Clean technologies in agriculture : how to prioritise measures?

As agriculture continues to be under pressure due to its negative environmental impacts, resource-efficiency and the use of clean technologies gain importance. Meanwhile, there is an abundance of technological solutions that help “clean” agriculture’s hotspots, either by reducing inputs, by producing renewable energy or by protecting ecosystems. Decisions about clean technologies remain difficult due to the variety of options, difficulties in cost-benefit calculations, and potential trade-offs in sustainability. We therefore addressed the issue of decision-making regarding clean technologies in agriculture. A multi-criteria decision analysis (MCDA) was used to rank the most sustainable technologies. Evaluation of 17 selected clean technologies was based on literature information and expert opinion. Wireless sensor irrigation networks, frequency converters for vacuum pumps and stable air conditioning, PV electricity and drip irrigation were the five technologies with the highest sustainability scores, outperforming the 12 other clean technologies. When all sustainability dimensions and criteria were equally weighted, PV electricity was superseded by variable speed drive technology for irrigation in the top five. This paper shows that MCDAs are a useful method for choosing between sustainable clean technology options. By applying different weighting, the MCDA can reflect the priorities of the decision maker and provide customised results

Der Einfluss organischer Düngung im Langzeitdüngungsversuch auf das Ausmaß der Wurzelinfektion mit Arbuskulärer Mykorrhiza sowie die Entwicklung des wurzelexternen Myzels bei Kartoffel (Solanum tuberosum)

In the present study, AMF root colonisation of potato plants was compared between organically and minerally fertilised field plots, which did not significantly differ in the total amount of plant available P. The AMF root colonisation was increased in response to organic fertilisation. This indicates that organic fertilisation can enhance AMF development independently from the soil P fertilisation level. Furthermore, soil grown mycelium was trapped in fungal compartments. This technique allowed the extraction and quantification of coarse and finely branched soil grown hyphae after harvest. The soil in the fungal compartments was either fertilised with low or with high amounts of mineral P. In organically fertilised field plots, the amounts of finely branched hyphae in fungal compartments filled with soil of a high P fertilisation level were much higher compared to compartments filled with low P soil. It is discussed, whether AMF isolates from organically managed field sites have a better ability to forage for locally restricted, P rich soil patches compared to AMF isolates from minerally fertilised fields

The environmental mitigation potential of photovoltaic-powered irrigation in the production of South African maize

Agriculture is under pressure to reduce its environmental impact. The use of renewable energy sources has potential to decrease these impacts. Maize is one of the most significant crops in South Africa and approximately 241,000 hectares are irrigated. This irrigation is most commonly powered by grid electricity generated using coal. However, South Africa has high solar irradiation, which could be used to generate photovoltaic electricity. The aim of this study was to determine the environmental mitigation potential of replacing grid-powered irrigation in South African maize production with photovoltaic irrigation systems using Life Cycle Assessment. The study included the value chain of maize production from cultivation to storage. Replacing grid electricity with photovoltaic-generated electricity leads to a 34% reduction in the global warming potential of maize produced under irrigation, and – applied at a national level – could potentially reduce South Africa’s greenhouse gas emissions by 536,000 t CO2-eq. per year. Non-renewable energy demand, freshwater eutrophication, acidification, and particulate matter emissions are also significantly lowered. Replacing grid electricity with renewable energy in irrigation has been shown to be an effective means of reducing the environmental impacts associated with South African maize production

Assessment of cleantech options to mitigate the environmental impact of South African dairy farming

Milk production in South Africa has increased substantially over the past ten years and is associated with various environmental impacts. These can be reduced by different means, four of which were analysed in this study: choice of breed, the use of methane emission reducing feed additives, solar power as well as variable frequency drive usage in fodder irrigation. The results showed that Holstein cows had a lower impact than Ayrshire cows per litre of milk, but that differences between farms were greater than between breeds alone. The feed additive 3-nitrooxypropanol (3NOP) led to an 18% reduction in the climate change impact category, and did not have negative effects in other categories. Using solar power for irrigation decreased the environmental impact by a larger degree than integrating a variable frequency drive to reduce the electricity demand of the water pump. All four are adequate means of reducing the environmental impact of milk

Clean Technologies in Agriculture—How to Prioritise Measures?

