生物质炭对土壤保水性和作物抗干旱能力的影响研究进展

Effect of biochar amendment on soil water retention and crop drought resistance:A review

随着全球气候变化的加剧,干旱胁迫已成为影响农业生产的主要限制因素之一。在农业生产中合理施用生物质炭具有改善土壤质量、提高土壤保水保肥能力和增加作物产量的作用。从生物质炭对作物抗干旱胁迫的应用效果和作用机制,以及生物质炭对土壤保水性的影响角度,探讨干旱胁迫下施用生物质炭保障作物生产的应用潜力。结果表明:生物质炭自身的高孔隙度和丰富的含氧官能团使其具有较好的持水性,而且施入土壤中能够改善土壤孔隙结构,提高土壤保水性能。生物质炭的施入能够促进作物根系伸长,增加根系分泌物的产生,并且通过调控作物渗透压和抗氧化物酶活性等机制,提高作物抗旱能力。由于生物质炭性质和土壤条件的变异性,生物质炭对土壤持水性和作物抗旱性的影响仍具有不确定性。因此,亟需系统性研究生物质炭对土壤持水性和作物抗干旱胁迫的影响机制,明确其关键因子和持续效应,从而为应用生物质炭促进农业的可持续发展提供理论和实践依据。

[Background]With the aggravation of global climate change,drought stress has become one of the main limiting factors affecting agricultural production.Reports showed that most crop yield reduction was related to drought,which would result in food shortages especially in arid and semi-arid areas.Therefore,it is critical to improve the drought resistance of crops,and the increase of soil water holding capacity may ensure agricultural production and food security.Biochar soil amendment shows the benefit in promoting crop growth and improving soil structure and fertilizer retaining,and have the function of increasing soil water holding capacity and alleviating crop drought stress.[Methods]We reviewed the literatures related to the effect of biochar amendment on soil water retention and on crop drought resistance ability.We conducted literature search via Web of Science,Wiley-Blackwell and CNKI,using the keywords of“biochar”“soil water”and“drought stress”.We discussed the effect of biochar soil amendment on soil water retention and crop resistance for drought stress,and the potential mechanisms,and gave a brief overview of the future research direction.[Results]Drought stress is the main environmental stress factor affecting agricultural production,which seriously affects crop growth,especially the continuous severe drought may cause the disorder of crop metabolism and even lead to crop death.Under drought stress,crops may adjust biomass allocation,especially promoting root growth to get more water,and crops may adapt to drought stress through a series of physiological and biochemical reactions.Researches demonstrated that biochar improved the drought resistance of crops,including mechanisms of improvement of root architecture,and increased the secretion of root exudate,increased the activity of soil microbe.And biochar may adjust crop osmotic potential and increase the water use efficiency of crops.In addition,biochar soil amendment may increase soil water holding capacity,and the key mechanisms including the large numbers of hydrophilic functional group of biochar,the improvement of soil porosity especially the decrease of soil bulk density increased the field water capacity.Due to the variability of biochar properties and soil conditions,it leads to the variability effect of biochar soil amendment on soil water retention and crop resistance for drought stress,and the mechanisms had insufficient understanding.[Conclusions]It is certainly that biochar soil amendment demonstrates the potential to increase soil water retention and increase the drought resistance of crops,and shows a long-term lasting effect.While the mechanisms of biochar on soil water holding capacity and on crop physiological response in different types and textures of soils,and it is urgent to identify the key influencing factors under different.Field experiments are necessary to explore the suitable biochar application method for different soil conditions,and determine the persistence effect,and develop the biochar-based water-retaining products.