《1 Engineering research hotspots and engineering research focus》

1 Engineering research hotspots and engineering research focus

《1.1 Development trends of engineering research hotspots》

1.1 Development trends of engineering research hotspots

The top 10 hotspots in agricultural engineering research are classified into two categories:

• Hotspots involving in-depth traditional research. They include “Conservation farming systems” in crop science, “Healthy growth of livestock and poultry” in agricultural bioengineering and veterinary medicine, “Vegetation diversity and classification” and “Soil fungal communities” in agricultural resource science, “Grazing and lactating dairy cows” in livestock science, and “Behavior among wild animals” in applied ecology.

• Emerging research hotspots. They include “Soil organic carbon mapping,” “Reduction of methane emission,” and “Soil moisture data assimilation” in agricultural resource science and “In vitro antibacterial activity” in animal med- icine.
There are no revolutionary research hotspots in this cat- egory. The number of core papers supporting each hotspot is approximately 50, and the average citation frequency   is approximately 30. Among hotspot papers, the propor- tion of consistently cited papers is less than 30%, with an average of approximately 16%. The number of papers cited in patents is relatively small, with an average of less than two (Table 1.1.1). In addition, the data indicate that the core papers in the top 10 research hotspots have been generally published around 2013. Among them, the overall number of core papers on “Healthy growth of livestock and poul- try” and “Reduction of methane emissions” reveals an up- ward trend, whereas no clear pattern is found for the rest hotspots (Table 1.1.2).

Brief descriptions of all the top 10 hot engineering re- search topics are provided below.

1.1.1 Conservation farming systems

Conservation farming systems is a hotspot in crop science, which involves in-depth traditional research. It ensures crop yield and quality improvement based on considerations from the levels of soil, crop, and environ- mental stress. Techniques included in this hotspot are as follows:

(a) Conservation tillage technique: After harvest, the crop residues are crushed and left as ground cover. In the next season, cultivation is carried out without tillage to re- duce mineralization, erosion, soil and water loss, and the chemical inputs, and to increase crop yields and agricul- tural income.

(b) Crop genetic improvement technique: The tradition- al breeding, cell engineering, chromosome engineering, transgenic techniques, and other methods are utilized

《Table 1.1.1》

Table 1.1.1 Top 10 engineering research hotspots in agriculture

No Engineering research hotspots Core papers Citation frequency Average citation frequency Mean year Proportion of consistently cited papers Patent-cited publications
1 Conservation farming systems 44 1396 31.73 2013.11 29.50% 0
2 Soil organic carbon mapping 49 1328 27.1 2013.47 2.00% 0
3 Healthy growth of livestock and poultry 90 2251 25.01 2013.89 20.00% 1
4 In vitro antibacterial activity 46 1329 28.89 2014.24 21.70% 4
5 Vegetation diversity and classification 48 1614 33.63 2013.17 12.50% 2
6 Reduction of methane emission 48 872 18.17 2013.98 18.80% 1
7 Soil fungal communities 50 1637 32.74 2013.3 10.00% 2
8 Grazing and lactating dairy cows 49 1083 22.1 2013.02 14.30% 4
9 Soil moisture data assimilation 47 1385 29.47 2013.02 6.40% 2
10 Behavior among wild animals 46 1310 28.48 2013.43 23.90% 1

《Table 1.1.2 》

Table 1.1.2 Annual number of core papers belonging to each of the top 10 engineering research hotspots in agriculture

No. Engineering development hotspots 2011 2012 2013 2014 2015 2016
1 Green city and green building 225 215 171 115 100 63
2 New materials for civil engineering 274 213 176 139 32 14
3 Intelligent building construction 75 78 55 70 40 16
4 Intelligent urban transportation systems 166 158 135 112 31 7
5 Digital urban planning 68 41 35 17 4 0
6 Seismic and vibration control 155 115 86 68 12 8
7 Monitoring, inspection, and informatization of geotechnical and underground engineering 153 139 150 79 11 5
8 Global positioning navigation 211 205 147 102 41 25
9 Bridge and steel structure industrialization 56 69 73 54 53 11
10  Urban rainwater flood control and utilization 0 0 0 37 125 30

for the alteration, transfer, and recombination of crop genetic materials, to promote crop yield, and to improve quality.

