Soil salinization has become one of the major environmental and socioeconomic issues globally and this is expected to be exacerbated further with projected climatic change. Determining how climate change influences the dynamics of naturally-occurring soil salinization has scarcely been addressed due to highly complex processes influencing salinization. This paper sets out to address this long-standing challenge by developing data-driven models capable of predicting primary (naturally-occurring) soil salinity and its variations in the world's drylands up to the year 2100 under changing climate. Analysis of the future predictions made here identifies the dryland areas of South America, southern and western Australia, Mexico, southwest United States, and South Africa as the salinization hotspots. Conversely, we project a decrease in the soil salinity of the drylands in the northwest United States, the Horn of Africa, Eastern Europe, Turkmenistan, and west Kazakhstan in response to climate change over the same period.© 2021. The Author(s).

Soil salinization is a significant threat to soil health, especially to the agricultural ecosystem; it reduces vegetation biomass, destroys ecosystem diversity, and limits land use efficiency. This area of investigation has garnered extensive attention in China, especially in the arid and semi-arid areas, totaling 7.66 × 106 ha. A variety of theoretical research and technology developments have contributed to soil water and salt regulation and the screening of salt-tolerant varieties to improve nutrient utilization efficiency and microbial control and reduce ecological problems due to saline-based obstacles. These techniques can be classified into physical treatments, chemical treatments, biological treatments, and combined treatments; these different measures are all aimed at primarily solving saline–alkali stress. In general, the improvement and utilization of saline–alkali soil contribute to soil health improvement, concentrating on high-quality development, food security, ecological security, cultivated land protection, and agricultural upgrading. However, the risks of various technologies in the practical production process should be highlighted; green and healthy measures are still expected to be applied to saline–alkali land.

Global agriculture is severely hampered by soil salinity, jeopardizing environmental sustainability and food security. An excessive buildup of soluble salts in the soil hinders plant development and production by interfering with water intake, changing nutrient availability, and causing ion toxicity. This phenomenon is especially common in arid and semi-arid areas, where poor drainage and inappropriate irrigation techniques worsen salt problems. To deal with osmotic stress, ion imbalance, and oxidative damage, plants exposed to saline environments trigger intricate physiological and biochemical processes at the cellular level. These reactions include the production of proline and other osmoprotectants, the overexpression of antioxidant enzymes to lessen oxidative stress, and activating ion transporters to preserve ionic equilibrium. Despite these adaptive responses, long-term salt frequently overwhelms plant defenses, resulting in restricted development and yield reductions. A multifaceted strategy incorporating cutting-edge technologies and sustainable farming methods is needed to address soil salinity. Techniques including using halophyte-based farming systems, adopting soil supplements, increasing irrigation efficiency, and using salt-tolerant crop types have demonstrated promise in reducing the consequences of salinity. Additionally, using salt-tolerant microorganisms for bioremediation and sophisticated remote sensing methods for salinity monitoring might improve the accuracy of saline landscape management. A thorough grasp of salinity dynamics and using scalable, sustainable remedies will be essential to preserving ecological health and agricultural output as climate change worsens.

土壤盐碱化作为制约农业生产的全球性生态难题，其生物修复技术备受关注。本研究聚焦耐盐促生微生物的开发与应用，从天津典型盐碱土中筛选出3株具有显著促生功能的耐盐菌株（WQ-08、WQ-26、BH-39），经16S rRNA基因序列分析分别鉴定为枯草芽孢杆菌(Bacillus subtilis)、巨大普斯里斯特氏菌(Priestia megaterium)和短小芽孢杆菌(B. pumilus)。通过砂培模拟实验，探究其在100 mmol/L NaCl盐胁迫下对玉米幼苗（MC812）的缓解效应。结果显示，接种上述菌株可有效逆转盐胁迫导致玉米幼苗MC812的生长抑制，其中WQ-08处理组的株高、茎叶和根干重较其他处理分别提升33.32%、37.04%和36.84%；BH-39处理组根长、茎叶和根鲜重较其他处理分别增加27.33%、29.35%和30.55%。生理指标表明，各处理组玉米幼苗抗氧化酶活性显著降低，如玉米幼苗超氧化物歧化酶(SOD)活性下降9.77%、5.60%和7.71%，过氧化物酶(POD)活性下降了20.44%、22.24%和25.27%，过氧化氢酶(CAT)活性下降了34.46%、31.27%和23.28%(P<0.05)。研究表明，3株菌株兼具耐盐性与促生能力，可有效缓解玉米幼苗盐胁迫损伤，为盐碱地作物改良提供了潜在微生物资源。

