Current Issue

2023, Volume 31,  Issue 9

Crop Cultivation and Physiological Ecology
Changes and influencing factors of crop coefficient of summer maize during the past 40 years in the North China Plain
LIU Zimeng, LI Lu, LI Haotian, LIU Na, WANG Hongxi, SHAO Liwei
2023, 31(9): 1355-1367. doi: 10.12357/cjea.20230197
Abstract(129) HTML (41) PDF(44)
As a key parameter for determining crop water consumption, accurate estimation of the crop coefficient (Kc) is important for irrigation scheduling. Kc is influenced by changes in production and meteorological conditions. This study analyzed Kc changes from 1980 to 2018 for summer maize under sufficient water supply based on long-term field experiments at the Luancheng Agro-Ecosystem Experimental Station of the Chinese Academy of Sciences. Using data of the three most recent seasons from 2019 to 2021 for maize under normal and water-deficit conditions, the calibration coefficient of Kc by soil water content was developed and tested. The results showed that the reference crop evapotranspiration (ETo) was stable from 1980 to 2018; however, seasonal fluctuations were observed. The actual evapotranspiration (ETc) of summer maize under adequate water supply conditions has substantially changed over recent years. The multiyear average Kc for maize was 0.91, and the interseasonal variation coefficient was 12.36%. Kc is affected by crop yield and atmospheric conditions. An increase in yield was accompanied by an increase in the ETc of summer maize. ETo was mainly affected by average wind speed and sunshine hours. Our analysis revealed that Kc is determined by ETo and ETc and is greatly affected by the ETc of summer maize. For the three most recent seasons, the difference in irrigation quantity was the main factor causing differences in Kc among the different treatments in the same season. Kc adjustment using different methods considering the soil water content could be used to estimate ETc. Incorporating the root length distribution factor into the soil water status for Kc adjustment provided a better estimate of ETc using the crop coefficient method. Therefore, Kc can be adjusted according to the root-zone soil moisture status to determine the actual crop water consumption.
Effects of large-spike type maize on interspecific competition and intercropping advantage in maize–peanut intercropping system
LIU Han, ZAN Zhiman, WANG Jiangtao, SUN Zengguang, CHEN Junnan, JIANG Wenyang, YIN Fei, LIU Ling, JIAO Nianyuan, FU Guozhan
2023, 31(9): 1368-1378. doi: 10.12357/cjea.20220929
Abstract(129) HTML (53) PDF(38)
Maize–peanut intercropping (maize||peanut) has a significant advantage in terms of yield. However, interspecific competition between maize and peanut in the later period of coexistence limits further yields increasing. Investigating the coordination effects of large-spike maize on interspecific competition and intercropping advantages in maize||peanut systems can provide a theoretical basis for high yield and efficiency. The experiment was conducted at the experimental farm of Henan University of Science and Technology from 2020 to 2021, with medium-spik maize cultivar ‘Zhengdan 958’ intercropping with peanut (MZD||P) as the control. The effects of large-spike maize cultivar ‘MC4520’ intercropping with peanut (MMC||P) on crop dry matter accumulation and distribution, leaf area index, interspecific competitiveness index, photosynthetic characteristics, yield, and intercropping advantages were studied in a two-year field experiment. The results showed that compared with MZD||P, MMC||P significantly increased the dry matter weight per plant of maize and peanut by 7.55%–9.68% and 16.07%–26.77% (P<0.05), respectively. MMC||P improved dry matter accumulation of maize grains and peanut pods at the harvest stage, which was significantly increased by 9.74%–10.84% and 34.56%–38.33% (P<0.05), respectively. MMC||P promoted the distribution of dry matter to maize grain and peanut pod, in particular for peanut, significantly increased by 9.12%–15.93%. MMC||P increased the leaf area index of peanuts by 5.78%–29.58%, and the interspecific competitiveness index of peanuts relative to maize by 24.44%–65.12% (P<0.05). MMC||P significantly increased the net photosynthetic rate of maize and peanut by 8.18%–15.74% and 3.15%–18.05% (P<0.05), respectively. In addition, the stomatal conductance and transpiration rate of maize and peanuts increased, whereas the intercellular CO2 concentration of peanuts decreased. The yield of peanuts in MMC||P significantly increased by 26.39%–51.61%, and the intercropping advantage and land equivalent ratio improved by 22.21%–24.08% and 13.26%–15.27%, respectively (P<0.05). In conclusion, in maize||peanut systems, large-spike type maize intercropping with peanuts can effectively coordinate interspecific competition at a later period of coexistence, which enhances the interspecific competitiveness of peanuts and improves the yield of peanuts, thus improving the yield and land equivalent ratio of intercropping systems and further enhancing the intercropping advantages.
