Current issue

• 2020 Vol.36 No.9 Published:25 March 2020

  Research article

  Direct Seeding Mode of Rice: Nitrogen Regulation of Flag Leaf Photosynthesis, Superior and Inferior Grains Filling Characteristics and Yield Chunyuan Yin, Jianquan Sun, Shuyu Wang, Hemei Liu, Xiuming Hu, Hele Wang, Fanghui Tian, Chaoyang Ma, Xingkuan Shao, Shengli Hu, Donghai Wang, Xu Zhang, Ruiping Zhang 2020, 36 (9):  1-8.  DOI: 10.11924/j.issn.1000-6850.casb18110133 Abstract + ( 491 )   HTML ( 3 )   PDF ( 1226KB )   ( 97 ) The objective is to explore the effects of different nitrogen levels on photosynthesis of flag leaves, grain filling characteristics and yield of rice. The test took ‘Xindao 567’, ‘Xindao 568’ and ‘Xinkedao 31’ with short growth period as test materials, under direct seeding mode, three nitrogen levels were set up, 0 kg/hm2, 255 kg/hm2 and 300 kg/hm2. The leaf photosynthetic rate, grain filling rate and yield after heading were determined, and the physiological mechanism of nitrogen fertilizer controlling yield was studied. The results showed that the yield of the three varieties increased first and then decreased along with the increase of nitrogen. High rate of leaf area and grain leaf ratio showed higher level under middle nitrogen, and they were lower under high nitrogen level. The flag leaf photosynthetic rate at grain filling stage was first increased and then decreased, and it was higher under middle nitrogen treatment than that of high nitrogen treatment. Superior and inferior grain filling rate had an open downward parabolic trend at the whole grain filling period, and the differences were higher between the peak and middle-late grain filling stage. The grain filling rate under zero nitrogen treatment and middle nitrogen treatment were higher than that of high nitrogen treatment, and the difference was small at later grain filling stage. Yield was positively correlated with flag leaf photosynthetic rate during grain filling stage, and negatively correlated with grain filling rate at early grain filling stage, and positively correlated at middle and late stage. The appropriate amount of nitrogen fertilizer is beneficial to improving the efficient leaf area rate, grain leaf ratio, and increasing flag leaf photosynthetic rate and grain filling rate of strong and weak grain in direct seeding rice, so as to promote the high yield of rice.

  Effect of Straw Returning on Yield and Soil Potassium Balance of Double Cropping Rice Zhixiang Sun, Shang Han, Ji Wu, Min Li, Hui Wang, Wenlong Cheng, Shan Tang, Lin Zhu 2020, 36 (9):  9-13.  DOI: 10.11924/j.issn.1000-6850.casb18110052 Abstract + ( 519 )   HTML ( 2 )   PDF ( 999KB )   ( 165 ) Field experiments were carried out to explore the effects of straw returning on rice yield and soil potassium balance, to provide a basis for straw returning and potassium use in double cropping rice area. The experiments were set in Tongcheng, Anhui in 2013 to 2015 with five treatments, including no fertilization (CK), no fertilization + straw returning (CK+S), fertilization (NPK), fertilization + straw returning (NPK+S) and nitrogen and phosphorus + 80% potassium + straw returning (NP+80%K+S). The results showed that there was no significant negative effect on rice yield among these treatments, and the rice yield under NP+80%K+S was not reduced. The apparent balance coefficient of potassium of CK+S, NPK and NPK+S was 0.90, 0.48 and 1.40, respectively. These results indicate that the application of chemical fertilizer can not inhibit the consumption of potassium by crops. The straw returning can increase the content of soil available potassium significantly, and improve the balance of soil potassium, which is important to maintain the local soil potassium level.

  Drought Stress at Jointing Stage: Effects on Physiological Characteristics and Drought Resistance of Maize Varieties Jinsheng Guo, Liru Cao, Xin Zhang, Qianjin Zhang, Xin Wei, Zhenhua Wang, Xiaomin Lu 2020, 36 (9):  14-18.  DOI: 10.11924/j.issn.1000-6850.casb18120011 Abstract + ( 647 )   HTML ( 1 )   PDF ( 1176KB )   ( 59 ) The aims are to screen drought-resistant varieties and explore drought-resistant mechanisms of maize. Six maize varieties were selected as materials, and moderate water stress was carried out at jointing stage. The malondialdehyde content, chlorophyll content, soluble protein content and strontium ammonia of the six maize varieties were analyzed under drought stress. It was found that the six maize varieties showed different physiological response mechanisms under drought stress. The malondialdehyde content and chlorophyll content of the leaves of the six maize varieties decreased significantly, and the proline content, soluble protein content, superoxide dismutase and peroxidase activities increased significantly. Under drought stress, the increase of MDA content in ‘Zhengdan 988’ and ‘Zhengdan 6386’ was relatively low, the decrease of chlorophyll content was smaller, the activity of antioxidant enzyme increased, and the content of soluble protein and proline was higher. On the contrary, ‘Zhengdan958’ showed weaker drought resistance on the physiological and biochemical level than ‘Zhengdan 6386’ and ‘Zhengdan 988’. The results showed that the drought resistance of ‘Zhengdan 988’ and ‘Zhengdan 6386’ in jointing stage was stronger than that of ‘Zhengdan958’. The results have certain significance for revealing the drought tolerance mechanism of maize, and can provide guidance and reference for screening, improving and molecular breeding of drought-tolerant germplasm in maize.

