Calculation of the net greenhouse gas emissions of fertilization and irrigation strategies in a potato cropping system

Abstract In the context of modern agriculture, irrigation is a widespread technique employed to help crop growth and ensure food production. However, there are various irrigation strategies, each with its distinct set of components and machinery. These differences in irrigation methodologies impact the environment in different ways. In this work, we focus on greenhouse gases emissions throughout the agricultural process. Our primary research objective is to comprehensively evaluate the environmental impact, in terms of kg of CO2 equivalent, of several irrigation strategies both in scenarios with and without the use of fertilizers, with the aim of identifying the most environmentally sustainable option. To complete this objective, we have done extensive potato cultivation experiments over a span of three years, in 2019, 2020, and 2021. The experiments include using of different irrigation strategies: 1.??Drip Irrigation with N Fertilization 2.??Drip Irrigation without N Fertilization 3.??Sprinkler Irrigation with N Fertilization 4.??Sprinkler Irrigation Without N Fertilization 5.??No Irrigation, No Fertilization 6.??No Irrigation with N Fertilization 7.??Fertigation 8.??Fertigation with No Crop Our research methodology started with a life cycle assessment approach, which provided an overview to all activities related to potato production, from cradle to gate. The input data for calculating greenhouse gas emissions, including material input data and type of machinery used, were provided by the Leibniz Institute of Agricultural Engineering and Bio-economy for each of the three years and the emission factors were provided mostly from KTBL and ecoinvent data base. In our analysis, we observed that drip irrigation consistently appeared as the most environmentally sustainable strategy, consistently yielding lower greenhouse gas emissions. On the other hand, the fertigation method, while potentially effective in nutrient management, included higher machinery utilization and therefore increased emissions making it a less practical choice for sustainable agriculture. The results of this work are useful to choose the most sustainable irrigation strategy, that emits the least amount of greenhouse gases while being productive. Based on the balance between yield and greenhouse gas emission use, our results show that the drip irrigation is the best strategy, under the conditions specific of this case study in Germany.