Effects of water and nitrogen regulation on physiological characteristics and yield of cotton
MENG Yanjun, MA Xinying, SONG Chen, SUN Hongchun, LIU Liantao, ZHANG Ke, ZHANG Yongjiang, BAI Zhiying, LI Cundong
2023, 31(9): 1379-1391. doi: 10.12357/cjea.20230002
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Water and nitrogen are the main factors affecting the growth, development, and yield of cotton. In this study, “Nongda Cotton No. 36” was selected to investigate the effects of water and nitrogen on morphology, physiological characteristics, and yield of cotton. Two water conditions were set: drought stress (W1, relative water content was 45%±5%) and normal water supply (W2, relative water content was 70%±5%), and three nitrogen levels: no nitrogen (N0), low nitrogen [N1, 69 mg(N)∙kg1], and normal nitrogen fertilizers [N2, 138 mg(N)∙kg1]. Changes in aboveground and root morphology, photosynthetic characteristics, antioxidant enzyme activity, nitrogen metabolism enzyme activity, and cotton yield were analyzed under different water and nitrogen fertilizer conditions. The results showed that compared with the W2 treatments, the W1 treatments significantly inhibited cotton growth and decreased plant height, stem diameter, leaf area, total root length, total root surface area, and average root diameter (P<0.05). The activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly enhanced, the relative chlorophyll content (SPAD) and maximum photochemical efficiency (Fv/Fm) were decreased, and the photosynthetic capacity was weakened, resulting in a decrease in cotton yield (P<0.05). Compared with the N2 treatments, the N0 and N1 treatments significantly reduced plant height, stem diameter, leaf area, total root length, total root surface area, and average root diameter of cotton (P<0.05). The activities of SOD, POD, CAT, glutamine synthetase (GS), nitrate reductase (NR), SPAD, and Fv/Fm in cotton were significantly decreased under the N0 and N1 treatments, and the photosynthetic capacity of cotton was weakened. Thus, the cotton yield decreased (P<0.05). Under drought stress, conventional nitrogen application promoted the growth of the aboveground and underground parts of cotton; significantly increased the SPAD, net photosynthetic rate, and Fv/Fm in main-stem leaves (P<0.05); and enhanced the activities of antioxidant enzymes (SOD, POD, and CAT) and nitrogen metabolism enzymes (GS and NR) (P<0.05), which alleviated the damage caused by drought stress and increased the cotton yield. Under low-nitrogen conditions, the normal water supply treatment promoted the growth of cotton; enhanced photosynthesis, nitrogen metabolism enzyme activities, and yield (P<0.05); and alleviated the adverse effects of low-nitrogen stress on cotton. Therefore, cotton yield under drought stress can be increased by increasing nitrogen fertilizer, and cotton yield under low-nitrogen stress can be increased by appropriately increasing irrigation water. The results provide a theoretical basis for clarifying rational water and fertilizer management of cotton under nitrogen and water stresses.
Effects of drip irrigation modes on activities of starch synthesis-related enzymes and accumulation of starch of kernels located in different ear positions of maize in the irrigation area of the Xiliaohe Plain
ZHANG Yuqin, YANG Hengshan, ZHANG Ruifu, LI Congfeng, ZHANG Jiahua, YANG Yulu
2023, 31(9): 1392-1402. doi: 10.12357/cjea.20220935
Abstract(116) HTML (48) PDF(17)
To explore the effects of drip irrigation modes on starch content and the activities of starch synthesis-related enzymes in spring maize at different grain positions in the irrigation area of the Xiliaohe Plain, the characteristics of starch accumulation and changes in the activities of adenosine diphosphate glucose pyrophosphorylase (AGPase), bound starch synthase (GBSS), and soluble starch synthase (SSS) at different grain positions were studied using ‘Nonghua 101’ as the test variety under mulch and shallow burial drip irrigation in 2019 and 2020. The results showed that the yield of shallow burial drip irrigation increased by 5.0% and 4.7% compared with mulch drip irrigation, and the 1000-grain weight increased by 7.4% and 6.9% from 2019 to 2020, in which grains in the middle ears improved by 7.7% and 4.1%, and in and upper ears by 10.8%, and 9.8%, respectively. The starch content, accumulation amount, and activities of synthesis-related enzymes of kernels located in different positions of spring maize ear were the lower part > the middle part > the upper part; the content and accumulation amount of starch under the two drip irrigation modes had little difference in the early stage, which were more advantageous in the upper part of the ear under shallow drip irrigation in the later growth stage. The activities of AGPase, GBSS, and SSS of shallowly buried drip irrigation were all higher than those of mulch drip irrigation in the late grain filling stage. The time to reach the maximum rate of starch accumulation in the middle and upper grains of the ear of the shallow burial drip irrigation was longer than that of the mulch drip irrigation, in which the active starch accumulation period was also longer, especially in the upper grains. The time to the maximum accumulation rate was delayed by 5.38 days, the average accumulation rate increased by 0.2836 mg·g1·d 1, and the final starch accumulation increased by 16.6%. Path and correlation analysis showed that the time to reach the maximum rate, the average accumulation rate, and the maximum accumulation rate had a great influence on the final starch accumulation. Starch synthesis-related enzymes activities were significantly positively correlated with the starch accumulation rate, which showed that the activity of starch-related enzymes in the kernels located in the middle and upper parts of the ear at the late grain filling stage was strong under shallow drip irrigation. The active accumulation period of starch was also longer, the time for the accumulation to reach the maximum rate was delayed, and the average accumulation rate was high, which was one of the reasons for the increase in grain weight and yield under shallow drip irrigation compared with mulch drip irrigation.