Biochar can act as a carrier and a soil carbon source for rapid colonization by plant growth-promoting rhizobacteria (PGPR). However, the effects of a combined application of biochar and PGPR on soil physicochemical properties, humus components, and their stability in the rhizosphere around fruit mulberry seedlings remain unclear. A pot experiment using 1-year-old fruit mulberry seedlings with five treatments (control (CK), salt stress (SS), salt stress + Bacillus fexus (SS+P), salt stress + biochar (SS+B), and salt stress + B. fexus + biochar (SS+P+B)) was conducted to analyze the variations in soil physicochemical properties and humic acid (HA), fulvic acid (FA), and humin (HM) contents in the soil when planting fruit mulberry seedlings. The results indicated that the SS treatment significantly reduced total soil porosity, non-capillary porosity, water stable macro-aggregates content, available potassium content, and pH value compared to CK, but increased the soil bulk density, capillary porosity, and available phosphorus content. The SS+P+B treatment significantly increased soil total porosity, non-capillary porosity, pH value, electrical conductivity, the water stable macro-aggregates, organic matter, HA and HM contents, the HA/FA and HA/HE (humus-extractable) ratios, and the activities of catalase and urease. It significantly increased the water stable macro-aggregates and the HA/HE ratio by 27.83% and 25.00%, respectively. However, it significantly decreased soil bulk density and capillary porosity by 9.93% and 20.64%, respectively, compared to the SS treatment. The results suggest that the simultaneous addition of biochar and B. fexus under salt-stress conditions improves the soil physicochemical properties and increases the humus components content and stability, which is of great significance for improving the soil quality of saline–alkali land and enhancing the productivity of fruit mulberry.

In response to China’s drive to bring newly cultivated land into production, this study evaluated how combined organic fertilizer and microbial inoculants affect soil quality, bacterial community structure, and maize yield. Four treatments were evaluated: FC (chemical fertilizer only), T50 (50% organic fertilizer + 50% chemical fertilizer), T50M (T50 plus microbial inoculant), and CK (no fertilizer). T50M significantly increased yield compared to FC and CK (p < 0.05), achieving the highest yield of 6995.73 kg ha−1. This was 20.09% greater than FC. Community composition analyses showed that soil in newly cultivated land was dominated by Blastocatellia, Vicinamibacteria, and Alphaproteobacteria, together accounting for over 35.7% of total bacterial abundance. Redundancy analysis at the class level explained 55.7% of variance; soil organic matter (SOM) and available potassium positively correlated with Alphaproteobacteria and Bacteroidia, while available phosphorus and nitrate nitrogen aligned with Actinobacteria and Bacilli. Path analysis indicated that SOM and total nitrogen were the strongest positive drivers of yield. Actinobacteria and Acidobacteriae also showed direct positive effects, whereas Verrucomicrobiae had a negative effect. These results demonstrate that integrated organic–microbial amendments can enhance soil fertility and alter microbial diversity toward taxa that can improve maize productivity.

 In recent years, soil salinization has become a serious problem in the global environment. The application of organic fertilizer to improve saline-alkali soil has been widely concerned because of its advantages of improving soil fertility, improving soil structure and improving soil salt ion composition. This paper reviews the mechanism of saline-alkali soil improvement, and expounds the improvement prospect of organic fertilizer on saline-alkali soil from the influence of organic fertilizer on soil physical and chemical properties, water and salt transport law, crop yield and quality, in order to provide theoretical guidance for saline-alkali soil restoration.

设施土壤次生盐渍化已成为制约设施农业发展的主要问题,为验证施用有机物料对次生盐渍化设施土壤的修复效果,本研究采用田间小区试验,以河北永清典型次生盐渍化设施土壤为研究对象,选择牛粪和生物炭两种有机物料并结合微生物菌剂作为外源有机物料,处理包括不施用有机物料(CK)、单施牛粪(DM)、单施生物炭(BC)、牛粪配施菌剂(DM+MI)、生物炭配施菌剂(BC+MI),通过分析各处理土壤的水溶性盐分总量、各盐分离子以及植株生长状况,探讨了有机物料对设施土壤次生盐渍化的改良效果。结果表明：施用有机物料和微生物菌剂可以不同程度的减轻土壤次生盐渍化。与对照相比,对降低土壤盐分效果最显著的为DM+MI处理,最高可降低土壤可溶盐总量18.26%,以及Na⁺、Ca²⁺与Mg²⁺含量24.1%、18.75%、24.29%,其他降盐效果表现为DM处理>BC+MI处理>BC处理。施用有机物料对辣椒植株的生长有一定的促进作用,至第10周时显著增加株高与茎粗达10.40%~16.00%和19.50%~21.30%。对辣椒植株生长与土壤水溶性盐分含量的相关性分析表明,在设施次生盐渍化土壤中,辣椒植株生长与土壤中Ca²⁺和Mg²⁺的含量呈显著负相关关系。综上,有机物料配施微生物菌剂能改善土壤条件,降低土壤含盐量,缓解设施土壤次生盐渍化状况,并促进辣椒正常生长。

