ITS2.6/BG9

One of the most important tasks for humans in the 21^st century is to ensure food security in the face of water scarcity. Steep-slope cultivated landscapes are widely distributed and feed more than 10% people in the world. They play an important role in Sustainable Development Goals (SDG) set in the United Nations Sustainable Development Summit which aimed to thoroughly solve the food problems in a sustainable way. In addition, more than 49 steep-slope cultivated landscapes are recognised and protected by UNESCO and FAO for their cultural and agronomic importance. It is necessary to find appropriate solutions towards climate-resilient water resources management and save more water for other ecosystems or human activities.

Climate change-induced drought and high intensity rainstorms are global challenges for water resources management in agricultural landscapes. Growing aridity and extreme rainfall are particularly exacerbating the problem of water scarcity in steep slope cultivated landscapes. Though a number of studies have shown the potential impact of climate change on agricultural systems, little is known about role of water resource management (water storages, water harvest, drainage systems, etc.) in the mitigation of these climate impacts to ensure sustainable farming in steep slope agricultural landscapes. The aim of our work is to analyse the threats and challenges of steep-slope agriculture due to climate change and provide examples of resilient water management and agricultural practices in these landscapes. In detail, the aims are to better understand and compare how shifting climatic zones particularly affect steep cultivated landscapes and to find a feasible way for water storage to sustain ecosystem service and agricultural cultivation on hillslope in long periods of drought. GIS-based techniques were employed to determine the global distribution of steep agricultural landscapes, and to quantify the fraction of these that are facing future aridity. Finally, key examples of best practices in sustainable water resource management around the world are discussed, providing a guideline for improving the resilience of steep cultivation systems in future climatic conditions.

How to cite: Wang, W., Pijl, A., and Tarolli, P.: Steep-slope cultivated landscapes: towards climate-resilient water resources management, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2358, https://doi.org/10.5194/egusphere-egu21-2358, 2021.

Expansion of irrigated agriculture is central to efforts to enhance food security, reduce rural poverty, and increase resilience to climate change across Sub-Saharan Africa (SSA). A broad variety of irrigation system typologies currently exist in SSA, ranging from ‘formal’ publically-financed surface water irrigation systems served by engineered infrastructure (e.g. dams and canals) to ‘informal’ farmer-led irrigation systems that receive little official support or recognition (e.g. private groundwater pumping and small-scale river diversions). Yet, at present, there is little objective or reliable information about the about the differences in agricultural productivity and livelihood outcomes resulting from these alternative approaches to irrigation developments in SSA, limiting capacity to design effectively new irrigation investments and evaluate reliably current and future trade-offs with other water uses (e.g. hydropower). Understanding the comparative performance of alternative existing approaches to irrigation development, along with the extent to which formal and informal systems complement or substitute one another, offers a valuable opportunity to generate new insights about best practice approaches for irrigation expansion. This paper seeks to address this challenge by exploring how alternative bio-physical, socio-economic, and institutional characteristics of irrigation developments influence welfare outcomes for smallholders.

Our analysis uses primary household panel data (n=646) collected in 2018 and 2019 from Upper East Ghana evaluate the characteristics of irrigation typologies and impacts on agricultural productivity. As a basis for our empirical analysis, we analyse the drivers of productivity differences across farmers in different irrigation typologies. We use descriptive statistics from the survey data to make inferences on heterogeneity of irrigation access across farmer groups. We then use a subset of the sample - limited to the main crops, paddy rice in the rainy season and pepper in the dry season- to analyse the differences in crop yields across farmer groups. To assess whether irrigation access and behaviour affects agricultural production and technical efficiency, we decompose the effects of agricultural inputs - including irrigation - and technical efficiency on crop yields.

