Eddy covariance quantification of carbon and water dynamics in twin-row vs. single-row planted corn

For sustainable irrigated crop production, enhancing the productivity of pumped water from aquifers, which are fast declining, is critical. In this investigation, the yield and water use efficiency (WUE) of corn planted in a single-row (SR) on a raised-bed ridge-furrow system was compared with corn planted in a twin-row (TR) pattern. The crop's consumptive water use (evapotranspiration, ET) was quantified using the eddy covariance (EC) technology. The crops for the investigation were raised on large-scale farmer’s fields (above 100 ha). In the EC system, CO2 and water vapor fluxes over corn plant canopies were monitored using an infrared gas analyzer, and wind turbulence was quantified using an omnidirectional 3D sonic anemometer. The LAI, grain yield, ET, net ecosystem exchange of CO2 (NEE), and gross primary productivity (GPP) measured under TR were higher than SR by 18%, 19%, 22%, 90%, and 41%, respectively. Also, WUE in NEE (WUENE, ratio of NEE to ET) was higher under TR than SR by 40%, rendering TR the best choice for corn planting in the region. WUE for grain yield (WUEGY, ratio of grain yield to ET) and net ecosystem respiration did not differ appreciably across TR and SR systems. The measured ET in TR was 518 mm, while SR was 426 mm during the crop season (emergence to physiological maturity). The study conducted in large-scale farm fields gives better confidence than results obtained based on conventional small-plot studies recommending the TR over SR planting in the region for grain yield and WUENE in corn production systems.