Effects of drought stresses during key growth periods on root growth of spring maize in Northeast China
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DOI:10.7606/j.issn.1000-7601.2018.01.24
Key Words: spring maize in northeast China  drought stress  root distribution  jointing stage  tasseling stage  root length density
Author NameAffiliation
CHEN Peng-shi Liaoning Institute of Meteorological Science, Shenyang 110166, China 
JI Rui-peng Institute of Atmospheric Environment, China Meteorological Administration, Shenyang 110166, China 
XIE Yan-bing Institute of Atmospheric Environment, China Meteorological Administration, Shenyang 110166, China 
SHI Kui-qiao Jinzhou Ecological and Agricultural Meteorology Center, Jinzhou 121001, China 
YANG Yang Jinzhou Ecological and Agricultural Meteorology Center, Jinzhou 121001, China 
ZHANG Hui Jinzhou Ecological and Agricultural Meteorology Center, Jinzhou 121001, China 
CAI Fu Institute of Atmospheric Environment, China Meteorological Administration, Shenyang 110166, China 
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Abstract:
      To investigate the effects of drought stress during growing periods on root distribution (RD) of spring maize during the jointing (BJ) and tasseling (CX) stages of maize, the root length densities (RLDs) at different soil depths during the corresponding growth periods were dynamically measured with the minirhizotron method, and the parameters d50 and d95 related to RD representing respectively the soil depths where cumulative root fraction are 50% and 95% were simulated using root distribution model, and then spatio-temporal characteristics of soil relative water contents (SWC), RDs and theirs parameters were analyzed. The results showed that after water stress, actual SWC was basically consistent with the expectant condition though there were some differences between the two. More specifically, the SWC above the soil depth of 130 cm basically achieved the intended result, that is, the SWCs above the soil depth of 100 cm for the BJ and CX treatments were respectively below 40%. Conversely, the SWCs in the deeper soil layers were not impacted by water stress and still kept suitable soil water conditions. In addition, the maximums of RLDs were 1.24±0.77 cm·cm-3 at the depth of 40 cm for the CK treatment and 2.18±0.89 cm·cm-3 and 2.10±0.47 cm·cm-3 at the depth of 60 cm for the BJ and CX treatments, respectively. Below the depth of the maximum RLD, the RLDs for the CK and BJ treatments decreased with the increasin g soil depth and the RLD for CX treatment kept a larger value below the soil depth of 80 cm. Furthermore, the d50, d95 for BJ and CX treatments were 45% and 59%, 8% and 41% larger than those of the CK treatment respectively, which proved that the maize root will grow to deeper soil layers when suffering drought stress relative to normal condition. In conclusion, this study can offer a reference for optimizing the root water uptake parameterization schemes in land surface, ecological and crop growth models.