中国生态农业学报(中英文)

Conceptual model based on climate for comprehensive evaluation of crop planting conditions:A case study in Bayannur Hetao Irrigation District in Inner Mongolia

WANG Xiurong, WANG Qiong, LU Yanyu, YANG Song, YU Han, WANG Lisheng, ZHAO Rong

2020, 28(11): 1649-1660. doi: 10.13930/j.cnki.cjea.200442

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Abstract:
In response to climate change and to the progress of social economy, science, and technology, alterations to crop planting conditions in various places are warrant further scientific, technological, and ecological development. In order to adapt and enhance crop planting conditions, as well as to promote the development of market economy, it is an urgent need to conduct a comprehensive assessment of local crop planting conditions. In this study, analytic hierarchy process (AHP) methodology was applied, combined with the principles of meteorology, climatology, and agrometeorology, to design a framework for assessing the crop planting conditions. Taking into account the needs of local ecological and economic development, the framework was constructed by selecting three major criteria, namely climate resources, disaster prevention, and supporting conditions for cultivation, as well as 14 related sub-indicators, including light resources, heat resources, water resources, air quality, meteorological disasters, plant diseases and insect pests, soil conditions, geographical environment, infrastructure, and management system. Through statistical analysis, the scoring rules for the 14 sub-indicators were set up and the conceptual model for comprehensive evaluation of crop planting conditions was created. To validate the novel assessment model, a comprehensive evaluation experiment was carried out on the main crop planting conditions at the Bayannaoer Hetao Irrigation District of Inner Mongolia. The assessment results indicated that Bayannur Hetao Irrigation District had sufficient light resources, stable heat resources, high climate suitability, and excellent irrigation conditions. The guarantee rate of light, cumulative temperature, and temperature suitability for key growing periods for major crops, such as spring wheat, maize, and sunflower, were more than 85%, whereas water guarantee rate was 100%. The temperature diurnal range was larger. The air quality was excellent and the irrigated areas had fertile soil. The frequency of major meteorological disasters such as high temperature, strong wind, hail, and heavy rain and plant diseases and insect pests were low, and the ability of prediction and defense for these disasters were strong. Natural, geographical, and cultural policies and various resources had prominent advantages in allocation. The comprehensive evaluation of crop cultivation conditions in the region was excellent, level Ⅰ. These results demonstrated that the selected indicators used by the conceptual model were interrelated and independent, hierarchical and structural, and could quantitatively reflect the complex setting formed by the regional climate system and relevant supporting conditions. Indexes were easy to obtain and operate, and the evaluation results were reliable. Therefore, the proposed conceptual model may be applied to the comprehensive evaluation of planting conditions in different regions or different crops, so as to guarantee the ecological and sustainable development of agriculture.

Impact of climate change on potential productivities of main grain crops in the Sichuan Basin

PANG Yanmei, CHEN Chao, XU Fuxian, GUO Xiaoyi

2020, 28(11): 1661-1672. doi: 10.13930/j.cnki.cjea.200150

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Abstract:
Potential crop productivity is important for evaluating agricultural climate resources. This study calculated the climatic potential productivity (CPP) of three grain crops (rice, maize, and winter wheat) using meteorological data. Daily measurements from 1961 to 2018 from 63 meteorological stations (Sichuan Basin, China) and crop phenology data from 1981 to 2018 from 46 agricultural meteorological stations were used to analyze productivity. Climatic factors, such as radiation, air temperature, and precipitation, and the effects of climate change were evaluated to provide regionally specific guidance for increasing agricultural productivity and sustainability. The results showed that the rice CPP in the Sichuan Basin increased from west to east between 1961 and 2018, the maize CPP was higher in the north and southwest, and the CPP of winter wheat was higher in the north and south. Reduced radiation negatively affected the CPPs of three crops, and higher temperatures positively affected the crop CPPs. Precipitation was the dominant climatic factor, affecting the spatial change of the CPP. Increased precipitation positively affected the crop CPPs, and decreased precipitation negatively affected the CPPs. The impact of climate change on the rice, maize, and winter wheat CPP was variable (positive in some basin areas, but negative in others); the overall effects of climate change on the CPPs were 0.5 kg·hm^-2·a^-1 for rice, -1.4 kg·hm^-2·a^-1 for maize, and 9.9 kg·hm^-2·a^-1 for winter wheat. Improving the selection of photosynthetically-efficient and drought-resistant crop varieties and crop field management are needed for climate change adaptation and to ensure food security.