(c) Environmental stress prevention technique: Bio- logical environmental stress, such as pests and diseases,  is an important factor restricting crop production. Most strategies for crop protection involve increasing the ability of crops to resist pests and pathogens or using chemicals. Non-biological environmental stress, such as drought, low temperature, high temperature, and wind damage, will lead to the decline in crop yield and quality.

1.1.2 Soil organic carbon mapping

This is an emerging research hotspot in agricultural science. Soil organic matter (SOM) refers to the collection of humus, animal and plant residues, and microbiome formed by microbial action The carbon in SOM is referred to as soil organic carbon (SOC). SOC content is the bal- ance between the input of organic matter (e.g., biological debris) into the soil and the loss of organic matter mainly caused by microbial decomposition. SOC content and distribution are important factors in the soil classification system. In the soil classification system of the USA, there are many diagnostic horizons, all of which involve organic carbon content and distribution. The isohumic property is utilized in the Chinese system of soil classification; i.e., the ratio of the SOC content at 0–20 and 0–100 cm is used as   a classification index. SOC is an important component of the terrestrial ecosystem carbon pool and has a profound impact on the physical, chemical, and biological proper- ties of the soil.

1.1.3 Healthy growth of livestock and poultry

This is a hotspot in agricultural bioengineering and vet- erinary medicine involving in-depth traditional research. Healthy growth refers to creating a suitable environment for livestock and poultry, providing adequate feed, pro- tecting the health of livestock and poultry, reducing dis- ease incidences, ensuring the product quality and safety, decreasing pollution, achieving ecological balance, and reflecting a high degree of unity of the economical, eco- logical, and social benefits of modern animal husbandry. Healthy growth mainly focuses on the health of livestock and poultry, product safety, and environmental protec- tion. It can ensure product safety by effective regulation of the production process.

1.1.4 In vitro antibacterial activity

This is an emerging research hotspot in animal medi- cine. Antibiotic activity refers to the ability of antibiotics to inhibit or kill pathogenic microorganisms, and it can   be determined using in vitro antibacterial tests and in vivo experimental treatments. In vitro antibacterial experiments are important references for clinical medication. The min- imum inhibitory concentration (MIC) is the minimum concentration that can inhibit the growth of bacteria in the culture medium. When the proportion of bacteria killed are used as assessment criteria, the concentration that can de- crease the total number of viable bacteria by 99.0% or more than 99.5% is known as the minimum bactericidal concen- tration (MBC). In a batch of experiments, the MICs that can inhibit 50.0% or 90.0% of the test bacteria are known as MIC50 and MIC90, respectively. The bacteriostatic and bac-tericidal activities of antibiotics are relative, and some an- tibiotics show bacteriostatic activity at low concentrations, but bactericidal activity at high concentrations.

1.1.5 Vegetation diversity and classification

Vegetation diversity and classification, which is a hotspot in agricultural resource science, involves in-depth traditional research. Vegetation diversity includes spe- cies, habitat, nutritional, life cycle, and genetic diversity. Among them, species diversity is determined by the ge- netic diversity in different ecological environments. The complexity of gene expression in vegetation growth and development on the spatial and temporal scale determines the diversities of vegetable external morphology, physio- logical metabolism, and the DNA molecular level.

1.1.6 Reduction of methane emission

This is an emerging research hotspot in agricultural re- source science. Methane is the hydrocarbon with the sim- plest structure. In recent years, a rapid growth in methane emissions has occurred, and its reduction is the key for avoiding the exacerbation of global warming. Several studies have indicated that anthropogenic methane emis- sions account for 60% of global methane emissions, and approximately one-third of anthropogenic methane emis- sions come from agricultural production. Rice cultivation and animal husbandry are its largest sources.

1.1.7 Soil fungal communities

This is a hotspot in agricultural resource science, in- volving in-depth traditional research. Soil fungi refer to the unicellular or multicellular branching filamentous eukaryotic organisms live in the soil. They use the soil as their habitat for completing all or a part of their life histo- ry. Fungal hyphae have the ability to decompose organic matter, have a lower soil pH requirement than actinomy- cetes and bacteria have, and they are the main decompos- ers of organic matter in acidic soils, particularly in forests.

