Singh Manpreet, Singh Sukhbir, Parkash Ved, Ritchie Glen, Wallace Russell W, Deb Sanjit K
Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, United States.
Department of Crop and Soil Sciences, University of Georgia, Tifton, GA, United States.
Front Plant Sci. 2022 Apr 22;13:853746. doi: 10.3389/fpls.2022.853746. eCollection 2022.
The integration of biochar and deficit irrigation is increasingly being evaluated as a water-saving strategy to minimize crop yield losses under reduced irrigation in arid and semi-arid regions such as West Texas. A 2-year (2019 and 2020) open-field study evaluated the effect of two types of biochar amendments (hardwood and softwood) and three irrigation rates [100, 70, and 40% crop evapotranspiration (ET ) replacement] on the physiology, plant growth, and yield of sweet corn in semi-arid West Texas. All experimental units were replicated four times in a split-plot design. The chlorophyll content (Chl ) in 40% ET dropped significantly compared to 100% ET and 70% ET during the reproductive phase. Although water stress under 40% ET decreased photosynthesis ( ) to limit transpiration (E) by stomatal closure, it improved intrinsic water use efficiency (iWUE). The above-mentioned gas exchange parameters were comparable between 100% ET and 70% ET . Both biochar treatments increased Chl content over non-amended plots, however, their effect on gas exchange parameters was non-significant. All growth and yield-related parameters were comparable between 100% ET and 70% ET , but significantly greater than 40% ET , except water productivity (WP). Both deficit irrigation treatments improved WP over full irrigation in 2019, but in 2020, the WP gains were observed only under 70% ET . Hardwood biochar decreased soil bulk density and increased soil porosity, but it had a marginal effect on the water retention characteristics. These results suggest that 70% ET can be used as an alternative to full irrigation to save water with a minimal yield penalty for sweet corn production in the West Texas region. The hardwood biochar application improved the vegetative biomass significantly but yield marginally during the first 2 years of application. A long-term study is required to test the effect of biochar under deficit irrigation beyond 2 years.
生物炭与亏缺灌溉相结合，正日益被视为一种节水策略，可将干旱和半干旱地区（如西德克萨斯州）在灌溉减少情况下的作物产量损失降至最低。一项为期两年（2019年和2020年）的田间试验，评估了两种生物炭改良剂（硬木和软木）以及三种灌溉率[分别替代作物蒸散量（ET）的100%、70%和40%]对西德克萨斯州半干旱地区甜玉米生理、植株生长和产量的影响。所有试验单元在裂区设计中重复4次。在生殖阶段，40%ET处理下的叶绿素含量（Chl）与100%ET和70%ET处理相比显著下降。虽然40%ET处理下的水分胁迫通过气孔关闭降低了光合作用（ ）以限制蒸腾作用（E），但提高了内在水分利用效率（iWUE）。上述气体交换参数在100%ET和70%ET处理之间相当。两种生物炭处理均使Chl含量高于未改良地块，然而，它们对气体交换参数的影响不显著。100%ET和70%ET处理之间所有与生长和产量相关的参数相当，但显著高于40%ET处理，水分生产率（WP）除外。两种亏缺灌溉处理在2019年的WP均高于充分灌溉，但在2020年，仅在70%ET处理下观察到WP增加。硬木生物炭降低了土壤容重，增加了土壤孔隙度，但对保水特性影响较小。这些结果表明，70%ET可作为充分灌溉的替代方案，在西德克萨斯州地区生产甜玉米时节约用水，同时产量损失最小。在施用的前两年，硬木生物炭的施用显著提高了营养生物量，但对产量的影响较小。需要进行长期研究来测试生物炭在亏缺灌溉条件下超过两年的效果。
