This study was designed to investigate the effect on wheat yield of applying organic fertilizers (OF) with five different selenium (Se) concentrations. The mineral nutrients, cadmium (Cd) content, and the distribution of Se in wheat plants were also measured. The results showed that wheat yields reached a maximum of 9979.78 kg ha⁻¹ in Mengcheng (MC) County and 8868.97 kg ha⁻¹ in Dingyuan (DY) County, Anhui Province, China when the application amount of selenium-containing organic fertilizer (SOF) was up to 600 kg ha⁻¹. Among the six mineral nutrients measured, only the calcium (Ca) content of the grains significantly increased with an increase in the application amount of SOF in the two regions under study. Cd content showed antagonistic effects with the Se content of wheat grains, and when the SOF was applied at 1200 kg ha⁻¹, the Cd content of the grains was significantly reduced by 30.1% in MC and 67.3% in DY, compared with under the Se0 treatment. After application of SOF, the Se content of different parts of the wheat plant ranked root > grain > spike-stalk > glume > leaf > stem. In summary, SOF application at a suitable concentration could increase wheat yields and significantly promote the Ca content of the grains. Meanwhile, the addition of Se effectively inhibited the level of toxic Cd in the wheat grains.

Banana Fusarium wilt-suppressive soils are effective against pathogen invasion, yet soil physicochemical factors responsible for conducive or suppressive behavior have not been reported. Here, we investigated the changes in banana biomass, disease incidence (DI), soil culturable microbes and physicochemical properties by incorporating pepper and banana residues into conducive and suppressive soils. Before the incorporation of any residues, the suppressive soil significantly increased banana biomass and decreased DI compared to the conducive soil. The biomass of the suppressive soil was significantly higher than that of the conducive soil after the incorporation of either pepper or banana residues. Compared with the control (CK), the incorporation of pepper residues to both soils significantly reduced DI, while banana residues had the opposite effect. Additionally, both conducive and suppressive soils supplemented with pepper residues significantly reduced the amounts of culturable Fusarium oxysporum and increased the amounts of beneficial Pseudomonas and Bacillus. The pepper residue extracts significantly inhibited the growth of F. oxysporum mycelium. Soil alkali-hydrolyzable nitrogen (AN) responded most strongly to residue application to suppressive soil. The AN factor was significantly and positively correlated with banana biomass; however, there was no direct and significant negative correlation with DI. Further analysis of the results showed that elevated AN content could stimulate the amounts of culturable Bacillus in the soil, and Bacillus antagonized the proliferation of pathogen and thus indirectly and effectively reduced banana DI. In conclusion, soil AN content can indirectly improve the disease suppression ability of pepper-residue-mediated suppressive soil by manipulating the soil microbiome.

Long-term continuous cropping often leads to soil-borne pathogen enrichment, and reducing pathogen abundance in continuously cropped soils is an important control measure. In this study, three rotation crops—carrot (C), garlic (G), and bok choy (B)—were introduced into potato pathogen-infested soils. The effects of different systems on pathogen abundance, soil physicochemical properties, and soil microbial abundance were investigated to preliminarily clarify mechanisms by which crop rotation suppressed pathogen enrichment. The results showed that all rotation systems significantly reduced soil pathogen abundance (Fusarium oxysporum, Fo). Among the rotation systems, carrot rotation achieved the greatest Fo reduction and exhibited the strongest increase in soil pH, followed by garlic rotation, while bok choy rotation had the weakest effect. Carrot rotation significantly increased soil bacterial abundance over other treatments. Moreover, crop rotation effectively suppressed soil pathogen enrichment by increasing soil pH and bacterial abundance. Importantly, carrot rotation enhanced soil pathogen-suppressive enzyme activities and the abundance of antagonistic bacteria in the soil. In contrast, garlic root exudates directly inhibited the pathogen, while bok choy and carrot root exudates promoted pathogen growth. These findings demonstrated different rotation crops exhibit distinct pathogen suppression mechanisms. Carrot rotation may indirectly suppress soil pathogen enrichment by increasing the abundance of antagonistic bacteria and enhancing antifungal enzymes, whereas garlic rotation may directly inhibit the pathogen via root exudates. This study provides practical guidance for growers to select optimal rotation crops and design rational continuous cropping systems.

Advances in plant nutrition have driven substantial progress in modern fertilization technologies. Nevertheless, excessive chemical fertilizer application, low nutrient-use efficiency, and the resulting environmental pollution remain widespread. We have reviewed the research progress and existing limitations in the field of plant nutrition and fertilization technology. Based on the traditional plant nutrition diagnosis and integrating visual diagnosis methods, this study explores the intrinsic relationship between plant growth status, nutrient supply conditions, and crop yield and proposed the concept of “status nutrition”. Variations in environmental nutrient conditions lead plants to exhibit distinct growth status in terms of vigor and phenotype. We define the plant nutritional status reflected by this growth status as “status nutrition”. Based on growth characteristics, plant growth status can be classified as weak, normal, or vigorous, corresponding to deficient, appropriate, and excessive environmental nutrient supply, respectively. Guided by this concept, an innovative rice “extremely dense planting” technology is integrated by increasing planting density, eliminating tiller-stage fertilization, and optimizing nitrogen management. The technology adapts to growth status with low nutrient demand, coordinates population growth and main-stem panicle formation, and achieves high yield with reduced fertilizer inputs. Further research is needed on the nutrient metabolism mechanisms of plants under different growth statuses and the growth status grading system. The promotion of “extremely dense planting” is constrained by crop variety traits and soil fertility, and its parameters urgently need to be optimized. Overall, the framework of “status nutrition” provides important theoretical support for the development and application of crop high-yield cultivation technologies.

