Browsing by Subject "Crop yield"

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Agrivoltaic system impacts on microclimate and yield of different crops within an organic crop rotation in a temperate climate
(2021) Weselek, Axel; Bauerle, Andrea; Hartung, Jens; Zikeli, Sabine; Lewandowski, Iris; Högy, Petra
Agrivoltaic (AV) systems integrate the production of agricultural crops and electric power on the same land area through the installation of solar panels several meters above the soil surface. It has been demonstrated that AV can increase land productivity and contribute to the expansion of renewable energy production. Its utilization is expected to affect crop production by altering microclimatic conditions but has so far hardly been investigated. The present study aimed to determine for the first time how changes in microclimatic conditions through AV affect selected agricultural crops within an organic crop rotation. For this purpose, an AV research plant was installed near Lake Constance in south-west Germany in 2016. A field experiment was established with four crops (celeriac, winter wheat, potato and grass-clover) cultivated both underneath the AV system and on an adjacent reference site without solar panels. Microclimatic parameters, crop development and harvestable yields were monitored in 2017 and 2018. Overall, an alteration in microclimatic conditions and crop production under AV was confirmed. Photosynthetic active radiation was on average reduced by about 30% under AV. During summertime, soil temperature was decreased under AV in both years. Furthermore, reduced soil moisture and air temperatures as well as an altered rain distribution have been found under AV. In both years, plant height of all crops was increased under AV. In 2017 and 2018, yield ranges of the crops cultivated under AV compared to the reference site were −19 to +3% for winter wheat, −20 to +11% for potato and −8 to −5% for grass-clover. In the hot, dry summer 2018, crop yields of winter wheat and potato were increased by AV by 2.7% and 11%, respectively. These findings show that yield reductions under AV are likely, but under hot and dry weather conditions, growing conditions can become favorable.
Modeling crop yield and farmer adaptation to rainfall variability
the case of Southern Ethiopia
(2016) Bocher, Temesgen Fitamo; Berger, Thomas
Improving the livelihood of poor households in developing countries by increasing agricultural productivity and production becomes the priority agenda for development actors. However, variability in rainfall has confronted success in achieving this goal. There is pressing interest in analyzing the effects of rainfall variability on household welfare and identifying policy interventions to mitigate its adverse effects. Ethiopian economy primarily depends on rain-fed agriculture. Agriculture is the backbone of the country’s economy; it contributes the lions share of GDP, employment, export earnings, and livelihood. Fluctuations in rainfall distribution and intensity have severely affected the economy in general and the livelihood of smallholder households in particular; the agricultural sector is more prone to changes in climatic condition, which increases the risk of poverty and hunger for poor farm households. Few studies have attempted to analyze the direct effects of rainfall variability on crop yield and its indirect effect on household welfare. Therefore, this thesis aimed at filling the knowledge gap on the impacts of rainfall variability on crop yield and welfare. Moreover, the study explores the role of adaptation strategies in mimicking the negative effects of rainfall variability accounting for household performance decision under resource constraint for Ethiopian farmers. The study employed Mathematical Programming Based Multi-Agent System (MP-MAS) computer simulation techniques to analyze the effects of rainfall variability on crop yield, household welfare and the role of adaptation strategies in mitigating the adverse effects of rainfall variability. Prior to application to the study, the MP-MAS simulation model is parametrized, calibrated, and validated using data from the Ethiopian Rural Household Survey (ERHS), primary data collected from the research area and thirty year rainfall time series data obtained from meteorological stations located near to the study area. To address the mentioned research question a wide range of rainfall and adaptation strategy scenarios were designed. The agent - based model enables us to incorporate different bioeconomic systems in the decision-making process by smallholder farmers, which is otherwise difficult under a real world situation where farm households face inseparable decision-making process. Moreover, the model accounts for the heterogeneity in resource endowment, investment, production, consumption, agro-ecology, input constraints, and demographic distribution among households. Livestock, consumption, crop growth and irrigation water distribution models were combined in this study. The household food consumption decision is estimated by using three stages advanced consumption module and crop water requirement and irrigation water distribution modeled using inbuilt FAO CropWat and EDIC modules, and finally an empirical analysis was done by using STATA version 12. The simulation result suggested that: (i) Both current and future rainfall variability would have negative effects on crop yield and household welfare. (ii) The yield of cereals crops and vegetables are negatively affected by rainfall variability: some perennial crops such as enset gains yield under rainfall variability. (iii) Household welfare deteriorated with rainfall variability; resource poor households are severely affected by rainfall variability. (iv) Adaptation strategies such as non-farm activities, irrigation, and soil and water conservation activities mitigate the negative effects of rainfall variability. (v) Improving the financial or non-farm constraints alone leads to increased income inequality. Therefore, the recommended solution to reduce adverse effects of rainfall variability includes: (i) Implementing integrated policy interventions than a single strategy. (ii) Improving access to credit and access to non-farm activities. (iii) Designing a pro-poor intervention (such as improving the asset base of the poor households). (iv) Improving access and use of improved agricultural technologies, and (v) Increasing access and use of irrigation to enhance agricultural productivity.