  Drought Stress Affects Height, Ear Characteristics and Yield of Maize at Different Growth Stages Qian Cheng, Liwen Ren, Wenkui Ding, Heling Wang, Hua Yang, Xingyu Li 2020, 36 (9):  19-23.  DOI: 10.11924/j.issn.1000-6850.casb18110092 Abstract + ( 749 )   HTML ( 5 )   PDF ( 1071KB )   ( 266 ) To study the effects of drought stress on plant height, ear characteristics and yield of the same maize variety at different growth stages, a comparative experiment was set up with six treatments, including sufficient water supply during the whole growth period, the natural drought, the water control at the jointing stage, the water control at the tasseling stage, the water control and re-watering at the jointing stage and the water control and re-watering at the tasseling stage. The differences of the maize height, ear characteristics and yield under different treatments were compared. The results showed that the drought stress shortened the maize plant, decreased the ear length by 7.88%-54.55%, decreased the ear diameter by 14.58%-52.08%, increased the barren ear tip length by 66.67%-258.33%, decreased the 100-kernel weight by 0.99%-41.36%, and decreased the yield per plant by 15.03%-94.41%, which eventually led to a yield reduction of 23.57%-90.03%. The effects of drought stress on yield were significantly different at different growth stages. The effect of the drought stress during the whole growth period was the most serious, with almost no yield, followed by that at the jointing stage. The effect of the drought stress at the tasseling stage was the least. After re-watering, the biomass reduced by the previous drought stress was partially compensated, so the ear characteristics and 100-kernel weight were all improved, and the yield reduction was reduced.

  Effects of Four Chlorine Preparations on High Nitrate and Nitrite in Aquaculture Wastewater Bo Wang, Haipeng Qin, Xuzheng Liao, Xiuyu Lin, Shikang Hu, Chengbo Sun 2020, 36 (9):  24-29.  DOI: 10.11924/j.issn.1000-6850.casb18120045 Abstract + ( 657 )   HTML ( 2 )   PDF ( 1231KB )   ( 92 ) A certain concentration of chlorine was added to the high nitrate and nitrite culture water to study the effects of bleaching powder, bleaching powder concentrated, strong chlorine and chlorine dioxide on the high nitrite and high nitrate elimination ability of the aquaculture water. The results showed that the four chlorine preparations had significant effects on the elimination of high nitrate and nitrite (P<0.05), and the ammonia nitrogen in the water did not change significantly during the test, the concentration was 0.00 mg/L; the elimination effect of chlorine dioxide group was the most obvious, the elimination rate of nitrate and nitrite was 99% and 100% at 30 min, and the nitrate concentration of the treatment group and the control group was (0.15±0.72) and (16.82±0.97) mg/L, nitrite concentration was (0.07±0.01) and (19.95±0.61) mg/L, followed by strong chlorine, and bleaching powder was the worst, the elimination rate was 50% and 38% at 30 min, respectively, and the nitrate concentration of the bleaching powder group and the control group was (8.49±0.66) and 16.82±0.97) mg/L, and the nitrite concentration was (12.33±0.48) and (19.95±0.6) mg/L. After the test, the pH value of the water changed significantly in each treatment group (P<0.05). The pH value of the control group was pH 7.63±0.10. The pH value of the strong chlorine and chlorine dioxide group showed a decreasing trend and the chlorine dioxide group decreased the most (pH 2.68±0.06), the pH value of the bleaching powder and bleaching powder concentrated group increased, and the pH value of the bleaching powder group increased the most (pH 9.6). In summary, the four kinds of chlorine preparations have significant effect on eliminating high nitrite in aquaculture wastewater, and there is no accumulation of ammonia nitrogen and no secondary pollutant, and the research is of great significance for the treatment, discharge and recycling of aquaculture wastewater.

  Water Environmental Quality Assessment of Zhangwu Reservoir Zhongyuan Li, Guozhong Wang, Jiyu Zhang, Qiting Zuo, Huanling Cheng 2020, 36 (9):  30-36.  DOI: 10.11924/j.issn.1000-6850.casb18110114 Abstract + ( 584 )   HTML ( 0 )   PDF ( 1380KB )   ( 219 ) Three methods were applied to water quality assessment for Zhangwu reservoir, including the single factor water quality identification index, comprehensive pollution index and organic pollution index methods, so as to know its environmental quality status. The assessment was based on water quality data from 2009 to 2015 and water quality requirements. The results suggested that (1) TN was the main pollution factor in the reservoir, it could meet the requirement of water quality for only four months, and its annual single factor water quality identification index was greater than six; TP was the second factor exceeding the standard of water quality in 53 months, and its annual average index could not meet the requirement except in 2013; (2) from the perspective of comprehensive pollution, the water quality of only five months in the reservoir was qualified and that of the rest months were in pollution, with severe pollution in 39 months, which resulted in the pollution index of annual average and water phase changing between pollution and severe pollution; (3) from the perspective of organic matter pollution, the water quality of the reservoir changed between the grade of good and relatively good, and that of 7 months was basically qualified, there was no organic pollution; the organic pollution index of annual average and water phase varied between the level of good and relatively good, and there was a tendency to organic pollution.