Continuous cropping obstacles constrain the sustainability of intensive agricultural production, and investigating the dynamics of soil properties across different continuous cropping durations is important for the prevention and control of this problem. This study focused on field-grown Chrysanthemum morifolium and collected soil samples from plots with continuous cropping durations of 1 year (CR1), 3 years (CR3), 5 years (CR5), and 10 years (CR10) with three independent replicate plots per treatment, to analyze the changes and interrelationships among key soil physicochemical and microbial properties. The results showed that different soil properties exhibited distinct divergence patterns with different inflection points. The activities of fluorescein diacetate (FDA) hydrolase and chitinase decreased significantly during the first 1–3 years of continuous cropping and recovered continuously from years 5 to 10, representing the earliest responses. The target gene copies of Fusarium oxysporum f. sp. chrysanthemi (Foc) increased rapidly to a peak at CR5 and declined significantly at CR10; fungal target gene copies showed a similar pattern, peaking at 14.6 × 10⁷ copies·g⁻¹ in CR5. In contrast, bacterial target gene copies remained stable during years 1–5 but increased significantly by CR10. Meanwhile, fungal target gene copies (F), pH, and electrical conductivity (EC) all reached peaks or troughs between years 1 and 5, with significant rebound by year 10. Soil pH and EC dropped to their lowest levels in CR5 (pH 5.1, EC 85 μS·cm⁻¹) and recovered markedly by CR10 (pH 6.5, EC 150 μS·cm⁻¹). Soil organic matter, available phosphorus, and nitrate nitrogen increased continuously, with the highest values recorded in CR10, whereas ammonium nitrogen declined sharply to 0.52 mg·kg⁻¹ in CR5. Correlation analysis and random forest modeling indicated that bacterial target gene copies, FDA hydrolase, chitinase, nitrate (NO₃⁻), and pH were the most important predictors of Foc target gene copies, with fungal target gene copies ranking highest in predictive importance (%IncMSE = 26%), followed by bacterial target gene copies; the latter exhibited a significant negative association with Foc target gene copies. The proportion of antagonistic bacteria declined continuously from 6.0% to 1.0% during years 1–5 and recovered to 5.0% during years 5–10, exhibiting a trade-off pattern with Foc target gene copies. This study shows that different soil properties exhibit clear temporal divergence under continuous cropping, with microbial factors emerging as the dominant predictors of variation in pathogen target gene copies.

Crop rotation effectively mitigates soil continuous cropping obstacles. Exploring the impacts of different cropping systems (rotational cultivation vs. long-term monocropping of rotatable non-host crop) on the physicochemical (including pH, electrical conductivity, soil organic matter, available phosphorus, available potassium, ammonium nitrogen, and nitrate nitrogen) and microbial properties (including the abundances of Fusarium oxysporum f. sp. cubense (FOC) total bacteria, fungi, and actinomycetes, as well as catalase, urease, and chitinase activities) of monocropped soil is essential for targeted obstacle management. In a long-term fixed-site experiment, three treatments were established: continuous banana monocropping (BB), single-season pineapple rotation (BP), and long-term pineapple monocropping after continuous banana monocropping (PP). Soil physicochemical and microbial properties were determined, and their interrelationships were analyzed. Compared with BB, both BP and PP significantly reduced the target gene copies of FOC with the FOC target gene copies in BP being significantly (p < 0.05) higher than in PP. BP significantly (p < 0.05) increased the target gene copies of fungi (F), bacteria (B) and actinomycetes (A) as well as the activities of catalase (Cat), urease (Ure) and chitinase (Chi). In contrast, PP caused no significant changes in actinomycetes’ target gene copies or any tested enzyme activity. All of the microbial target gene copies and enzyme activities in BP were significantly (p < 0.05) higher than those in PP. Relative to BB, BP significantly (p < 0.05) decreased the soil available potassium (SK), available phosphorus (SP) and soil organic matter (SOM). Soil pH and SOM were significantly (p < 0.05) higher in BP than in PP, while electrical conductivity (EC) and nitrate nitrogen (NO₃⁻) were significantly (p < 0.05) higher in PP than in BB. Model analysis indicated that SOM, SK, SP and NH₄⁺-N were the core physicochemical factors explaining the variation in FOC target gene copies, and the target gene copies of actinomycetes and fungi, together with catalase, urease and chitinase activities, were the key biological drivers. Verification tests showed that the proportions of pathogen-antagonistic fungi and actinomycetes in BP reached 23.6% and 10%, respectively, which were significantly (p < 0.05) higher than those in PP and BB. Banana seedlings grown in BP soil had significantly (p < 0.05) greater plant height, stem diameter and leaf area than those in BB. PP showed a mild upward trend in growth indicators, but the difference from BB was not significant. In conclusion, single-season pineapple rotation and the long-term monocropping of rotatable non-host crop both reduce FOC target gene copies in continuously cropped soil, yet the two patterns operate through distinct suppression mechanisms for continuous cropping obstacles. Single-season rotation achieves better improvement in soil physicochemical and microbial properties, while the long-term monocropping of a rotatable non-host crop showed lower soil FOC target gene copies.