Effects of returns of full straws of different seasons on summer maize root exudates
CHEN Xiang, XU Bo, WU Yu, XU Hui, CAI Hongmei, SUN Dongyue, YU Min, LIU Lyuzhou, ZHENG Baoqiang, LI Jincai
2023, 31(9): 1403-1415. doi: 10.12357/cjea.20230122
Abstract(170) HTML (31) PDF(52)
Root exudates are carriers of material exchange, and could improve the rhizosphere environment and play an important role in the response of plants to environmental changes through chemical information exchange and energy transfer between plants and microenvironments. Different straw-returning modes change the growth environment of summer maize roots. Furthermore, the composition and quantity of maize root exudates have different response characteristics to different straw-returning modes. Screening suitable straw-returning modes is a key issue that needs to be clarified to obtain a high yield, high quality, and efficient development of maize production. In this study, we explored the effects of returens of full straw from different seasons on maize root secretions in the lime concretion black soil area in the Huaibei Plain. Four straw returning modes were developed for collecting root exudates: wheat single-season straw full smashed mulching and returning to the field (T1), wheat straw full smashed mulching and returning to the field + maize straw full crushed burying and returning to the field (T2), maize single-season straw full crushed burying and returning to the field (T3), and straw not returned to the field (CK). The metabolomics of root exudates collected under different straw-returning modes was investigated using non-targeted metabolomics combined with gas chromatography-mass spectrometry (GC-MS). The results showed that root length, surface area, dry matter weight, root vigor of T1 and T2 treatments were significantly increased compared with CK by 9.8%, 21.2%, 20.9%, 16.4%, and 12.4%, 23.9%, 29.2%, 21.3%, respectively. T1, T2, and T3 screened 60, 38, and 39 differential metabolites, respectively, compared to CK. There were nine categories of differential metabolites, and returning straw to the field mainly influenced carbohydrates and amino acids in root exudates. Compared with CK, T1, T2, and T3 treatments were significantly enriched in 45, 56, and 39 metabolic pathways, respectively. Straw returns mainly influenced carbohydrate and amino acid metabolic pathways. Compared with CK, glycerol and melibiose in the root exudates of T2 treatment were upregulated, which upregulated the galactose metabolism pathway. The upregulation of amino acids in the root exudates of T2 treatment, such as L-tyrosine and L-glutamine, significantly increased the metabolism of alanine, aspartic acid, glutamic acid, and tyrosine. Organic acids in the root exudates of the T2 treatment, such as 5-aminosalicylic acid, succinic acid, and aminoethyl phosphate, were upregulated. The results indicated that T2 treatment promoted the growth of maize roots by increasing the relative content of sugars, amino acids, and organic acids in maize root exudates, increasing the accumulation of dry matter in the aboveground and underground parts, coordinating the relationship between the aboveground and underground parts, and promoting the coordinated growth of roots and canopies. This study provides a theoretical basis for the efficient utilization of straw resources and the high yield, high quality, and efficient development of summer maize in the lime concretion black soil area of the Huaibei Plain.
Agricultural Resources and Environment
Life cycle analysis of soybean production in typical district of the North China Plain
LI Ying, XIE Qize, LIU Bingqiang, HE Suqin, WU Xizeng, YANG Qing, LIU Zhi, SHI Xiaolei, ZHANG Mengchen, YANG Chunyan, YAN Long, ZHANG Ruifang, TAO Peijun
2023, 31(9): 1416-1427. doi: 10.12357/cjea.20220841
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In recent years, the low self-sufficiency ratio of soybeans has become an urgent issue in China. Gaocheng District of Shijiazhuang City of Hebei Province is an important county for soybean production in the Huang-Huai-Hai area. Although soybean has symbiotic nitrogen fixation efficiency, excessive inputs like fertilizers and pesticides still cause environmental pollution. Therefore, scientific evaluation of the eco-efficiency of soybean production is conducive to promoting the sustainable development of the soybean industry in the Gaocheng District. Based on a survey of 50 farmer households in the Gaocheng District, we evaluated the environmental impact and eco-efficiency of local soybean production using a life cycle assessment (LCA) and a super-efficiency slakck-based measure (SBM) model (super-SBM). The environmental impact results showed that the four indices, global warming potential (GWP), terrestrial eco-toxicity potential (TETP), acidification potential (AP), and eutrophication potential (EP), were the dominant potential environmental impact categories in soybean production. The sowing-to-seedling stage contributed to the largest part (1.45E−5) of GWP, the largest part (5.34E−6) of AP, and the largest part (3.21E−6) of EP; the largest part (5.85E−6) of TETP was attributed to the flowering-to-podding stage. Among the four indicators, GWP, TETP, and EP of large-scale farming were the highest according to the planting scale. Concerning irrigation methods, GWP and AP were highest in trickle irrigation, and TETP and EP were highest in furrow irrigation. Based on the planting areas, GWP, AP, and EP in northern Gaocheng were higher than in southern Gaocheng. The eco-efficiency analysis showed that the mean value of all farmers’ eco-efficiency was 0.84, indicating that local soybean production was inefficient and had room for improvement. Concerning