Table of Content

16 August 2025, Volume 58 Issue 16

Previous Issue   

SPECIAL FOCUS: NUTRIENT MANAGEMENT FOR ANNUAL RICE-RAPESEED ROTATION

Integrated Nutrient Management Technology and Its Effects for Annual Rice-Rapeseed Rotation

REN Tao, FANG YaTing, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3159-3163.  doi:10.3864/j.issn.0578-1752.2025.16.001

Abstract ( 66 )   HTML ( 14 )   PDF (246KB) ( 32 )   Save

References | Related Articles | Metrics

Effects of Long-Term Chemical Fertilizer and Organic Material Application on Crop Yield and Nutrient Utilization in Rice-Rapeseed Rotation System

FANG YaTing, ZHAO Jian, SHENG QianNan, LI KaiXu, WANG XiangHua, ZHANG YangYang, ZHU Jun, CONG RiHuan, LU ZhiFeng, LI XiaoKun, REN Tao, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3164-3177.  doi:10.3864/j.issn.0578-1752.2025.16.002

Abstract ( 42 )   HTML ( 7 )   PDF (1104KB) ( 19 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The application of chemical fertilizers and organic materials is a crucial measure for increasing agricultural production. Rice-rapeseed rotation system is a primary paddy-upland crop rotation pattern in the Yangtze River basin of China. Clarifying the impact of chemical fertilizers and organic material inputs on the annual crop yield and nutrient utilization in rice-rapeseed rotation could provide a scientific basis for ensuring food and oil security and achieving green and sustainable agricultural development. 【Method】From 2017 to 2022, a continuous field experiment was conducted at the Huazhong Agricultural University's Shayang Experimental Station in Shayang County, Hubei Province. Four treatments were established: no fertilizer (CK), chemical fertilizer only (NPK), chemical fertilizer with straw return (NPK+S), and chemical fertilizer with straw return plus organic fertilizer (NPK+S+M). The crop yields, nitrogen (N), phosphorus (P) and potassium (K) nutrient absorption of rapeseed and rice were analyzed. The nutrient use efficiency, apparent nutrient balances, and their relationships with yield were also assessed.【Result】The average results over 6 years showed that compared with no fertilization, the application of chemical fertilizers and organic materials significantly increased the yield of rapeseed (493.5%-758.8%) and rice (94.3%-106.4%), and enhanced crop yield stability (24.6%-72.1%) and sustainability (17.2%-85.0%). Compared with the NPK treatment, the NPK+S treatment increased the yield of rapeseed by 6.3%, but decreased yield stability and sustainability; it decreased the yield of rice by 0.8%, but increased yield stability and sustainability. The NPK+S+M treatment increased the yield of rapeseed and rice by 44.7% and 5.4%, respectively, and improved the sustainability of yield. Throughout the rotation cycle, nutrient uptake by rapeseed was consistently lower than that by rice across all treatments. The addition of organic materials significantly enhanced nutrient uptake in both rapeseed and rice. Relative to the NPK treatment, the NPK+S+M treatment resulted in increases of 5.1%-91.2% in average nutrient uptake and 12.2%-100.4% in trend nutrient uptake. The NPK+S treatment did not significantly differ from the NPK treatment in average nutrient uptake but exhibited a 7.7%-25.4% higher trend nutrient uptake. The input of organic materials decreased the physiological nutrient use efficiency of rapeseed and rice. Compared with the NPK treatment, the physiological N use efficiency of rapeseed and rice in the NPK+S+M treatment decreased by 3.0 and 3.7 percentage points, respectively, and the physiological P use efficiency decreased by 19.3 and 25.5 percentage points, respectively. Further analysis revealed that the application of organic materials led to higher apparent nutrient surpluses, which caused the annual increase in the cumulative yield of crops in the rice-rapeseed rotation. The cumulative apparent nutrient surplus was significantly positively correlated with the cumulative crop yield. 【Conclusion】The application of chemical fertilizers and organic materials significantly increased crop yields and nutrient use efficiency, and its effects were jointly influenced by crop and nutrient type. Increasing organic fertilization along with chemical fertilizers and straw application could further enhance soil fertility and increase crop yield; however, efforts should focus on improving the physiological nutrient use efficiency to fully realize the potential of organic amendments for sustainable grain and oil production.

Organic-Inorganic Fertilization Application and Deep Tillage Enhance Productivity and Nutrient Use Efficiency in Rice-Rapeseed Rotations

BU RongYan, CHENG WenLong, WU Ji, TANG Shan, LI Min, LU JianWei, JI GenXue, WANG Hui, ZHU Rui, JIANG FaHui, TANG MengMeng, HAN Shang

Scientia Agricultura Sinica. 2025, 58(16):  3178-3189.  doi:10.3864/j.issn.0578-1752.2025.16.003

Abstract ( 26 )   HTML ( 3 )   PDF (697KB) ( 14 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The aim of this study is to elucidate the long-term effects of tillage practices and fertilization measures on annual crop yield and nutrient utilization in a rapeseed- rice rotation system in the Yangtze River Basin, for providing a scientific basis for sustainable nutrient management to achieve synergistic grain and oilseed production in the region.【Method】Based on a site-specific field experiment (2016-2023) with a rice-rapeseed rotation system, a split-plot design was adopted. The main treatments were different tillage methods: rotary tillage (RT, 12 cm depth) and deep tillage (DT, 20 cm depth). The sub-treatments included three fertilization regimes: no fertilization (CK), chemical fertilizer alone (F), and combined organic-inorganic fertilization (FM, where chemical fertilizer in the rice season matched the F treatment, while the rapeseed season received organic-chemical fertilization). This study analyzed the rapeseed and rice yields, nutrient uptake, and nutrient use efficiency, with a comprehensive evaluation incorporating yield stability index (YSI) and sustainability index (SYI).【Result】Compared with CK, fertilization application significantly increased rice and rapeseed yields by 47.6% and 288.1%, respectively, while improving yield stability (YSI increased by 6.1% and 10.6%) and sustainability (SYI increased by 14.7% and 16.7%). Fertilization was the primary factor influencing crop yield, with FM outperforming F. DT further enhanced rice (9.2%) and rapeseed (7.0%) yields compared with RT, while significantly improving rice and rapeseed yield stability (YSI decreased by 17.9% and 4.7%, respectively) and sustainability (SYI increased by 5.7% and 7.7%, respectively). Among all treatments, FM-DT achieved the highest yields, stability, and sustainability for both crops. Further analysis revealed that FM-DT most effectively promoted nutrient translocation to grains, increasing N and phosphorus (P) harvest indices. The N and P harvest indices reached 76.9% and 76.0% in rice and 68.5% and 69.5% in rapeseed, respectively. Organic fertilizer substitution reduced chemical fertilizer input but enhanced N and P use efficiency, increasing them by 23.1% and 24.5% in rice and 63.7% and 22.8% in rapeseed, respectively. DT combined with organic substitution further improved N and P apparent recovery efficiency. 【Conclusion】The integration of FM with DT significantly enhanced productivity, stability, and sustainability in the rice-rapeseed rotation system while improving nutrient use efficiency. This approach represented an effective nutrient management strategy for achieving sustainable development in rice-rapeseed rotation in the Yangtze River Basin.