As agriculture continues to be under pressure due to its negative environmental impacts, resource-efficiency and the use of clean technologies gain importance. Meanwhile, there is an abundance of technological solutions that help “clean” agriculture’s hotspots, either by reducing inputs, by producing renewable energy or by protecting ecosystems. Decisions about clean technologies remain difficult due to the variety of options, difficulties in cost-benefit calculations, and potential trade-offs in sustainability. We therefore addressed the issue of decision-making regarding clean technologies in agriculture. A multi-criteria decision analysis (MCDA) was used to rank the most sustainable technologies. Evaluation of 17 selected clean technologies was based on literature information and expert opinion. Wireless sensor irrigation networks, frequency converters for vacuum pumps and stable air conditioning, PV electricity and drip irrigation were the five technologies with the highest sustainability scores, outperforming the 12 other clean technologies. When all sustainability dimensions and criteria were equally weighted, PV electricity was superseded by variable speed drive technology for irrigation in the top five. This paper shows that MCDAs are a useful method for choosing between sustainable clean technology options. By applying different weighting, the MCDA can reflect the priorities of the decision maker and provide customised results

Green technologies for food production : the mitigation potential in cereal, fruit and dairy value chains

Oral presentatio

Agricultural biogas plants as a hub to foster circular economy and bioenergy: An assessment using substance and energy flow analysis

Today's agro-food system is typically based on linear fluxes (e.g., mineral fertilizers importation) when a circular approach should be privileged. The production of biogas as a renewable energy source and digestate as an organic fertilizer is essential for the circular economy in agriculture. This study investigates the current utilization of biomass in agricultural anaerobic digestion plants in Switzerland in terms of mass, nutrients, and energy flows to assess its contribution to the circular economy and climate change mitigation through the substitution of mineral fertilizers and fossil fuels. We quantify the system and its benefits in detail and examine potential future developments using different scenarios. Today, agricultural anaerobic digestion provides 1300 TJ/a of biogas. Our results demonstrate that the system could be largely expanded and provide ten times more biogas by 2050 while saving significant mineral fertilizer amounts (over 10 kt/a of dry mass nutrients yielding 38 kt/a of CO2 equivalent).ISSN:0921-3449ISSN:1879-065

Mitigating environmental impacts from agriculture in emerging economies : a case study of solar powered irrigation in the South African maize production

Oral presentationAgriculture is among the largest contributors to greenhouse gas emissions. Particularly in emerging countries, crops are commonly irrigated with fossil fuel based energy. A joint research project of the University of Cape Town and the Zurich University of Applied Sciences was aimed to quantify the mitigation of environmental impacts through photovoltaic electricity for irrigation in the South African maize production by mean of life cycle assessment (LCA). The study focused on maize, since it is the most important staple food for South African's people. Based on a life cycle assessment covering the whole value chain of maize production in South Africa, electricity consumption for irrigation figured out to be one of the hotspots according to environmental impacts in the maize production. Consequently, the substitution of South African electricity mix for irrigation with electricity from photovoltaic was defined as an effective clean technology to mitigate the environmental impacts of the South African maize production. By switching to photovoltaic electricity supply, the global warming potential of maize production under irrigation can be reduced by 33%. Referring to the depletion of energy resources, a reduction of 47 % can be achieved. Extrapolating to the total South African maize production area under irrigation (226'000 ha), 199 ha of solar panels are needed to produce the required electricity. Regarding to the total maize production under irrigation in South Africa, 500'000 t CO2 could be saved per year, if electricity for irrigation systems would be produced by solar panels. The clean technology of electricity production with photovoltaic for irrigation has a notable saving potential for CO2 emissions and resource depletion in the South African maize production. The benefit would be even higher, if renewable energy is expanded to further irrigated crops