1.1.8 Grazing and lactating dairy cows

This is a hotspot in animal husbandry science and in- volves in-depth traditional research. Milk production in cows used in the dairy industry can be improved by breeding programs. Cows have poor heat resistance and high requirements for grazing and feed management. Breeding high-quality beef cattle and high quality lac-
 
tating dairy cows with high and stable yield is the only method of enhancing the development of this industry. The performance determination system of cows, i.e., dairy herd improvement (DHI), is the main method of deter- mining the improvement of dairy herds.

1.1.9 Soil moisture data assimilation

This is an emerging research hotspot in agricultural resource science. Soil moisture is an important physical factor in land-air interaction affecting the surface evapo- transpiration, runoff, surface albedo, surface emissivity, and surface heat and latent heat fluxes. Land surface data assimilation is based on land surface model and hydro- logical model. Different data assimilation algorithms are used for assimilating surface observation data as well as satellite and radar data, and optimizing the estimations of soil moisture, temperature, and surface energy flux on the surface and root zone.

1.1.10 Behavior among wild animals

Animal behavior is a hotspot in applied ecology that re- quires in-depth traditional research. The behaviors of wild animals are complex and diverse. According to the different behaviors displayed, they can be divided into foraging be- havior, storage behavior, aggressive behavior (within the same species), defensive behavior (among species), territori- al behavior, reproductive behavior, rhythmic behavior (mi- gratory behavior), social behavior, directed behavior, and communication behaviors. All kinds of behavior are adap- tive responses of wild animals to the complex environment. Based on their learning process, behaviors of wild animals can be divided into innate behavior and learned behavior.

《1.2 Understanding of engineering research focus》

1.2 Understanding of engineering research focus

1.2.1 Conservation farming systems

Conservation farming systems ensure crop yield and quality improvement based on comprehensive consid- erations from the levels of soil, crop, and environmental stress. It includes conservation tillage techniques, crop genetic improvement techniques, and environmental stress prevention techniques. A number of international funds have conducted long-term surveys on soil fertility status and studies on conservation farming systems in African countries, such as Zimbabwe. These studies have proposed new systematic methods for crop rotation, straw mulching, weed control, and pest management to ensure high and stable crop yields.

The major countries publishing the core papers are Zim- babwe, the Netherlands, France, Kenya, and Brazil (Table 1.2.1). The consistently cited papers are from Zimbabwe, Kenya, and the USA. Based on the distribution of research papers among institutions (Table 1.2.2), the papers are mainly published by the International Maize and Wheat Improvement Center (CIMMYT) in Mexico, Wageningen University in the Netherlands, and the French Agricultural Research Centre for International Development (CIRAD). The cooperation network diagram indicates that Zimba- bwe, the Netherlands, France, Kenya, and Brazil have a close cross-citation relationship (Figure 1.2.1). For institutions, a close cooperation exists among CIMMYT in Mexico, Wageningen University in the Netherlands, and CIRAD (Figure 1.2.2). A wide range of international cooperations has formed among countries, regions, and institutions. In this focus, the countries or regions with a large proportion of cited papers are Zimbabwe, the Netherlands, and France (Table 1.2.3), and the major research institutions are CIM- MYT, the CIRAD, and Wageningen University (Table 1.2.4). The paper titled “Communicating complexity: Integrated assessment of trade-offs concerning soil fertility manage- ment in African reproductive systems to support innova- tion and development”, which was published in the journal Agricultural Systems on 2011, has been cited 78 times. This paper and two other highly cited papers published in Field Crops are examples of international collaborative research

《Table 1.2.1》

Table 1.2.1 Major producing countries or regions of core papers on the engineering research focus “Conservation farming systems”

No. Country/Region Core papers Proportion of core papers Citation frequency Proportion of citation frequency Average citation frequency Consistently cited papers Patent-cited publications
1 Zimbabwe 30 68.18% 919 73.93% 30.63 6 0
2 The Netherlands 16 36.36% 562 45.21% 35.13 2 0
3 France 11 25.00% 322 25.91% 29.27 1 0
4 Kenya 10 22.73% 393 31.62% 39.3 4 0
5 Brazil 7 15.91% 197 15.85% 28.14 1 0
6 Ethiopia 7 15.91% 161 12.95% 23 2 0
7 Italy 5 11.36% 207 16.65% 41.4 2 0
8 USA 5 11.36% 146 11.75% 29.2 4 0
9 Mexico 5 11.36% 99 7.96% 19.8 1 0
10 Malawi 4 9.09% 196 15.77% 49 1 0