Balanced Application of Nitrogen, Phosphorus and Potassium Fertilizer in Rice-Rapeseed Rotation System Improves Crop Yield and Nutrient Utilization

MENG ZiZhen, REN Tao, LIU Chen, WANG KunKun, LIAO ShiPeng, LI XiaoKun, CONG RiHuan, LU ZhiFeng, FANG YaTing, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3190-3200.  doi:10.3864/j.issn.0578-1752.2025.16.004

Abstract ( 28 )   HTML ( 5 )   PDF (697KB) ( 9 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】Rice-rapeseed rotation is an important paddy-upland crop rotation in China, and the application of nitrogen (N), phosphorus (P) and potassium (K) fertilizer plays an important role in guaranteeing high and stable crop yields. This study systematically assessed the effects of different types of nutrient inputs on the yield and nutrient utilization of the annual crop of a continuous term rotation, so as to provide a reference to the management of nutrients in rice-rapeseed rotation.【Method】A rice-rapeseed rotation field trial was carried out for 8 continuous years from 2016 to 2024, with 4 treatments of equal application of N, P and K (NPK), and no N (-N), no P (-P), and no K (-K), to analyze the yield of annual crops, yield components, nutrient utilization, and apparent balance.【Result】Imbalanced fertilization significantly reduced crop yields, compared with the NPK treatment, the -N, -P and -K treatments reduced yields by 26.7%, 36.7% and 2.8% in rice and 57.4%, 86.4% and 12.3% in rapeseed, respectively, and the reduction in the number of effective number of panicles in rice and the number of pods in rapeseed were the main reasons for the crop yields reduction. With the increase of rotation year, the cumulative crop yield under -N, -P and -K treatments gradually increased the degree of yield reduction; compared with NPK treatment, the yield stability and sustainability of rice and rapeseed were significantly reduced under -P treatment. In terms of annual nutrient allocation in crop rotation, the N, P₂O₅ and K₂O accumulation in rice was higher than that in rapeseed, and the trends of nutrient accumulation in rice, rapeseed and crop annual rotation under imbalanced fertilizer application conditions were consistent with yields. Fertilizer use efficiency analysis showed that the fertilizer contribution rates of N, P and K fertilizers were lower in rice than in rapeseed, while the agronomic efficiency of N and P fertilizers, and the recovery efficiency of P and K fertilizers were higher than those of rapeseed. From the nutrient apparent balance of the annual rotation, the nutrient surpluses of the soil in the rice season were all lower than those of the soil in the rapeseed season, and the annual rotation of the NPK treatment had surpluses of 135.1 kg N·hm^-2, 49.6 kg P₂O₅·hm^-2, and deficits of 225.1 kg K₂O·hm^-2, deficiency of a single nutrient exacerbated the surplus of other nutrients.【Conclusion】In the rice-rapeseed rotation system, the deficiency of any single essential nutrient notably diminished crop yield as well as the utilization of nutrients, and the rate of yield reduction was related to the basic soil fertility level. Under the conditions of this study, the -P treatment had the largest yield reduction, followed by the -N treatment, while the -K treatment showed the smallest reduction. The magnitude of yield reduction in rapeseed was significantly higher than that in rice. Therefore, it was necessary to pay attention to the input of N and P fertilizers to achieve high and stable crop yields, and appropriate supplementation of K fertilizer to alleviate the depletion of soil K reservoirs, in order to realize high yield, high efficiency and sustainable development of the long-term rice-rapeseed rotation system.

Changes in Annual Yield and Soil Fertility of Rice-Rapeseed Rotation Under Different Fertilization Modes

DONG YunQi, HUANG Jian, CHAI YiXiao, YANG ShiChao, WANG Min, MENG XuSheng, GUO ShiWei

Scientia Agricultura Sinica. 2025, 58(16):  3201-3219.  doi:10.3864/j.issn.0578-1752.2025.16.005

Abstract ( 29 )   HTML ( 6 )   PDF (836KB) ( 10 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】To explore the potential of optimizing fertilization under rice-rapeseed rotation for increasing crop yield and efficiency in medium and low yield fields, this study analyzed the effects of optimized fertilization on yield, nutrient absorption, and soil fertility in rice-rapeseed rotation, as well as the effectiveness of rice-rapeseed rotation in improving soil fertility. This study aimed to identify fertilization strategies suitable for medium and low yield fields and the potential for improving quality and efficiency in rice-rapeseed rotation, so as to provide the theoretical guidance for reducing obstacles in medium and low yield fields, promoting efficient production in rice-rapeseed rotation, and achieving sustainable development of rice-rapeseed rotation.【Method】The experiment was conducted at the Agricultural Science Research Institute in Rugao City, Jiangsu Province from 2017 to 2024, with low yield fields as the research objects. Through small-scale experiments, no fertilization treatment (CK), no nitrogen treatment (PK), no phosphorus treatment (NK), farmer's habitual fertilization treatment (FFP), and optimized fertilization treatment (OPT) were set up. By analyzing the annual yield of crops in both water and drought seasons, the nutrient absorption of aboveground parts during maturity, and soil nutrient content, the yield change rules under different fertilization systems of rice-rapeseed rotation were clarified, and the main influencing factors were explored.【Result】During the seven year rotation period, compared with FFP, the yield and yield composition of rice and rapeseed treated with OPT were more stable with increasing rotation cycles. Compared with FFP, OPT treatment significantly increased the nitrogen and phosphorus partial productivity of rice and rapeseed, with rice showing 51.5%-73.3% and 81.8%-107.9% higher nitrogen and phosphorus partial productivity, respectively; rapeseed was 137.2%-152.3% and 89.8%-101.9% higher, respectively. During the four-year rotation period, the aboveground biomass of rice and rapeseed treated with OPT was higher than that treated with FFP. Comparing the two annual rotation periods at the beginning and end of the comparative experiment, it was found that the accumulation of nitrogen, phosphorus, and potassium in the aboveground parts of rice and rapeseed treated with OPT was higher than that under FFP treatment, and OPT treatment had a better effect on improving soil organic matter, total nitrogen, and available potassium than FFP treatment. After 7 years of rice-rapeseed rotation, the soil fertility index significantly increased (63.8%-117.2%) under all treatments. Compared with FFP treatment, the average membership degree of five soil chemical indicators in the rice season treated with OPT was higher than that under FFP treatment, and its comprehensive fertility index increased by 13.4%-19.2%. In addition, the soil phosphorus activation coefficient during the three-year rotation period was monitored, and it was found that the OPT treatment had a higher soil phosphorus activation coefficient than under FFP treatment. 【Conclusion】Compared with the traditional fertilization practices of farmers, optimizing fertilization could be achieved by optimizing fertilizer management. Based on reducing nitrogen and phosphorus fertilizer application by 40% and 50% in rice and 60% and 50% in rapeseed, stabilizing their yield composition, maintaining high biomass and nutrient absorption, and achieving stable annual yield in the rice-rapeseed intercropping system; the performance of optimized fertilization treatment in improving fertilizer utilization efficiency and soil fertility was better than that of farmers' habitual treatment. Therefore, optimizing fertilization under long-term fertilizer reduction could coordinate crop nutrient needs and nutrient supply, maintain stable or increased crop yields, and improve fertilizer utilization efficiency. Rice-rapeseed rotation could improve soil fertility in medium and low yield fields, achieve obstacle reduction in medium and low yield fields, and promote sustainable development of rice-rapeseed rotation.

