No tillage (NT) has been proposed as a practice to reduce the adverse effects of tillage on contaminant (e.g., sediment and nutrient) losses to waterways. Nonetheless, previous reports on impacts of NT on nitrate () leaching are inconsistent. A global meta‐analysis was conducted to test the hypothesis that the response of leaching under NT, relative to tillage, is associated with tillage type (inversion vs non‐inversion tillage), soil properties (e.g., soil organic carbon [SOC]), climate factors (i.e., water input), and management practices (e.g., NT duration and nitrogen fertilizer inputs). Overall, compared with all forms of tillage combined, NT had 4% and 14% greater area‐scaled and yield‐scaled leaching losses, respectively. The leaching under NT tended to be 7% greater than that of inversion tillage but comparable to non‐inversion tillage. Greater leaching under NT, compared with inversion tillage, was most evident under short‐duration NT (<5 years), where water inputs were low (<2 mm day⁻¹), in medium texture and low SOC (200 kg ha⁻¹) and lower (0–100 kg ha⁻¹) rates of nitrogen addition. Of these, SOC was the most important factor affecting the risk of NO₃⁻ leaching under NT compared with inversion tillage. Globally, on average, the greater amount of NO₃⁻ leached under NT, compared with inversion tillage, was mainly attributed to corresponding increases in drainage. The percentage of global cropping land with lower risk of NO₃⁻ leaching under NT, relative to inversion tillage, increased with NT duration from 3 years (31%) to 15 years (54%). This study highlighted that the benefits of NT adoption for mitigating leaching are most likely in long‐term NT cropping systems on high‐SOC soils.

The management and use of saline–alkaline land is a global concern and research focus. Although there is extensive long-term global research on soil salinization and improvement, systematic summaries of research progress in this field are insufficient. This study, based on the Web of Science (WOS) and incoPat database, analyzes the literature and patents on saline–alkaline land over the past 30 years, sums up research progress and current status, and proposes future directions to lay a foundation for further study. Research hotspots are mainly salt-tolerant plant growth mechanisms and gene expression under salt stress, interactions between salt-tolerant plants and microbes, soil conditioner use, remote sensing monitoring of saline–alkaline land changes, irrigation and drainage techniques, and soil nutrient status and improvement. Saline–alkaline land management research is moving toward integrated application of multiple improvement measures. Priority should be given to developing land remediation technologies and salt-tolerant plant varieties suited to different regions; studying the compatibility among technologies, plant varieties, and cultivation techniques; establishing region- and type-specific integrated management and ecological use methods; and creating comprehensive development plans to boost soil productivity and protect the ecology.

In coastal saline–alkali regions, the intrusion of saline water exacerbates the nutrient depletion in the plow layer, posing a significant challenge to agricultural productivity. Given the limited understanding of soil fertility in these areas and the inconsistent results among different assessment methods, this study aims to develop a more accurate and reliable soil fertility evaluation system. To achieve this objective, 108 topsoil samples were systematically collected from saline–alkali lands in Jiangsu Province. Several key soil fertility indicators, including soil pH, total salinity (TS), soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkaline-hydrolyzable nitrogen (AN), available phosphorus (AP), and available potassium (AK), were comprehensively evaluated. Four advanced methods, namely principal component analysis indexing–linear scoring (SQI_PCAL), principal component analysis indexing–nonlinear scoring (SQI_PCANL), modified Nemerow–linear scoring (SQI_NemeroL), and modified Nemerow indexing–nonlinear scoring (SQI_NemeroNL), were employed to conduct a multi-dimensional examination of soil fertility. Additionally, principal component analysis (PCA) was utilized to establish a minimum data set (MDS), which was then compared with the total data set (TDS) for a more precise assessment of soil fertility. Linear scoring methods (SQI_PCAL and SQI_NemeroL) had higher semi-variogram R² values compared to nonlinear methods. Moreover, under the SQI_PCAL and SQI_NemeroL evaluation methods, a strong correlation was observed between the TDS and MDS, with R² values reaching 0.63 and 0.65, respectively. Based on these findings, the SQI_NemeroL method, integrated with MDS, is recommended as an effective approach for soil fertility assessments in coastal saline–alkali regions in Jiangsu Province. This research not only enriches the theoretical understanding of soil fertility in such regions but also provides practical insights for sustainable agricultural management.

Organic amendments are widely used to enhance soil fertility and nutrient cycling in greenhouse cultivation, but their effectiveness can vary depending on their origin and composition. This study investigated the impact of four organic materials (rice husk, coconut coir, biochar, and sheep manure) on nutrient cycling and enzyme activities in two of greenhouse tomato soils. The distribution of soil nutrients and enzyme activities was analyzed under controlled conditions during a pot experiment. The addition of organic amendments, regardless of their source, significantly altered the microbial resource allocation, reducing the carbon limitation while increasing the nitrogen demand. The effect on soil nutrient pools was largely determined by the chemical composition of the amendments. In clayey soils, biochar and rice husk additions most effectively promoted enzyme activities related to carbon, nitrogen, and phosphorus acquisition. Under sandy soil conditions, sheep manure increased carbon and phosphorus acquisition enzymes, while biochar most effectively enhanced nitrogen acquisition enzymes. Biochar emerged as a particularly effective amendment, enhancing organic carbon sequestration across different soil types. The chemical composition of the amendments, specifically, the content of carboxyl C, aromatic C, and O-alkyl C, played a crucial role in influencing soil nutrient limitations. In clayey soils, the mean C:N:P ratios for CK, T1, T2, T3, and T4 treatments were 1:1.375:0.625, 1:1.244:0.662, 1:0.839:0.610, 1:1.161:0.689, and 1:1.038:0.549, respectively. In sandy soils, the ratios were 1:1.117:0.698, 1:1.18:0.75, 1:1.096:0.731, 1:1.217:0.689, and 1:1.06:0.669, respectively. These findings suggest that the addition of organic amendments can improve nutrient retention and enzyme activities, but their effects on soil nutrient pools are influenced by both the composition of the amendments and the soil texture. This research enhances our understanding of organic amendments and soil nutrient transformations, and aids in optimizing the application of organic materials for improved soil management in greenhouse cultivation.