Our preliminary findings demonstrate that farmers in formal irrigation schemes have higher yields, technical efficiency of agricultural production and lower costs compared to farmers in informal schemes across both growing seasons. We also find that farmers in formal schemes enjoy a broad range of benefits (for e.g., subsidised fertilizers and higher prices for their produce), which go beyond direct benefits from reliable and inexpensive water access. As a result, these farmers have lower agricultural costs, higher production and better welfare outcomes. These findings highlight the need for broadening public support for irrigators outside the government managed irrigation schemes, who are often neglected in official irrigation development narratives. Fertilizer subsidies, proper channels to sell agricultural output and proper maintenance of existing infrastructure outside formal schemes present opportunities to increase the efficiency and agricultural productivity of farmers in informal schemes.

How to cite: Adhikari, R., Foster, T., Dimova, R., Redicker, S., and Higginbottom, T.: Alternative Models of irrigation development in Ghana, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15252, https://doi.org/10.5194/egusphere-egu21-15252, 2021.

South Africa is a water scarce country, with 98% of available water resources already allocated. In addition, only 12% of the land is considered suitable for growing rainfed crops, making commercial agriculture production heavily dependent on irrigation. Current climate projections suggest that South Africa will experience increased frequency of drought events over the next century. This will have notable implications for food security, especially in rural communities that still depend on rainfed production for their livelihoods. In this work, we evaluate water sustainability for seventeen major crops produced in South Africa under current climatic and management conditions as well as under future climate scenarios. We map the spatial distribution of source- and crop-specific water use, and asses their sustainability in terms of water debt repayment time (i.e., the time needed to renew water resources used for annual crop production). We find high water debts in the Western and Eastern Cape regions, revealing unsustainable production due to irrigation in arid areas. Results from climate change scenarios suggest an intensification of such pressure on water resources and allow us to identify crop types and locations where production is likely to be more (or less) sustainable under future climatic conditions, a key step to informing land use planning decisions.

How to cite: Bonetti, S., Mabhaudhi, T., Slotow, R., and Dalin, C.: Water sustainability of South African crop production under current and future climatic conditions, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1659, https://doi.org/10.5194/egusphere-egu21-1659, 2021.

Groundwater irrigation has played a critical role in the Green Revolution in South Asia, helping to increase crop yields and improve livelihoods of millions of rural households. However, the spread of irrigation has not been homogeneous, with many farmers in the Eastern Indo-Gangetic Plains (EIGP – Nepal Terai and parts of eastern India) still lacking reliable and affordable irrigation access. As a result, agricultural productivity in the EIGP is some of the lowest found across South Asia, with many farmers trapped in chronic cycles of poverty and food insecurity.

A major focus of government and donor efforts to support intensification of groundwater irrigation in the EIGP has been the replacement of existing diesel-based pumping systems with alternative electric or solar powered pumping technologies. These technologies are viewed as being cheaper for to operate and less environmentally damaging due to their lower operational carbon emissions. However, scaling these technologies in practice has proved challenging due to their high upfront capital costs and the unique socio-technical constraints posed by farming systems in the EIGP (e.g., land fragmentation and poorly developed supply chains).

In response to these challenges, our research explores whether opportunities exist to make existing diesel pump systems more cost effective for farmers to support adaptation to climate change and reduce poverty. In particular, we seek to identify what factors lead to disparities in groundwater access costs for irrigation, how these disparities affect farmers’ water use behavior, and in turn how this impacts agricultural production outcomes. Our work draws on evidence from a recent survey of over 400 farmer households in the Nepal Terai, along with detailed in-situ testing and analysis of the fuel efficiency and cost-effectiveness of over 100 diesel pumpsets in the same region conducted between 2019-20.

Our results demonstrate that substantial variability exists in the costs of diesel pump irrigation in the EIGP and that higher costs of groundwater access are associated with lower levels of agricultural productivity and household income. Dependence on expensive pumpset rental markets, in particular amongst credit constrained households, is a major driver of the highest irrigation access costs. Additionally, many farmers also continue to operate and invest in pumpset models and designs that are significantly oversized for local hydrological conditions, resulting in fuel inefficiencies and excess costs that reduce the overall profitability of irrigation water use.