为明确微生物菌剂在内蒙古河套地区中度盐碱土壤改良中的作用，可为盐碱土壤质量提升提供技术支撑。采用大田随机区组试验设计方法，以空白处理（CK）为对照，设置3种微生物菌剂处理，包括丹路牌微生物菌剂（DL）、自主研发的复合微生物菌剂BZ1^T/1-15（由芽孢杆菌、芽单胞菌和草炭组成），其使用量分别为570 kg·hm^-2（BL1）和1140 kg·hm^-2（BL2）。分析不同处理措施下的土壤盐分、养分以及细菌群落结构组成和多样性的变化特征。结果表明：施用微生物菌剂（DL、BL）均可显著降低土壤盐分和pH值，其中BL2处理对降低土壤盐分的效果最显著，与CK、DL、BL1相比分别降低了14.0%、4.2%、7.4%（P<0.05）。同时，施用BL1和BL2微生物菌剂对提高根际土壤的碱解氮、速效钾和有效磷含量有显著作用，其中BL1、BL2处理的碱解氮含量较CK和DL分别显著提高26.4%和11.67%、50.94%和33.33%，BL2处理的速效钾含量较CK、DL和BL1分别显著提高24.1%、24.7%和11.1%（P<0.05）。高通量测序结果表明，BL2处理的丰富度指数（ACE、Chao1）显著高于其他处理，还可显著提升放线菌门、厚壁菌门和蓝细菌门的优势菌群丰度，另外BL1和BL2处理显著降低了酸杆菌门、芽单胞菌门、拟杆菌门、硝化螺旋菌门和浮霉菌门细菌菌群的相对丰度（P<0.05）。相关性分析结果显示，放线菌门与土壤pH值、碱解氮分别呈显著负相关、正相关（r分别为-0.581*、0.595*）；土壤速效钾与变形菌门、酸杆菌门和绿弯菌门分别呈极显著负相关、正相关和正相关（r分别为-0.753**、0.503*和0.569*）。因子分析结果表明，有机质、盐分和养分等是影响土壤细菌群落结构的主控环境因子，因为其总共解释了67.0%的群落变化；它们的贡献率依次为：土壤有机质>盐分>速效钾>pH>有效磷>碱解氮。另外，BL1和BL2菌剂的施用对提高向日葵的产量有显著作用，且作物产量与养分含量呈极显著正相关关系。因此，施用微生物菌剂不仅可以降低土壤盐分和pH值，而且还可显著提高土壤养分含量和作物产量，改善细菌菌群结构。该研究可以为微生物菌剂在内蒙古河套灌区盐碱土壤改良方面提供试验基础和参考。

采用大田小区试验,分析了常规秸秆还田(CK)和秸秆还田配施促腐菌剂(IT)两种处理下稻田0～20和20～40 cm土壤团聚体粒径分布,评估了土壤团聚体水稳定性(土壤水稳性大团聚体数量R_0.25、平均重量直径MWD、几何平均直径GMD),并测定了不同粒径(＜0.053、0.053～0.25、0.25～1、＞1 mm)土壤团聚体中有机碳(SOC)、全氮(TN)、全磷(TP)的含量。结果表明: 1)IT处理＜0.053、0.053～0.25及＞0.25 mm团聚体数量在0～20和20～40 cm土层分别较CK下降10.0%和6.8%、提高3.0%和5.7%及17.9%和26.1%;与CK相比,IT有效提高了R_0.25、MWD、GMD,在0～20和20～40 cm土层中分别提高了26.4%、20.0%、18.2%和18.2%、10.5%、10.0%。2)与CK相比,IT处理0～20和20～40 cm土层中0.25～1 mm粒级团聚体的TP含量分别显著提高了40.3%和37.5%,TN和SOC含量无显著差异;其他粒径各养分在两处理间无显著差异,大团聚体(＞0.25 mm)的SOC和TN含量高于粉黏团聚体(<0.053 mm)。不同土层IT处理<0.053 mm粒级团聚体的SOC、TN和TP累计贡献率较CK有所降低;0.053～0.25 mm粒级团聚体的养分累计贡献率与CK差异不显著;大团聚体(＞0.25 mm)的SOC、TN和TP累积贡献率在0～20和20～40 cm土层中较CK分别提高了32.1%、19.6%、52.8%和22.8%、11.8%、42.9%。3)土壤<0.053 mm粒级团聚体数量与SOC和TP含量呈显著负相关,0.053～0.25 mm团聚体数量与养分含量呈负相关,大团聚体(＞0.25 mm)数量与SOC、TN和TP含量呈显著正相关。综上,秸秆还田配施促腐菌剂可以促进土壤大团聚体(＞0.25 mm)形成,提高了团聚体水稳定性,增加了土壤大团聚体中养分含量,促使养分从粉黏团聚体向大团聚体转移。