Spatial and temporal characteristics and meteorological indexes of late spring coldness in Qingdao

LI Deping, ZHANG Kaijing, ZHANG Lu, DONG Haiying, GUO Lina, LIU Xuegang

2020, 28(11): 1673-1681. doi: 10.13930/j.cnki.cjea.200560

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Abstract:
Meteorological services play a role in agriculture and improve defense capability. This study used data from seven national meteorological stations in Qingdao, China, including the daily mean and minimum temperatures during the spring (3-5 months) of 1961-2015 and the crop frost or low-temperature damage from disasters, as categorized by the national standard of GB/T 34816-2017 "meteorological indicators of late spring coldness."The meteorological index and temporal and spatial characteristics of the late spring coldness were statistically analyzed. The results showed that there were two grades of mild and moderate cold periods (no severe) in late spring (67.3% and 32.7%, respectively). The average annual occurrence of late spring coldness was 1.1 stations, mainly in April. Since the 1990s, the interannual or intergenerational changes had decreased, and the spatial distribution gradually decreased from the northwest to the southeast coast. Moderate Jimo had the greatest probability of occurrence, and the probability of causing late spring coldness was 26.3%. Based on the meteorological conditions of the disaster, we can derive the meteorological index of disaster-induced late spring coldness. The mild minimum temperature dropped to 0-5℃, the average temperature anomaly was -4 to -2℃, and the duration was 3-5 days. The moderate minimum temperature dropped below 0℃, and the average temperature anomaly was < -4℃ for more than 6 days. From the influence scope, occurrence time, and disaster-causing analysis, the moderate spring coldness impact range was regional and occurred from late March to mid-April, which may cause crop freezing damage. The mild influence range was small, generally < 2 stations, the time was late, and the probability was greater in the middle and late April, which may cause frost or chilling damage. The cold spring weather caused late spring coldness; 26.3% of the coldness resulted in agricultural production-associated economic losses. Interestingly, the frequency of mild late spring coldness was higher than that of moderate late spring coldness, and the occurrence time overlapped with the critical growth period of the main crops (i.e., the wheat jointing stage to booting stage, the flowering stage of most fruit trees). This needs to be prevented. Frost damage, late frost injury, or low-temperature damage in the Qingdao area were all caused by late spring coldness. The interannual variability of the late spring coldness in Qingdao was not obvious, even interdecadal variability had even increased, which was not consistent with the overall distribution in Qingdao. This was related to the regulatory effects of the ocean. There are temperature differences from the south-eastern coast to the north-western inland region of Qingdao, and the marine climate effects also gradually weaken.

Effect of continuous overlay mulching of rice straw-plastic film on control of invasive plant Bidens pilosa L.

LI Saifei, XU Qiuyuan, ZHANG Jia'en, YE Yanqiong

2020, 28(11): 1682-1691. doi: 10.13930/j.cnki.cjea.200101

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Abstract:
The invasive plant, Bidens pilosa L., has extensively damaged the agricultural, forestry, and animal husbandry industries in China. Combining rice straw and plastic film mulching may be an ecological and efficient control method and was investigated in this study. Three straw mulching amounts (0 kg·m^-2, 1 kg·m^-2, and 1.5 kg·m^-2) were used, which was performed during winter followed by overlaid film mulching in spring. The environmental indicators (i.e., soil temperature, soil relative water content, surface air temperature, and relative humidity) and community indicators (i.e., weed biomass, seed germination amount, weed community structure, and soil seed bank) were measured in the middle periods both of straw mulching and film mulching. The results showed that rice straw mulching in winter significantly reduced the midday soil temperature, surface air temperature, B. pilosa L. biomass, seed germination amount, the dominant weed species coverage, and the number of subordinate weed species. The 1.5 kg·m^-2 treatment had the greatest effect. When film mulch was overlaid in spring, the temperatures of the shallow soil and surface air all increased, the humidity of shallow soil decreased, while the surface air humidity increased. The seed density of B. pilosa L. in 0-5 cm soil layer mulched by film was significantly decreased by 79.49% compared to non-film mulched. Overlaid film mulching after rice straw mulching, all B. pilosa L. died, and no seeds germinated. Rice straw mulching in winter followed by film mulching in spring can effectively prevent and control B. pilosa L. growth. This study provides an alternative method to prevent and control the spread of invasive weed species in different seasons.