  Drought Monitoring in Qujing Based on Temperature Vegetation Drought Index Ya Gao, Xiaofei Wang, Maofang Gao, Shuo Huang, Shilei Li, Pei Leng 2020, 36 (9):  37-45.  DOI: 10.11924/j.issn.1000-6850.casb18110107 Abstract + ( 521 )   HTML ( 5 )   PDF ( 4343KB )   ( 226 ) Based on the data of MODIS normalized vegetation index (NDVI) and surface temperature (Ts) products, we constructed Ts-NDVI feature space, calculated temperature vegetation drought index (TVDI), and analyzed and evaluated the spatial and temporal distribution of drought in Qujing, Yunnan from 2010 to 2012. The results showed that: Qujing suffered from severe drought in 2010 with the drought area accounted for more than 80% of the total study area, the drought dynamic monitoring method based on the TVDI index was suitable for drought monitoring. The temperature vegetation drought index model established in this study can improve the practicability of drought monitoring and has a good adaptability in Qujing, and can be widely used for improving the disaster prevention and mitigation and the sustainable development of agriculture.

  The Soil Effect of Biochar: A Review Junye Zhang, Xiaodong Liu, Lin Wang, Yuanchun Yu 2020, 36 (9):  46-50.  DOI: 10.11924/j.issn.1000-6850.casb18120046 Abstract + ( 556 )   HTML ( 2 )   PDF ( 1041KB )   ( 122 ) To explore the effects of biochar on soil physical and chemical properties, soil mycorrhizal fungi and plants, and provide an effective way to improve soil properties, based on the research results of biochar at home and abroad, this paper mainly studied the soil effect of biochar, systematically expounded the role of biochar and the existing problems after it was added to soil, and analyzed the physical and chemical properties of soil, the reaction of soil mycorrhizal fungi and plants to the addition of biochar. The results show that biochar has high carbon content, alkaline, multi-microporous structure, large specific surface area, rich functional groups on the surface and strong cation exchange capacity. When added to soil, it can increase soil bulk density and soil water holding capacity, increase soil porosity, change soil aggregate distribution, increase soil pH value, increase soil organic matter content and decrease soil nutrient leaching, thus to change soil physical and chemical properties, at the same time, it can promote the growth and colonization of soil mycorrhizal fungi and indirectly affect plant growth and development. As an old and new biomass material, biochar has superior performance in improving soil structure and promoting plant growth, fully understanding the characteristics of biomass charcoal could enable biochar play an important role in building a green and sustainable ecological environment.

  Cu, Cd, Cr(Ⅵ) in Sludge Nutrient Soil: Toxicity Effect on Wheat Root Elongation Ping Han, Bin Xu, Yufen Xue 2020, 36 (9):  51-55.  DOI: 10.11924/j.issn.1000-6850.casb18120013 Abstract + ( 224 )   HTML ( 0 )   PDF ( 1201KB )   ( 158 ) The paper aims to evaluate the eco-toxicological effects of heavy metals in sludge nutrient soil on plants and assess the ecological risk in sludge farming. We carried out single and combined toxicity tests on wheat root elongation cultured in sludge nutrient soil by choosing 3 heavy metals [Cu, Cd and Cr (Ⅵ)]. The results showed that: the 4-day EC50 of Cu, Cd and Cr(Ⅵ) in nutrient soil was 0.624, 3.27 and 119 μmol/L, respectively, and the toxicity from strong to weak was: Cu>Cd>Cr(Ⅵ); there was a synergistic effect between low concentration Cu and high concentration Cd in inhibition of wheat root elongation, however, it was from weak antagonistic effect to mutual independent effect with the increase of Cu concentration in solution; the combined toxicity of Cu and Cr(Ⅵ) showed that: low concentration of Cu had a synergistic effect on Cr(Ⅵ), and low concentration Cr(Ⅵ) had antagonistic effect on Cu; the combined toxicity of Cd and Cr(Ⅵ) showed that: high concentration Cd had antagonistic effect on Cr(Ⅵ), while non-low concentration Cr(Ⅵ) had synergistic effects on Cd.

  Effect of Bt Early Japonica Rice on Soil Microorganism Quantity and Transfer of Exogenous Genes of Rice Rongtian Li, Shitong Gao, Yi Gao, Changhua Liu 2020, 36 (9):  56-64.  DOI: 10.11924/j.issn.1000-6850.casb20191000720 Abstract + ( 308 )   HTML ( 0 )   PDF ( 1835KB )   ( 112 ) To study the effect of transplanting Bt early japonica rice on soil microorganism number and the horizontal transfer of exogenous DNA of rice to soil microorganism, using field soil at different growth stages of rice as material, the number of soil microorganisms and exogenous DNA fragments such as Bt gene were measured with plate colony counting and PCR detection. The results showed that there were no significant differences among Bt early rice lines (‘HD1’, ‘HD2’) and corresponding recipient variety or among lines (‘HD3’, ‘HD4’) and their receptor in the number of bacteria, actinomycetes and fungus of rhizosphere and inter-row soil at rice growth and development stages of returning green, tillering, booting, heading and maturity. It was not found that exogenous DNA fragments of Bt early japonica rice lines were horizontally transferred to bacteria, actinomycetes and fungi of soil microorganism. There was no significant difference in the number of soil microorganisms between Bt early japonica rice and normal rice, and no exogenous DNA of Bt rice was found in soil microorganisms.

