Water scarcity threatens the sustainability of irrigated agriculture in semi-arid regions, and ridge-furrow planting systems (RFPS) can be a prospective rainwater harvesting approach. In this study, we aimed to develop a promising water-saving strategy to boost maize productivity and water use efficiency (WUE). In 2017, we carried out a field experiment to study the effects of various RFPS with multiple irrigation levels on the yield-water relationship of maize (Zea mays L.). Eleven treatments were set up: RFPS with film mulching on both ridges and furrows and without water supply after seed emergence, abbreviated as QF; RFPS with film mulching on continuous ridges, abbreviated as MD, including SMD, MMD, and LMD (S, M, and L—three water supply (irrigation plus precipitation) levels of 650 mm, 500 mm, and 350 mm during the whole growing season); RFPS without film mulching, abbreviated as DD, including SDD, MDD, and LDD; conventional flat planting with no film mulching, abbreviated as GG, including SGG, MGG, and LGG; localized full irrigation (actual amount of irrigation excessively exceeding the quantity needed), abbreviated as NM. A positive linear relationship (R² = 0.95–1), a quadratic curve, and a negative linear relationship were observed between the irrigation water level and actual crop evapotranspiration (ET_c), grain yield, and WUE, respectively. The ET_c of QF (292 mm) was substantially lower than that of the other treatments (p < 0.01), saving 649 mm of irrigation water and increasing the yield by 2.24% compared with those of NM. Meanwhile, the WUE and irrigation water use efficiency (IWUE) of QF reached maximums of 6.3 and 47.36 kg m⁻³, respectively, which were significantly higher than those of other treatments (p < 0.001). The results showed that planting in an RFPS with film mulching on both ridges and furrows (a ridge-to-furrow ratio of 50:30, with a 38 mm irrigation level) is suitable for maize to obtain high yield and reduce irrigation water use significantly.

Forest landscape restoration and ecosystem of Loess Plateau have enhanced prominently, since the policy implementation (1999) of the Grain for Green Project in China. Land ecological security (LES) performs an extremely critical function for protecting vulnerable land resources and sustaining forest ecosystem stability. Predecessors’ studies substantially concentrate on biophysical and meteorologic variables using numerous grounded methodologies, little research has been launched on systematic natural-socio-economic-ecological relationships and how these contributions and regulations for LES evaluation. Here, pressure-state-response (PSR) model was used to establish the evaluation system of LES in regional-scale, and LES was classified into five levels measured by ecological security index (S), including high (S ≥ 0.75), medium−high (0.65 ≤ S < 0.75), medium (0.55 ≤ S < 0.65), medium−low (0.45 ≤ S < 0.55), and low (S < 0.45) level, for systematically analyzing its spatiotemporal distribution characteristic and response mechanism to explanatory variables in Yan’an, northwest China, from 2000 to 2018. The results demonstrated that: (1) LES status was mainly characterized by medium−high level and medium level, and maintained profound stability. (2) zone with medium−high LES level was mainly concentrated in western and southern regions, continuously expanding to northeast regions, and possessed the largest territorial area, accounting for 37.22–46.27% of the total area in Yan’an. (3) LES was primarily susceptible to normalized differential vegetation index, vegetation coverage, and land surface temperature with their optimal impacting thresholds of 0.20–0.64, 0.20–0.55, and 11.20–13.00 °C, respectively. (4) Normalized differential vegetation index and vegetation coverage had a significant synergistic effect upon LES based on their interactive explanation rate of 31% and had significant variation consistency (positive and negative) with LES, which were powerfully suggested to signal the intensification of the regional eco-security level in the persistent eco-greening process.

Ca and Mg are essential micronutrients for plant growth, and they play a crucial role in plant development and responses to adversity by influencing the activities of endogenous hormones and antioxidant enzymes. However, the specific mechanisms through which calcium (Ca) and magnesium (Mg) regulate the kernel sugar content through endogenous hormones and antioxidant enzymes remain unclear. In this study, we analyzed the impact of Ca and Mg on the physiology of maize leaves and kernel quality by determining the activities of antioxidant enzymes and endogenous hormones, and the kernel sugar content in maize leaves when supplemented with different levels of Ca and Mg. Our main findings were as follows: (1) Elevated Mg levels augmented superoxide dismutase (SOD) activity, bolstering antioxidant defenses, whereas low Ca and Mg levels diminished SOD activity. High Ca levels enhanced catalase (CAT) activity during kernel development. Low−Ca conditions stimulated gibberellin (GA) synthesis, while high−Ca and high−Mg conditions suppressed it. High Mg levels also elevated abscisic acid (ABA) levels, potentially improving stress tolerance. (2) High Ca levels increased the reducing sugar content in kernels, augmenting the energy supply, while both low and high Mg levels increased soluble sugars, with low Mg levels specifically enhancing the sucrose content, which is a critical energy reserve in plants. (3) CAT exerted a pivotal regulatory role in the sugar accumulation in maize kernels. GA, under the influence of Ca, modulated the sucrose and soluble sugar contents by inhibiting CAT, whereas ABA, under the influence of Mg, promoted CAT activity, thereby affecting the kernel sugar content. This study reveals a new mechanism through which the addition of Ca and Mg regulate the sugar content in maize kernels by affecting endogenous hormones and antioxidant enzyme activities. These findings not only enhance our understanding of the role of micronutrients in plant growth and development but also provide new strategies for improving crop yield and stress tolerance.

