Relationships among soil respiration, soil temperature and dry matter accumulation for wheat-maize intercropping in an arid environment

Liu, S. B., Chai, Q. and Huang, G. B. 2013. Relationships among soil respiration, soil temperature and dry matter accumulation for wheat-maize intercropping in an arid environment. Can. J. Plant Sci. 93: 715–724. Spring wheat (Triticum aestivum L.) intercropped with maize (Zea mays L.) offers an opportunity to boost grain production in short-season areas, but little is known about the sustainability of the intercropping system. This study, conducted at an arid irrigation site in 2009 and 2010, determined water consumption and soil respiration (Rs) characteristics and their relationships to soil temperature (Ts) and above-ground dry matter (DM) accumulation for wheat/maize (W/M) intercropping compared with sole wheat and sole maize. The W/M intercropping had a co-growth period of 70-80 d, allowing the two intercropped species to complete their life cycles. Maximum DM rate for the wheat in the W/M system was significantly greater than that for sole wheat (57 vs. 51 g d −1 ), which occurred at around 72 to 77 d after sowing (DAS), whereas the maximum DM rate for the maize in the W/M system was between 31.6 and 44.9 g m −2 d −1 , or 30 to 43% lower than that of sole maize. The ercroppedhe umulation of a thetime to reach maximum DM was 96 DAS in 2009 and 80 DAS in 2010 for sole maize, and the corresponding time for the intercropped maize was delayed by 6 to 10 d. Soil respiration and DM was a curvilinear relationship; with the increase in DM accumulation, Rs increased, reached a peak at the early flowering stage for wheat and at the silking stage for maize, and then declined. Soil respiration increased linearly with increases in soil temperature during the growth period for both sole and intercropping, suggesting that farming practices aimed at reducing soil temperature will be effective in reducing carbon emissions. Evapotranspiration during the co-growth period averaged 44.1 mm for sole wheat and 48.5 mm for the intercropped wheat and 57.0 mm for sole maize and 48.0 mm for the intercropped maize, but soil water status had little or no effect on Rs. Wheat/maize intercropping had greater grain yield with lower soil respiration over the corresponding sole plantings, and it can serve as a sustainable cropping system for arid irrigation areas.