  Soil Hardening at Seedling Stage of Spring Maize in Hetao Irrigation District: Precipitation Index Xiangwei Sun 2020, 36 (9):  65-68.  DOI: 10.11924/j.issn.1000-6850.casb18120018 Abstract + ( 393 )   HTML ( 1 )   PDF ( 1156KB )   ( 55 ) The paper aims to perfect the local meteorological disaster indicators and provide better meteorological service for seeding in spring. The author chose major local maize variety ‘Denghai No.605’ as material to simulate the natural precipitation process by using the artificial precipitation system, and detected the soil compaction, emergence rate, plant height, and root-shoot ratio, to determine the precipitation index causing soil hardening at seedling stage of spring maize in Hetao irrigation district. The results showed that: (1) the precipitation index causing slight soil hardening was 2-3 mm; the precipitation index causing the medium soil hardening was 4-8 mm, ≥9 mm was considered the precipitation index causing severe soil hardening; (2) the earlier and greater the precipitation was after seeding, the easier the soil hardening formed and the thicker the hardening layer became.

  Simulation of the Response and Adaptation of Flue-cured Tobacco Planting to Climate Change Hua Liu, Zhenping Zhang, Yuhong Liu, Yanying Chen 2020, 36 (9):  69-74.  DOI: 10.11924/j.issn.1000-6850.casb18120049 Abstract + ( 612 )   HTML ( 0 )   PDF ( 1594KB )   ( 57 ) The paper aims to forecast the impact of future climate change on the yields of tobacco. Based on the crop growth model, and combined with the climate change scenario A2 (concentration on the economic development) and B2 (concentration on the sustainable development) of SRES, the response and adaption of flue-cured tobacco planting in Chongqing to climate change are quantitatively simulated. The results show that: the flue-cured tobacco yield will change from -4.7% to 5.7% in 2020 under the A2 scenario with current varieties, with little increase and decrease. There will be a slight increase of flue-cured tobacco yield in Wushan, Qianjiang, Youyang, Nanchuan etc. and a slight decrease in the other regions. Under the B2 scenario, the flue-cured tobacco yield will change from -35.3% to 8.1% in 2020. There will be a slight increase in tobacco growing areas of Wushan, Wuxi, Qianjiang, most parts of Nanchuan and so on, but the other regions will have a diminished output, and Fengjie and Wulong will have a yield decrease above 15%. In 2040, the flue-cured tobacco yield will change from -15.85% to 1.93% under A2 scenario, except for a slight increase in Wanzhou tobacco growing areas, the yield of the rest areas will reduce, and the central part of Youyang and southern Wulong will have a higher reduction rate over 10%. Under the B2 scenario, the flue-cured tobacco yield will change from -14.45% to 8.18%, Youyang, Pengshui and southern Qianjiang will have a yield increase, and the rest areas will have a yield reduction. Either under A2 scenario or B2 scenario, most tobacco growing areas of Chongqing will show different reduction trends, some areas will have a higher reduction rate. If new varieties adapting to climate warming could be introduced in Chongqing (only prolonging the accumulated temperature of the late growth of flue-cured tobacco in the model from flowering to parietal maturity), under the A2 scenario, the flue-cured tobacco yield will increase by 105-170 kg/hm2, with an increase rate of 6.9%-10.6%, under the B2 scenario, the flue-cured tobacco yield will increase by 40-78 kg/hm2, with an increase rate of 2.5%-5.12%.

  Sambucus williamsii Clones at Seedling Stage: Response to Drought Stress and Comprehensive Evaluation of Drought Resistance Junxiu Yao, Xueliang Liu, Shanwen Li, Fei Ren, Qinghua Li, Haitao Wu, Honglian Zhai, Dejun Wu 2020, 36 (9):  75-81.  DOI: 10.11924/j.issn.1000-6850.casb18120009 Abstract + ( 369 )   HTML ( 1 )   PDF ( 1384KB )   ( 45 ) The paper aims to reveal the drought resistance of different clones of Sambucus williamsii, to explore the adaptability of Sambucus williamsii to arid environment, and to provide experimental materials for afforestation in arid and barren mountains. We carried out the natural drought stress test by pot experiment method, and comprehensively evaluated the physiological indexes of each clone under different treatments by using the principal component analysis. The results showed that: the biomass increment of PT-1 was the largest, the root-shoot ratio of PT-2 was the largest under drought stress; with the increase of drought stress, the permeability of cell membrane increased, the permeability cell membrane of PT-2 and PT-1 was the smallest when the drought reached moderate and severe degree; the chlorophyll content and the SOD activity increased firstly and then decreased, the soluble sugar and proline increased with the increase of drought stress; under severe drought stress, the soluble sugar content of PT-1 was the highest. The principal component analysis showed that: the drought resistance ability from strong to weak was XY-2, JY-1, XY-1, XY-3, PT-1, PT-3, PT-2, among them, XY-2 and JY-1 had relatively strong drought resistance and could be further studied as drought-resistant clonal materials.