the planting scales, eco-efficiency followed the order of large-scale > mid-scale > small-scale. Concerning irrigation methods, eco-efficiency decreased in the order of trickle irrigation, sprinkling irrigation, no irrigation, and furrow irrigation. Concerning the planting areas, the eco-efficiency in southern Gaocheng was higher than that in northern Gaocheng. Moreover, six redundancy indices were compared under three planting scales. The range of redundancy ratio (max−min) in pesticides was the highest (5.89%), indicating that the change in planting scale had the greatest impact on the use of insecticides. Six redundancy indices were compared under four irrigation methods, and the range of redundancy ratio in water was the highest (8.40%), indicating that irrigation methods had the greatest influence on irrigation water. Six redundancy indices were compared under two planting areas. The range of the redundancy ratio in fertilizer was the highest (2.79%), indicating that the difference in planting area had the greatest impact on fertilizer application. Overall, to ensure the yield and improve the ecological efficiency of soybean production in Gaocheng District, we suggest farming soybean at a large scale, constructing water conservancy facilities, developing trickle irrigation, and controlling the use of fertilizers and pesticides at the different stages of soybean production. These results provide a reference basis for the eco-efficiency evaluation of local soybean production that might benefit the sustainable development of the soybean industry in the Gaocheng District.
Effects of iron oxides on carbon sequestration characteristics of red soil aggregates in paddy fields and upland under varying long-term fertilization practices
XUE Yikang, LIU Kailou, WU Lei, WANG Bin, ZHANG Wenju, XU Minggang, LI Yu’e, CAI Andong
2023, 31(9): 1428-1438. doi: 10.12357/cjea.20230241
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Iron oxide in red soil is a critical factor regulating soil organic carbon sequestration. Our objective was to explore the relationship between soil organic carbon and iron oxide in uplands and paddies, which is beneficial for understanding the stabilization mechanism of soil organic carbon and provides scientific guidance for rational land use. Based on upland and paddy long-term fertilization experiments (over 35 years) in the red soil of southern China, the designed treatments included no fertilizer control (CK), chemical nitrogen (N), chemical nitrogen, phosphorus, and potassium fertilizers (NPK), and NPK combined with manure (NPKM). According to the method of Shavinov, the dry screening of soil aggregates was used to obtain large soil macroaggregates (>2 mm), small aggregates (0.25−2 mm), and microaggregates (<0.25 mm). All soil aggregates were used to determine soil organic carbon, soil dissolved organic carbon, complex iron oxide, free iron oxide, amorphous iron oxide, and iron activity. Compared with CK, NPK and NPKM treatments in uplands decreased soil macroaggregates but significantly increased soil small aggregates and microaggregates. N, NPK, and NPKM treatments in paddy reduced soil macroaggregates but increased small aggregates. The average organic carbon contents of soil aggregates were 8.21, 7.65, and 2.08 g·kg1 in paddy fields, and 2.93, 6.68, and 1.33 g·kg1 soil in uplands, respectively. The average contents of dissolved organic carbon in macroaggregates, small aggregates and microaggregates in paddy soils were 70.72, 79.83, and 30.29 mg·kg1, respectively, whereas those in upland soils were 7.27, 21.49, and 5.88 mg·kg1, respectively, under treatments of N, NPK and NPKM. For upland, the amorphous iron oxides in macroaggregates, small aggregates, and microaggregates under NPKM treatment were 2.45, 7.62, and 1.82 g·kg1, respectively, which was significantly higher than that in CK, N, and NPK. For paddy, the amorphous iron oxides in soil macroaggregates, small aggregates, and microaggregates under NPKM treatment were 5.27, 6.45, and 2.83 g·kg1, respectively. Compared with CK, NPKM treatment significantly increased the free iron oxides in each soil aggregate, and N treatment significantly increased only the free iron oxides in soil microaggregates. There was no significant difference in the free iron oxides in macroaggregates and small aggregates under N, NPK, and NPKM treatments. The iron oxides contents first increased and then decreased with soil aggregate size. For uplands, the amorphous iron oxide in small aggregates and microaggregates was positively correlated with soil organic carbon, with slopes of 0.64 and 0.45, respectively. The amorphous iron oxide in macroaggregates, small aggregates, and microaggregates was positively correlated with soil dissolved organic carbon, with slopes of 10.33, 7.36, and 7.34, respectively. For paddy, the free iron oxide in macroaggregates, small aggregates, and microaggregates showed a significant positive correlation with soil organic carbon, with slopes of 0.45, 0.29, and 0.84, respectively. The free iron oxide in soil microaggregates was positively correlated with soil dissolved organic carbon, with a slope of 23.12. There was a significant positive correlation between the content of amorphous iron oxide in small aggregates and microaggregates and soil organic carbon. The amorphous iron oxide in macroaggregates, small aggregates, and microaggregates was positively correlated with soil dissolved organic carbon, with slopes of 15.30, 17.91, and 13.78, respectively. In conclusion, the amorphous iron oxides has positive effect on soil carbon sequestration both in upland and paddy soils, while free iron oxides play an important role in soil carbon sequestration only in paddy fields.