Characteristics of Crop Yield, Stability and Nitrogen Utilization in Rice-Rapeseed Rotation System Under Different Nitrogen Application Rates

FANG Wen, LIU JunQuan, CUI Xin, LIU AiHua, FANG YaTing, CONG RiHuan, LU ZhiFeng, LI XiaoKun, REN Tao, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3220-3232.  doi:10.3864/j.issn.0578-1752.2025.16.006

Abstract ( 28 )   HTML ( 4 )   PDF (630KB) ( 11 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】By studying the effects of nitrogen fertilizer application rates on the annual crop yields, stability, and nitrogen uptake in the rice-rapeseed rotation system, this study explored the changing trends of the appropriate annual nitrogen fertilizer application rates for rice and rapeseed, so as to provide a theoretical basis for rational fertilization in the rice-rapeseed rotation in the middle reaches of the Yangtze River region.【Method】This locational trial was located in Wuxue City, Hubei Province, and was started in 2016. In this study, eight consecutive years of field locational trials were selected from 2016 to 2024. Five nitrogen fertilizer application rate gradients of 0, 90, 180, 270, and 360 kg N·hm^-2 were set up for both crops in the two seasons. The yields and their stability, nitrogen accumulation amounts, nitrogen fertilizer use efficiency, apparent nitrogen surplus, and the annual trends of appropriate nitrogen fertilizer application rates in the rice-rapeseed rotation system were analyzed. 【Result】Nitrogen fertilization significantly enhanced crop productivity in rice-rapeseed rotation systems. Compared with the nitrogen-free treatment, in each nitrogen-applied treatment, the average annual yield of rice increased by 1 035-1 769 kg·hm^-2, with an increase range of 19.4%-33.2%. The application of nitrogen fertilizer had a significant yield-increasing effect on winter rape; compared with the nitrogen-free treatment, the average annual winter rape yield increased by 1 041-2 208 kg·hm^-2, and the yield increased by 1.3-2.8 times. Aboveground nitrogen accumulation in rice and rapeseed increased progressively with elevated N inputs, averaging 36.8-108.2 kg·hm^-2 and 43.4-139.3 kg·hm^-2 higher than that under the zero-N control, respectively. Continuous observations indicated rising trends in both N accumulation and N recovery efficiency (NRE) for both crops under continuous rotation. During the rice season, with the increase in nitrogen fertilizer application rate, compared with the previous year, the average annual increase in nitrogen accumulation increased from 2.6% to 9.8%. In the rapeseed season, the increase in nitrogen accumulation in the nitrogen-free treatment was not significant among years. After applying nitrogen fertilizer, the nitrogen accumulation increased by an average of 3.4%-5.1% annually compared with the previous year. NRE in rice remained stable during the first three years but exhibited a parabolic rise starting from the fourth year. For rapeseed, NRE under 90-270 kg N·hm^-2 N rates increased by 5.6% annually, whereas no significant improvement occurred at 360 kg N·hm^-2. Apparent N balance in the zero-N treatment consistently showed deficits, while N-surplus in fertilized plots declined annually by 3.6%-8.3% (rice) and 2.4%-6.7% (rapeseed). Systematic analysis revealed an annual increase of 2.3% in optimal N rates for rice (annual mean: 146.8 kg N·hm^-2) and 0.9% for rapeseed (annual mean: 198.0 kg N·hm^-2).【Conclusion】In the continuous rice-rapeseed rotation planting mode, it was necessary to apply fertilizers with appropriate nitrogen application rates according to the nitrogen absorption characteristics of the crops in the rotation system, and to dynamically adjust the annual nitrogen allocation amount according to the soil nitrogen status.

The Impact of Annual Nitrogen Fertilizer Management on Crop Yield and Nitrogen Utilization in Rice-Rapeseed Rotation System

LIU Chen, FANG YaTing, REN Tao, WANG KunKun, REN YuFang, MENG ZiZhen, LIAO ShiPeng, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3233-3244.  doi:10.3864/j.issn.0578-1752.2025.16.007

