Soil salinization constrains agricultural sustainability in coastal low plain regions, yet the mechanisms regulating salt spatial heterogeneity under different water management regimes remain unclear. This study investigated soil soluble ion distribution and influencing factors across 0–200 cm profiles (n = 78) under freshwater irrigation (FWI), brackish water irrigation (BWI), and non-irrigation (NOI) in the North China Plain. We hypothesized that irrigation affects soil salinization through dual pathways: direct ion inputs and indirect modification of soil physicochemical properties. Partial least squares structural equation modeling was used to quantify these effects. Results identified irrigation as an important correlate, exerting a significant direct negative effect on salt accumulation (−0.117) and an indirect effect mediated by soil physicochemical properties (0.218). The three regimes produced markedly distinct soluble ion composition and vertical salt distribution. FWI exhibited a bottom-accumulated distribution of soil salinity. BWI was characterized by significant Na+ and Cl− enrichment in the 50–100 cm layer, displaying a mid-profile accumulation pattern despite temporary surface desalination. NOI exhibited the most severe soil sodification, alongside a surface-accumulated profile. These findings reveal a trade-off in coastal water management: brackish water can partially offset freshwater scarcity, but long-term sustainability requires depth-specific salinity monitoring to mitigate subsurface salt accumulation risks.
This study aims to investigate the early post-termination phase as a critical window for assessing soil responses and improving agricultural management decisions. The experiment was conducted in Southern Italy and arranged as a split–split plot design involving three factors: irrigation system (sprinkler vs. drip); cover crop mixture (fava bean, oat, and rapeseed, vs. vetch, barley, and white mustard); and cover crop termination method (incorporation vs. mulch). Four soil parameters were selected for this experiment: soil organic matter, soil aggregate stability, total nitrogen, and soil infiltration rate. Findings highlight no significant differences in total nitrogen among treatments, whereas the soil infiltration rate increased in drip-irrigated treatments and decreased in sprinkler-irrigated ones. Soil aggregate stability increased across all treatments, as did soil organic matter, which increased by approximately 20% within a few weeks. Overall, the irrigation system acted as the main regulator of early soil physicochemical responses. The interaction between irrigation system and cover crop termination methods produced the largest differences among the investigated parameters. The combination of sprinkler irrigation and biomass incorporation resulted in the highest increase in soil organic matter.
The cytochrome P450 superfamily is vital for plant growth and stress responses, yet the CYP90 gene family in Brassica napus remains poorly characterized. In this study, we systematically identified 25 BnCYP90 genes across 16 chromosomes, classifying them into CYP90A, CYP90B, CYP90C, and CYP90D phylogenetic groups. Synteny and evolutionary analyses were consistent with purifying selection acting on this gene family. Promoter analysis identified diverse stress- and hormone-responsive elements, while network analyses predicted BnCYP90_4, BnCYP90_6, and BnCYP90_11 as highly connected nodes in candidate protein–protein interaction and miRNA-mediated regulatory networks. Furthermore, single nucleotide polymorphism (SNP) analysis of a natural population demonstrated that a missense variant (C09:66,297,283) in BnCYP90_25 was significantly associated with seed germination rate and aboveground biomass under salt stress. Transcriptome and RT-qPCR analyses highlighted distinct spatiotemporal expression profiles under abiotic stresses: BnCYP90_25 showed sustained activation under salt stress, BnCYP90_9 and BnCYP90_20 exhibited mid-stage responses to osmotic stress, and BnCYP90_21 and BnCYP90_25 rapidly responded to alkaline stress. Finally, weighted gene co-expression network analysis (WGCNA) identified BnCYP90_13 as a hub gene in the T1 developmental stage. Overall, this study comprehensively characterizes the BnCYP90 family, providing valuable candidate genes for future functional validation in breeding stress-tolerant B. napus.
Although the tasseling stage is a pivotal window for drought stress in maize, the photosynthetic physiological mechanism by which straw mulching compensates for drought-induced impairment relative to conventional rain-fed practice remains unclear. In this study, a two-factor randomized block experiment was conducted with two straw mulching levels (full mulching, FM, 9000 kg ha−1; half mulching, HM, 4500 kg ha−1) and three drought gradients (mild, 60–70% FC; moderate, 50–60% FC; severe, 40–50% FC) during the tasseling stage, with the conventional rain-fed control (CK) being non-mulched and well-watered (80% FC). The results show that only FM under mild drought (FM + LD) maintained the net photosynthetic rate, PSII photochemical efficiency (Fv/Fm), and grain yield at levels not significantly different from the CK (p > 0.05). Under mild drought, photosynthetic inhibition was dominated by stomatal limitation, with FM maintaining effective stomatal regulation. As drought intensified, the limiting factor shifted to non-stomatal limitation; however, FM showed significantly higher Fv/Fm and lower Vj than HM, indicating better PSII preservation. At 24 h after rewatering, donor-side function largely recovered across all treatments, whereas acceptor-side parameters remained elevated except in T1 (FM + LD). Overall, FM under mild drought at the tasseling stage achieved photosynthetic performance and yield comparable to conventional rain-fed management, providing a theoretical basis for water-saving cultivation in semi-arid regions.
Despite declining water availability in semi-arid environments, demand for high-quality forages by the livestock and dairy industries continues to grow. Researching alternative crops for high quality forage and water use efficiency remains a priority for these regions to meet this growing demand. Cereal grass-legume intercropping system may provide such a viable alternative to traditional sole cropping to improve nutritive value, while maintaining the current yield levels with limited supply of water. A study was conducted near West Texas A&M University, Canyon, TX, USA. during 2020 and 2021 to evaluate forage sorghum [Sorghum bicolor (L.) Moench]-cowpea [Vigna unguiculata (L.) Walp] and pearl millet [Pennisetum glaucum (L.) Leeke]-cowpea intercrops for forage production, nutritive value (crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and in vitro dry matter digestibility (IVTDMD)), and water use efficiency (WUE) under limited irrigation. Treatments were sole pearl millet (PM), sole forage sorghum (FS), sole cowpea (C), or mixtures of either pearl millet-cowpea or forage sorghum-cowpea planted in the same row (PM-C or FS-C), alternating rows (millet-cowpea 1:1 (PM-C 1:1) or forage sorghum-cowpea 1:1 (FS-C 1:1), or two rows alternating (millet-cowpea 2:2 (PM-C 2:2) or sorghum-cowpea 2:2 (FS-C 2:2). Results from both study years indicated that FS-C 1:1 intercrop showed either greater or equal forage dry matter (DM) yield compared to sole FS or sole PM (14.5 Mg ha−1 (FS-C 1:1) vs. 13.8 Mg ha−1 (FS) vs. 11.9 Mg ha−1 (PM)). Similarly, the relative advantage of FS-C 1:1 intercrop in improving WUE was also observed in the study compared to sole FS and sole PM (44 kg ha−1 mm−1 (FS-C 1:1) vs. 41.6 kg ha−1 mm−1 (FS) vs. 35.9 kg ha−1 mm−1 (PM). CP yield per hectare (estimate based on DM yield and percent CP content) was also greater for the forage sorghum-cowpea planted in 1:1 alternate rows. This suggests that producers in the semi-arid USA, especially in the Southern High Plains, can be significantly benefited from the utilization of cereal grass-legume intercropping production systems in lieu of sole cropping as the basis for livestock rations without compromising yield and water productivity.