  A Method for Detecting SNP Markers Based on PCR in Rice Yu Wang, Xue Xu, Ruiying Qin, Xuzhong Lu, Li Li, Jianbo Yang, Jinlong Ni, Hui Ma, Xiufeng Wang 2020, 36 (9):  82-93.  DOI: 10.11924/j.issn.1000-6850.casb18120040 Abstract + ( 492 )   HTML ( 9 )   PDF ( 2599KB )   ( 54 ) This study aims to find a simple SNPs detection method for rice species identification and genetic diversity analysis. 245 main hybrid rice varieties and their parents widely cultivated in the middle-lower reaches of the Yangtze River were used as materials. 124 pairs of highly polymorphic loci were screened out from 1319 SNP loci and an efficient SNP detection system was constructed. One of the selected SNP markers, sf0141821553, and a SSR maker RM7120 were used to identify the purity of hybrid seed. The genotypes of Wx in parental species and hybrid generation groups were amplified by Caps-AccI and SNP-sf0601764762, respectively, and they had the same result. The genetic diversity analysis was conducted with the 124 pairs of loci among the 245 rice varieties. The clustering analysis revealed that the genetic similarity coefficients within the 245 varieties were from 0.64 to 0.97. The 245 varieties were classified into two cluster groups with the similarity coefficient of 0.64. Each of the two cluster groups was further divided into two subgroups with the similarity coefficient of 0.712 and 0.667 respectively. These results showed obvious population structure among these rice varieties, and the genotypes of the tested varieties and the genetic differences among varieties were accurately distinguished. The detection of SNP markers by polyacrylamide gel electrophoresis is simple, and does not require large instruments and expensive reagents, which is convenient for laboratory identification of rice varieties.

  The Optimal Condition for Callus Induction and Redifferentiation of Panicum miliaceum L. Chunfang Wang, Jingjing Liu, Wei Li, Surong Luan, Shenkui Shi, Guoqing Liu 2020, 36 (9):  94-99.  DOI: 10.11924/j.issn.1000-6850.casb18120078 Abstract + ( 472 )   HTML ( 0 )   PDF ( 1455KB )   ( 83 ) The aim is to explore the optimum condition for callus induction and redifferentiation by tissue culture technology, so as to lay a foundation for the establishment of genetic transformation system of Panicum miliaceum L.. Five Panicum miliaceum L. varieties were used to study the optimal condition for callus induction and redifferentiation. Plant hormone 2,4-dichlorophenoxyacetic acid (2,4-D) was applied to induce shoot tip callus. Varieties with high germination rate, high callus induction rate and low bacterial infection rate were screened. The optimum hormone concentration and ratio for inducing callus were identified. The results showed that ‘Jishu No. 2’ had high germination and callus induction rates and low bacterial infection rate, showing it was suitable for tissue culture. 2,4-D had the best induction effect on ‘Jishu No. 2’, with the optimum concentration of 2.5 mg/L and the induction rate of 86.67%. The callus was light yellow block, compact in structure and hard in texture. The embryogenic callus formed after subculture was better than that of other varieties. In the process of redifferentiation, when the culture condition was 2.5 mg/L 2,4-D + 3.5 mg/L TDZ, tender buds appeared obviously. The optimum condition for callus induction and redifferentiation of ‘Jishu No. 2’ are obtained, which could provide reference for constructing the regeneration system of Panicum miliaceum L..

  A Strain of Abiogenous Azotobacter in Upland Red Soil: Isolation, Identification and Nitrogen Fixation Capacity Evaluation Yanhong Cheng, Qianru Huang, Lin Wu, Shangshu Huang, Xiaofei Li, Kun Zhang 2020, 36 (9):  100-106.  DOI: 10.11924/j.issn.1000-6850.casb18110061 Abstract + ( 664 )   HTML ( 9 )   PDF ( 1299KB )   ( 170 ) To identify a strain of abiogenous azotobacter isolated from red soil and to explore the nitrogen fixation capacity of the strain, morphological observation, physiological and biochemical determination and 16S rDNA sequence identification were used to study the taxonomic status of the strain, and acetylene reduction method was used to determine nitrogenase activity. A peanut and maize seedling pot experiment in greenhouse condition was conducted to study the effect of abiogenous azotobacter on soil microbial biomass nitrogen (MBN), mineralized nitrogen and nitrogen accumulation. The results showed that: 15 azotobacter strains were isolated from maize rhizosphere in red soil, and the strain CM12 had the strongest nitrogen fixation capacity, which was classified as Burkholderia sp.. The nitrogenase activity of CM12 was C2H4 39.1 nmol/(h·mL). The pot experiments showed that, inoculation with CM12 significantly increased MBN content by 2.38 and 2.37-fold in the soil planted with peanut or maize, respectively, compared with the control. In the peanut system, MBN content had no significant difference between CM12 and chemical nitrogen fertilizer application. Abiogenous azotobacter inoculation affected the ratio of soil NO3--N and NH4+-N, decreased the content of soil NO3--N, and the decrease was obvious in maize planting system. Nitrogen accumulation of peanut roots and maize seedlings increased after short-term application of CM12. These results provided the theoretical basis for the application of the strain in the agriculture production in upland red soil.