Effects of Nutrient Expert recommended fertilization on winter wheat yield, nutrient accumulation, transportation, and utilization

WANG Dandan, LI Lantao, HAN Bengao, ZHANG Qian, MIAO Yuhong, WANG Yilun

2020, 28(11): 1692-1702. doi: 10.13930/j.cnki.cjea.200189

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Abstract:
The overuse of fertilizer, unreasonable fertilization rates, and low fertilizer use efficiency affect modern agricultural systems, limiting farmers' income and development of sustainable agriculture in Henan Province, China. This study investigated the effect of the Nutrient Expert system on winter wheat yield, nutrient accumulation, transportation, and fertilizer utilization efficiency. Field experiments were conducted during the 2018-2019 growing season in Hebi and Xinxiang, Henan Province, with seven treatments:farmer conventional fertilization (FP), local official recommended fertilization (ST), Nutrient Expert recommended fertilization (NE), Nutrient Expert recommended fertilization with controlled-release N fertilizer (RNE), and the elimination of N, P, or K input in the NE treatment (NE-N, NE-P, and NE-K, respectively). Compared to the FP treatment, N, P, and K fertilizer rates in the NE treatment decreased by 16.2%, 43.3%, and -13.2% in Hebi and 19.5%, 48.0%, -57.9% in Xinxiang, respectively. The yields of the NE and RNE treatments were higher than those of FP by 4.7%-6.6% and 5.5%-9.6%, respectively; NE and FP did not differ significantly on yield, but the RNE yield was significantly higher than that of FP. Compared to the other treatments, NE and RNE also improved plant nutrition concentrations and accumulation during the growing season. The dry matter accumulation after anthesis in NE and RNE was significantly higher than that in FP (by 9.2%-14.0% and 11.9%-18.6%, respectively), and the contribution of N, P, and K remobilization to the grains before anthesis also increased significantly. The average fertilizer use efficiency of N, P, and K was 42.1%, 19.2%, and 46.6%, respectively, and the average agronomic efficiency was 11.5 kg·kg^-1, 13.2 kg·kg^-1, and 13.3 kg·kg^-1, respectively, based on the Nutrient Expert system of winter wheat. In general, the Nutrient Expert recommended fertilization optimized the fertilizer management, promoted the absorption and utilization of N, P, and K, and improved the winter wheat yield and fertilizer utilization efficiency. Therefore, we encourage the use of the Nutrient Expert system for fertilizer management in the winter wheat fields of Henan Province, China.

Effect of various crops rotations on soil quality in double cropping rice field in the middle reaches of the Yangtze River

WANG Zhiqiang, MIU Jianqun, LIU Ying, TANG Haiying, ZHANG Peng, ZHONG Chuan, HUANG Guoqin, ZHAO Qiguo

2020, 28(11): 1703-1714. doi: 10.13930/j.cnki.cjea.200177

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Abstract:
Improved knowledge that may support the efficient utilization and sustainable development of agricultural resources in the middle reaches of the Yangtze River is still needed. Herein, changes on soil nutrients, organic carbon, and enzyme activities under different planting patterns and straw retention were assessed, and the impact of agricultural management measures on soil quality was evaluated in this particular geographical region. The long-term positioning experiment of different rotational and continuous cropping was carried out from 2012 to 2017, and five treatments of rotation patterns including winter fallow-early rice-late rice, winter Chinese milk vetch-early rice-late rice, winter oilseed rape-early rice-late rice, winter garlic-early rice-late rice, and winter rotation (interannual rotation of potato, Chinese milk vetch, oilseed rape, and garlic)-early rice-late rice were set up. Under the condition of winter crop straw and rice straw retention, the soil quality indexes in minimum data set were selected and determined using multiple variance analysis, correlation analysis, and principal component analysis combined with the suitability of the soil in the southern double cropping rice field. Lastly, the fuzzy mathematics method was used to evaluate the soil quality in the double cropping rice area. The data indicated that six years of winter planting suitable crops and straw retention in the double cropping rice area could effectively improve the soil quality of paddy field by 10.73%-12.91% compared with the winter fallow treatment, with exception of the garlic treatment. The soil quality of double cropping rice field under different rotation patterns was in the order of winter rotation (planting different crops in different years during winter) (0.726) > planting oilseed rape in winter (0.723) > planting Chinese milk vetch in winter (0.712) > winter fallow (0.643) > planting garlic in winter (0.638). Therefore, the soil quality of double cropping rice can be significantly improved by suitable rotation with winter crops and double straw returning, which provides a solid foundation for the healthy and sustainable development of paddy fields in southern China.

