AimsA sound root system architecture (RSA) is important for e cient nutrient and water acquisition. The adaptation of root growth and RSA to the special soil structure under conservative strip tillage (ST) system is largely unknown.
MethodsWe describe three-year eld experimentation on a meadow black soil in the Northeast China to investigate the RSA and the dynamic root growth of maize under ST by comparison with the conventional tillage (CT).
ResultsGrain yield in ST and CT were not signi cantly different, but their yield components differed. Compared to CT, grain number per ear was reduced by 4.4%, while 1000-grain weight was increased by 6.6% in ST. Root growth in ST plants was inhibited in the vegetative stage, as indicated by the reduced total root length (by 27.7-40.1%) compared to CT. During post-silking stage, however, the total root length was not different between ST and CT plants. Accordingly, the root xylem bleeding rate in ST plants was 70.7%-449.9% greater than CT plants. Because ST practice caused uneven horizontal distribution of soil bulk density, the RSA became steeper in ST plants compared to CT. Moreover, the D 95 of ST plant roots was greater, indicating their roots grew deeper.
ConclusionsIn conclusion, although root growth is inhibited at vegetative stage, the slow-aging and steep, deep roots in ST plants may contribute to larger grain weight by favoring water and nutrient acquisition during grain lling stage. As a result, grain yield of ST plants is maintained though grain number per ear is reduced.