  Chiral Amidine Fungicides: Research Progress Jinsheng Duan, Yang Shen, Mei Wang, Xu Dong, Mingna Sun, Tongchun Gao 2020, 36 (9):  107-112.  DOI: 10.11924/j.issn.1000-6850.casb18120006 Abstract + ( 435 )   HTML ( 7 )   PDF ( 1077KB )   ( 107 ) Chiral pesticides exhibit differences in environmental behaviors and biological activities in organisms and environments. Traditional evaluation methods can not fully assess the risk of chiral pesticides to the environment and humans. Amide fungicides have good control effects on plant diseases caused by Basidiomycetes and Rhizoctonia solani. However, the accuracy of the risk evaluation could be affected by some amide fungicides enantiomers containing chiral central atoms. This paper summarizes the research progress of chiral amide fungicides in enantiomeric separation methods, stereoselective environmental behavior, stereoselective toxicity and biological activity, and could provide certain guidance for its scientific use.

  Toxicity and Joint Action of Fluralaner and Four Insecticides Against Spodoptera litura Fabricius Di Liu, Qiong Bu, Tao Tang, Han Ling, Chunqing Zhao 2020, 36 (9):  113-116.  DOI: 10.11924/j.issn.1000-6850.casb18120032 Abstract + ( 1196 )   HTML ( 1 )   PDF ( 1173KB )   ( 43 ) To identify the toxicity of fluralaner and its joint action with four traditional insecticides (chlorpyrifos, indoxacarb, deltamethrin and emamectin benzoate) to Spodoptera litura F. and explore the optimum ratio of insecticides, the 3rd instar larvae of S. litura and artificial food mixing insecticides were used in the study, the toxicity was measured and the joint action was evaluated by co-toxicity coefficient. The results of single dosage showed that fluralaner, deltamethrin and emamectin benzoate exhibited high activity with LC50 values of 0.48, 0.65 and 0.38 mg/kg at 48 h, respectively. Meanwhile, chlorpyrifos and indoxacarb exhibited moderate activity to S. litura with LC50 values of 8.71 and 3.08 mg/kg, respectively. The results of joint action showed that fluralaner mixing with chlorpyrifos at 3:2, the mixture showed the highest synergistic effect with co-toxicity coefficient (CTC) as 164.2, the mixture with indoxacarb showed additive effect, the mixture with deltamethrin or emamectin benzoate showed antagonistic effect. In conclusion, these results demonstrate that fluralaner and chlorpyrifos could be considered as effective insecticidal mixture to be used for control of S. litura. On the contrary, the fluralaner and deltamethrin or emamectin benzoate should avoid combined application due to their antagonism.

  Wheat Field Weeds with Different Community Structures: Chemical Control and Herbicide Susceptibility Xueying Wang, Yan Jin, Shouzhu Liu 2020, 36 (9):  117-121.  DOI: 10.11924/j.issn.1000-6850.casb18110094 Abstract + ( 330 )   HTML ( 0 )   PDF ( 1164KB )   ( 77 ) By studying the control effect of herbicides on different weed community structures in wheat fields, and exploring the susceptibility of weeds against the herbicides, we aim to provide support for chemical control of weeds in wheat field. By field trials, we determined the control effect of herbicides against broadleaf weeds, gramineous weeds and both broadlear-gramineous weeds in wheat fields. The results showed that: florasulam was the best herbicides against broadleaf weeds, while mesosulfuron-methyl, pyroxsulam and flucarbazone had good control effect against gramineous weeds and some broadleaf weeds; broadleaf weeds, such as Descuminia sophia and Capsella bursa-pastoris were still susceptible to most tested herbicides, the susceptibility to florasulam was the highest, and florasulam had excellent control effect against Galium aparine L.; most gramineous weeds were susceptible to mesosulfuron-methyl, pyroxsulam and flucarbazone, but only mesosulfuron-methyl was effective against Aegilops tauschii Coss. The preferred herbicide to control broadleaf weeds is florasulam, while the best choice for gramineous weeds and broadlear-gramineous weeds is mesosulfuron-methyl.

  Field Control Effect of Five Biological Agents on Main Potato Diseases Xueliang Xu, Zirong Liu, Shaomin Zeng, Xiaojuan Liu, Huiyun Fan, Yanzhang Huang, Yingjuan Yao, Fenshan Wang 2020, 36 (9):  122-126.  DOI: 10.11924/j.issn.1000-6850.casb18110110 Abstract + ( 739 )   HTML ( 4 )   PDF ( 1077KB )   ( 71 ) To screen better effective biological fungicides on the main diseases of potato in the dry farmland and rotation paddy-upland crop field by the soil treatment during sowing, the control effects of 5 biological fungicides (Bacillus subtilis, amino oligosaccharide, polymycin, pythium and horseradish) on potato early blight, late blight and scab were investigated. The results suggested that the effects of horseradish and amino oligosaccharide on early blight were the best and higher than 60% in the two types of plots, the effects of polymycin and amino oligosaccharide on potato late blight were the best and higher than 40% and 25% in the dry farmland and rotation paddy-upland crop field, respectively, and the effects of Bacillus subtilis and amino oligosaccharide on potato scab were the best and higher than 80% and 25% in the dry farmland and rotation paddy-upland crop field, respectively. The overall control effect of each pesticides in dryland was better than that in rotation paddy-upland crop field.