为探究不同改良物料对盐碱土壤理化性质及玉米产量的影响，在内蒙古土默特右旗中度盐碱地上开展了脱硫石膏、新型改良剂和有机肥对盐碱土壤改良和玉米生长的影响研究。结果表明：（1）施用改良物料降低了0~20 cm和20~40 cm土层土壤pH和全盐含量，其中，T₄处理对土壤pH降低效果最好，不同土层土壤pH较对照分别显著下降了8.38%和6.65%；T₆处理对0~20 cm土层盐分抑制效果最好，较对照显著下降了44.84%，T₄处理对20~40 cm土层盐分抑制效果最好，较对照显著下降了44.84%。（2）施用改良物料增加了0~20 cm和20~40 cm土层土壤速效磷、速效钾和碱解氮含量，平均增幅分别为15.8%~65.48%、3.06%~19.07%和3.45%~20.24%。（3）施用改良物料增加了不同生育时期玉米株高、茎粗，提高了玉米产量和产量构成，T₇处理较其他改良处理对玉米生长和产量提升效果较好，玉米株高、茎粗、百粒重、产量较对照分别显著提高了26.21%、20.64%、21.56%、55.21%。综上，施用改良物料可以改善盐碱土壤质量，提升土壤养分，促进玉米生长和提高玉米产量。

探究不同有机物料投入对滨海盐碱地土壤理化性质及玉米生长发育的调控作用, 为滨海盐碱地夏玉米生产提供理论依据。试验于2021—2022年夏玉米生长季在山东省滨州市无棣县滨海盐碱型农田进行。有机物料类型及用量分别为腐植酸(3000 kg hm^-2, HA)、生物炭(15,000 kg hm^-2, BC)、生物有机肥(15,000 kg hm^-2, BO), 以不添加有机物料为对照(CK), 探究0~40 cm土层土壤容重、总孔隙度、田间持水量、pH值、电导率及总有机碳含量的变化, 分析不同有机物料投入对玉米地上部干物质积累和产量形成的影响。结果表明, 腐植酸、生物炭和生物有机肥的施用均可在一定程度上改善盐碱土理化性质。3种有机物料连续处理能有效降低表层土壤容重, 增加土壤总孔隙度和田间持水量; 可显著降低0~10 cm土层pH, 分别平均降低0.17、0.08和0.20。连续施用2年后, 腐植酸显著降低0~40 cm土层电导率, 平均降低32.74%; 3种有机物料显著增加0~20 cm土层中总有机碳的含量, 其中生物炭处理能显著增加57.99%。腐植酸和生物有机肥处理显著增加夏玉米地上部干物质积累量和产量; 连续使用2年后腐植酸处理产量显著增加了11.01%, 表现较好。综上所述, 本试验条件下腐植酸施用后能改善土壤物理结构、降低0~10 cm土层pH、提高土壤中有机碳含量、显著降低土壤电导率, 促进夏玉米地上部干物质积累、提高籽粒产量, 且连续施用2年后较CK增加纯收益。故而腐植酸可作为改良滨海盐碱地土壤理化性状、促进夏玉米生长发育的有机物料。生物有机肥的施用可改善土壤理化性状, 但仍需进行定位试验以验证其长期经济效应。