Our findings have important implications for national and regional policy debates about sustainable intensification of irrigated agriculture in the EIGP and other regions. We suggest that intensification of water use and improvements in agricultural productivity can be achieved in the near-term without need for radical technology changes. Targeted credit support, combined with data-driven advisories and improved supply chains for maintenance services and spare parts, could incentivize and enable adoption of low-cost fuel-efficient diesel pumpsets resulting in substantial reductions in costs of irrigation for many farmers. This would have positive near-term impacts on agricultural productivity and rural livelihoods, supporting adaptation to climate change and future transitions to alternative low-carbon irrigation technologies in the region.

How to cite: Foster, T., Adhikari, R., Adhikari, S., Justice, S., Urfels, A., and Krupnik, T.: Sustainable intensification of groundwater irrigation in the Eastern Indo-Gangetic Plains, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11580, https://doi.org/10.5194/egusphere-egu21-11580, 2021.

Forests make over 30% of global land and perform functions of vital importance for the well-being of humans on Earth. Yet, forest cover is declining due to deforestation  that mainly affect tropical biomes, due to land use changes for agricultural, mining, and urban use to satisfy growing global demands. Globalization of markets and development have in fact raised the pressure on environmental resources by humans, and at least 30% of global deforestation is linked to the production of exported goods. 
We propose here a method to quantify the impact of global trade on forest cover, by assessing the deforestation embodied in the production, trade, and consumption of  forest-risk agricultural products and by-products. from 2000 to 2020. We provide the first estimate of a country-based deforestation footprint, an indicator of the pressure on forest cover by countries that consume goods produced on land previously occupied by forests.
This is a first attempt to systematically and critically address the issue taking into account responsibilities of both exporting and importing countries. Our methods and first assessment can support domestic and international policies aiming at reducing  deforestation through a correct assessment of a country's impact on global forests and their services. 

How to cite: Vacchiano, G., Lahoz, M. G., Ventrice, A., and Bagliani, M.: A global deforestation footprint from production and consumption of primary goods, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15932, https://doi.org/10.5194/egusphere-egu21-15932, 2021.

Rising temperatures, shifts in precipitation patterns and longer dry periods provoke a need for better adapted crops in Switzerland to maintain agricultural productivity in the long term. The aim of this work was to identify plants with a high climatic suitability in the future. A simple mechanistic model (ecocrop) was applied to determine suitability for different time periods under RCP scenarios 4.5 and 8.5. The model considers temperature and precipitation ranges. From a pool of 600 edible plants, 21 plants were identified that would benefit from progressing climate change in terms of average climatic yield potentials. In addition, these plants were found to have a high nutritional quality and could thus be seen as good candidate crops to expand the portfolio of cultivated crops in Switzerland in efforts to adapt to climate change and maintain or even increase food productivity in a future climate. The potentials of selected crops are discussed in terms of cultivation requirements, spatial suitability, and market potentials.

How to cite: Heinz, M., Romppainen-Martius, O., and Holzkämper, A.: Alternative crops for a changing climate in Switzerland, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14699, https://doi.org/10.5194/egusphere-egu21-14699, 2021.

Given the importance of food imports for food security and the role of exports in income generation, food trade is an indispensable component of most countries’ development strategies. Global and regional agreements set the rules for trade policies between countries. In this context, we investigate the impact of trade agreements on the trade network of agricultural products. We study whether the ratification of agricultural-oriented trade agreements has an influence on the topology of the cereal trade network (link establishment) and the variation of flows through existing links.

Our analysis differs from previous studies for three main reasons. Firstly, it is a data-driven analysis, based on a dataset that combines the trade agreement structure provided by the World Bank and cereal trade flow data from FAOSTAT. Secondly, the analysis focuses on a global scale, considering data for all countries where information is available. Finally, we carried out the analysis at the level of aggregated cereals, both from a monetary (US$) and diet-based (Kcal) perspective, over the period from 1993 to 2015. This time interval includes the most important recent reforms in the agricultural sector.

The results show that a new trade agreement between two countries increases the probability of activating a grain trade link by 7.3% in the year after the agreement is ratified. In the case where trade agreements are not considered, the probability of triggering a new link between two countries drops to 1.3%.