Prediction of nitrogen leaching loss from summer maize production in North China
ZHAO Xiaoying, WANG Nuoting, CUI Bin, YIN Shilei, YANG Xuan, MENG Fanqiao
2023, 31(9): 1439-1448. doi: 10.12357/cjea.20230041
Abstract(112) HTML (49) PDF(19)
North China has seen intensive flood irrigation and excessive nitrogen (N) fertilization over the past four decades as a main cereal crop-producing region in China. N leaching from farmland in this region has rapidly increased with agricultural intensification, and the non-point source pollution has become increasingly prominent. It is necessary to quantify the amount of N leaching during crop production systematically. Literature on N leaching loss from summer maize production in North China published from 1980–2021 was screened, and soil properties and agricultural management practices were chosen as independent variables to predict N leaching loss based on linear, exponential, polynomial, and multiple regression models. Soil properties included soil organic matter, total N, clay content, sand content, pH, and depth, and agricultural management practices included straw incorporation, N application, and soil water. The results showed that soil water and N fertilizer input significantly influenced N leaching loss. Soil organic matter, soil total N, and clay content positively correlated with the total N leaching amount, whereas straw incorporation, soil depth, pH, and sand content negatively correlated with the total N leaching amount. For the single-factor simulation model, the exponential equation was more appropriate for quantifying total N leaching loss with fertilizer N input than the linear equation, indicating the importance of optimizing fertilizer N in summer maize production in North China. It also indicated that the risk of excess N leaching from summer maize production in North China was relatively high after a certain threshold of fertilizer N input, and optimization of N fertilization should be adopted as an important practice. Unlike many previous studies that directly selected fertilizer N input for predicting N leaching loss, this study combined N (total N rate, N surplus) and water (water input, water balance, water percolation) in various combinations to obtain an optimal prediction combination. The combination of the total N rate and water percolation had the highest R2 (0.3413). The stepwise regression equation of Ytotal N leaching loss=−23.07+1.14Xsoil organic matter+0.34Xclay content−0.13Xsand content+0.06Xtotal N rate+0.18Xwater percolation (R2=0.414) was better than the prediction effects of exponential, linear, and polynomial models. The standardized regression coefficients of the predictive variables were 0.18, 0.11, 0.07, 0.23, and 0.31 for soil organic matter, clay content, sand content, total N rate, and water percolation, respectively, which showed that water percolation was the most important, followed by total N rate and soil organic matter. Considering the complexity of the water percolation calculation process, the water input can be used to replace water percolation in the equation, that is, Ytotal N leaching loss=−18.60+0.64Xsoil organic matter−10.27Xstraw incorporation−0.30Xsand content+0.13Xtotal N rate+0.04Xwater input; however, the prediction accuracy of the regression equation was affected. Future research on predicting N leaching loss in North China should focus on accurately quantifying water percolation. The quantitative model obtained in this study provides technical support for precise N management and effective pollution prevention in North China.
Impacts of biochar application on soil nutrient availability and exchangeable based cations: a meta-analysis
RAN Jiwei, QI Xin, WU Dong, HUANG Min, CAI Zejiang, HUANG Yaping, ZHANG Wenju
2023, 31(9): 1449-1459. doi: 10.12357/cjea.20230026
Abstract(149) HTML (61) PDF(32)
In order to accurately assess the effects of biochar application on soil nutrient availability and exchangeable based cations, a total of 2000−2020 published literature was collected to obtain 648 matched data for no biochar application (blank or no addition) and single biochar application, and 430 matched data for no biochar application and biochar co-application with fertilizer. A meta-analysis was performed to quantify the effects of different biochar applications on soil N and P availability (total N, NH4+-N, NO3-N, Olsen-P), salt-based ions contents (K+, Ca2+, Na+, and Mg2+), and cation exchange capacity (CEC). Results showed that the application of biochar (alone or combined with chemical fertilizers) significantly increased soil N and P content by 14.0%−128.1%, and salt-based ions contents by 22.5%−270.2%, respectively. By comparing the effects of different biochar application, it was found that the increasing of soil N and P availability in chemical fertilizer combination treatment was higher than that in biochar application alone, while the increasing of salt-based ions contents in biochar application alone was higher than that in chemical fertilizer combination. Further analysis showed that when the pH of biochar was higher than 8, the application of biochar alone significantly increased soil Olsen-P content by 10.3%−58.5%. When the biochar pyrolysis temperature was higher than 500℃, the application of biochar alone increased the soil salt-based ions contents by 33.9%−384.7%. When the application rate of biochar was less than 10 t∙hm−2, soil Olsen-P content increased higher under biochar combined with chemical fertilizer (374.1%) than that of biochar application alone (2.1%). In addition, applying biochar to soil with pH<6.5 could effectively increase soil N, P and Ca2+ contents, with Olsen-P content and CEC increased by 45.0% and 17.9%, respectively, under biochar application alone. Therefore, the application of biochar could effectively improve soil nutrient availability and ion exchange properties, and reducing environmental risks. In practical applications, biochar can be applied alone or in combination with fertilizer depending on the specific aims. Taking into account the characteristics of biochar, application rate, and soil conditions, the effective use of biochar to improve soil fertility will be the priority direction of the high-quality agricultural development in the future.
