Effects of precision planting patterns and irrigation on winter wheat yields and water productivity

The production of winter wheat (Triticum aestivum L.) is affected by crop population structures and field microclimates. This 3-year study assessed the effect of different precision planting patterns and irrigation conditions on relative humidity (RH), air and soil temperature within the canopy, intercepted photosynthetically active radiation (iPAR), evapotranspiration (ET), water productivity (WP) and grain yields. Field experiments were conducted from 2011 to 2014 on a two-factor split-plot design with three replicates. The experiments involved three precision planting patterns (single row, alternating single and twin rows [hereafter 'single-twin'] and twin row) and three irrigation treatments (0 mm (I-0), 90 mm (I-90) and 180 mm (I-180)). Planting patterns and irrigation treatments exerted a significant effect on RH, air and soil temperature, iPAR, ET, WP and grain yield. The lowest RH and iPAR levels were detected in the single row pattern. When the irrigation treatment was identical, the highest soil and air temperatures were detected in the single row pattern, followed by the single-twin row and twin row patterns. Compared with the single row, the single-twin and twin row patterns increased ET by 0.3 and 1.4, WP by 4.7 and 5.7% and yields by 6.0 and 7.9%, respectively. Compared with I-0, the I-90 and I-180 irrigation treatments increased ET by 0.3 and 1.4%, and WP by 4.7 and 5.7%, respectively. The grain yields of the twin row pattern were 5.8 and 1.7% higher than those of the single row and single-twin row patterns, respectively. Compared with I-0, I-90 increased yield by 19.3%. The twin row pattern improved crop structure and farmland microclimate by increasing RH and iPAR, and reducing soil and air temperatures, thus increasing grain yield. These results indicated that a twin row pattern effectively improved grain yield at I-0. On the basis of iPAR, WP and grain yield, it was concluded that a twin row pattern combined with an I-90 irrigation treatment provided optimal cropping conditions for the North China plain.