Regarding the volume of flows, we classify variations into three categories: flow decrease (negative variation of the flux), mild increase (<50% increase in the flow intensity), and sharp increase (>50% increase).

The results obtained, both in economic value (US$) and in quantitative variations (Kcal), show that the entry force of a trade agreement has two main effects: in flows covered by trade agreements, there is a significant increase in the percentage of flows experiencing a sharp increase, and a reduction of the percentage of flows experiencing a negative variation. 

We, therefore, provide here global-scale, data-based evidence. Previous results suggest that trade agreements are facilitators of the connections between different countries and, therefore, facilitators in terms of global food trade accessibility.  This work aims to be a first attempt to investigate the impacts of international agreements simultaneously on the topology of the agricultural product trade network, and on the increase of existing link flows. Our intention is to dedicate further analysis about which trade agreements perform better, increasing the traded volume, to explore the role of trade liberalization at a worldwide level.

How to cite: Falsetti, B., Ridolfi, L., and Laio, F.: Do trade agreements activate new links and increase flows? A data-driven analysis of the global cereal market., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14664, https://doi.org/10.5194/egusphere-egu21-14664, 2021.

Diversity and diversification in agricultural systems are often presented in the literature as having multiple benefits such as enhancing resilience, increasing food production and decreasing risks in production systems and is often postulated to benefit food and nutrition security in low- and middle-income countries. Our study aims to provide an overview of the potential for agricultural diversification to improve food security status as reported in recently published research articles analysing the diversity-food security relationship. We consider results for different scales, from individual to global and for different food security dimensions: availability, access, stability and utilisation.

We carried out a literature review that includes exhaustive, comprehensive searching. We search for peer-reviewed publications in the Web of Science core collection (v.5.32) written in English, between 2010 and February 2020 on the association between diversity in agricultural systems and at least one dimension or measure of food security. From the original list of articles we exclude all publications that (1) focus on a study area outside a low- to middle income country; (2) do not include at least one metric of farm-, regional-, or global-level diversity as specified with the search terms; (3) do not explicitly measure at least one food security dimension, or (4) were exclusively focussed on describing drivers and trends in diversity or food security.

We find that a total number of 87 research articles assessed a total of 328 diversity-food security relationships using one or more statistical modelling approach. About half of them are positive (54%) and mostly refer to the diversity-food access relationship on the individual, household and farm scale as this was the food security dimension and spatial scale most analysed. Of all results for food access 60% were positive relationships and only 4% were negative relationships with the remainder having no or ambiguous relationships. Twenty-nine studies used household dietary diversity as a measure of food access and 10 studies used at least one food access indicator that is a validated proxy for nutrient adequacy. Positive relationships were more often reported for food availability (65%) than for food utilisation (33%) also because for food utilisation there are a lot of mixed findings for different measures of anthropometric and nutritional status. The most common spatial scale assessed was the household and farm scale (58%).

There is no food security dimension that primarily has a negative relationship with agricultural diversity but there is a considerable number of relationships that are found to be neutral or ambiguous. Diversity can be an important driver of food security, but the magnitude of the contribution depends on the  socio-economic and biophysical characteristics of the local farming system. We conclude that farmers mostly see diversification as a potential strategy to improve livelihoods, agricultural production and/or food and nutrition security where other strategies are more expensive but not as a desirable characteristic of the agricultural systems at all costs especially in the presence of other strategies that can achieve the same outcome.

How to cite: Waha, K., Accatino, F., Godde, C., Rigolot, C., Bogard, J., Domingues, J. P., Gotor, E., Martin, G., Mason D'Croz, D., Tacconi, F., van Wijk, M., and Herrero, M.: Agricultural diversification and food security in low- and middle-income countries: Where is the evidence?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6748, https://doi.org/10.5194/egusphere-egu21-6748, 2021.