Changes in the area and water consumption of winter wheat under limiting groundwater exploitation in the Hebei Plain
QUAN Tao, LI Hongjun, SHEN Yanjun, WANG Zhuoran, MIN Leilei, QI Yongqing, ZHANG Jianyong
2023, 31(9): 1460-1470. doi: 10.12357/cjea.20230125
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The shortage of water resources and long-term high-intensity agricultural production have further intensified the water crisis in the Hebei Plain, an important grain production region. The local government has implemented a limiting groundwater exploitation policy since 2014 to alleviate the contradiction between water and food security. Measures such as seasonal fallow, rain-fed agriculture, and water-saving agriculture have been implemented in terms of agricultural production. To explore the impact of this policy on agricultural water use, the changes in planting area and water consumption characteristics for winter wheat in the Hebei Plain during the years before and after the implementation of the policy were analyzed. Based on the spectral variation characteristics of winter wheat, distribution maps of winter wheat from 2009 to 2019 were retrieved using MODIS NDVI data. Combined with the TSEB (two-source energy balance model) evapotranspiration dataset and agricultural production statistics, the water consumption characteristics of winter wheat before and after the policy were compared, and the driving factors for these changes were investigated. Our study found that the planting area of winter wheat in the Hebei Plain increased by 183 700 hm2 from 2009 to 2019. Five years after the implementation of the policy, the total planting area of winter wheat increased by 104 000 hm2, mainly concentrated in the east; while it decreased in the west. In terms of water consumption of winter wheat, the level of evapotranspiration and total water consumption of winter wheat increased by 32.58 mm and 1.09 billion m3 compared with those before the policy. Compared with the winter wheat field, seasonal fallow land reduced evapotranspiration by 73 mm in addition to not pumping groundwater for irrigation. During the study period, the annual average water use efficiency of winter wheat was 1.67 kg∙m3. After the implementation of the policy, the water use efficiency of winter wheat in 2/3 regions of the Hebei Plain had been increasing annually. The main reason for the decrease in winter wheat area was the change in planting structure caused by farmers’ pursuit of higher agricultural economic benefits and urbanization. The support policy from the government to ensure food security and improve the mechanization degree of winter wheat planting promoted an increase in its planting area. The fragmentation of farmland, the unstable transfer of farmland management rights, and the lack of initiative and pressure to save water led to the low popularity of water-saving irrigation for winter wheat. Facing the contradiction between water shortage and food production, it is still necessary to strengthen water-saving agriculture and significantly reduce the water consumption of evapotranspiration to alleviate the contradiction.