《Table 1.2.2》

Table 1.2.2 Major producing institutions of core papers on the engineering research focus “Conservation farming systems”

No. Institution Core papers Proportion of core papers Citation frequency Proportion of citation frequency Average citation frequency Consistently cited papers Patent-cited publications
1 CIMMYT 25 56.82% 609 48.99% 24.36 7 0
2 Wageningen Univ 16 36.36% 562 45.21% 35.13 2 0
3 CIRAD 15 34.09% 478 38.46% 31.87 2 0
4 Int Ctr Trop Agr 10 22.73% 319 25.66% 31.9 2 0
5 Int Livestock Res Inst 8 18.18% 318 25.58% 39.75 2 0
6 Int Crops Res Inst Semi Arid Trop 7 15.91% 294 23.65% 42 0 0
7 Univ Zimbabwe 6 13.64% 212 17.06% 35.33 2 0
8 Embrapa Cerrados 5 11.36% 81 6.52% 16.2 1 0
9 Int Inst Trop Agr 3 6.82% 105 8.45% 35 0 0
10 Food & Agr Org United Nations 3 6.82% 73 5.87% 24.33 1 0

Note: CIMMYT stands for International Maize and Wheat Improvement Center in Mexico; CIRAD stands for French Agricultural Research Center for International Development.

《Figure 1.2.1》

Figure 1.2.1 Collaboration network of the major producing countries or regions of core papers on the engineering research focus “Conservation farming system” 1

1 In the figure, the nodes refer to the countries or regions, the size of the nodes refers to number of papers, the connecting line between nodes refers to papers published based on research cooperation, and the thickness of the connecting line indicates the number of papers based on research cooperation. These are the same in full text.

《Figure 1.2.2》

Figure 1.2.2 Collaboration network of the major producing institutions of core papers on the engineering research focus “Conservation farming system”

《Table 1.2.3 》

Table 1.2.3 Major producing countries or regions of core papers that are cited by core papers on the engineering research focus “Conservation farming systems”

No. Country/Region Number of core papers cited by core papers   Proportion Mean year
1 Zimbabwe 23 19.66% 2013.13
2 The Netherlands 13 11.11% 2013.38
3 France 10 8.55% 2013.7
4 Kenya 8 6.84% 2013.25
5 Ethiopia 7 5.98% 2014.29
6 Brazil 6 5.13% 2013.83
7 Mexico 5 4.27% 2014.4
8 USA 4 3.42% 2013.5
9 Italy 3 2.56% 2013
10 Norway 3 2.56% 2013.33

at the University of Wageningen in the Netherlands. The contributions from China to this discipline are insufficient, with only a few core or consistently cited papers. The possi- ble reasons may be that this discipline is regionally focused, the relevant researchers have mainly focused on the exist- ing problems of agricultural development in China, and the number of relevant scientific studies in internationally relevant institutions is still low.

1.2.2 Soil organic carbon mapping

SOM refers to the collection of humus, plant and animal residues, and microbiome, and the carbon in SOM is referred to as SOC. SOC has a profound effect on the physical, chemical, and biological properties of the soil, and its content and distribution are important in the soil classification system. To date, seven global workshops on soil mapping have been held.

The USA, Australia, France, India, and Germany are the major countries publishing the core papers (Table 1.2.5), and the countries publishing consistently cited papers are the USA and Australia. The University of Sydney, the French National Institution for Agricultural Research (INRA), and the Louisiana State University are the main contributors of core papers (Table 1.2.6). The cooperation

《Table 1.2.4》

Table 1.2.4 Major producing institutions of core papers that are cited by core papers on the engineering research focus “Conservation farming systems”

No. Institution Number of core papers cited by core papers   Proportion Mean year
1 CIMMYT 20 14.60% 2013.65
2 CIRAD 13 9.49% 2013.54
3 Wageningen Univ 13 9.49% 2013.38
4 Int Ctr Trop Agr 8 5.84% 2013.5
5 Int Livestock Res Inst 6 4.38% 2013.67
6 Embrapa Cerrados 5 3.65% 2014.2
7 Univ Zimbabwe 4 2.92% 2012.75
8 Int Crops Res Inst Semi Arid Trop 4 2.92% 2012.75
9 Univ Life Sci 3 2.19% 2013.33
10 Int Inst Trop Agr 3 2.19% 2013.67