  Determination of Metamifop Residue in Rice by UPLC-MS/MS Yue Zhang 2020, 36 (9):  127-131.  DOI: 10.11924/j.issn.1000-6850.casb18120042 Abstract + ( 307 )   HTML ( 0 )   PDF ( 1231KB )   ( 80 ) An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to detect metamifop residue in rice plant, rise husk, brown rice and rice field water was established, the samples were extracted with acetonitrile, and cleaned up by PSA, separated by ACQUITY UPLC BEH C18 column (50 mm×2.1 mm, 1.7 μm) and gradient eluted with methanol-water, detected with multiple reaction monitoring (MRM) modes with electrospray ionization and then quantified with external standard method. The results showed that a good linear relationship in the range of 0.005-0.05 μg/mL was found of metamifop with rice plant, brown rice, rise husk and rice field water, with the correlation coefficients (r) of 0.998, 0.996, 0.994 and 0.996, respectively. The method was validated at three spike levels (0.005, 0.05 and 0.5 mg/kg), the average recoveries were 85.8%-114.6%, 80.6%-106.4%, 84.2%-95.0% and 92.8%-109.3% in rice plant, rise husk, brown rice and rice field water, with RSD of 2.7%-6.7%, 3.8%-9.2%, 2.9%-4.6% and 5.0%-12.3%, respectively. The limit of quantization (LOQs) was 0.005 mg/kg. This method could meet the determination requirements, and it was simple, quick, accurate and sensitive, could be used to study the residues of metamifop in rice.

  Genetic Diversity of Pseudomonas syringae pv. actinidiae strains in Sichuan Xiaoxiang Yang, Wenxian Wu, Xiaoqin Huang, Lei Zhang, Lei Du, Yong Liu 2020, 36 (9):  132-137.  DOI: 10.11924/j.issn.1000-6850.casb18110082 Abstract + ( 295 )   HTML ( 3 )   PDF ( 1744KB )   ( 41 ) To determine the genetic diversity of kiwifruit ulcer pathogen Pseudomonas syringae pv. actinidiae (Psa) in Sichuan and the correlation between genetic group division and geographical origin, 40 Psa strains from different regions of Sichuan were used as the research materials, rep-PCR was used for molecular marker, and UPGMA clustering was conducted with NTSYS software. A total of 42 loci were obtained by 3 primer combinations (REP, ERIC and BOX), including 38 polymorphic loci, the rate of polymorphism was 90.5%. The results of UPMGA cluster analysis indicated that 40 Psa strains were divided into two groups (Ⅰ, Ⅱ) in the genetic similarity coefficient of 0.70, and 85.0% of the strains belonged to the Ⅱ group. The group Ⅰ contained two sub-groups (I-1, I-2) and the group Ⅱ consisted of five sub-groups (Ⅱ-1, Ⅱ-2, Ⅱ-3, Ⅱ-4, Ⅱ-5) in the genetic similarity coefficient of 0.80, but all strains had no obvious clustering of collecting locations. This study showed a rich polymorphism of Psa strains from different regions of Sichuan, but the genetic diversity had no significant correlation with geographical location.

  Dynamic Influence of Rapeseed Straw Mulching on Weed Occurrence and Weed Seed Bank in Cotton Field Under Rape-cotton Continuous Cropping System Shuying Li, Xianyong Lu, Furu Cheng, Xiaoming Yan, Shufeng Zheng, Yan Ma 2020, 36 (9):  138-144.  DOI: 10.11924/j.issn.1000-6850.casb18110084 Abstract + ( 434 )   HTML ( 8 )   PDF ( 1227KB )   ( 38 ) Field studies were conducted in cotton fields under rapeseed-cotton continuous cropping system to determine rapeseed straw mulching effect on weed control, the dynamic pattern of soil weed seed bank, the growth and yield of cotton along the Yangtze River in Anhui Province. The results showed that with the increase of straw mulching, the weed control effect in cotton field was enhanced. The boll number per plant and seed cotton yield in 7000 kg/hm2 straw mulching treatment were significantly higher than those of no-weeding treatment without straw mulching. The weed seed bank density in 0-20 cm soil layer gradually decreased under 7000 kg/hm2 straw mulching treatment after 30, 60 and 120 d, which was in consistent with the whole-course herbicide treatment. The decline degree of the weed seed bank density in 0-20 cm soil layer was decreased by the decline of rapeseed straw mulching amount. The weed seed bank diversity in 0-5 cm soil layer was decreased by whole-course herbicide treatment, while that might be increased by rapeseed straw mulching. In the treatment of 3500 kg/hm2 mulching + spraying herbicide 30 d later after straw mulching, the effect on weed control and cotton yield was more identical with that of the whole-course herbicide treatment. As a result, it is recommended that 3500 kg/hm2 mulching + spraying herbicide 30 d later after straw mulching should be put in practice in the rapeseed-cotton continuous cropping system along the Yangtze River in Anhui Province.

