Water Use, Intercepted Radiation, and Soil Temperature of Skip‐Row and Equidistant‐Row Barley

Cropping systems are sought in the subarctic that improve the plant growing environment for sustained and diversified production of crops. This study assessed whether microclimate and water use of barley ( Hordeum vulgare L.) could be altered in the subarctic by crop row configuration and fertilizer placement. Treatments established at Fairbanks, AK, included equidistant‐row planting (0.18‐m equidistant rows) with N banded between alternate rows or broadcast, and skiprow planting (skipping every third row of equidistant rows) with N banded between the closely spaced rows or broadcast. Crop water use, net and reflected radiation, interception of photon flux density (PFD), and soil temperatures were monitored during 1987 through 1989. Banding N resulted in a higher water‐use efficiency (WUE) than did broadcasting N in 1989 but not 1988. Seasonal water use was equal among treatments, although higher leaf area index (LAI) for equidistant‐ row barley suggested less evaporation and greater transpiration than for skip‐row barley. Equidistant‐row barley intercepted 5% more PFD at heading, resulting in part from higher canopy reflectance. Skip‐row barley, however, intercepted more PFD per unit leaf area. Midday net radiation was 3% higher and midday soil temperatures at 0.01 m in the interrow were as much as 5 °C higher for skip‐row barley. In this subarctic environment, barley grown in equidistant rows appeared to utilize water more effectively in transpirational processes and to intercept more PFD for improving production efficiency compared to skip‐row planting.