Climate change cause extreme weather effects with temperature increases and drops in humidity, such as drought and heatwaves, which will lead to more evaporation in arid and semi-arid lands. The application of biochar made from crop straw without burning to farmland can effectively improve the water retention capacity of soil. A testing program has been carried out in a climate simulation laboratory to study the effects of different straw biochars on the cracking and evaporation of soils due to drying. Biochar from wheat straw (WS), corn straw (CS) and rice straw (RS) is produced at a pyrolysis temperature of 500℃. Thermogravimetric analysis and elemental analysis are carried out to obtain the properties of the biochar. Five percent of WS, CS and RS biochar by weight is added to acidic soil. Digital camera and digital image processing technology are used to analyze the crack morphology of the samples during evaporation. The results indicate that the RS biochar has the highest ash content (32.5 %), CS biochar has the highest content of volatile solid (25.36 %) and WS biochar has the highest content of fixed carbon (55.38 %). Biochar can effectively improve the water retention capacity of soil. The final water contents of the WS, CS and RS biochar soil samples are 132.3 %, 101.0 %, and 20.7 % respectively higher than that of the soil without biochar. Moreover, biochar can effectively reduce the degree of soil cracking. The addition of WS, CS and RS biochar can reduce soil cracking by 9.21 %, 16.57 %, and 7.46 %, respectively. WS contains more total cellulose than CS and RS, so WS biochar is the best choice to improve soil water retention ability. Therefore, biochar technology helps to optimize soil water retention while avoiding environmental pollution from straw burning.

中文翻译：

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不同秸秆生物炭在 500℃ 热解温度下的特性：其用于改善酸性土壤保水能力的意义


气候变化会导致极端天气影响，如气温升高和湿度下降，例如干旱和热浪，这将导致干旱和半干旱地区蒸发更多。将农作物秸秆不燃烧制成的生物炭应用于农田，可以有效提高土壤的保水能力。气候模拟实验室进行了一项测试计划，研究不同秸秆生物炭对干燥导致的土壤开裂和蒸发的影响。以小麦秸秆（WS）、玉米秸秆（CS）和稻草（RS）为原料，在500℃的热解温度下生产生物炭。进行热重分析和元素分析以获得生物炭的特性。将按重量计 5% 的 WS、CS 和 RS 生物炭添加到酸性土壤中。利用数码相机和数字图像处理技术对样品蒸发过程中的裂纹形貌进行分析。结果表明，RS生物炭的灰分含量最高（32.5%），CS生物炭的挥发性固形物含量最高（25.36%），WS生物炭的固定碳含量最高（55.38%）。生物炭可以有效提高土壤的保水能力。 WS、CS和RS生物炭土壤样品的最终含水量分别比不含生物炭的土壤高132.3%、101.0%和20.7%。而且，生物炭可以有效减少土壤开裂程度。添加WS、CS和RS生物炭可分别减少土壤开裂9.21%、16.57%和7.46%。 WS比CS和RS含有更多的总纤维素，因此WS生物炭是提高土壤保水能力的最佳选择。因此，生物炭技术有助于优化土壤保水性，同时避免秸秆燃烧造成的环境污染。