Effects of potato intercropped with maize on soil bacterial diversity

FU Yunzhen, MA Kun, LI Qian, LI Guangwen, CUI Huizhen

2020, 28(11): 1715-1725. doi: 10.13930/j.cnki.cjea.200240

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Abstract:
One of the reasons for the replanting problem in continuous potato cropping is the change in the soil microbial community structure. Many studies have shown that reasonable intercropping can alleviate replant disease, and the relationships of crop-soil-microorganisms are a hot topic in current agricultural ecosystem research. Therefore, the objective of this study was to examine the difference in the soil bacterial community composition after continuous potato and maize monoculture and intercropping. The IonS5^TMXL high-throughput sequencing platform was used to analyze the soil bacterial community composition and diversity under maize monoculture (M), potato monoculture (P), and potato intercropped with maize (PM). The results revealed that soil organic matter significantly increased in the treatment of potato intercropped with maize (P < 0.05), when compared with the monocultures. However, there were no significant changes in the soil total nitrogen, available nitrogen, total phosphorus, available potassium, and pH among different treatments. Moreover, the total 56 787 Operational Taxonomic Units (OTUs) of bacteria were classified as 46 phyla, 55 classes, 114 orders, 208 families, and 455 genera. Proteobacteria, Acidobacteria, and Actinobacteria were the dominant phyla and accounted for 57.68%-65.11% of the total relative abundance of bacteria. The diversity index (Shannon-Wiener and Simpson) and the richness index (ACE and Chao1) of soil bacterial communities did not change; however, the relative abundance of the soil bacterial communities changed at the phylum and genus levels. Compared to the potato monoculture, the relative abundance of Proteobacteria decreased significantly after potato was intercropped with maize (P=0.023), while the relative abundance of Planctomycetes increased (P=0.043). Furthermore, Gemmatimonas and Candidatus Solibacter, with lower relative abundance, were found to be more easily influenced by the planting patterns. Moreover, intercropping increased the relative abundance of Arthrobacter, Blastococcus, and Bacillus. With the change in the bacterial community, the soil bacterial functions were separately classified into 7 and 35 functional categories at hierarchy level 1 and 2, respectively, using the KEGG function prediction, which implied abundant soil bacteria functions. From this, we garnered that soil bacteria were active in metabolic processes, genetic information processing, and cellular processes. Furthermore, the metabolic functional groups in the 7 primary functional layers had significant differences between potato intercropped with maize and potato monoculture (P=0.046). Additionally, forward selection of the soil environmental factors was used, and the result of the Monte Carlo test showed that there was no significant correlation between soil physicochemical and biological properties and the soil bacterial community composition and diversity after the five-year experiment. In conclusion, the relationship between the interspecific mutualism and competition in potato intercropped with maize was the driving factor of the change in the soil bacterial community.

Association analysis of SSR markers with leaf morphology in maize (Zea mays) under diverse watering regimes

ZHONG Yuan, ZHAO Xiaoqiang, LI Wenli

2020, 28(11): 1726-1738. doi: 10.13930/j.cnki.cjea.200507

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Abstract:
The leaf morphology of maize (Zea mays) is closely related to its drought resistance. The molecular markers correlated with leaf morphology traits under different watering regimes may provide insights into the genetic mechanisms and identify the breeding varieties. In this study, changes in the leaf length (LL), leaf width (LW), leaf angle (LA), leaf orientation value (LOV), leaf size (LS), leaf shape coefficient (LSC), and leaf rolling index (LRI) of 187 maize inbred lines were analyzed under different watering regimes. A genome-wide scan and the genetic diversity were analyzed with simple-sequence repeat (SSR) markers, and the associations between the markers and the leaf morphological traits were assessed via a general linear model (GLM). The results showed that:1) the coefficients of variation for the leaf morphological traits of the 187 inbred lines were 13.21%-59.23% and 9.62%-28.22% under normal water and dry conditions, respectively, indicating abundant genetic variation. There were significant differences in the seven leaf morphological traits, so the leaf morphology was adjusted by the hereditary character of the inbred line. LL, LW, LA, and LS decreased significantly under drought stress, whereas LOV, LSC, and LRI increased, and the variance rate of the seven traits was 30.53%-198.31%. 2) A total of 652 alleles were detected using 145 SSR markers. The polymorphism information content (PIC) ranged from 0.201 to 0.966, with an average of 0.478. The tested materials were divided into five groups based on unweighted pair group method with arithmetic mean clustering and population structure; the Luda red cob group, Tangsipingtou group, Lancaster group, P group, and Reid group. 3) A total of 15 SSR markers were associated with seven leaf morphologies under different watering regimes (GLM, P < 0.01), and the amount of explained phenotypic variance was 2.25%-27.30%. Approximately 72.97% of the SSR markers were detected under drought conditions. The umc1124, umc2363, umc1742, phi331888, umc1378, bnlg1863, umc2134, and umc1345 markers were simultaneously associated with multiple leaf morphologies under different watering regimes, indicating pleiotropy. These results provide useful information for the genetic improvement of leaf morphology and marker-assisted selection breeding programs for maize drought resistance and optimization.

