Effects of Row Spacing on the Yields Advantage and Interspecific Interaction of the Intercropped Maize and Potato

PurposeBeing an important crop population layout, row spacing determines crop growth and yield. However, there is a lack of research on maize and potato intercropping.

MethodThe most widely used model in Yunnan Province is that the row ration of intercropping is 2∶2. We conducted a two-year field experiment to study the effects of different row spacing on intercropping advantage and interspecific relations. The spacing range of interspecific row space (ZJ) designed from 30 cm to 70 cm at 10 cm interval, while that of intraspecific row space (ZN) designed from 65 cm to 25 cm correspondingly. As a result, there were five row spacing layout modes (ZJ70 cm+ZN25 cm, ZJ60 cm+ZN35 cm, ZJ50 cm+ZN45 cm, ZJ40 cm+ZN55 cm, ZJ30 cm+ZN65 cm). We also included the maize (Ms) and potato (Ps) monoculture as references.

Result(1) All five modes of row spacing layout displayed the intercropping advantage with the land equivalent ratio (LER) greater than 1 (1.21-1.42). Overall, the yield of potato and maize gradually increased when the jointing stage of maize were the gluttonous period of competition between the two crops. ZJ decreased gradually from 70 to 30 cm. However, the yield decreased when ZJ further decreased from 70 to 30 cm. The yield of both maize and potato maximized at ZJ40 cm+ZN55 cm treatment, reaching 13 833 kg/hm² for potato, 7 808 kg/hm² for maize, and LER was 1.42. The overall performance was that the narrow ZJ (>50 cm) modes had a higher yield than those of the wider (ZJ<50 cm), which had prominent intercropping advantage and high system productivity. (2) At the early flowering stage of potato, as ZJ decreased from 70 cm to 30 cm, the potato competitiveness gradually increased (RII was −0.06 to 0.01) and the maize gradually decreased (RII was −0.04 to −0.23). With the advancement of maize growth period, the competitiveness of the two crops gradually reduced, but the competitiveness of potato was always greater than that of maize. At any stages, the plants with a row spacing of 40 cm were relatively competitive. (3) The dry matter transfer rate (DMME %) and contribution rate (DMCR %) of potato increased with the decrease of interspecific row space, and the highest ones were 32.6 % and 25.5% of ZJ40 cm+ZN55 cm, which were 39.5% and 47.7% higher than the minimum values of ZJ70 cm+ZN25 cm. In general, the inter-species narrow row mode was higher than the inter-species wide row mode, and the demarcation point was 40 cm. (4) The restorative growth capacity (RGR) showed that the interspecific narrow row mode was better than the interspecific wide row mode for jointing to silking and silking to physiology maturity, the best was ZJ40 cm +ZN55 cm treatment, which was 37% and 30% higher than the smallest of ZJ70 cm + ZN25 cm, and the demarcation point was ZJ40 cm.

ConclusionIt follows that under the mode of corn/potato 2∶2 row ratio and bandwidth of 190 cm, the intercropping advantage of the inter-species narrow row mode was significantly higher than that of the inter-species wide row mode, with the highest interspecies row spacing being ZJ40 cm+ ZN55 cm. This discovery not only has important significance for actual production, but also provides a reference for efficient planting of this model in other ecological environments.