State Key Laboratory of Crop Biology, Key Laboratory of Crop Water Physiology and Drought Tolerance Germplasm Improvement of Ministry of Agriculture, Shandong Agricultural University, Tai'an, China.
PeerJ. 2022 Feb 11;10:e12891. doi: 10.7717/peerj.12891. eCollection 2022.
Based on two years of field experiments, under different soil tillage methods and straw management practices, which included conventional tillage (CT), subsoiling (SS), rotary tillage (RT), and no-tillage (NT), combined with either straw return (S) or straw removal (0), we characterized the dynamic changes in ΔC among three height layers [upper (U, 240 cm above the ground), middle (M, 120 cm above the ground), and lower (L, 30 cm above the ground)] of the summer maize canopy. The ΔC, the factors affecting it, and the relationships between ΔC and soil water content (SWC), the leaf area index (LAI), canopy microclimate, and the CO concentration were elucidated. The results indicated that the ΔC of summer maize at the pre-filling stage was greater than that at the post-filling stage. ΔC also varied at different heights, with the order of the ΔC values being L > U > M. Among the different tillage methods, the ΔC values were ordered SS > CT > RT > NT. SS and NT significantly increased the LAI; air temperature and relative humidity tended to gradually decrease with the increase in height of summer maize. Correlation analyses of the various influencing factors and ΔC showed that SWC, LAI, air temperature, and CO concentration were all positively correlated with ΔC, in which LAI and air temperature were significantly or extremely significantly positively correlated with ΔC. In addition, we show that ΔC can be used as a prediction index for summer maize yield, providing a theoretical basis for future yield research that may save precious time in summer maize breeding efforts.
基于两年的田间试验，在不同的土壤耕作方法和秸秆管理措施下，包括传统耕作（CT）、深松（SS）、旋耕（RT）和免耕（NT），结合秸秆还田（S）或秸秆移除（0），我们描述了夏季玉米冠层三个高度层[上层（U，距地面 240 厘米）、中层（M，距地面 120 厘米）和下层（L，距地面 30 厘米）]中ΔC 的动态变化。阐述了ΔC、影响ΔC 的因素以及ΔC 与土壤水分含量（SWC）、叶面积指数（LAI）、冠层微气候和 CO 浓度之间的关系。结果表明，夏玉米灌浆前ΔC 大于灌浆后ΔC。ΔC 也在不同高度处发生变化，ΔC 值的顺序为 L > U > M。在不同的耕作方法中，ΔC 值的顺序为 SS > CT > RT > NT。SS 和 NT 显著增加了 LAI；空气温度和相对湿度随着夏玉米高度的增加而逐渐降低。对各种影响因素与ΔC 的相关分析表明，SWC、LAI、空气温度和 CO 浓度均与ΔC 呈正相关，其中 LAI 和空气温度与ΔC 呈显著或极显著正相关。此外，我们表明ΔC 可以作为夏季玉米产量的预测指标，为未来的产量研究提供理论基础，这可能会在夏季玉米育种工作中节省宝贵的时间。
