No-tillage reduces competition and enhances compensatory growth of maize (Zea mays L.) intercropped with pea (Pisum sativum L.)

Compensatory growth is a mechanism that explains the recovery in stature and yield of a subordinate crop after the dominant competitor is harvested from an intercropping system. This mechanism might be affected by agronomic practices, particularly those related to the crop water supply in arid regions. The objective of this study was to evaluate the effects of tillage and irrigation practices on competition and compensatory growth in pea-maize intercropping systems at Wuwei station in northwest China from 2014 to 2016. The field experiment included two forms of tillage with plastic film (no-tillage, NT; conventional tillage CT) and three irrigation levels (450 mm, I1; 495 mm, I2; 540 mm, I3). As pea was planted first, it was the dominant competitor and caused greater suppression of maize when crops were grown under I1 > I2 > I3 levels in NT than at the corresponding irrigation levels in CT. Compensatory growth of maize after pea harvest was, on average, 8 to 16% greater in the NT than CT. Growing the intercropped maize strip under NT with plastic mulch was as effective as CT with plastic mulch to achieve a favorable yield outcome. However, the intercropped pea yield was 20-29% greater, with 0-5% more maize yield under deficit irrigation level (I1) and the land equivalent ratio was 3-15% greater in NT than CT plots during this study. Yield gains were related to improved water use efficiency, which was 8 to 18% greater in the intercropping system under NT than CT management. We recommend the NT with plastic mulch method as a water-saving strategy that can sustain the productivity of maize-pea intercropping systems while reducing plastic pollution from agricultural activities in arid regions.