Effects of bacterial root rot on photosynthetic characteristics in Panax notoginseng

WU Hongmin, SHA Bencai, ZHANG Jinyan, CUN Zhu, CHEN Junwen

2020, 28(11): 1739-1752. doi: 10.13930/j.cnki.cjea.200266

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Root rot is an important factor that has threatened the cultivation of Panax notoginseng, with an incidence rate of 5% to 20%. Bacterial root rot caused by Pseudomon adaceaecan might only be discovered after infected leaves have wilted, and by then there will no longer be any effective control measures. The objective of this study was to explore the differences in effects of bacterial root rot on the photosynthetic physiological characteristics between control (CK) and diseased plants (DP), thus providing a theoretical basis for the understanding of disease physiology in P. notoginseng. The results showed that the taproot of DP was browned and rotted from root rot, accompanied by broken fibrous roots, decay and hollow stems, withering leaves, and low water content. There was no significant difference in plant height, leaf area, and thickness of leaf antomical strucutres (including thickness of upper epidermis, lower epidermis, palisade tissue, and sponge tissue) between DP and CK. However, the chlorophyll content, net photosynthetic rate (P_n), stomatal conductance (G_s), instantaneous water use efficiency (WUE_inst), intrinsic water use efficiency (WUE_i), and apparent mesophyll conductance (AMC) were significantly lower in DP than in CK (P ≤ 0.05), with intercellular CO₂ concentration (C_i) inversely proportional to P_n in DP individuals. The maximum fluorescence signal of the P700 reaction center (P_m) in DP was not affected during the period of initial infection, but the maximum quantum efficiency of photosystem Ⅱ (PSⅡ) under dark adaptation (F_v/F_m), electron transfer rate of PSⅡ[ETR(Ⅱ)], actual photochemical quantum yields of PSⅡ[Y(Ⅱ)], electron transfer rate of PSⅠ[ETR(Ⅰ)], cyclic electron flow around PSI (CEF), and actual photochemical quantum yields of PSⅠ[Y(Ⅰ)] were significantly lower in DP than in CK (P ≤ 0.05). Additionally, the fraction of energy passively dissipated in the forms of heat and fluorescence[Y(NO)] were significantly higher in DP than in CK (P ≤ 0.05). Furthermore, The K phase in the fast chlorophyll fluorescence kinetic curves was significantly higher in DP than in CK (P ≤ 0.05). Overall, the degree of damage for the various organs of DP was:root>stem>leaf. Root rot significantly degraded leaf chlorophyll, along with irreversible damage to PSⅡ and inhibition of PSⅠelectron transfer and reduced the assimilation ability of mesophyll cells, consequently restricting photosynthetic performance.

Straw degradation ability and composition of microbial consortium for corn straw decomposition at low temperature

Qing geer, YU Xiaofang, GAO Julin, WANG Zhigang, HU Wanji, Naogan chaolu, WANG Zhen, HU Shuping, SUN Jiying, QU Jiawei

2020, 28(11): 1753-1765. doi: 10.13930/j.cnki.cjea.200128

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It is common practice to return field straw with urea to accelerate decomposition. To improve the microbial screening methodology and investigate the microbes responsible for decomposition of corn straw, nitrogen acclimatization of the microbial consortium GF-20 (GF-20) was performed. Compositional differences in the cultured microbial consortium and the microbe source were also evaluated. GF-20 was cultured until the 10^th generation in variable nitrogen conditions[ammonium sulfate (N1), mixtures of ammonium sulfate and urea (N2-N5), and urea (N6)]. The corn straw decomposition ratio was determined to estimate the activity of the composite microbial system, and the composition diversity and function were analyzed by MiSeq high-throughput sequencing. The results showed that the N2 degradation rate was significantly higher than the other treatments. The bacterial source alpha diversity index (ADI) was significantly higher than the cultured microbial consortium, and the N2 ADI was significantly higher than the other nitrogen treatments. The bacterial composition also significantly differed between the source and consortium, as well as among the nitrogen treatments. The N2 treatment yielded the most diverse bacterial composition, with richer and more uniform flora structures and a higher carbohydrate metabolic pathway activity (which promotes corn straw degradation). Functional microbial strains involved in corn straw degradation were obtained after restrictive sub-generation of the microbial sources, which can accelerate corn straw degradation. The highest corn straw degradation efficiency of microbial consortium was observed with the 0.16% ammonium sulfate + 0.04% of urea nitrogen (N2) treatment. These findings provide a basis for developing microbial consortium used in commercial production decomposition.

