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Phosphorus (P) is an important soil element for sustaining plant growth and the integrity of terrestrial ecosystems, and the soil P cycle is strongly influenced by climate change and agricultural activities. However, little is known about how soil P has evolved with climate change and intensive agriculture at mid‐high latitudes, where the soil P cycle is sensitive to climate change. To answer this question, an ecohydrological model (EcoHAT‐P) driven by remote sensing data was used in this study to calculate soil P concentration and loss and was calibrated and validated using 272 soil samples collected in the Sanjiang Plain, a typical mid‐high latitude region with a long history of strong agricultural activity. Soil P concentration and loss, and plant uptake of soil P, were analyzed for the years 2000–2019 and 2020–2040. The results showed that soil total P, soil P loss, and plant P uptake all increased under intensive agriculture. The soil P cycle at mid‐high latitudes was more sensitive to temperature than to precipitation. Increased temperature would increase soil P loss and plant P uptake by 93.94% and 8.16%, respectively, and soil legacy P from intensive agriculture would become the main source even if external P inputs were eliminated. The results highlight the evolution of soil P transport at mid‐high latitudes and clarify the response of soil P cycle to climate change under intensive agriculture. [ABSTRACT FROM AUTHOR]

With the development of human society, the balance between the minimum ecological instream flow requirement (MEIFR), which is an essential part of the ecological water demand in arid areas, and anthropogenic water depletion has received increasing attention. However, due to the lack of hydrological station data and river information on arid basins, previous researchers usually considered only the individual ecological water demand of rivers, lakes, or oases. To address this issue, a new method that combines river hydraulic parameters and the wet circumference obtained by an unmanned aerial vehicle (UAV) and remote sensing hydrological station (RSHS) technologies was applied to obtain the MEIFR and, then, systematically and quantitatively explore the balance from the perspective of the entire basin of Aiding Lake from 1990 to 2022, which is the lowest point of Chinese terrestrial territory. The results showed the following: (1) since 1990, the discharge of the seven rivers in the study area increased by 1–6%, and the MEIFR of these rivers increased by 15–100%; both quantities decreased by 3–5% from the upper to the lower reaches of the basin; (2) the surface area and water level of Aiding Lake decreased by 5% and 14%, respectively, but the MEIFR first decreased by 25% from 1990 to 2013 and, then, increased by 66.7% from 2013 to 2022; and (3) from 2011 to 2022, the MEIFR and anthropogenic water depletion exhibited a balance. Against the background of climate change, this research revealed that the MEIFR of the rivers in the Aiding Lake Basin have shown an upward trend over the past 30 years and quantitatively determined the above balance relationship and the period of its occurrence. This study supplied a method that could provide guidance for water resource management by decision-makers at a global level, thus helping achieve the sustainable development goals (SDGs). [ABSTRACT FROM AUTHOR]

Lack of surface water is a key factor leading to agricultural drought in karst regions and exacerbates the karst rocky desertification, which is characterized by high rate of exposed bedrock. With the characteristics of impermeability, runoff collection, and wide distribution, stone bud and karren (SBK), a unique karst landscape type composed of exposed bedrock and gullies, has a great potential to solve water shortage in agricultural irrigation, especially in the rain-rich karst regions of Guizhou Province, China. Using unmanned aerial vehicle images to identify SBK and measured rainfall–runoff data for validation, we applied SBK as a basic unit to harvest rainfall water on rocky desertification slopes and analyzed the benefits of rainfall water collection and irrigation via SBK. The results showed the following: (1) Karrens on rocky desertification slopes could be identified using a method coupling terrain opening difference and depression filling, and the simulated runoff on SBK could achieved the average NSE and R 2 of 0.82 and 0.86, with RMSE and RSR less than 0.03 m3 and 0.51, respectively. (2) The exposed bedrock utilization rate and rainfall water collection coefficient of SBK were 0.62 and 0.55, respectively, such that the area ratio of exposed bedrock to the cultivated land meeting irrigation water demand reached 1:3.1, 1:3.7 and 1:7.0 under 90 %, 80 % and 50 % possibilities of irrigation. (3) Implementing SBK for rainfall water harvesting and irrigation could efficiently avoid crop failure in the karst regions where crops faced drought within only one week after rainfall, and was at an affordable cost to local farmers with limited environmental damage. The use of SBK to harvest rainfall water could also alleviate surface water shortages in karst regions caused by problems such as uneven temporal distribution of rainfall and engineering water shortages. Consequently, SBK demonstrate a strong application potential to alleviate agricultural drought in karst rocky desertification regions. • Stone bud and karren (SBK) on rocky desertification slope were effectively identified. • The simulated runoff on SBK achieved the average NSE and R 2 of 0.82 and 0.86, respectively. • The rainfall water collection coefficient of SBK was 0.55 resulting in a high irrigation capacity. • SBK demonstrated low costly but beneficial to alleviate agricultural drought in karst regions. [ABSTRACT FROM AUTHOR]