deficit irrigation did not affect the plant height. Number of seeds per plant at flowering and commencement of maturity were reduced significantly by deficit irrigation. The number of seeds per pod was significantly reduced when irrigation was skipped at pod initiation only. Seed yields were significantly reduced when irrigation was skipped during seed filling. In the 2013 irrigation season water productivity when irrigation was skipped during flowering was 2.3, 16.1, 23.5, and 36.1% higher than water productivity for full irrigation, when irrigation was skipped during pod initiation, commencement of maturity and seed filling respectively. In the same season, irrigation water productivity when irrigation was skipped during flowering was 15, 20, 29.3 and 36.4% higher than for full irrigation, when irrigation was skipped during pod initiation, commencement of maturity and seed filling respectively. In the 2013/2014 irrigation season, however, water productivity for full irrigation was 8.7, 16.3, 24.7 and 35.7% higher than when irrigation was skipped during pod initiation, commencement of maturity, flowering and seed filling respectively. Similarly, irrigation water productivity was 7.2, 15.4, 24.1 and 32.5% higher than when irrigation was skipped during pod initiation, commencement of maturity, flowering and seed filling respectively. In addition, irrigation water productivity for full irrigation was 24.1 and 32.5% higher than when irrigation was skipped during flowering and seed filling respectively. Stage of growth, its duration, water requirements and seasonal environmental conditions influenced the seasonal water use, water productivity and irrigation water productivity of Soybean. Maximum water productivity and irrigation water productivity were obtained when irrigation was skipped every other week during flowering only in the first season, whereas in the second season full irrigation gave the peak water and irrigation water productivity. This suggests that irrigation water productivity of Soybean can be improved upon by skipping irrigation during flowering and pod initiation.

In this study, the costs of production for all the irrigation scenarios were high. This is due to the high cost of water, which constituted between 54 to 59% of the production cost if water is purchased and cost of drip irrigation equipment, which constituted between 75.6 to 76.7% of the total cost of production if water would be given without financial implication. Under the prevailing price and economic conditions after harvest, the use of in-line drip irrigation does not offer economic benefit to peasant farmers, who are the predominant growers of the crop in the study area. Economic benefit may be achieved after long periods of usage with proper maintenance of the irrigation facilities and elimination of the fixed cost from the total cost of production.

The water driven crop model AquaCrop was calibrated and validated to predict canopy cover, dry above ground biomass, seed yield, evapotranspiration, soil moisture content and water productivity of the crop. The simulated and measured data compare adequately except for water productivity that was over predicted in the validation data set. The AquaCrop model predicted canopy cover with error statistics of 0.93 ≤ E ≤ 0.98 for both full and deficit irrigation and the degree of agreement d = 0.99 with 4.3 ≤ RMSE ≤ 5.9 (root mean square error) for full irrigation while for deficit irrigation, 0.96 ≤ d ≤ 0.99 with 5.3 ≤ RMSE ≤ 5.8. Dry above ground biomass was predicted with error statistics of 0.08 ≤ RMSE ≤ 0.14 t ha-1 with 0.98 ≤ d ≤ 0.99 for full irrigation, while for deficit irrigation it was 0.06 ≤ RMSE ≤ 1.09 t ha-1 with 0.85 ≤ d ≤ 0.99. One in every five predictions of the above ground biomass was outside 20% deviation from the measured values.

The seed yields were predicted with error statistics of RMSE = 0.10 t ha-1 and d = 0.99 and one in five predictions was outside 15% deviation from the measured data. The prediction error statistics for seasonal crop water use for both full and deficit irrigation treatments was 15.4 ≤ RMSE ≤ 58.3 in the two seasons. The AquaCrop model over predicted percolation also in the validation data set. These observations suggest that the percolation components of the model need to be adjusted to ensure better performance. The performance of the AquaCrop model in predicting canopy cover, seed yield and other quantities in this study are commendable and satisfactory.

Specific and distinct features, such as the use of canopy cover rather than leaf area index, make the model suitable for developing countries like Nigeria, where researchers may not have access to state-of-the-art equipment for measuring the leaf area index. Similarly, water productivity that is normalized for atmospheric demand and carbon dioxide concentration and its focus on water makes it suitable for diverse locations. Over the years, it has been observed that no model is universal in its ability to take into consideration all differences in cultivar, environment, weather and management conditions. Other cultivars of Soybeans in Nigeria and other agro-climatic environments need to be tested and fine-tuned in the model, in order to ascertain the accuracy of the model. generally, the model predicted the stated parameters with reasonable degree of accuracy and is hereby recommended for use in Ile-Ife and other parts of Ogun-Osun River Basin and Nigeria.