Rainfall redistribution of different vegetations in Taihang Mountain, China
SUN Tianmiao, YANG Hui, CAO Jiansheng
2023, 31(9): 1471-1481. doi: 10.12357/cjea.20220980
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With the implementation of ecological restoration projects, vegetation cover in the Taihang Mountains has increased, but the current situation of water shortages has still not been effectively improved. The impact of increased vegetation on hydrological processes is unknown. As the first action layer of rainfall reaches the terrestrial ecosystem, the vegetation canopy divides rainfall into throughfall, stemflow, and canopy interception. This changes the spatial distribution of the rainfall. Therefore, studying rainfall redistribution processes is important for exploring the relationship between vegetation and water. This study selected eight typical forests, natural Vitex negundo, and artificial froests of Robinia pseudoacacia, Pinus bungeana, Pistacia chinensis, Eucommia ulmoides, Cerasus pseudocerasus, Fraxinus chinensis, and Garcinia multiflora. Field monitoring and indoor experiments were conducted to explore the rainfall redistribution characteristics of different forest stands of the Taihang Mountains. The results of the study were as follows: 1) During the study year (2022), the rainfall amount was 480.0 mm, rainfall in the rainy season was 283.25 mm, the number of rainfall events in the rainy season was 20, the average amount per rainfall was 14.16 mm, and the variation range of rainfall intensity was 0.05−0.72 mm∙h−1, mainly consisting of rainfall events less than 5 mm∙h−1. The hypo-rainfall in the rainy season of 2022 fluctuated greatly, and the uneven distribution of rainfall time was mainly concentrated in July and August. 2) The proportion of total throughfall to total rainfall was greater than 60%. The lowest threshold of rainfall amount among eight vegetations for producing throughfall was 0.77 mm; E. ulmoides forest has the largest proportion of total stemflow in total rainfall, with a value of 13.94%, followed by G. multiflora forest (6.78%), and the proportion of total stemflow in the remaining species was less than 5%. The lowest threshold of rainfall amount for eight vegetations for producing stemflow was 3.35 mm; the proportion of total canopy interception of total rainfall was the largest in F. chinensis forest, accounting for 32.97%, and the smallest in P. bungeana forest, accounting for 7.53%. The overall performance was as follows: throughfall>canopy interception>stem flow. 3) Throughfall, stemflow, and canopy interception increased significantly with rainfall. Throughfall rate, stemflow rate, and funneling ratio increased rapidly and then leveled off with increasing rainfall amount. The canopy interception rate decreased rapidly and then leveled off with increasing rainfall. Rainfall redistribution characteristics were greatly affected by rainfall amount and leaf water absorption capacity. It was found that the canopy interception rate of P. bungeana, R. pseudoacacia, E. ulmoides, and G. multiflora forests was significantly smaller than that of natural V. negundo, which was important for reducing rainfall canopy interception evaporation and increasing effective rainfall. These four forests could therefore be considered for planting in water-shortage areas. Thus, reasonable selection of stand type and adjustment of stand proportions can reduce canopy interception and improve the efficiency of precipitation utilization. The results of this study provide a theoretical basis and data support for the selection of tree species in reforestation projects in the Taihang Mountains.
Agricultural Ecologic Economics and Ecoagriculture
Influence of rural land transfer on agricultural green total factor productivity: effect, spatial characteristics and regional heterogeneity
LIU Huimin, SHANG Jie
2023, 31(9): 1482-1495. doi: 10.12357/cjea.20220975
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Improving green agricultural total factor productivity (TFP) is important for rural revitalization. Existing studies do not thoroughly analyze the impact of the major agricultural reform of rural land transfer on agricultural green total factor productivity. Therefore, based on existing research results, we first conducted a theoretical analysis of the impact of the rural land transfer on agricultural green total factor productivity. We then comprehensively used the undesirable output SBM-DEA model, GML index, double-fixed effect panel regression model, instrumental variable model, and spatial measurement model to systematically analyze the influence, spatial effect, and regional heterogeneity of agricultural land transfer on agricultural green total factor productivity. The results show that: 1) rural land transfer has a significant positive impact on agricultural green total factor productivity, and the expansion of rural land transfer areas will promote an increase in agricultural green total factor productivity. 2) The positive influence of rural land transfer on agricultural green total factor productivity has regional heterogeneity, and this effect is significant in northern China, but not significant in southern China. 3) There is a threshold effect of rural land transfer on agricultural green total factor productivity, and the positive effect of farmland transfer area on agricultural green total factor productivity decreases when it exceeds the threshold value. 4) Rural land transfer has a positive spatial effect on agricultural green total factor productivity, and its spatial spillover effect is significant. Based on the research results, we suggest that relevant departments took effective measures to promote rural land transfer to exert its positive impact of the rural land transfer on agricultural green total factor productivity. Simultaneously, we propose promoting the transfer of rural land according to local conditions. In addition, we believe that the relevant departments should pay more attention to the application of green agricultural technology and other advanced technologies that consider both agricultural production and environmental protection in the later stages of promoting rural land transfer. Finally, we suggest that the government should pay attention to the interprovincial coordination of the rural land transfer process. The marginal contributions of this study are as follows:1) the effect of rural land transfer, a major agricultural reform, on agricultural green total factor productivity is deeply explored; 2) the impact of the agricultural production process on the agro-ecological environment is incorporated into the efficiency measurement system, and the threshold and spatial effects of the impact of the rural land transfer on agricultural green total are explored.