Soil water variation of different vegetation community in Taihang Mountain Area

SI Mengke, CAO Jiansheng, YANG Hui, ZHU Chunyu

2020, 28(11): 1766-1777. doi: 10.13930/j.cnki.cjea.200172

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Soil water storage and movement are highly heterogeneous across ecosystems. However, variation characteristics of soil moisture are not well understood at present, due to the high heterogeneity of environmental conditions. The Taihang Mountain region is an important water collection area of the North China Plain, and a functional area for water conservation in the national Beijing-Tianjin-Hebei coordinated development strategy. However, little is known about the soil water regime of the main plant species that inhabit this region. In this study, the soil water content for four representative vegetation types, Triticum aestivum/Zea mays, Themeda triandra var. Japonica, Vitex negundo var. heterophylla and Juglans regia, that are widely distributed in the semi-arid area of the Taihang Mountain, were observed using large scale weighing lysimeters, during the growing season (April to October) in 2018 and 2019. Weighing lysimeters systematically measured the soil water content, seepage, and evapotranspiration among different vegetation communities, and the collected data on the variation characteristic of soil moisture content for four vegetation types were analyzed by means of statistical analysis. The results showed that average soil water content for T. aestivum/Z. mays, T. triandra, V. negundo, and J. regia were 0.30 cm³·cm^-3, 0.35 cm³·cm^-3, 0.32 cm³·cm^-3 and 0.36 cm³·cm^-3 in 2018, and 0.28 cm³×cm^-3, 0.26 cm³·cm^-3, 0.23 cm³·cm^-3 and 0.31 cm³·cm^-3 in 2019, respectively. Similarly, the decrease of soil water content for T. aestivum/Z. mays, T. triandra, V. negundo, and J. regia were 0.05 cm³×cm^-3, 0.04 cm³·cm^-3, 0.09 cm³·cm^-3, and 0.05 cm³·cm^-3 in 2018, and 0.07 cm³×cm^-3, 0.13 cm³·cm^-3, 0.18 cm³·cm^-3, and 0.10 cm³·cm^-3 in 2019, respectively, compared to the soil water content at the end of growing season (December) of 2017. The decrease of the soil water content for V. negundo was greatest, and that for T. aestivum/Z. mays was the smallest, among the four vegetation types. The direction of vertical gradient of soil water content was consistent among the four vegetation types, with the soil water content decreasing as the depth of soil increased. However, the depth of water uptake from soil was discrepant. In T. aestivum/Z. mays fields, the main depth was between 45-100 cm. In T. triandra and J. regia fields, the main soil depth was between 100-150 cm. In V. negundo fields, the main soil depth was between 150-180 cm. These results may be due to differences in root distribution. T. aestivum/Z. mays and T. triandra are from Gramineae family, and their root systems are distributed in shallow soil. Although J. regia is arboreal, it has shallow-rooted plants. V. exnegundo has lateral roots radiating out from the main root crown, one or more deeply penetrating tap (sinker) roots, and can uptake water from deep soil. This indicated that V. exnegundo was the species with the greatest water consumption. The pattern of plant water consumption needs to be considered in plant species selection, ecological management, and restoration of semi-arid ecosystems in the Taihang Mountain region.

Determination of premium rates for tea cold-frost damage in Fujian Province based on risk assessment

TAO Hongchao, CHEN Jiajin, CHEN Zhibiao, HUANG Chuanrong, SUN Chaofeng, WU Li

2020, 28(11): 1778-1788. doi: 10.13930/j.cnki.cjea.200190

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The aim of this study was to improve the rationale of the premium damage insurance rate design for cold-frost damage in tea plants from different risk areas in Fujian Province. In doing so, we first calculated the tea yield decrement rate, both grade and probability of cold-frost damage occurrence by using historical data, so as to determine the pure rate and benchmark rate of cold-frost damage insurance for tea within each county of Fujian Province. Then, we determined the regional premium damage insurance rates for the conditions of each risk area and different triggers, combined with the cold-frost damage risk zoning area. The results showed that under the trigger condition for tea plants damage in Fujian Province, i.e., extremely low temperatures below 4℃, the regional premium damage insurance rates were 1.4%, 4.5%, 7.2%, and 10.2%, respectively, in the northwest area for < 200 m, 200-600 m, 600-900 m, and >900 m altitudes. At the same time, the regional premium damage insurance rates were 0.9%, 2.6%, 4.8%, and 6.4%, respectively, in the northeast area for < 200 m, 200-600 m, 600-900 m, and >900 m altitudes. The regional premium damage insurance rates were 0.5%, 2.3%, 4.0%, and 5.5%, respectively, in the southwest area for < 300 m, 300-700 m, 700-1 100 m, and >1 100 m altitudes. Moreover, the regional premium rates were 0.5%, 1.9%, 3.9%, and 5.4%, respectively, in the southeast area for < 300 m, 300-700 m, 700-1 100 m, and >1 100 m altitudes. In general, the regional premium damage insurance rate increased with latitude and altitude. These results can provide technical support for the actuarial calculation of the premium damage insurance rate in relation to the design of insurance products for the cold-frost damage index of tea plants in Fujian Province.