Although land, water, and economic productivity of the crop were higher where water was conserved under rainfed conditions, treatment of the soil to conserve water and regular maintenance increased the average seasonal cost of production compared with the conventional practice. High cost of production may reduce the benefits obtained by the crop growers, except when there is improvement in the market price. Therefore, sustainable practice of the water conservation measures must be accompanied with lower cost of production. Under irrigation conditions, the land and water productivity are lower compared with rainfed cultivation. The productivity in the dry season reduces with the severity of the water stress. Average crop water productivity and economic water productivity of all the six water conservation measures in the rainy season were higher than with full irrigation in the dry season. The costs of production of the crop in the dry season were significantly above the cost during the rainfed conditions. Higher water productivity under rainfed conditions in this study is in agreement with the finding that in a significant part of the least developed and emerging countries there is larger opportunity for improving water productivity under rainfed conditions compared to irrigated agriculture.

Expansion of arable land may not be feasible in Ile-Ife because of the huge investments involved. Thus, the focus of efforts to expand food production in the area would have to be on raising land productivity on the existing arable lands and improving production efficiencies, outcomes that can only be achieved by using improved cultivars together with improved agronomic practices. Agronomic practices, especially under rainfed conditions, would have to be designed to improve water productivity. Improving water productivity requires vapour shift (transfer) whereby soil physical conditions, soil fertility, crop varieties and agronomy are applied in tandem and managed to shift the evaporation into useful transpiration by plants. During the dry season, the crop would have to be irrigated in order to achieve maximum land and water productivity. Skipping of irrigation during seed filling would have to be avoided in order to prevent significant reduction in yield. Irrigation at the commencement of maturity after the pods have been completely filled with seeds can be skipped. Under water limiting conditions, the amount of water saved by skipping irrigation during flowering, pod initiation, seed filling and maturity can be used for cultivating other crops and thereby increasing the opportunity cost. Incidental rainfall during the dry season would have to be used in order to increase irrigation water productivity of the crop.