新垦耕地固碳培肥过程中,土壤微生物代谢对有机物料投入的响应及主控因素尚不明确。本研究于2022年在浙江建德进行大田定位试验,以常规化肥(NPK)为对照,等碳原则下设置NPK基础上增施秸秆+有机肥(MS)、有机肥(M)、秸秆炭基有机肥(MBF)、秸秆源生物质炭(MB)处理,探究不同有机物料投入对稻麦轮作下新垦耕地土壤养分、有机碳组分、胞外酶活性、微生物代谢和碳利用效率的影响。结果表明: 与NPK相比,有机物料投入均提高了土壤总氮磷钾养分、有机碳含量和微生物活性。土壤养分表现为M>MBF>MS>MB,作物产量表现为MS>M>MBF>MB。活性有机碳含量表现为M>MS>MBF>MB,其中M处理最高,较对照提高了91.7%;惰性有机碳含量表现为MB>MBF>M>MS,MB处理最高,较对照提高了160.7%。微生物生物量表现为M>MS>MBF>MB,M处理微生物生物量碳、氮、磷平均分别较对照提高81.1%、140.9%、261.1%。胞外酶活性表现为MS>M>MB>MBF,MS处理碳循环相关酶(β-葡萄糖苷酶、β-木糖苷酶、纤维素酶)活性平均分别较对照提高176.3%、180.4%、439.2%,氮循环相关酶(N-乙酰-β-葡萄糖苷酶)活性较对照提高331.4%。Mantel相关性分析和冗余分析表明,溶解性有机碳和微生物生物量碳分别是小麦和水稻种植季土壤胞外酶活性的最强驱动因子。酶向量模型和偏最小二乘路径模型分析显示,新垦耕地土壤微生物代谢同时受到碳和磷限制,有机物料投入通过提高新垦耕地土壤速效养分直接缓解磷限制,通过增加土壤活性有机碳含量降低了微生物碳利用效率。综上,有机物料投入在新垦耕地固碳培肥中具有积极作用,其中秸秆炭基有机肥处理固碳培肥综合作用最好。

The coastal saline-alkali soil in eastern China is an important reserve arable land resource. Adding exogenous organic material is an effective way to improve soil fertility and promote the conversion of saline-alkali soil to agricultural soil. In this study, a field plot experiment was used to investigate the influences of different organic materials (vinegar residue, VR; sewage sludge, SS; vermicompost, VC) on the reduction in salinity-alkalinity barrier factors, the accumulation of soil organic carbon (SOC), and the improvement in soil fertility in saline-alkali soil. The results indicated that applying different types of exogenous organic materials reduced soil electrical conductivity (EC) and pH, promoted SOC accumulation, and increased the barley yield. With the same application rate, VR application was more beneficial in reducing soil EC and pH, accumulating SOC, and increasing barley yield compared to SS and VC applications. In particular, the barley yield with VR application was higher than that with SS and VC applications by 18.4% and 26.6% on average, respectively, during the two-year experiment. Correlation and path analysis revealed that the barley yield was significantly negatively correlated with soil barrier factors (EC and pH), but EC in SS and VC-treated soils had an indirect negative effect on barley yield, while EC in VR-treated soil had a direct negative effect (−2.24). In addition, the direct (−4.46) and indirect (5.39) contributions of SOC to barley yield were higher with VR than those with SS and VC, while the direct contribution of soil aggregate to barley yield was lower with VR than that with SS and VC. Therefore, compared with SS and VC applications, VR application led to a fast reduction in soil barrier factors and the rapid accumulation of SOC, which were more beneficial for increasing barley yields in saline-alkali soil.

探明有机肥施用对盐碱土氮循环的调控机制,解析微生物群落-功能基因协同作用路径,可为盐碱土可持续改良提供理论依据。本研究基于中国科学院南皮生态农业试验站4年小麦定位试验(2018—2022年),设置化肥(复合肥N∶P₂O₅∶K₂O为18∶22∶5)和有机肥(等氮量施用腐熟牛粪有机肥)2个处理,通过常规养分分析和高通量宏基因组测序技术,结合Mantel检验与功能基因关联分析法,分析有机肥对盐碱土氮转化微生物群落的影响及其调控机制。结果表明: 与化肥处理相比,施用有机肥处理耕层土壤总氮和碱解氮含量分别显著提高了26.9%和34.5%,硝态氮含量显著降低了28.3%。施用有机肥显著提高了微生物ACE指数,但Shannon指数无显著变化。有机肥处理提高了假双头斧形菌属(耐盐菌属)的相对丰度,增幅达517.0%,显著改变了微生物群落结构,显著上调了硝酸盐还原基因(napA)和反硝化基因(norB/nosZ)丰度,协同提高了谷氨酰胺合成酶的相对丰度。Mantel检验揭示,假双头斧形菌属相对丰度与土壤总氮、碱解氮和铵态氮含量均呈显著正相关,norB基因相对丰度与上述3个氮素指标亦呈显著正相关。表明有机肥通过调控关键菌群和功能基因丰度改变了盐碱土氮代谢网络,缓解了盐碱土的氮素阻滞。