Liu Donghua, Jia Qianmin, Li Juan, Zhang Peng, Ren Xiaolong, Jia Zhikuan
College of Agronomy, Northwest A&F University, Yingling, China.
Institute of Water Saving Agriculture in Arid Areas of China, Northwest A&F University, Yingling, China.
PeerJ. 2020 Oct 6;8:e9959. doi: 10.7717/peerj.9959. eCollection 2020.
In order to design a water-saving and high-yield maize planting model suitable for semiarid areas, we conducted trials by combining supplementary irrigation with different planting densities. Three planting densities (L: 52,500, M: 75,000, and H: 97,500 plants ha) and four supplementary irrigation modes (NI: no irrigation; IV: 375 m ha during the 11-leaf stage; IS: 375 m ha in the silking stage; and IVS: 375 m ha during both stages) were tested. The irrigation treatments significantly increased the leaf relative water content, but the high planting density significantly decreased the relative water content during the silking and filling stages. After supplementary irrigation during the 11-leaf stage, IV and IVS significantly increased the photosynthetic capacity, but decreased the leaf water use efficiency. IS and IVS significantly increased the photosynthetic capacity after supplementary irrigation in the silking stage over two years. During the filling stage, IV, IS, and IVS increased the two-year average net photosynthetic rate by 17.0%, 27.2%, and 30.3%, respectively. The intercellular CO concentration increased as the density increased, whereas the stomatal conductance, transpiration rate, net photosynthetic rate, and leaf water use efficiency decreased, and the high planting density significantly reduced the leaf photosynthetic capacity. The highest grain yield was obtained using the IVS treatment under the medium planting density, but it did not differ significantly from that with the IS treatment. Furthermore, the IVS treatment used two times more water than the IS treatment. Thus, the medium planting density combined with supplementary irrigation during the silking stage was identified as a suitable water-saving planting model to improve the photosynthetic capacity and grain yield, and to cope with drought and water shortages in semiarid regions.
为了设计出适合半干旱地区的节水高产玉米种植模式，我们通过将补充灌溉与不同种植密度相结合进行了试验。测试了三种种植密度（低密度：52500株/公顷、中密度：75000株/公顷、高密度：97500株/公顷）和四种补充灌溉模式（不灌溉：NI；11叶期灌溉375立方米/公顷：IV；抽丝期灌溉375立方米/公顷：IS；两个阶段均灌溉375立方米/公顷：IVS）。灌溉处理显著提高了叶片相对含水量，但高种植密度显著降低了抽丝期和灌浆期的相对含水量。11叶期补充灌溉后，IV和IVS显著提高了光合能力，但降低了叶片水分利用效率。在两年的时间里，IS和IVS在抽丝期补充灌溉后显著提高了光合能力。在灌浆期，IV、IS和IVS使两年平均净光合速率分别提高了17.0%、27.2%和30.3%。胞间CO₂浓度随密度增加而升高，而气孔导度、蒸腾速率、净光合速率和叶片水分利用效率降低，高种植密度显著降低了叶片光合能力。在中等种植密度下，IVS处理获得了最高的籽粒产量，但与IS处理的产量差异不显著。此外，IVS处理的用水量是IS处理的两倍。因此，中等种植密度与抽丝期补充灌溉相结合被确定为一种合适的节水种植模式，可提高光合能力和籽粒产量，应对半干旱地区的干旱和水资源短缺问题。