Waterbesparing door slimme en betaalbare sensor
Balendonck, J. - \ 2015
Kas techniek 2015 (2015)april. - p. 34 - 37.
teelt onder bescherming - cultuurmethoden - kunststoftunnels - irrigatie - sensors - instrumenten (meters) - waterbehoefte - vochtmeters - watergebruik - efficiëntie - watergebruiksrendement - irrigatiesystemen - protected cultivation - cultural methods - plastic tunnels - irrigation - instruments - water requirements - moisture meters - water use - efficiency - water use efficiency - irrigation systems
Onderzoekers van Wageningen UR Glastuinbouw hebben in het kader van een Partners voor Water-project laten zien dat Turkse telers met behulp van de AquaTag veel efficiënter kunnen irrigeren. Sturen op vochtsensoren is niet nieuw, maar beschikbare sensoren zijn relatief duur en meten alleen lokaal, terwijl het vochtgehalte sterk kan variëren binnen een kraanvak. Met de AquaTag is nu een goedkope en slimme oplossing voor handen.
Agricultural water productivity optimization for irrigated Teff (Eragrostic Tef) in water scarce semi-arid region of EthiopiaAgricultural water productivity optimization for irrigated Teff (Eragrostic Tef) in water scarce semi-arid region of Ethiopia
Yihun, Y.M. - \ 2015
Wageningen University. Promotor(en): E. Schultz, co-promotor(en): T. Erkossa Jijo; A. Mehari Haile. - Leiden : CRC Press/Balkema - ISBN 9789462571709 - 82
eragrostis tef - waterbeheer - watergebruik - water - watergebruiksrendement - optimalisatie - ethiopië - water management - water use - water use efficiency - optimization - ethiopia
Eindrapport 20 juni 2014 : deelrapport B: wateraanbod glastuinbouw Haaglanden
Koeman-Stein, N. ; Appelman, W. ; Creusen, R. ; Paalman, M. ; Raterman, B. ; Voogt, W. - \ 2014
Utrecht : Programmabureau Kennis voor Klimaat (Kvk rapport nummer KvK105/2013B) - 48
glastuinbouw - watervoorziening - neerslag - zoet water - watergebruik - zuid-holland - westland - greenhouse horticulture - water supply - precipitation - fresh water - water use
In de regio Haaglanden is veel glastuinbouw. Op dit moment wordt hemelwater als primaire gietwaterbron gebruikt voor de substraatteelt, wat 88% van het glastuinbouw areaal in deze regio beslaat. Bedrijven zijn verplicht een hemel-waterberging te hebben van minimaal 500 m3/ha. Dit is echter niet genoeg voor de meeste bedrijven. Doordat water tijdens piekbuien onvoldoende kan worden opgevangen, en het meeste water nodig is in een periode met weinig regenval, ontstaat een watertekort. Om het huidige tekort op te lossen wordt een alternatieve bron ingezet als aanvullend gietwater. Een veelbelovende alternatieve gietwaterbron lijkt water van de afvalwaterzui-vering Harnaschpolder. Behalve het inzetten van een alternatieve waterbron, of het vergroten van de bergingscapaciteit, kan ook gezocht worden naar manieren om de watervraag te verminderen.
Efficiënt bemesten en watergeven in grondgebonden teelt : hoe te komen tot nul-emissie?
Voogt, Wim - \ 2014
water use - overhead irrigation - fertilizer application - field crops - emission reduction - greenhouse horticulture - air conditioning - cropping systems - lysimetry - moisture meters
Handreiking voor het berekenen van een ecologische voetafdruk : eindrapport KBIV WOt 2013
Verzandvoort, S.J.E. ; Arets, E.J.M.M. ; Hack-ten Broeke, M.J.D. - \ 2014
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2554) - 91
landgebruik - watergebruik - ecologische verstoring - productieprocessen - consumptiepatronen - inventarisaties - land use - water use - ecological disturbance - production processes - consumption patterns - inventories
Dit rapport geeft een raamwerk voor het bepalen van een ecologische voetafdruk voor veranderingen in productie- en consumptiesystemen. Het raamwerk kan worden gebruikt voor het bepalen van benodigd land- en watergebruik voor productie van goederen en diensten.
Enzyme-assisted separation and hydrolysis of gluten : options for intensification
Hardt, N.A. - \ 2014
Wageningen University. Promotor(en): Remko Boom, co-promotor(en): Atze Jan van der Goot. - Wageningen : Wageningen University - ISBN 9789462571228 - 165
gluten - graaneiwitten - scheiding - enzymen - hydrolyse - voedseltechniek - watergehalte - watergebruik - cereal proteins - separation - enzymes - hydrolysis - food engineering - water content - water use

The food industry is one of the largest water consumers in industry. Using large amounts of water, however, is undesirable from an environmental point of view because freshwater is a scarce good in many regions of the world and undesirable from an economic point of view because high water loadings require high amounts of energy for dehydration and signify high amounts of wastewater. This thesis uses wheat, one of the major crops in human nutrition, to study the influence of low water concentrations on two relevant processes in wheat processing:

The separation of starch and gluten. Separation is often performed using 10–15 L water per kg dry matter. Instead, starch and gluten can be separated by inducing shear using 0.5 L water per kg dry matter. In this thesis we make use of xylanases to hydrolyze arabinoxylan present in wheat, thereby releasing the water associated with arabinoxylan. In doing so, shear-induced starch–gluten separation is performed at even more concentrated conditions. The influence of arabinoxylan hydrolysis in wheat dough at low water contents is studied in chapters 2 and 3.The hydrolysis of gluten. Hydrolysis is currently performed using approximately 4 L water per kg dry mater. In this thesis we perform gluten hydrolysis at solid concentrations of up to 70%, thereby investigating the changes in the hydrolysis reaction and the functionality of the resulting hydrolysates. Wheat gluten hydrolysis at low water contents is studied in chapters 4, 5 and 6.

This thesis consists of seven chapters. Chapter 1 gives a general introduction of the thesis. In chapter 2, wheat dough rheology at low water contents below 40% and the influence of xylanases is studied. A reduction in water content from 43.5–44.8% (representing optimal Farinograph water absorption) to 34% (the lowest water content where a dough forms) results in a non-linear increase in the dough consistency, elastic modulus G’, and a decrease in the maximum creep compliance Jc,max of 1–2 orders of magnitude. Addition of xylanases has the same effect on the dough consistency, G’ and Jc,max as an increase in water content of 2–5% (on a water basis). Tan δ is hardly and Jel not influenced by xylanase addition showing that the influence of xylanases on the mechanism of hydration is negligible.

