水保所知识产出(1956---)知识库

Understanding the morphological response of maize roots in the presence of soybeans in fields under varied
water conditions is vital for identifying maize-dominant intercropping systems suitable for climate change. In
this study, two maize-soybean intercropping systems (maize with and without film mulching) were compared
with maize and soybean sole crops in rainfed farmland on the Loess Plateau. Different features, including the
maize root morphological traits, root vertical distribution, shoot traits, interspecific root overlap, and grain yield
of intercrops, were determined after silking in 2017 (dry year) and 2018 (wet year). The intercropped maize
(without film mulching) employed a thin root system under dry conditions and a profuse root system under wet
conditions, with shallow roots and active root-diameter strategy to adapt to varied water conditions. These
features resulted in higher grain yield in per unit area for the intercropped maize (16.97 % overyielding) than
sole maize without film mulching. Film mulching of intercropped maize modified the roots with confined growth
under dry conditions and inhibited the roots with excessive growth under wet conditions; as a consequence, the
two morphologies of intercropped maize root system were reshaped into the optimal one (less profuse but not
thin), with S-type vertical distribution (1 m soil profile) for root length and more beneficial root-diameter
strategy. Besides, film mulching improved interspecific root interaction through an evident increase in root
length or mass in the interspecific overlap regions. Finally, film mulching improved the maize overyielding
dramatically (84 %) due to high leaf adaptability and efficient root-shoot synergy in maize plants. Importantly,
the maize mulching did not decrease intercropped soybean yield significantly when compared with sole soybean
due to the benefits from interspecific facilitation, while it enhanced total grain yield (10.67 %) for the inter-
cropping system. Thus, film mulching improved maize root morphology and balanced soil resource exploitation
and shoot development, consequently strengthening the attainable grain yield in the intercropping system. To
conclude, the research elucidates the plant root mechanisms (root morphological changes) underlying over-
yielding of intercropped maize in varied water conditions. It identifies film mulching of maize as a strategy to
optimize root growth and function for higher intercropping yield advantage in dryland.