Current situation of the main crop straw nutrient resources and the substitute potential of crop straw for chemical fertilizer:A case study of Anhui Province

CHENG Wenlong, HAN Shang, LI Min, WANG Hui, BU Rongyan, CAO Zhewei, TANG Shan, WU Ji

2020, 28(11): 1789-1798. doi: 10.13930/j.cnki.cjea.200219

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Anhui Province is rich in crop straw resources, it is important to fully utilize straw nutrient resources for the purpose of maintaining a nutrient balance in farmlands. For this cause, the potential of straw as a natural alternative to chemical fertilizers was evaluated in order to provide a scientific basis for the reduced use of chemical fertilizers in Anhui Province. In this study, we selected main crops such as rice, wheat, corn, soybean, peanut, and rape as study subjects in Anhui Province. We consulted the published literature and statistical data, and estimated the amount of straw, straw return rate, and nutrient utilization rate of main crops in Anhui Province in 2017. The results showed that the amount of straw estimated at 46.999 million tons in 2017. Furthermore, the distribution of straw resources was more in the northern and the middle regions of the province, and less in the southern regions. We also found that the total amount of straw nutrient resources was 1.248 million tons. The amounts of N, P₂O₅, and K₂O were 0.381, 0.114, and 0.753 million tons, respectively, and these accounted for 40.1%, 32.1%, and 68.9% of the main crop nutrient requirements of the entire province. Therefore, the potential of straw replacing chemical fertilizers is great in theory when all the straw is returned to the soil and the nutrients in the straw are fully utilized. However, the utilization rates of N, P₂O₅, and K₂O were only 38.9%, 52.3%, and 69.9%, respectively. The actual nutrients contents of N, P₂O₅, and K₂O of crop straws returned to the field accounted for only 15.6%, 16.8%, and 48.2%, respectively, of the nutrient demands of the main crops. Moreover, the actual amounts of N, P₂O₅, and K₂O returned to the field accounted for 8.6%, 6.4%, and 41.4% of the total input, respectively. By returning straw to the farmland, approximately 0.633 million tons of chemical fertilizer can be saved, representing 19.8% of the amount of chemical fertilizer that would have been used without the straw. It is also worth noting that the application reduction rates of N, P₂O₅, and K₂O were 11.4%, 17.2%, and 40.7%, respectively. Thus, the improvement in straw returning-to-field rate and release rate of nutrients in crop growth period point towards the benefits of promoting the reduced use of chemical fertilizers.

N excretion coefficient based on the whole process of pig production and manure N excretion in China

FU Min, JIANG Xiaosong, HE Zhiping, LIU Yi, CHEN Tianbao

2020, 28(11): 1799-1810. doi: 10.13930/j.cnki.cjea.200355

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Abstract:
The present study aimed to improve the nitrogen (N) excretion parameter system applied to pig breeding to accurately calculate the related manure N excretions. Metabolic assessment of full fecal and urine production in the whole process of pig breading (reproduction-weaning-growth-fattening, for a total of 285 days) were performed in 12 breeding sows (Yorkshire×Landrace) and 12 commercial pigs (Yorkshire×Landrace×Duroc). We recorded the feed intake, fecal and urine production, and collected samples every day for moisture and N content evaluation. The collected data were combined with the pig production performance parameters to calculate the pig breeding-associated annual N excretion coefficient. Lastly, we evaluated changes on N excretion and regional distribution of pig-production based on the statistical data and cultivated land area of different provinces (cities) from 2000 to 2018 in China. The results indicated that pigs had significantly different N intake and excretion at different growth physiological stages, being 72.32 and 49.42 g·d^-1 in open days, 55.79 and 45.36 g·d^-1 during early pregnancy, 56.25 and 22.27 g·d^-1 in mid-gestation, 72.41 and 26.36 g·d^-1 in late pregnancy, and 114.28 and 38.84 g·d^-1 during lactation, respectively. In commercial pigs, the N intake and excretion was 22.86 and 10.96 g·d^-1 in weaning, 34.87 and 18.34 g·d^-1 during early growth, 54.67 and 34.50 g·d^-1 during late growth, and 55.15 and 35.79 g·d^-1 during fattening, respectively. Moreover, urinary N excretion was higher than fecal N excretion at each stage. The annual N excretion coefficient of commercial pigs and sows was 9.00 and 11.75 kg·head^-1·a^-1, respectively. From 2000 to 2018, the total N excretion from pig breeding in China increased and then gradually decreased; however, the N excretion per unit pork product decreased every year. The N excretion by commercial pigs accounted for the largest proportion of the total manure N, with an average of 84.03%. Sichuan, Henan, Hunan, and Shandong were the top four provinces with the highest N emission, accounting for 33.67% of the total N emission from pig-production in China, whereas the provinces (cities) with the largest N load per unit cultivated area were Fujian, Guangdong, Hunan, Beijing, and Shanghai. Therefore, we should consider the population structure and the corresponding N excretion coefficient when calculating the amount of N emission from pig breeding, and fully consider the environmental carrying capacity when making development plans.

