MECHANISTIC PROCESS-LEVEL CROP SIMULATION MODELS FOR ASSESSMENT OF AGRICULTURAL SYSTEMS
Location: Crop Systems & Global Change
Title: Effects of carbon dioxide and phosphorus supply on potato dry matter allocation and canopy morphology
Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 18, 2011
Publication Date: N/A
Interpretive Summary: Atmospheric carbon dioxide concentration (CO2) is predicted to increase as a result of climate change. Higher levels of CO2 affect potato growth and may influence how nutrients, such as phosphorus (P) and nitrogen are used by the plant. A lot of previous research has looked at interactions with CO2 and nitrogen in some plants, but no studies with CO2 and phosphorus have been conducted in potato. Such data is required to make science-based recommendations for nutrient management strategies. Experiments conducted as part of this research measured an increase in potato yield in response to higher CO2 and P fertilizer levels. The quantity of stems and leaves in the potato plant also increased with CO2 and P fertilizer. The relative concentration of P inside different potato organs (leaves, stems, tubers) was not influenced by CO2 but did increase with fertilization. Since plants were larger at higher CO2 levels, the results indicate more P fertilizer will likely be required to support high potato yields under increased CO2 levels with respect to certain climate change predictions. These findings also suggest that if the length of the growing season were to be extended, potato growth and yield may increase further in response to CO2 enrichment if the plant is adequately fertilized. This information helps scientists understand how higher CO2 levels affect potato growth and will be used to develop appropriate mitigation strategies and mathematical modeling tools for potato crop nutrient management. The results benefit scientists, policy planners, crop consultants, and farmers.
Potatoes (Solanum tuberosum L.) generally exhibit a positive growth response to elevated atmospheric carbon dioxide concentration (CO2) and require high amounts of phosphorus (P) fertilizer. Despite its prominence as a world-wide staple crop, there is little data that quantifies effects of P, and no research on possible interactions with CO2, on potato growth and canopy morphology. Two seven week, six soil-plant-atmosphere research growth chamber studies (E1 and E2) that used three different levels of P fertilization (0 (L), 1 or 2 (M), and 8 (H) grams P per pot) and two levels of CO2 (400 or 800 parts per million) were conducted. Few interactions between CO2 and P were observed on measured responses in either study. Leaf, stem, tuber, and stolon dry matter increased with P level, with the majority of the increase occurring between the L and M levels. The growth and development of lateral-stems in the canopy were particularly sensitive to P, with a minimum 2.5- to 4-fold increase in branch and stem mass respectively across the studies between the L and M P treatments. Individual leaf length increased by an average 20.2 percent in E1 and 38.2 percent in E2 from L to H P levels and total leaf area increased by an average 336 percent in E1 and 470 percent in E2 over the same range. Tuber dry mass increased by 22 percent in E1 and 38.2 percent in E2 in response to elevated CO2 and total dry mass by 14.1 and 15.4 percent. Tissue P contents increased in response to P fertilizer but were unaffected by CO2 in either study. The results also indicated the effect of P on canopy branching is likely associated with the plant N status. The studies suggest elevated CO2 levels are unlikely to directly alter potato P fertilizer requirements on a unit mass basis. Data are expected to aid development of modeling tools for potato crop nutrient management in response to climate change.