Introducing edible salt-tolerant plant species to professional cultivation is a concept compatible with the need of improving the resilience of food systems to shocks and stresses, which is  required to tackle eminent global challenges, such as water scarcity and climate change (Cuevas et al., 2019). Hydroponic systems can contribute to substantial savings of water, nutrients, and space, while increasing yield and produce quality (Savvas and Gruda, 2018). In the current study, we examined the feasibility of cultivating the wild edible green Scolymus hispanicus L. under moderate levels of salinity in a soilless cultivation system. The experiment was installed in October 2019, in an unheated saddle roof double-span greenhouse, as a completely randomized block design with 4 treatments and 4 blocks per treatment (Papadimitriou et al., 2020). Treatments were formed by supplying a standard nutrient solution (NS) with four NaCl concentrations (0.5, 5.0, 10.0, and 15.0 mM), resulting in electrical conductivities of 2.2, 2.8, 3.2, and 3.8 dS m^-1, respectively. Measurements of chlorophyll fluorescence (Fv/Fm) and relative chlorophyll levels (SPAD), which were performed to assess the photosynthetic capacity of leaves, did not indicate any significant differences between the non-salinized control (0.5 mM NaCl) and the salinity treatments (5.0, 10.0, and 15.0 mM NaCl), until 60 days after seedling transplanting (DAT). However, by 90 DAT, salinity levels of 10.0 and 15.0 mM significantly reduced leaf chlorophyll levels, as indicated by the SPAD indices, compared to 5.0 and 0.5 mM NaCl in the supplied NS. Moreover, by 90 DAT, the chlorophyll fluorescence (Fv/Fm) was significantly reduced at the salinity level of 15.0 mM compared to 0.5 and 5.0 mM. Nevertheless, no salinity treatment had a significant impact on leaf fresh weight, root fresh weight, rosette diameter, number of leaves and post-harvest storability in plants harvested 90 and 120 DAT, compared to the control. Based on these results, S. hispanicus L. exhibits a considerable resilience to moderate salinity and can be considered a promising candidate plant for introduction in hydroponic cropping systems.

Acknowledgements

The research work was supported by the Hellenic Foundation for Research and Innovation (HFRI) under the HFRI PhD Fellowship grant (Fellowship Number: 240).

References

Cuevas, J., Daliakopoulos, I.N., del Moral, F., Hueso, J.J., Tsanis, I.K., 2019. A Review of Soil-Improving Cropping Systems for Soil Salinization. Agronomy 9, 295. https://doi.org/10.3390/agronomy9060295

Papadimitriou, D., Kontaxakis, E., Daliakopoulos, I., Manios, T., Savvas, D., 2020. Effect of N:K Ratio and Electrical Conductivity of Nutrient Solution on Growth and Yield of Hydroponically Grown Golden Thistle (Scolymus hispanicus L.). Proceedings 30, 87.https://doi.org/10.3390/proceedings2019030087

Savvas, D., Gruda, N., 2018. Application of soilless culture technologies in the modern greenhouse industry - A review. Europ. J. Hort. Sci. 83, 280-293.

How to cite: Papadimitriou, D., Daliakopoulos, I., Manios, T., and Savvas, D.: Salinity tolerance in Scolymus hispanicus L: preliminary findings from a soilless cultivation, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14357, https://doi.org/10.5194/egusphere-egu21-14357, 2021.

Nitrogen (N) fertilizer management is challenging due to the many factors and have low N use efficiency (NUE). Heavy N losses from soil reduce plant yield and have negative impacts on the environment. Nitrogen processes inhibitors, such as urease and nitrification inhibitors (UI and NI), are chemical compounds which reduce urea hydrolysis and nitrification respectively. By coating ammonium based chemical fertilizers with N process inhibitors allows N to stay in a more stable form of ammonium (NH₄⁺) thus minimising N losses as well as improving NUE and consequently enhancing crop yield.