This study examined the regulatory mechanism of calcium (Ca) amendment on the dynamics of soil organic carbon (SOC) fractions and extracellular enzyme activities, elucidating the role of Ca in soil carbon cycling processes. A field experiment with maize was conducted, comparing treatments of low calcium (T1), high calcium (T2), and a calcium-free control (CK). Measurements included inter-root SOC fractions—soluble organic carbon (DOC), microbial biomass carbon (MBC), and readily oxidizable organic carbon (ROC)—and the activities of the following extracellular enzymes: β-xylanase, β-glucosidase (β-glu), phenol oxidase (Phox), peroxidase (Pero), phosphatase (Phos), acetylaminoglucosidase (NAG), and urease. The main findings indicated the following: (1) Calcium addition significantly increased SOC content (115.04% and 99.22% higher in T1 and T2, respectively, than CK during the entire reproductive period) and enhanced microbial activity (elevated DOC and MBC). However, SOC decreased by 8.44% (T1) and 16.38% (T2) relative to CK in the late reproductive stage (irrigation–ripening), potentially reflecting microbial utilization (supported by the inverse correlation between SOC and MBC/DOC), and maize carbon reallocation during grain filling. (2) Calcium activated β-glu, Phox, Phos, NAG, and urease (p < 0.05), with pronounced increases in Phox (241.13 IU·L⁻¹) and Phos (1126.65 U·L⁻¹), indicating enhanced organic matter mineralization and phosphorus availability. (3) Calcium-driven MBC and ROC accumulation was associated with the positive regulation of Phox (path coefficient > 0.8) and the negative regulation of Phos. SOC was co-regulated by β-glu and Phos (R² = 0.753). (4) Calcium dynamically optimized the short-term carbon distribution through enzyme activity while promoting long-term sequestration. Our study provides new evidence supporting multi-pathway interactions through which calcium mediates enzyme networks to influence the soil carbon cycle. The findings provide a theoretical foundation for calcium fertilizer management and soil carbon sequestration strategies in agriculture, advancing academic and practical goals for sustainable development and carbon neutrality.

Water shortage threatens agricultural sustainability in Horqin Sandy Land, northeast China. To explore the effects of various surface mulching patterns with micro-spray irrigation on the yield, water consumption (ET_c), and water-saving potential of maize (Zea mays L.), we used three treatments: straw mulching (JG), organic fertilizer mulching (NF), and no mulching (WG; control). In each treatment, plants were supplied with 500 mm of total water (irrigation plus precipitation) during the entire growing season and were irrigated with the amount of total water supply minus precipitation. Yield and water use efficiency (WUE) showed a significant negative correlation with water saving potential per unit yield (P_y) and water saving potential per unit area (S_p), which were also consistent with their relationships in the function model. Meanwhile, a remarkably positive correlation occurred between yield, WUE, and net economic profit, respectively. The JG treatment, which was mainly affected by light and temperature production potential (Y_c), grain yield, and ET_c, showed the lowest P_y (0.16 m³ kg⁻¹) and S_p (2572.31 m³ hm⁻²), and the maximum increase in yield, WUE, and net economic profit, extending to 16,178.40 kg hm⁻², 3.25 kg m⁻³, 17,610.09 yuan hm⁻², respectively, which were significantly higher than those in NF and WG, (p <0.05). Thus, straw mulching with micro-spray irrigation was the best treatment for maximizing yield and WUE. Organic manure mulching and no mulching need further investigation, as these showed high P_y and S_p, which were together responsible for lower WUE.

This study investigated the effects of varying levels and combinations of calcium (Ca) and magnesium (Mg) supplementation on the diversity, composition, and species differentiation of the rhizosphere soil bacterial community in rainfed maize, aiming to reveal their regulatory mechanisms on the rhizosphere micro-ecosystem. A field micro-plot experiment was conducted with seven treatments: low Ca (U), high Ca (V), low Mg (W), high Mg (X), low Ca and low Mg (Y), high Ca and high Mg (Z), and a control (K, no supplementation). The bacterial communities were analyzed using high-throughput sequencing of the 16S rRNA gene, and the data were processed using the QIIME2 pipeline, as well as multivariate statistical analyses, and LEfSe. The main results demonstrated that Ca and Mg supplementation significantly altered the rhizosphere bacterial community structure (beta-diversity). Analysis of Similarities (ANOSIM) indicated significant differences between treatments (R > 0.4, p < 0.01). LEfSe analysis successfully identified key biomarkers responsive to different treatments. For instance, high Ca treatment significantly enriched the genus Clostridium within the phylum Firmicutes, whereas high Mg treatment specifically enriched the genus Lysobacter. Furthermore, Ca-Mg interactions exhibited non-additive effects, and the coupled Ca-Mg supplementation treatments (Y, Z) formed unique species assemblages. As key environmental drivers, Ca and Mg supplementation specifically reshaped the rhizosphere bacterial community through “environmental filtering” in rainfed maize. This study provides a theoretical basis for understanding the microbiological pathways through which secondary element fertilizers influence soil health, offering practical implications for precisely managing rhizosphere micro-ecology through Ca and Mg supplementation to promote the sustainable development of dryland farming.