Abstract ( 25 )   HTML ( 4 )   PDF (527KB) ( 8 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The rice-rapeseed rotation is a typical paddy-upland rotation cropping pattern in the Yangtze River Basin of China. The seasonal wet-dry alternation in soil affects the transformation of soil nitrogen and the application effect of nitrogen fertilizers. From the perspective of annual rotation, this study explored the differences in the effects of nitrogen fertilizer management on crop yield and nitrogen distribution in the rice-rapeseed rotation system, so as to provide a scientific basis for the efficient utilization of annual nitrogen fertilizer in the rice-rapeseed rotation system.【Method】The field experiment was located in Wuhan, Hubei Province, and was founded in 2012. This study selected 11 consecutive rice-rapeseed rotation years from 2012 to 2023 to conduct the experiment, four nitrogen fertilizer treatments were designed in the experiment: (1) no nitrogen application in both the rapeseed and rice seasons (N0-0); (2) applying 150 kg N·hm^-2 of nitrogen fertilizer in both the rice and rapeseed seasons (N150-150); (3) adding 75 kg N·hm^-2 of nitrogen fertilizer to the rice season on the basis of treatment (2) (N225-150); (4) adding 75 kg N·hm^-2 of nitrogen fertilizer to the rapeseed season on the basis of treatment (2) (N150-225). The related indicators such as crop yield, annual system energy yield, yield components, nitrogen accumulation and soil nitrogen supply capacity were analyzed.【Result】There were differences in the response of yield and nitrogen accumulation to nitrogen fertilizer management between rapeseed and rice. When the nitrogen application rate was N150-150 in both rice and rapeseed seasons, compared with no nitrogen application, the yields of rapeseed and rice increased by an average of 207.1% and 92.4%, respectively, and the nitrogen accumulation increased by an average of 253.2% and 114.7%, respectively. Compared with the N150-150 treatment, further application of nitrogen fertilizer during the rice season increased rice and rapeseed yields by 9.6% and 6.6%, respectively, while application of nitrogen fertilizer during the rapeseed season increased yields by 4.4% and 23.7%, respectively. Nitrogen application mainly increased crop yield by increasing the number of siliques per plant in rapeseed, the number of effective panicles per area in rice, and the number of grains per panicle, with rapeseed having a higher yield increase effect. In addition, from the analysis of the annual nitrogen fertilizer yield-increasing effect in the rotation system, compared with the application of 150 kg·hm^-2 of nitrogen in both rice and rapeseed seasons, the system energy yield and nitrogen accumulation of the rotation system under N225-150 treatment increased by 8.4% and 13.5%, respectively, and those under N150-225 treatment increased by 10.6% and 18.4%, respectively; at the same time, the annual nitrogen fertilizer utilization rate in the rice season with additional nitrogen application was 2.7 percentage points lower than that in the rapeseed season with additional nitrogen application, which might be related to the fact that the soil basic nitrogen supply in the rice season was 91.1% higher than that in the rapeseed season, resulting in a lower demand for high nitrogen input.【Conclusion】Therefore, in actual production, the annual nitrogen allocation should be adjusted according to the crop nitrogen requirements and soil nitrogen supply characteristics of the rotation system. In the rapeseed season, the nitrogen fertilizer application could be appropriately increased to achieve high yield, while in the rice season, the soil nitrogen supply capacity should be fully utilized, and the nitrogen fertilizer application should be appropriately controlled to achieve stable and efficient production of the rice-rapeseed rotation system.

Characteristics of Potassium Utilization and Crop Yield Formation in Rice-Rapeseed Rotation System Under Different Potassium Fertilizer Application Rates

GAO ZiYi, WU HaiYa, LIU JunQuan, CUI Xin, LIU AiHua, FANG YaTing, REN Tao, LI XiaoKun, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3245-3255.  doi:10.3864/j.issn.0578-1752.2025.16.008

Abstract ( 23 )   HTML ( 4 )   PDF (569KB) ( 7 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The aim of this study was to investigate the effects of potassium (K) fertilizer application rates on crop productivity, K utilization, and apparent K balance under the rice-rapeseed rotation system in the Yangtze River Basin, so as to provide a scientific basis for the rational application and distribution of potassium fertilizer in the rice-rapeseed rotation system.【Method】A field experiment was carried out from 2016 in Wuxue City, Hubei Province, China. Five treatments were set up with 0 (K₀), 60 (K₆₀), 120 (K₁₂₀), 180 (K₁₈₀) and 240 (K₂₄₀) kg K₂O·hm^-2, respectively. The crop yield, K uptake, K fertilizer utilization and apparent K balance were studied from 2016 to 2024.【Result】K fertilization significantly increased crop yield and aboveground K uptake, with the increase in rapeseed yield and aboveground K uptake being greater than that of rice. Compared with K₀, K application significantly increased rice and rapeseed yield by 18.1%-32.7% and 46.7%-93.1%, respectively, and K uptake by 72.3%-240.1% and 124.6%-512.2%, respectively. K fertilization significantly reduced yield stability index of rapeseed yield by 24.2%-41.2%, and markedly increased yield sustainability index (SYI) by 23.2%-45.7%. The yield stability index of rice yield across all treatments was lower than that of rapeseed, and SYI was comparatively higher. The annual energy yield under the K₀ treatment exhibited a progressive decline with each successive year of crop rotation. The increase in rapeseed yield was primarily attributed to an increase in pod number and seed number, whereas in rice, it was mainly due to an increase in effective panicles and filled grains per panicle. As the K fertilizer application rates increased, the proportion of K uptake in rapeseed within the annual system rose, with the average K uptake ratio between rice and rapeseed being 3:2. The agronomy efficiency and the recovery efficiency of K fertilizer in rice were on average 4.5 kg·kg^-1 and 2.5 percentage points higher than those in rapeseed, respectively. Conversely, the K fertilizer dependency of rapeseed was 11.6 percentage points higher than that of rice. K application shifted the annual K apparent balance from deficit to surplus. When the K fertilizer application rate increased to 180 kg K₂O·hm^-2 during the rice season, the K balance transitioned from deficit to surplus, while in the rapeseed season, 60 kg K₂O·hm^-2 was required to achieve surplus. Fitting with a linear-plus-plateau model, the optimal K fertilizer application rates were determined to be 102 kg K₂O·hm^-2 for the rice season and 147 kg K₂O·hm^-2 for the rapeseed season. 【Conclusion】In summary, the application of potassium fertilizer increased the yield of rapeseed better than that of rice. The recommended annual potassium fertilizer application rate for the rice-rapeseed rotation system was 250 kg K₂O·hm^-2, with the fertilization ratio between the rice season and the rapeseed season being approximately 2:3.

Magnesium Fertilization Effects and Application Recommendations in the Rice-Rapeseed Rotation System

YE XiaoLei, TIAN GuiSheng, LIU JunQuan, GENG GuoTao, FANG YaTing, REN Tao, LI XiaoKun, CONG RiHuan, LU ZhiFeng, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3256-3266.  doi:10.3864/j.issn.0578-1752.2025.16.009

