Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.

Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.

Prospects for Yield Gains in High-Yielding Cropping Systems

Gonzalo Dario Rizzo Ayphassorho, University of Nebraska - Lincoln


Increasing food demand, rapid climate warming, and the concerns about environmental impact of agriculture will require improved agronomic management and policies during the next decades. Novel approaches to identifying causes of the yield gap are needed to increase the effectiveness of agricultural research and development (AR&D) programs and accelerate the generation and transfer of knowledge. This project combines case studies in two countries where proper prioritization of AR&D is key to meeting crop production goals towards the year 2050. The first case study presents an approach that combines farmer data and crop modeling to disentangle the contribution of climate, agronomic and genetic technologies to maize yield gain in irrigated environments in United States (U.S.). The second case study developed a farmer data-driven approach for prioritization of AR&D at a national level in the cereal-based systems in Indonesia. Subsequently, the extent of yield limitation due to potassium deficiencies over the most important rice and maize producing areas of Indonesia were further investigated by applying an approach that combined farmer survey data, in-situ foliar nutrient status diagnosis, data from a long-term fertility experiment, and a collection of data from on-farm fertility trials. High-yielding irrigated maize in the U.S. showed a linear yield gain of 186 kg ha-1 y-1 with climate representing 49% of the estimated yield gain, followed by agronomic practices represented (39%), and a marginal contribution of improved genetics (13%). In intensive rice-maize systems in Indonesia there was a discrepancy between local researchers' and extensionists' perceptions of the most important on-farm yield constraints versus the ones objectively detected. Partial nutrient balances estimated based on survey data and leaf tissue analyses showed a widespread potassium deficiency in rice and maize. Long-term experiments showed a low yield response to potassium over time compared to the yield response to nitrogen and phosphorus fertilizer additions. On-farm fertility trials showed low yield and net profit increases due to potassium fertilizer addition, leading to low return on investment which prevents the generalized adoption of this technology.

Subject Area


Recommended Citation

Rizzo Ayphassorho, Gonzalo Dario, "Prospects for Yield Gains in High-Yielding Cropping Systems" (2022). ETD collection for University of Nebraska-Lincoln. AAI29998272.