ABSTRACT Environmental pollution caused by excessive nitrogen fertilization has become increasingly serious, making optimized fertilization and straw management critical for improving agricultural sustainability. This study involved a two‐year field trial with three fertilization strategies: conventional fertilization (CF), 23.50% nitrogen reduction (RCF), and 23.50% nitrogen reduction with 20.00% organic fertilizer substitution (OF). Additionally, three straw management practices were tested: straw removal with shallow tillage (SRS), straw incorporation with shallow tillage (SIS), and straw incorporation with deep plowing (SID). The effects of these treatments on rice yield, pollutant emissions, and soil quality were systematically assessed. The results indicate that both RCF and OF maintained stable rice yields. RCF significantly reduced AUC‐NH 4 + ‐N (by 19.39%–23.40%) and AUC‐NO 3 − ‐N (by 10.72%–12.77%), whereas OF significantly decreased AUC‐TP (by 71.01%–74.25%) and methane emissions (by 22.06%–28.81%), while markedly increasing SOC and TN. SID showed the best performance across all straw management practices. Overall, the OF‐SID strategy maintained rice yield while reducing pollutant emissions and enhancing soil fertility, thereby contributing to agricultural sustainability. This study provides new insights into the synergistic effects of fertilization and straw management on rice productivity, environmental pollutant emissions, and soil fertility, offering a scientific basis for developing sustainable nutrient management strategies in rice‐based cropping systems.
ABSTRACT Nitrogen and phosphorus availability drive plant community composition, productivity, and ecosystem functioning. During succession, nutrient availability typically changes as organic matter accumulates in the soil, influencing both nitrogen and phosphorus pools. We assessed nutrient limitation along postmining chronosequences (10–50 years old), including sites reclaimed with alder ( Alnus ) plantations and unreclaimed sites undergoing spontaneous succession. Plots received N (50 kg ha −1 year −1 ) or P (5 kg ha −1 year −1 ) fertilization or served as controls, applied over 3 years. Vegetation surveys were conducted in the first and third years, and aboveground biomass of Calamagrostis epigejos was collected in the third year for chemical analysis. Redundancy analysis revealed a significant effect of fertilization on community composition at unreclaimed sites, explaining 7% of the variance, whereas the effect was not significant at reclaimed sites and explained only 2% of the variance. On unreclaimed sites, N fertilization increased herb‐layer cover, reduced species evenness and turnover, but did not accelerate vegetation change. Although the effects of N fertilization are significant in some cases, they are relatively small. Phosphorus fertilization had negligible effects on vegetation in both site types. Nutrient content analysis of C. epigejos biomass indicated that the plant community was more limited by P than by N. However, P fertilization had limited potential to alleviate this limitation. This effect likely results from alkaline soils, in which phosphorus is bound in insoluble compounds that are unavailable to plants. Moreover, the effects of both fertilizers do not appear to be clearly positive in terms of ecosystem restoration.
ABSTRACT Soil carbon‐nitrogen‐phosphorus (C:N:P) stoichiometry governs nutrient cycling and carbon sequestration in desert ecosystems, yet how large‐scale photovoltaic (PV) deployment, a cornerstone of global carbon neutrality, shifts these stoichiometric balances and whether such shifts enhance or degrade long‐term land function remain unresolved over decadal timescales. To resolve this uncertainty, this study selected six photovoltaic power stations with operational durations of 1, 3, 7, 9, 12, and 14 years, quantified the contents of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and the variations of their stoichiometric ratios across three microhabitat types (under panels, SUP; between panels, SBP; panel‐front leading edges, PFL), and identified their key environmental drivers. Results showed that SOC, TN, and TP contents significantly increased across all panel positions with prolonged PV operation. Crucially, by year 14, we identified a pronounced asymmetric accumulation pattern: SOC accumulated significantly faster (increasing by 182.61%–204.35% relative to control) compared to TN (37.31%–54.48%) and TP (50.11%–80.23%). This asymmetric accumulation led to a significant rise in C:N and C:P ratios, signifying a progressive shift toward stoichiometric C:N:P imbalance, particularly in the SUP microhabitat. Both random forest and PLS‐PM analyses identified operation duration and panel position as the primary drivers of these stoichiometric shifts, mediated by soil available nutrients. Climatic factors exerted positive effects on TP accumulation but negative effects on SOC, C:P, and N:P ratios. This study reveals that while long‐term photovoltaic operation significantly enhances carbon sequestration, it concurrently induces stoichiometric C:N:P imbalance. These findings highlight the necessity of implementing position‐specific management (e.g., targeted nutrient regulation) to mitigate nutrient imbalance risks, thereby ensuring the long‐term stability and sustainability of desert PV carbon sinks.
ABSTRACT New agricultural operating entities (NAOEs) are the organizational core of modern agricultural systems, yet whether and how they draw smallholders into green production remains empirically unsettled. Using survey data from 803 vegetable growers in Shandong Province, China, and combining the coefficient of variation method, propensity score matching, 2SLS, and mediation analysis, this study finds that growers linked to NAOEs exhibit a green production index that is 9.7 percentage points higher across a 14‐behavior index spanning pre‐production, in‐production, and post‐production stages. The effect operates through two of four theorized pathways: easing factor endowment constraints and improving transaction efficiency. Standardizing the production process and realizing product value addition are not significant, which we attribute to loose contractual ties, high supervision costs, and underdeveloped benefit‐sharing mechanisms. Among driving models, production services yield the largest effect (14.3%), followed by industrial chain extension (13.3%), new technology penetration (12.1%), and industry integration (8.2%); participating in multiple models raises the effect to 25.5%, with the pairing of new technology penetration and industry integration the strongest combination (22.1%).
ABSTRACT Understanding the multiscale patterns and interactions of cultivated land multifunctionality is important for conservation, governance, and agricultural spatial optimization in the Dongting Lake region. Using 2020 data, we evaluated economic production (EPF), social security (SSF), landscape‐based recreation (LRF), and ecological maintenance (EMF) functions at the 1‐km, 3‐km, and township scales. The Simpson reciprocal index, Spearman correlation, geographically weighted regression (GWR), and self‐organizing feature map (SOFM) were integrated to assess functional patterns, local relationships, and coupled zoning. The results showed that: (1) EPF and SSF were highest across the plains surrounding Dongting Lake, whereas LRF was highest around urban nodes and landscape‐resource clusters. EMF was highest in the western hills and mountains and the densely connected waterways of western and southern Dongting Lake. With increasing scale, the proportion of high‐value EPF areas declined from 29.25% to 13.22%; SSF and LRF also decreased markedly, whereas EMF remained relatively stable. (2) Functional provision and structural balance were spatially mismatched: the lake plain had stronger provision but lower balance, whereas peripheral hills and uplands showed the opposite pattern. (3) EPF and SSF maintained strong synergies across scales, with Spearman coefficients of 0.88, 0.93, and 0.86. GWR identified EPF–SSF synergies in 97.2%, 95.8%, and 98.6% of units, respectively, while many EMF‐related local relationships became non‐significant at the township scale. (4) SOFM separately identified two functional structures and three relationship structures. Coupling the two clustering results produced six management zones, of which the low‐function, trade‐off‐dominated zone (Z1) and high‐function, synergy‐dominated zone (Z6) accounted for 17.04% and 20.01%, respectively. These findings support differentiated cultivated land management. These findings support zone‐specific management based jointly on functional levels, structural balance, and relationship types.