Abstract ( 18 )   HTML ( 2 )   PDF (544KB) ( 3 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】To address the critical constraint of soil available magnesium (Mg) deficiency on annual productivity in the rice-rapeseed rotation systems of China’s Yangtze River Basin, this study systematically investigated the effects of Mg fertilizer application rates on annual crop yield formation, nutrient uptake, and Mg balance in the soil-crop system, for providing a theoretical basis for efficient Mg management in rotation systems.【Method】Based on a field experiment initiated in 2017 at Wuxue, Hubei Province, this study selected six rotation cycles (2017-2023) with five Mg fertilizer treatments (0, 15, 30, 45, and 60 kg MgO·hm^-2 per season). The crop yield components, nutrient concentrations in different plant parts, and biomass in the rice-rapeseed rotation system were measured. Based on these measurements, crop nutrient accumulation, fertilizer use efficiency, and soil nutrient balance were calculated to clarify the magnesium requirement characteristics of crops in the rotation system and establish fertilization strategies for the rotation system.【Result】(1) Mg application significantly increased annual system productivity, with yield increments of 9.5%-23.8% for rapeseed and 2.2%-4.0% for rice. A linear-plateau model indicated the maximum yields of 2 388 kg·hm^-2 (rapeseed) and 8306 kg·hm^-2 (rice) at an annual MgO rate of 60.4 kg·hm^-2 (38.1 kg·hm^-2 for rapeseed season; 22.3 kg·hm^-2 for rice season). Yield improvements in rapeseed were attributed to increased siliques per plant and seeds per pod, while rice yield gains resulted from higher effective panicles and filled grains per panicle. (2) Mg application significantly elevated Mg concentrations in all plant parts at maturity, with smaller effects on grains. The maximum increases were 45.1% (rapeseed stem), 66.2% (pod wall), and 8.5% (seed) for rapeseed, and 14.9% (stem and leaf) and 6.5% (seed) for rice. Annual biomass and Mg accumulation increased by up to 1 820 kg·hm^-2 (8.5%) and 6.3 kg·hm^-2 (29.5%), respectively. While rice showed higher absolute biomass and Mg accumulation, rapeseed 's proportional contribution to annual Mg uptake increased with Mg application. (3) Mg fertilizer apparent utilization rate and agronomic efficiency declined with increasing application rates, with rapeseed consistently exhibiting higher utilization than rice under equivalent Mg inputs. Mg removal by crops exceeded fertilizer input below 90 kg·hm^-2 annual application, while 120 kg·hm^-2 resulted in Mg surplus. If the straw was returned to the field, Mg surplus would occur when the annual Mg fertilizer application rate was 60 kg·hm^-2.【Conclusion】The application of Mg fertilizer significantly enhanced annual crop productivity in the rice-rapeseed rotation system, with rapeseed exhibiting more pronounced demand and utilization advantages for Mg. It was recommended that the annual Mg fertilizer application rate in the rotation system be approximately 60 kg·hm^-2, with a seasonal application ratio of about 2:1 between the rapeseed and rice seasons, to achieve efficient Mg fertilizer management and to improve annual productivity.

Effects of Fertilizer Reduction on Crop Yield and Soil Fertility Under Long-Term Straw-Return Conditions in Rice-Rice-Rapeseed Rotations

HUO RunXia, FANG YaTing, ZHANG YanKe, WU HaiYa, LIU GuiSheng, LI XiaoKun, REN Tao, LU ZhiFeng, CONG RiHuan, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3267-3279.  doi:10.3864/j.issn.0578-1752.2025.16.010

Abstract ( 23 )   HTML ( 3 )   PDF (552KB) ( 5 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】This study aimed to clarify the effects of long-term straw return on crop yield and soil fertility in rice-rice- rapeseed rotation, so as to provide a scientific basis for the efficient use of straw resources and fertilizer replacement and reduction technology in rice-rice-rapeseed rotation system.【Method】In this study, a positioning experiment on straw return in rice-rice- rapeseed triple cropping system were selected, which was carried out for 15 consecutive years from 2007 to 2022, and set up three treatments of conventional fertilizer application + straw not returned to the field (100%F), conventional fertilizer application + straw returned to the field (100%F+St), and fertilizer reduction of 20% + straw returned to the field (80%F+St). The effects of different fertilizer applications on crop yields, nitrogen, phosphorus and potassium nutrient accumulation and soil physico-chemical properties were investigated. Nutrient accumulation and soil physicochemical properties were analyzed to assess the annual nutrient apparent balance and soil comprehensive fertility index of rice-rice-rapeseed rotation. 【Result】The long-term straw return increased crop yield, yield stability and sustainability of the rice-rice-rapeseed rotation system, with the most significant increase in the rapeseed season. Compared with 2007-2010, the late rice and rapeseed average yields under the 100%F+St treatment in 2019-2022 increased by 28.9% and 58.7%, respectively. Compared with 100%F treatment, early rice, late rice, and rapeseed yields under 100%F+St treatment increased by an average of 7.2%, 6.9%, and 13.4%, respectively, and with an average increase in yield stability and sustainability under 100% F+St treatment of 23.6% and 12.5% in the 2019-2022 late rice season. After four consecutive years of straw return in combination with 20% fertilizer reduction, early rice, late rice, and rapeseed yields remained stable or higher than conventional fertilization. Compared with the 100%F treatment, the yields of early rice, late rice, and rapeseed under the 80%F+St treatmentincreased by 5.3%, 3.1%, and 0.8%, respectively, from 2019 to 2022. Long-term straw return (100%F+St) enhanced crop NPK nutrient accumulation and annual nutrient surpluses, and the 20% fertilizer reduction + straw return (80%F+St) treatment reduced the annual NPK surpluses of the rotation by 54.0 kg N·hm^-2, 13.7 kg P₂O₅·hm^-2, and 48.6 kg K₂O·hm^-2. Analysis of the integrated soil fertility index (IFI) of the rapeseed season and the rice season following the long-term straw return revealed that the IFI of 100%F+St treatment was 1.44 and 1.51 in rapeseed season and rice season, respectively, which was significantly increased by 6.4% and 4.3% compared with 100%F treatment, respectively. The increase in IFI was higher in the rapeseed season than in the rice season. Compared with 100%F treatment, 80%F+St treatment had no significant difference in rice season and rapeseed season, with soil IFI values of 1.29 and 1.45, respectively. The increase of IFI under 100%F+St treatment mainly depended on the increase of organic matter, total nitrogen, and available potassium content by 22.8%, 20.5%, and 13.7% in rapeseed season, and the increase of organic matter, total nitrogen, and available phosphorus content by 14.1%, 1.7%, and 4.3% in rice season, respectively.【Conclusion】In conclusion, long-term straw return to the field could improve crop yield, N, P₂O₅ and K₂O nutrient accumulation and comprehensive soil fertility index of rice-rice-rapeseed rotation system, and with the increase of the time period of returning to the field, the stability and sustainability of crop yield increased. Based on the straw return condition with 20% fertilizer reduction, crop yield and nutrient accumulation could be effectively guaranteed to be maintained or higher than the conventional fertilization level, and the sustainability and stability of yield in rice season was higher than that in rapeseed season. Therefore, a 20% reduction of chemical fertilizer in the rice season could guarantee the stable yield and high efficiency of the rice-rice-rapeseed rotation system.