Land space ecological restoration zoning based on ecosystem service supply and demand and ecological resilience: a case study in the Beijing-Tianjin-Hebei region
MENG Fandi, ZHOU Zhi, ZHANG Guijun, JIAO Cuili, KAN Yaochuan, ZHAO Li
2023, 31(9): 1496-1510. doi: 10.12357/cjea.20230010
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It is important to explore the coupling relationship between the supply and demand characteristics of ecosystem services and the attributes of ecological resilience, and to scientifically delineate the ecological restoration zones in the national land space for ecological security and regional sustainable development. This study took districts and counties of Beijing, Tianjin, and Hebei as the study unit. Based on multi-source data, the food production model, InVEST model, CSLE model, and other methods were used to measure the supply and demand of five ecosystem services, including food supply, water yield, carbon storage, soil conservation, and recreation supply. An ecological resilience evaluation index system was constructed to measure the ecological resilience of counties (districts). Based on the ecosystem service supply and demand as well as ecological resilience, the ecological restoration zones were delineated, and the corresponding optimization strategies were proposed according to the natural and socio-economic status and development characteristics within the zones. The results showed that: 1) the high-value areas of the ecosystem service supply in the Beijing-Tianjin-Hebei region were mainly distributed in the northern part of Chengde City, Qinhuangdao City, and Tangshan City, and scattered in the central counties (districts) of the region. The high-value areas of ecosystem service demand were mainly concentrated in the well-developed cities in the central and southeastern Beijing-Tianjin-Hebei region, whereas the demand for ecosystem services in the mountainous areas and plateaus in the northern Beijing-Tianjin-Hebei region was low. The supply and demand of ecosystem services in the study area were spatially negatively correlated. 2) The ecological resilience of each district and county had noticeable regional differences, and the high-value areas were mainly concentrated in the northeast of the Beijing-Tianjin-Hebei region. 3) There was no high surplus area in the comprehensive supply and demand of ecosystem services in the study area. The deficit area accounted for 42.26% of the total area, mainly resulting from the decline in system function caused by urban and industrial development, and the demand for ecological services was challenging to meet. 4) Based on the matching characteristics of the supply and demand of ecosystem services and the spatial distribution pattern of ecological resilience, the study area was divided into high supply-high demand-high resilience (13.68%), low supply-high demand-low resilience (0.51%), low supply-high demand-high resilience (10.54%), low supply-low demand-low resilience (12.07%), low supply-low demand-high resilience (20.22%), and high supply-low demand-high resilience (42.98%) areas. At the same time, different ecological restoration strategies were proposed for different areas. This study provides guidance for the systematic layout of ecological restoration projects and a methodological reference for the scientific preparation of comprehensive land space consolidation plans.
Evaluation of eco-environmental vulnerability in Jilin Province based on an AHP-PCA entropy weight model
ZOU Taohong, CHANG Yaxuan, CHEN Peng, LIU Jiafu
2023, 31(9): 1511-1524. doi: 10.12357/cjea.20230115
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Jilin Province is the main grain-producing area in China and has a considerable ecological function in Northeast China. Understanding the spatial and temporal characteristics of ecological vulnerability can aid effectively managing environmental change, guiding the rational use of land resources, and developing strategies for regional environmental protection. Based on the Sensitivity–Resilience–Pressure model of ecological vulnerability, a comprehensive evaluation indexes system for ecological vulnerability was established from the perspectives of human activities and natural environment in Jilin Province using meteorological, remote sensing, and statistical data. Thereafter, an entropy weight model constructed by using an analytic hierarchy process and principal component analysis was employed to analyze the geospatial and temporal dynamics of ecological vulnerability from 2000 to 2020 in the study area. Spatial autocorrelation analysis was used to probe spatial relationships between the different ecological vulnerability levels. The results revealed that 1) the overall environment was suitable with a light vulnerability level and below in the study area; however, ecological vulnerability varied among different regions and increased gradually from east to west. High vulnerability areas were mainly distributed in the western region, characterized by less rainfall and lower vegetation cover, and displayed a considerable global spatial autocorrelation with high-high aggregation. Potentially vulnerable areas were concentrated in the mountainous regions of eastern Jilin Province. 2) The ecological vulnerability index was divided into five levels as potential, slight, light, moderate and heavy. The area proportion was varied significantly among different levels. Taking 2020 as an example, the proportion in descending order is light>moderate>slight>potential>heavy, moreover, the area of light and below vulnerable area accounts for about 67.9%, indicating that Jilin Province is at a medium level of vulnerability in the whole. 3) Temporally, the vulnerability of the ecological environment in Jilin Province improved from 2000 to 2020. Compared to 2000, the proportions of heavyly and slightly vulnerable areas in 2020 decreased by 2.78% and 9.20%, respectively; whereas the proportions of light and moderately vulnerable areas in 2020 increased by 7.45% and 5.24%, respectively. The potentially vulnerable areas in 2020 were the same as those in 2000. 4) The value of Moran’s I index increased from 0.2335 to 0.3841 from 2000 to 2020, implying that spatial agglomeration was more pronounced, and high-high aggregation was distributed in the western region of the study area, whereas low-low aggregation was concentrated in the eastern region of Jilin Province. Relevant suggestions for environmental protection were proposed based on vulnerability assessments and impact factors. Existing ecological protection strategies should be continued in zones with potential and slight vulnerabilities. Zones with light and moderate vulnerability should prioritize black soil protection to ensure reasonable development of agricultural land resources. For heavyly vulnerable zones, investment in environmental protection should increase.ince. Relevant suggestions for environmental protection were proposed based on vulnerability assessments and impact factors. Existing ecological protection strategies should be continued in zones with potential and slight vulnerabilities. Zones with light and moderate vulnerability should prioritize black soil protection to ensure reasonable development of agricultural land resources. For heavyly vulnerable zones, investment in environmental protection should increase.