Biased green technology progress in China's scale pig breeding

YAN Guiquan, HE Yucheng, ZHANG Xiaoheng, CHEN Guoting

2020, 28(11): 1811-1822. doi: 10.13930/j.cnki.cjea.200306

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Abstract:
Operation scales are an important aspect of modern livestock and poultry breeding programs in China. However, intensive breeding scales often increase the contradiction between pig breeding scale and eco-environmental factors. Thus, the future development of China's pig breeding industry depends on boosting the scale of operations and curbing the associated environmental pollution. Technological progress, especially green-biased technology, is highly beneficial and optimizes resource allocation, improves pig breeding efficiency, promotes scaled production, and abates pollution. Therefore, it is important to broaden our understanding of the green-biased technological progress in scale of pig breeding operations. This study used data from China's small-, medium-and large-scale pig breeding operations from 2007 to 2017 and systematically calculated the emission of five pollutants generated during the breeding process, which were included as undesirable outputs in the green total factor productivity (GTFP) accounting system. This study also aimed to increase the following marginal contributions to academic discussion. First, the GTFP and the biased technology progress were combined, and not only was the green-biased technological progress in the scale of pig breeding operations in China identified but also the input-oriented green technological progress index was calculated. Second, the input bias of green technology progress was discussed considering the labor force and the concentrated feed input, which affected the long-term survivability and profitability of the pig breeding scale. Third, this study divided the Mainland of China into several meso-geographical units (i.e., key development areas, restricted development areas, potential development areas, and moderate development areas) and discussed whether the green technology progress bias was in harmony with the regional factor endowments. We also presented supporting evidence for the direction of the technological progressions in each area. This paper documented an input-oriented technology progress bias in various scales of pig breeding operations across different areas, and notably, the biases in all areas did not lead to lower GTFP. However, GTFP improvement may stem from a bias for neutral technology progress. The uptrend of technology progress bias in large-scale pig breeding was significant; i.e., the positive effects of technology progress bias on GTFP in pig breeding were increasing. The green technology progress bias for small-, medium-and large-scale pig breeding saved labor by substitutive adoption of concentrated feed. The information presented here indicated that the regional resource endowments determined the biases of technological progress factors in the scale of pig breeding operations in China. Thus, each region should adopt changes in technology based on its resource endowment and environmental regulation objectives.

The impact of information literacy and green prevention-control technology adoption behavior on farmer household income

YANG Chengfang, ZHENG Shaofeng, YANG Ning

2020, 28(11): 1823-1834. doi: 10.13930/j.cnki.cjea.200257

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Abstract:
Individual households are important to agricultural economic development and new rural construction. Household income directly affects the enthusiasm and creativity required for agricultural production and management. To help rural households stay up-to-date with new practices (including ecological farming), which may increase their income, this study created a four-dimensional measurement index system for information literacy from 786 vegetable-farming households in Shouguang, Shandong Province, China. An empirical test was performed to determine the impact of information literacy on green prevention-control technology adoption behavior and farmer household income using a hierarchical regression model and an instrumental variable method. Information literacy had significant positive effects on green prevention-control technology adoption behavior and farmer household income. Green prevention-control technology adoption behavior partially mediated the influence path of information literacy to farmer household income. The mediating effect of adopting (or not) green prevention-control technology was accounted for 73.09%, and the number of green prevention-control technologies adopted was accounted for 62.72%. The years of cultivation experience and the decision to attend technical training had significant positive effects on green prevention-control technology adoption behavior. Farmer household income was significantly positively affected by the years of education, household size, the years of cultivation experience and the proportion of income from vegetable farming, but farmer household income was significantly negatively affected by distances to the vegetable market. Information literacy had a direct impact on household income, but also indirectly influenced income by the mediating effect of green prevention-control technology adoption behavior. Therefore, policy changes to increase household income through information literacy training and promoting green prevention-control technologies may be beneficial. This study established an analysis framework to explore the effects of information literacy and green prevention-control technology adoption behavior on farmer household income. A measurement index system for household information literacy was created to measure aggregate levels, and a characteristic index of green prevention-control technology adoption behavior was optimized, providing guidance and insight into the increase of farmer household income.

2020 Vol. 28, No. 11