Response of the Shoot and Root Growth to Soil Temperature and Moisture of Spring Maize Seedlings in Western Liaoning Province

Objective Exploring the responses of maize shoot and root growth to soil temperature and moisture will provide a scientific basis for formulating agricultural management measures to deal with climate change.

Method Using the automated soil temperature and moisture observation data, combined with spring maize growth indicators of roots (root length, root number) and shoots (plant height, stem diameter, leaf area), biomass and meteorological data, correlation analysis and Partial Least Squares Path Model (PLS-PM) methods were employed to analyze the impacts of soil temperature and moisture on the growths of shoots and roots of spring maize during the seedling stage.

Result The soil moistures at 15 cm, 45 cm, 75 cm, 105 cm, and 135 cm depths during the seeding stage had variation coefficients of 0.023, 0.033, 0.024, 0.009, and 0.010, and their changes had temporal hysteresis relative to air humidity and precipitation, and the hysteresis increased with increasing soil depth. In addition, the soil temperature decreased with the increase of soil depth, and its variation coefficient at each above-mentioned layer was 0.115, 0.113, 0.114, 0.110, and 0.105, respectively. The hysteresis of variation of soil temperature relative to air temperature gradually increased with the increase of soil depth. Correlation analysis showed that the correlations between the growth indices and biomass and soil temperature and moisture at the 15 cm depth were greater (smaller) than those at the 45 cm depth during the three-leaf (seven-leaf) stage. Besides, PLS-PM analysis showed that the growths of shoots and roots were the main influencing factors by soil temperatures at 15 cm and 45 cm depths during the seedling stage, by the soil moisture at 15 cm depth during the three-leaf stage, and by soil moisture at 45 cm depth during the seven-leaf stage. Soil temperature and moisture at 15 cm depth had the greatest impact on biomass accumulation.

Conclusion Appropriate soil temperature and moisture configurations can constitute the optimal overall structure and function of the shoots and roots of spring maize, promote the growth of plant, and increase biomass accumulation and yield. In practice, soil moisture can be regulated to achieve the purpose of regulating soil temperature.