A field experiment was established at the Soil and Water Management and Crop Nutrition Laboratory (SWMCNL) in Seibersdorf, Austria to determine the effect of different N fertilizers coated with N process inhibitors on maize yield in summer 2020. The field site is characterised by a moderately shallow Chernozem soil with significant gravel content. Three combinations of N fertilizer (urea or NPK) with N process inhibitors (UI and/or NI)) were tested and compared with a control treatment (without N fertilizer) and a urea application without any inhibitor. All treatments received 60 kg ha^-1 P₂O₅ and 146 kg ha^-1 K₂O. The amount of N added to each treatment receiving N fertilizer was 120 kg N ha^-1. The inhibitors used were (i) UI (2-NPT: N-(2-nitrophenyl) phosphoric acid triamide), (ii) NI-1 (MPA: N-[3(5)-methyl-1H-pyrazol-1-yl) methyl] acetamide), and (iii) NI-2 (DMPP: 3,4-dimethylpyrazole phosphate). DMPP, a nitrification inhibitor, was used in combination with NPK fertilizer. A randomized complete block design with four replications was used in this study. Treatments were: T₁ (control treatment - without N fertilizer), T₂ (Urea only), T₃ (Urea + UI), T₄ (Urea + UI + NI-1), and T₅ (NPK + NI-2). Urea was applied through two split applications in the T₂ treatment. In T₃, T₄, and T₅ treatments, N fertilizers were applied only once. Supplemental irrigation was only applied in the early stages of growth, to ensure that the crop could establish. Harvest was carried out at 98 days after planting.

The yield data showed that different fertilizer treatments had a significant (p ≤ 0.01) effect on maize yield (dry matter production). There was no significant difference between treatments 4 and 5, which had the highest yield followed by treatments 2 and 3. The comparison between T₂ and T₃ showed that the application of a urease inhibitor avoids the need for a split application of urea, which decreases labour costs. Adding NI-1 (under T₄) further increases the yield. Also, the package of NPK, a common choice by farmers in Austria, in combination with the nitrification inhibitor NI-2 showed equally good results as urea combined with two inhibitors. Based on the yield results, it can be concluded that N process inhibitors play a significant role in enhancing maize yields.

How to cite: Heiling, M., Shorafa, M., Mirkhani, R., Willems, E., Toloza, A., Resch, C., Heng, L. K., and Dercon, G.: Influence of different nitrogen inhibitors on maize yield, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9859, https://doi.org/10.5194/egusphere-egu21-9859, 2021.

Nitrogen (N) is a crop nutrient that is commonly applied as fertilizer, however the dynamic nature of N and its propensity for loss from soil‐plant systems creates a unique and challenging environment for its efficient management. Nitrification inhibitors (NIs) are compounds that can reduce the bacterial oxidation of NH₄⁺ to NO₂⁻ by inhibiting the activity of ammonia-oxidizing bacteria and maintaining a higher proportion of applied nitrogen in the soil by preventing nitrate loss from leaching and gaseous N losses from nitrification and denitrification. The organic compound 2-chloro-6-(tri-chloromethyl) pyridine, commonly known as nitrapyrin (NP), is such a nitrification inhibitor that is used in agriculture. The objective of this study was to investigate the effect of NI (NP) on winter wheat yield compared to farmers practice without NI at a given N rate and same number of N split applications.

A randomized complete block design in five replications was used in this study. Treatments were: T₁ (control treatment - without urea), T₂ (farmers practice - 300 kg urea/ha), and T₃ (urea+NP - 300 kg urea/ha). Urea was applied in three split applications at tillering, stem elongation and booting stages in treatments T₂ (farmers practice) and T₃ (urea+NP). The average grain yield of winter wheat was 8.7 t ha^-1 for the farmers practice (T₂) and 9.1 t ha^-1 for the urea+NP treatment (T₃) at the same number of split fertilizer applications.

The crop yield data showed that urea applied with NP (T₃) did increase only slightly grain yield, as compared to farmers practice (T₂). The grain yield increase with NP was about 4%, however the statistical analysis showed that this increase due to the application of urea with NP was not significant. Further research is needed to investigate additional nitrification inhibitors and their effect on wheat production.

How to cite: Mirkhani, R., Ghavami, M. S., Ahmadi, E., and Moghiseh, E.: Influence of nitrification inhibitor (Nitrapyrin) on winter wheat yield, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9684, https://doi.org/10.5194/egusphere-egu21-9684, 2021.