Physiological trait networks enhance understanding of crop growth and water use in contrasting environments.

Plant function arises from a complex network of structural and physiological traits. Explicit representation of these traits, as well as their connections with other biophysical processes, is required to advance our understanding of plant-soil-climate interactions. We used the Terrestrial Regional Ecosystem Exchange Simulator (TREES) to evaluate physiological trait networks in maize. Net primary productivity (NPP) and grain yield were simulated across five contrasting climate scenarios. Simulations achieving high NPP and grain yield in high precipitation environments featured trait networks conferring high water use strategies: deep roots, high stomatal conductance at low water potential ("risky" stomatal regulation), high xylem hydraulic conductivity and high maximal leaf area index. In contrast, high NPP and grain yield was achieved in dry environments with low late-season precipitation via water conserving trait networks: deep roots, high embolism resistance and low stomatal conductance at low leaf water potential ("conservative" stomatal regulation). We suggest that our approach, which allows for the simultaneous evaluation of physiological traits, soil characteristics and their interactions (i.e., networks), has potential to improve our understanding of crop performance in different environments. In contrast, evaluating single traits in isolation of other coordinated traits does not appear to be an effective strategy for predicting plant performance.

USDA-ARS Colorado maize growth and development, yield and water-use under strategic timing of irrigation, 2012-2013.

This data set was collected over two years, 2012-2013, on maize under 12 irrigation treatments with varying levels of deficit during late-vegetative and grain-filling growth stages in semi-arid Northern Colorado supplied with surface drip irrigation. The data set, which can be found online at the USDA National Agricultural Library data repository (doi: 10.15482/USDA.ADC/1439968), includes hourly weather data; plant growth and canopy development over the season; final biomass, yield and harvest index; and daily water balance data including irrigation, precipitation, soil water content, and estimates of crop evapotranspiration. Soil parameters for the site, as well as data from a previous experiment on maize with different treatments can also be found online (doi: 10.15482/USDA.ADC/1254006). Here, we describe the synthesis of data collected from 2012 to 2013. These data can be used for modeling the relationship between maize yield and field-level water use under season water availability.