Effects of Direct and Biochar-Based Straw Incorporation on Crop Yield and Nitrogen Uptake and Utilization in a Rice-Rapeseed Rotation System

WANG AnXin, FANG YaTing, DUN Qian, WU YongQing, LIAO ShiPeng, LI XiaoKun, REN Tao, LU ZhiFeng, CONG RiHuan, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3280-3292.  doi:10.3864/j.issn.0578-1752.2025.16.011

Abstract ( 27 )   HTML ( 4 )   PDF (518KB) ( 4 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】Rice-rapeseed rotation is a major cropping system in the Yangtze River basin of China. Straw utilization is a crucial issue concerning agricultural sustainable development and environmental protection. This study aimed to explore the fertilizer-based utilization methods of straw in rice-rapeseed rotation systems, so as to provide the theoretical support for enhancing productivity and achieving efficient resource utilization in such systems.【Method】This study utilized a six-year (2017-2023) field experiment under rice-rapeseed rotation. Four treatments were chosen: no straw incorporation (NPK), direct incorporation of straw in both seasons (NPK+S/S), straw biochar incorporation in both seasons (NPK+B/B), and straw biochar incorporation in the rice season combined with direct straw incorporation in the rapeseed season (NPK+B/S). Crop yield and its stability, plant N absorption and utilization efficiency as well as the apparent N balance in soil were systematically analyzed.【Result】Direct and straw biochar incorporation significantly increased crop yields and yield stability. Compared with NPK, the rapeseed yields under NPK+S/S, NPK+B/B, and NPK+B/S increased by 13.9%, 14.8%, and 17.3% on average, respectively; rice yields increased by 8.5%, 7.2%, and 3.7%, respectively; annual energy yields improved by 10.5%, 9.9%, and 8.5%, respectively. Compared with NPK, the rapeseed yield sustainability index under NPK+S/S, NPK+B/B, and NPK+B/S was enhanced by 8.1% to 10.2%. Compared with NPK+S/S, NPK+B/B and NPK+B/S were more beneficial for enhancing rice yield stability (24.2% and 1.4%, respectively) and sustainability index (5.3% and 2.3%, respectively). Both straw management practices increased crop N uptake but decreased the N harvest index. Compared with NPK, aboveground N uptake in rapeseed increased by 7.4% to 20.7%, in rice by 3.3% to 15.0%, and in the annual rotation by 6.5% to 17.6% under NPK+S/S, NPK+B/B, and NPK+B/S treatments. However, the N harvest index in rapeseed and rice decreased by 0.2%-3.0% and 1.9%-3.8%, respectively. Compared with NPK+S/S treatment, NPK+B/B treatment significantly reduced N uptake in the above-ground part of rapeseed by 11.0%. The reduction in N uptake in rapeseed grains, rice grains, and the above-ground part of rice was not significant, while the N harvest index of rapeseed and rice was increased by 1.8% and 1.9%, respectively. Direct straw incorporation had an advantage in promoting crop N uptake, while straw biochar incorporation had an advantage in improving crop N distribution. Compared with NPK, NPK+S/S, NPK+B/B, and NPK+B/S significantly increased the partial factor productivity of applied N in rapeseed (13.9% to 17.2%) and rice (2.2% to 7.7%). All treatments showed N surplus, with the NPK+B/S treatment having the highest N surplus. Compared with the NPK treatment, the NPK+S/S, NPK+B/B and NPK+B/S treatments all increased the soil total N content (20.6%-22.7%). Soil total N content was the highest under straw biochar incorporation, which was more effective in converting surplus N into soil N and reducing N loss.【Conclusion】In rice-rapeseed rotation system, considering economic effects, compared with direct straw incorporation or straw biochar incorporation in both seasons, the strategy of applying straw biochar during the rice season and directly incorporating straw during the rapeseed season could not only ensure stable high crop yields but also enhance N fertilizer utilization and increase soil total N content, providing important support for the sustainable development of rice-rapeseed rotation systems.

Characterization of Crop Yield and Nutrient Apparent Balance Between Direct and Burning Straw Return in Rice-Rapeseed Rotation System

XIONG ZhiHao, LIU JunQuan, YE Lin, ZHU DanDan, HOU SuSu, FANG YaTing, CONG RiHuan, REN Tao, LI XiaoKun, LU JianWei

Scientia Agricultura Sinica. 2025, 58(16):  3293-3303.  doi:10.3864/j.issn.0578-1752.2025.16.012

Abstract ( 23 )   HTML ( 3 )   PDF (557KB) ( 5 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】This study aimed to investigate the effects of long-term different straw return methods on productivity and apparent balance of nitrogen, phosphorus and potassium nutrients in rice-rapeseed rotation system, in order to provide the theoretical basis for the efficient utilization of straw resources in the rotation system.【Method】The field experiment was located in Wuxue City, Hubei Province, and started in 2014, with three treatments of straw not return (NPK), direct straw return (NPK+St) and burning straw return (NPK+Sb), to determine and analyze the yields, nitrogen/phosphorus/potassium nutrient uptake and their apparent balances and other related indicators of rice and rapeseed in the consecutive 10-year period from 2014 to 2024.【Result】The average results of the 10-year experiment showed that compared with the NPK treatment, the rice and rapeseed yield in the NPK+St treatment increased significantly by 7.7% and 10.7%, respectively; the rapeseed yield in the NPK+Sb treatment increased significantly by 5.2%, and the effect of yield increase on rice was not significant. The yield increase effects of NPK+Sb and NPK+St increased with the increase in years of straw return, and in the 6th year reached the significant level. Based on the annual nutrient uptake characteristics, compared with the NPK treatment, the annual nitrogen uptake in the NPK+St and NPK+Sb treatments increased by an average of 11.6% and 2.9%, respectively, the annual phosphorus uptake increased by an average of 11.9% and 10.2%, respectively, and the annual potassium accumulation increased by an average of 55.8% and 39.1%, respectively. Direct straw return significantly enhanced the absorption of nitrogen, phosphorus and potassium nutrients in the rotation system. Burning straw return effectively increased the absorption of phosphorus and potassium nutrients in the rotation system. The annual nitrogen, phosphorus and potassium surplus of rice-rapeseed rotation in the NPK treatment were 101.3 kg N·hm^-2·a^-1, -8.9 kg P₂O₅·hm^-2·a^-1 and -296.6 kg K₂O·hm^-2·a^-1, respectively. The annual nitrogen surplus in the NPK+St treatment averaged 166.1 kg N·hm^-2·a^-1, with an increase of 64.0%. The annual phosphorus and potassium nutrient surpluses were realized for both NPK+St and NPK+Sb treatments, with surpluses of 33.0 and 19.0 kg P₂O₅·hm^-2·a^-1, 79.4 and 21.3 kg K₂O·hm^-2·a^-1, respectively. 【Conclusion】Direct and burning straw return significantly increased the crops production potential and nutrient uptake by promoting nutrient cycling in the rice-rapeseed rotation system. The effect of stabilizing rice yield and increasing rapeseed yield was shown among the different crops in the rotation. The straw direct return was more favorable to increase crop yield and to maintain the nutrient balance of the farmland than the straw burning return. Therefore, it was recommended to promote the direct straw return approach in the process of farmland production in order to fully utilize its advantages of yield enhancement, stabilization, and nutrient balancing, and to promote the sustainable development of the rice-oil rotation system.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Molecular Cytogenetic Characterization of Wheat-Thinopyrum intermedium 7J^S Addition Line CH71 with Resistance to Both Powdery Mildew and Stripe Rust