In chapter 3, shear-induced starch–gluten separation with the help of xylanases is studied at water contents from 43.5% to 34%. Addition of xylanases at the standard water content of 43.5% results in a slurry without any separation. As a result, lower water contents are used. At water contents below 40%, the local formation of gluten clusters is observed with and without xylanases addition. However, opposed to shear-induced separation at 43.5% water without xylanase, the gluten patches do not migrate to the center of the cone because of the densely packed dough and an inhomogeneity in the shear field. Nevertheless, gluten clusters can be concentrated up to 60% (N×5.7) protein. Similar to chapter 2, xylanase addition allows water savings of 3–5% (on a water basis).

Chapter 4 introduces enzymatic wheat gluten hydrolysis at high solid concentrations and describes the influence of high-solid hydrolysis on the resulting functional properties of the gluten hydrolysates. Wheat gluten can be hydrolyzed at solid concentrations of up to 60% (w/w). The water solubility of the dried hydrolysates is independent of the solid concentration during hydrolysis, just like the foam stabilizing properties at degrees of hydrolysis (DH%) below 8% At DH% above 8%, high solid concentrations even increase the foam stabilizing properties of the resulting hydrolysates, which is related to the presence of more peptides with a molecular mass >25 kDa. Furthermore, an increase in solid concentration results in an increase of the volumetric productivity.

Despite the advantages of high-solid gluten hydrolysis, we also observe lower hydrolysis rates in high-solid gluten hydrolysis compared to low-solid gluten hydrolysis at constant enzyme-to-substrate ratios. The factors causing this hydrolysis rate limitation are investigated in chapter 5. It is shown that enzyme inhibition, the water activity, and mass transfer limitations do not impede the hydrolysis up to 50% solids. However, the hydrolysis rate limitation can be explained by a second-order enzyme auto-inactivation rate along with the higher enzyme concentrations used. At solid concentrations above 50%, the hydrolysis rate further decreases due to mass transfer limitations. Furthermore, the addition of enzyme after 24 h at high solid concentrations hardly increases the DH%, suggesting that the maximum attainable DH% decreases at high solid concentrations. This DH% limitation is explained by a reduced enzyme activity due to a decline in water activity.

Based on the findings in chapters 4 and 5, a direct hydrolysis of gluten present in wheat flour at high solid concentrations is investigated in chapter 6, thereby omitting the starch–gluten separation. At a constant protein concentration, the protease activity is higher for wheat flour hydrolysis (at 40% total solids) than for vital wheat gluten hydrolysis (at 7.2% total solids) in the initial 6 h of hydrolysis, despite the high starch content in wheat flour and consequently lower water content. This is related to the starch granules in wheat flour, preventing the aggregation of (native) gluten. At wheat flour concentrations above 50% and for longer reaction times the positive effect of starch disappears. This is explained by mass transfer limitations and reduced water activities in the wheat flour slurry or dough, respectively.

Chapter 7 summarizes and generalizes the main findings of this thesis and compares the current status in starch–gluten separation and gluten hydrolysis with the concentrated separation and hydrolysis processes developed in this study. Water and energy savings of at least 50% are possible when separating and hydrolyzing at concentrated conditions. In the end, future prospects in high-solid wheat gluten hydrolysis are briefly discussed.

Watergebruik in de agrarische sector 2012
Meer, R.W. van der - \ 2014
Den Haag : LEI Wageningen UR (Nota / LEI Wageningen UR 14-069) - 18
landbouw - tuinbouw - veehouderij - watergebruik - irrigatiewater - grondwater - oppervlaktewater - landbouwstatistieken - agriculture - horticulture - livestock farming - water use - irrigation water - groundwater - surface water - agricultural statistics
In de land- en tuinbouw wordt water gebruikt. Dit kan leidingwater zijn dat bijvoorbeeld wordt gebruikt voor het drenken van vee of voor het reinigen van stallen. Ook wordt er oppervlakte- of grondwater gebruikt voor bijvoorbeeld het beregenen van gewassen. Met name het gebruik van oppervlakte- en grondwater wordt bepaald door de weersomstandigheden. Voor het watergebruik levert LEI Wageningen cijfers aan het CBS.
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