One approach to water optimization in agriculture is to increase soil water retention. A soil amendment that has received attention for its ability to increase soil water retention is biochar, the remaining biomass after high-C materials have been pyrolyzed. Two studies were conducted in Utah at two sites each during 2018–2020 to evaluate how a fast-pyrolysis wood biochar influenced the productivity and crop quality of irrigated alfalfa (Medicago sativa L.), corn (Zea mays L.), and wheat (Triticum aestivum L.) along with soil water tension. One study included a single biochar rate of 22 Mg ha⁻¹ at two levels of irrigation (full vs. partial), where soil-incorporated biochar increased silage corn yield by 12% in 2018 and reduced yield by 10% in 2019. Topdressed biochar had no effect on alfalfa yield from 2018 to 2020 in either irrigation rate. The other trial had six to seven biochar rates (0–67 Mg ha⁻¹) plus the addition of wood chips at a single rate (22 Mg ha⁻¹) at one site. This trial displayed a yield decrease of 0.01 Mg ha⁻¹ of wheat grain for each additional 1 Mg ha⁻¹ of biochar applied; however, there were no effects on silage corn production. Data obtained over 10 site-years showed minimal effects from this type of biochar on crop yield, quality, or soil water tension, leading us to conclude that this wood biochar was not an effective tool for enhancing short-term crop production or conserving irrigation water in arid agriculture.

中文翻译：

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生物炭对灌溉苜蓿、玉米和小麦的产量、质量和水分利用率影响较小

农业用水优化的一种方法是增加土壤保水性。一种因其提高土壤保水能力而受到关注的土壤改良剂是生物炭，它是高碳材料热解后剩余的生物质。2018-2020 年间，在犹他州的两个地点分别进行了两项研究，以评估快速热解木材生物炭如何影响灌溉苜蓿（Medicago sativa L.）、玉米（Zea mays L.）和小麦（Triticum aestivum L.) 以及土壤水分张力。^{一项研究包括 22 Mg ha -1}的单一生物炭速率在两个灌溉水平（全部灌溉与部分灌溉）中，掺入土壤的生物炭在 2018 年使青贮玉米产量增加了 12%，在 2019 年使产量减少了 10%。在 2018 年至 2020 年两种灌溉方式中，追施生物炭对苜蓿产量没有影响速度。另一项试验有六到七种生物炭比率（0-67 Mg ha ^{-1 ），外加在一个地点以单一比率（22 Mg ha -1} ）添加木屑。^{该试验表明，每增加 1 Mg ha -1}，小麦籽粒的产量就会减少 0.01 Mg ha ^-1应用生物炭；然而，对青贮玉米的生产没有影响。超过 10 个地点年获得的数据显示，这种类型的生物炭对作物产量、质量或土壤水分张力的影响很小，这使我们得出结论，这种木材生物炭不是提高短期作物产量或节约灌溉用水的有效工具在干旱农业中。