ZHANG ShuWei, SHI WenYu, LI BingJie, CHANG SongHe, QIAO LinYi, LI Xin, CHANG LiFang, CHEN Fang, GUO HuiJuan, CHANG ZhiJian, ZHANG XiaoJun

Scientia Agricultura Sinica. 2025, 58(16):  3304-3316.  doi:10.3864/j.issn.0578-1752.2025.16.013

Abstract ( 26 )   HTML ( 3 )   PDF (4299KB) ( 4 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】Thinopyrum intermedium, a tertiary gene pool of wheat, harbors valuable genetic resources for wheat improvement. This study aimed to develop novel wheat germplasms by transferring elite chromosomes from Thinopyrum intermedium into wheat via distant hybridization, investigating their impacts on disease resistance and agronomic traits to establish a theoretical foundation for wheat breeding. 【Method】A wheat-Thinopyrum intermedium disomic addition line, CH71 (2n=44), was developed from the BC₁F₆ progeny of a cross between common wheat cultivar Yannong 999 and the partial amphidiploid TAI8047 (2n=58). Non-denaturing fluorescence in situ hybridization (ND-FISH) with oligonucleotide probes (Oligo-pSc119.2, Oligo-pTa535, Oligo-B11, Oligo-pDb12H) was employed for karyotype analysis. Synteny-based (Synt) Oligo-FISH painting and Th. intermedium-specific STS markers were utilized to identify the homologous group and validate the origin of the alien chromosome. Disease resistance to powdery mildew (race E09) and stripe rust (mixed races CYR32, CYR33, CYR34) was evaluated under artificial inoculation. Agronomic traits, including plant height, spike length, spikelet number, thousand-grain weight, grain length, and grain width, were systematically measured.【Result】The wheat parent Yannong 999 exhibited a standard karyotype of 21 wheat chromosome pairs. TAI8047 contained 58 chromosomes (21 wheat pairs + 8 alien pairs), while CH71 harbored 44 chromosomes (21 wheat pairs + 1 alien pair, J^S-1). Synt-FISH and PCR amplification using 183 STS primers specific to Th. intermedium chromosome 7J^S confirmed J^S-1 as a 7J^S-derived chromosome. Twelve STS markers consistently amplified diagnostic bands in Th. intermedium, TAI8047, and CH71. CH71 displayed moderate resistance to powdery mildew and immunity to stripe rust, with genetic analysis indicating both resistances were conferred by the 7J^S chromosome. Compared to Yannong 999, CH71 exhibited significant increases in plant height (+24.0 cm), spike length (+3.44 cm), spikelet number (+1.6), and grain length (+0.68 mm), but reductions in thousand-grain weight (-6.78%) and grain width (-2.70%). 【Conclusion】The novel disomic addition line CH71 (wheat-Th. intermedium 7J^S) demonstrates dual resistance to powdery mildew and stripe rust, serving as a valuable germplasm resource for disease-resistant breeding and the cloning of alien resistance genes. The 12 STS markers identified herein provide an efficient molecular tool for rapid tracking of the 7J^S chromosome in wheat backgrounds.

Assessment of Salt Tolerance and Screening of Salt Tolerant Germplasm in Sorghum Seedling Stage

MENG ZiNuo, FU ChangQing, ZHANG LingYu, GAO ShunJuan, CHANG JinHua, CUI JiangHui

Scientia Agricultura Sinica. 2025, 58(16):  3317-3326.  doi:10.3864/j.issn.0578-1752.2025.16.014

Abstract ( 34 )   HTML ( 4 )   PDF (2800KB) ( 6 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】To screen salt-tolerant sorghum germplasm resources and identify the key indicators for evaluating sorghum salt tolerance, so as to provide a scientific basis for the subsequent research on salt-tolerant germplasm and the stress-resistant cultivation of sorghum in saline soils. 【Method】Using 160 domestic sorghum varieties (lines) and 25 foreign varieties (lines), totaling 185 sorghum varieties (lines) from different countries and regions as experimental materials, the relative values of 9 trait indicators (germination potential, germination rate, seedling length, seedling dry weight, seedling fresh weight, root length, root dry weight, root fresh weight, and number of lateral roots) were analyzed under 150 mmol·L^-1NaCl solution treatment with vermiculite as the substrate. Correlation analysis, principal component analysis (PCA), cluster analysis, and subordinate function method were employed to screen salt-tolerant germplasm resources. Piecewise linear regression and multiple stepwise linear regression were used to identify key indicators determining sorghum salt tolerance at the seedling stage and conduct comprehensive evaluation.【Result】Under salt stress conditions, the 9 trait indicators of sorghum at the seedling stage showed varying degrees of variation. Among them, seedling dry weight exhibited the most significant variation, while lateral root number was least affected. Correlation analysis revealed diverse relationships among the traits: Relative germination rate showed negative correlations with relative seedling length and relative lateral root number, whereas all other traits displayed positive correlations. The highest correlation coefficient (0.54) was observed between relative seedling length and relative root length. Through principal component analysis (PCA), the 9 traits were reduced to 4 comprehensive indicators, accounting for 72.10% of the cumulative variance. The subordinate function method was applied to calculate the comprehensive D values for all 185 varieties. Cluster analysis using the hclust function in R categorized the sorghum accessions into four salt-tolerance groups: highly salt-tolerant, salt-tolerant, moderately salt-tolerant, and salt-sensitive. Taking the comprehensive D value as the dependent variable and the other 9 indicators as independent variables, piecewise linear regression models were constructed, showing positive trends between all traits and D values. A multiple stepwise linear regression equation was further established: F=0.25RGR+0.255RSL+0.377RGP+0.283RSFW, (R²=0.894, P<0.01).【Conclusion】Thus, the germination potential, germination rate, seedling length and seedling weight were the key indicators for screening sorghum salt tolerant varieties in 150 mmol·L^-1 NaCl environment. Among the high salt tolerance varieties, sweet 319, Xin 52, MY 2, sweet 11, Sudan 1-2, and sensitive salt varieties S29241, N2902, 6-5A, IS-3977, 90111 were selected.