  Risk Analysis of Pesticide Residues in Large-scale Planting Vegetables: The Case of a District in Suburban Guiyang Lihua Pu, Xiaoqin Lang, Zhiguo Mu, Yun Zhao, Changmin Wu, Min Wu, Jianli Zhang 2020, 36 (9):  145-149.  DOI: 10.11924/j.issn.1000-6850.casb18120030 Abstract + ( 432 )   HTML ( 3 )   PDF ( 1254KB )   ( 68 ) The study is to analyze the status of pesticide residues in large-scale planting vegetables around the city (taking a district of Guiyang for example). Gas chromatography was used to quantitatively analyze 17 kinds of pesticides’ residue of organic phosphorus, organochlorine and pyrethroid in 7 vegetable bases. The international food standard was used to evaluate the safety of the vegetables. The results showed that three kinds of pesticides (chlorothalonil, fenpropathrin and chlorpyrifos) were detected at different degrees in the vegetable samples with an average detection rate of 6.63%. The highest detection rate was chlorothalonil (9.84%), and the detection rate of fenpropathrin was the second (8.2%), and the detection rate of chlorpyrifos was the lowest (1.83%). According to the national food safety standards, without the determination of chlorpyrifos, the other two pesticides’ residue did not exceed the standard. The quarterly detection rate of the year was the highest in the third quarter (15.68%), followed by that of the fourth quarter (15%). The 109 vegetable samples tested were classified according to 6 categories, the detection rate from high to low was bean vegetables (33.34%) > solanaceous vegetables (21.43%) > melon and fruit vegetables (17.06%) > leaf vegetables (3.13%). The vegetable samples’ ($\bar{IFS}$) was <<1. In 2017, pesticides had no impact on the seven vegetable bases in the region, and the detection rate of pesticide residue of vegetables was safe and acceptable to consumers. The research could provide some data for the quality and safety control in local vegetable production, thus ensuring the healthy diet for local residents．

  Empirical Study on the Choice of Livelihood Strategies Affected by Herdsmen’s Livelihood Capital Based on Multinomial Logit Model Wenqiang Ding, Haibin Dong, Xiangyang Hou, Xiliang Li, Yanting Yin 2020, 36 (9):  150-158.  DOI: 10.11924/j.issn.1000-6850.casb18120038 Abstract + ( 397 )   HTML ( 4 )   PDF ( 1162KB )   ( 159 ) The study aims to explore the impact of herdsmen’s livelihood capital on livelihood strategies, identify the key livelihood capital and livelihood capital indicators in the transformation of herdsmen's livelihood strategies, so as to guide herdsmen to adjust their livelihood structure and improve grassland governance ability. Taking 848 herdsmen in 15 banners (counties) of 5 grassland types in Inner Mongolia Autonomous Region as samples, this paper evaluates herdsmen’s livelihood capital by using the method of entropy, establishes multiple logit regression models, and identifies the key livelihood capital that affects the transformation of herdsmen’s livelihood strategies. The value of livelihood capital of pastoral households in the study area is 1.428. Four kinds of livelihood strategies are as follows: pure herdsman, facultative herdsman, facultative herdsman and non-herdsman, P<0.01. Five types of grassland herdsman’s livelihood capital stock from high to low are: meadow grassland, typical grassland, desert grassland, sandy grassland, grassland desertification, P<0.01. Pastoral households’ income is mainly transferred by the government, and pure pastoral livelihood strategy is the preferred strategy. Financial capital stock is the key livelihood capital affecting the transformation of livelihood strategy, which has a significant negative impact on the transformation of pastoral households’ livelihood strategy from pure pastoral to pastoral, pastoral and non-pastoral. The key livelihood capital indicators affecting the transformation of livelihood strategies are the household contract of grassland resources, the use of grassland resources and the total household income.

  Transformation Mechanism of Scientific and Technological Achievements Built by Scientific Research Institutions: A Case Study on Aquatic Research Institutes Yunyun Dai, Yongming Yuan, Yuan Yuan, Hongyan Zhang 2020, 36 (9):  159-164.  DOI: 10.11924/j.issn.1000-6850.casb18110129 Abstract + ( 513 )   HTML ( 3 )   PDF ( 1091KB )   ( 86 ) Taking the aquatic research institutes as typical cases, an empirical analysis was carried out on the transformation mechanism of scientific and technological achievements of scientific research institutions. The revenue-oriented transformation was one of the main modes of the transformation of fishery science and technology achievements in China's aquatic research institutes, including endogenous transformation and exogenous transformation. Taking the Fisheries Research Institute of Wuhan Academy of Agricultural Sciences and the Fishery Machinery and Instrument Research Institute of China Academy of Fishery Sciences as examples, this paper introduced the differences in the operation mechanism and promotion effect between the endogenous transformation and exogenous transformation, and pointed out the problems in both the two. Suggestions on speeding up the transformation of agricultural science and technology achievements were proposed.