Wheat Grain Quality Response to Tillage and Rotation with Field Pea

Preceding spring wheat (Triticum aestivum L.) with field pea (Pisum sativum L.) can enhance wheat grain yield in a wheat-pea (WP) rotation compared with continuous wheat (WW). The pea-rotation benefits to wheat grain quality are uncertain. A 6-yr study was conducted to determine (i) if grain protein content, kernel weight, and test weight were enhanced for wheat in a WP rotation compared with WW, and (ii) if an interaction between cropping and tillage systems existed. The WP and WW systems were maintained in subplots within clean-till (CT), reduced-till (RT), and no-till (NT) whole plots arranged in a randomized complete block as a split plot in southwestern North Dakota, USA. Grain protein content of wheat averaged 160 g kg(-1) and was unaffected by cropping system (P > 0.05). However, grain protein content was 10 to 30 g kg(-1) lower under NT compared with CT, depending on the year. Kernels were heavier in two of 6 yr in the WP rotation compared with WW. No difference in kernel weight was detected between cropping systems in the other 4 yr. A consistent trend in kernel weight was not detected across tillage systems, and interactions between cropping and tillage systems were not observed for either grain protein content or kernel weight. A three-way interaction between cropping systems, tillage systems, and years was detected for grain test weight. These results failed to demonstrate a consistent pea-rotation benefit to wheat grain quality.