PLANT PROTECTION

Mechanism of Tobacco Resistance to Bacterial Wilt Induced by Magnesium Oxide Nanoparticles

CHEN JuanNi, CHEN PinLu, LI Yu, XIE MengXiao, LI XinBei, DING Wei

Scientia Agricultura Sinica. 2025, 58(16):  3327-3344.  doi:10.3864/j.issn.0578-1752.2025.16.015

Abstract ( 29 )   HTML ( 3 )   PDF (3322KB) ( 5 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The objective of this study is to explore the effect and mechanism of magnesium oxide nanoparticles (MgO NPs) in inducing tobacco resistance to bacterial wilt, and by integrating the aboveground and underground synergistic response mechanism of plants, it will provide a new research perspective for revealing the molecular mechanism of nanomaterials inducing systemic resistance in plants.【Method】The physiological and biochemical defense response mechanisms of the aboveground part and the changes of the rhizosphere microecology of the underground part of diseased tobacco plants after MgO NPs treatment were evaluated by root irrigation pretreatment, combined with methods such as the determination of plant defense substances, qRT-PCR and high-throughput sequencing. 【Result】 Pretreatment with 300 μg·mL^-1 MgO NPs achieved optimal control efficacy against tobacco bacterial wilt, showing a relative control efficacy of 50.74% at 16 days post-inoculation. Compared with the water control, MgO NPs pretreatment significantly enhanced antioxidant enzyme activities in tobacco plants. The activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and polyphenol oxidase (PPO) were increased by 63.9%, 61.3%, 72.8%, and 66.4%, respectively. The contents of proline and soluble sugar in leaves pretreated with 300 μg·mL^-1 MgO NPs were significantly increased by 319.3% and 131.0% compared with the control, while malondialdehyde (MDA), hydrogen peroxide, and superoxide anion levels were significantly decreased compared with the control. Concurrently, MgO NPs pretreatment significantly enhanced the expression level of tobacco resistance genes and significantly changed the richness and diversity of microbial community in tobacco rhizosphere soil. Compared with the control group, beneficial bacteria and fungi such as Bacillus, Streptomyces, Humicola, Mortierella and Chaetomium in tobacco rhizosphere soil were significantly enriched after pretreatment with MgO NPs. The relative abundance of pathogens such as Ralstonia, Streptococcus and Fusarium decreased significantly. In field trials, the drench application of 300 μg·mL^-1 MgO NPs demonstrated a relative control efficacy of 53.67% against tobacco bacterial wilt.【Conclusion】MgO NPs can effectively control tobacco bacterial wilt while improving the rhizosphere microecology of tobacco plants, exhibiting potential for development as a novel nano-antibacterial agent to enhance tobacco’s defense against pathogen invasion.

ANIMAL SCIENCE·VETERINARY SCIENCE

Preparation of Monoclonal Antibody Against African Swine Fever Virus pD345L Protein and Identification of Its Epitope

HE XiaoPing, ZHANG YuanFeng, LIU XueMin, HUANG Li, WENG ChangJiang

Scientia Agricultura Sinica. 2025, 58(16):  3345-3356.  doi:10.3864/j.issn.0578-1752.2025.16.016

Abstract ( 24 )   HTML ( 5 )   PDF (1872KB) ( 4 )   Save

Figures and Tables | References | Related Articles | Metrics

【Objective】The aim of this study was to prepare monoclonal antibodies (mAbs) against the pD345L protein (pD345L) of African swine fever virus (ASFV), and to analyze the linear B-cell epitopes recognized by these antibodies, so as to lay a foundation for exploring the function of pD345L in the infection and pathogenesis of ASFV. 【Method】The prokaryotic expression plasmid pET-28a-D345L was constructed, transformed into Escherichia coli BL21(DE3) receptor cells, expressed and purified recombinant pD345L protein (rpD345L) by affinity chromatography. The purified recombinant pD345L protein was emulsified with an equal volume of Freund's complete adjuvant and immunized 5-week-old SPF BALB/c mice once every two weeks for a total of 3 times. Both the second and third immunization were emulsified with Freund's incomplete adjuvant. A week after the third immunization, the blood sample was collected through the submaxillary vein of mice, serum was separated, serum antibody titer was detected by indirect enzyme-linked immunosorbent assay (ELISA), and mice with high antibody titer were selected to enhance immunity. After 3 days of immunization, the mouse spleen cells were fused with mouse myeloma cells (SP2/0). Recombinant GST-pD345L was used as the coated antigen, and positive hybridoma cells were screened by ELISA. After three-time screening, hybridoma cell lines that could secrete pD345L protein mAbs were obtained and injected into the abdominal cavity of mice to prepare ascites. The heavy and light chain types of mAbs were identified using the monoclonal antibody subclass identification kit. The overexpressed pD345L protein and ASFV HLJ/18 infected porcine alveolar macrophages (PAMs) were identified by Western blot and indirect immunofluorescence (IFA), respectively, using the prepared mAbs as the primary antibody. Then the truncated pD345L protein was fused with GST, and the epitopes were identified with screened mAbs, and the conserved types of identified epitopes in different ASFV strains were analyzed. 【Result】After induction by IPTG, pD345L was expressed as an inclusion body with a molecular weight of 40.5 kDa. After immunizing BALB/c mice, two hybridoma cell lines with stable secretion of pD345L mAbs were selected by indirect ELISA method, and named 10H3 and 5G1. The results of subclass identification showed that the heavy chain type of the two strains of mAbs was IgG1 type, the light chain type was κ chain, and the antibody titer was 1:1 638 400. Western blot and IFA results showed that the prepared mAbs could recognize naturally expressed pD345L. The results showed that the minimum linear B-cell epitopes of 10H3 and 5G1 mAbs were ¹METFVRLFKD¹⁰ and ³²¹YEKICCSEES³³⁰, respectively. These two epitopes were conserved in different ASFV strains. 【Conclusion】In this study, the recombinant pD345L protein was expressed and purified in prokaryotes, two strains of pD345L protein mAbs were prepared, and their recognized epitopes were identified. Both strains of mAbs could effectively recognize pD345L protein expressed during ASFV infection, which laid a foundation for further research on the function of ASFV pD345L protein.