《Table 1.2.5》

Table 1.2.5 Major producing countries or regions of core papers on the engineering research focus “Soil organic carbon mapping”

No. Country/Region Core papers Proportion of core papers Citation frequency Proportion of citation frequency Average citation frequency Consistently cited papers Patent-cited publications
1 USA 19 38.78% 466 39.86% 24.53 3 0
2 Australia 15 30.61% 314 26.86% 20.93 2 0
3 France 8 16.33% 239 20.44% 29.88 0 0
4 India 6 12.24% 114 9.75% 19 1 0
5 Germany 5 10.20% 209 17.88% 41.8 1 0
6 Italy 4 8.16% 89 7.61% 22.25 0 0
7 England 4 8.16% 72 6.16% 18 0 0
8 Belgium 4 8.16% 69 5.90% 17.25 1 0
9 China 4 8.16% 61 5.22% 15.25 0 0
10 Canada 3 6.12% 95 8.13% 31.67 1 0

《Table 1.2.6》

Table 1.2.6 Major producing institutions of core papers on the engineering research focus “Soil organic carbon mapping”

No. Institution Core papers Proportion of core papers Citation frequency Proportion of citation frequency Average citation frequency Consistently cited papers Patent-cited publications
1 Univ Sydney 15 30.61% 314 26.86% 20.93 2 0
2 INRA 6 12.24% 178 15.23% 29.67 0 0
3 Louisiana State Univ 6 12.24% 131 11.21% 21.83 0 0
4 Ramakrishna Mission Vivekananda Univ 5 10.20% 88 7.53% 17.6 1 0
5 Texas Tech Univ 5 10.20% 80 6.84% 16 1 0
6 Inst Environm & Sustainabil 4 8.16% 89 7.61% 22.25 0 0
7 Joint Res Ctr 4 8.16% 89 7.61% 22.25 0 0
8 Catholic Univ Louvain 4 8.16% 69 5.90% 17.25 1 0
9 Tech Univ Munich 3 6.12% 106 9.07% 35.33 1 0
10 W Virginia Univ 3 6.12% 105 8.98% 35 0 0

Note: INRA stands for the French National Institution for Agricultural Research.

network diagram suggests that the USA plays a leading role among all the countries or regions (Figure 1.2.3) and works closely with India. Although the University of Syd- ney has produced the largest number of core papers, the cooperation among the universities in the USA is more extensive (Figure 1.2.4). Based on the cited core papers, the USA and Australia are dominant among all the coun- tries or regions (Table 1.2.7), the University of Sydney being the most dominant institution (Table 1.2.8). China  is among the top 10 countries in this research focus, but it is in a relatively backward state in terms of the number of core papers, average citation frequency, and consistently cited papers.

Among the 49 core papers in this focus, 33 have been published in Geoderma. The most cited paper, “Spatial distribution of soil organic carbon stocks in France,” published in Biogeosciences by INRA, has been  cited 75 times. It is based on a regional research project on SOC. “SoilGrids1km―Global soil information based on automated mapping,” published later in Plos One in 2014, is a highly cited paper on digital mapping of SOC of different regions or different types.

1.2.3 Healthy growth of livestock and poultry

The key to healthy growth of livestock and poultry is   to ensure their healthy growth during the nursing and production processes. Porcine epidemic diarrhea virus and avian brood parasites are two major threats to safe livestock and poultry products. The healthy growth of livestock and poultry can ensure product safety from the source.

《Figure 1.2.3》

Figure 1.2.3 Collaboration network of the major producing countries or regions of core papers on the engineering research focus “Soil organic carbon mapping”

《Figure 1.2.4》

Figure 1.2.4 Collaboration network of the major producing institutions of core papers on the engineering research focus “Soil organic carbon mapping”

《Table 1.2.7》

Table 1.2.7 Major producing countries or regions of core papers that are cited by core papers on the engineering research focus “Soil or- ganic carbon mapping”

No. Country/Region Number of core papers cited by core papers   Proportion Mean year
1 USA 14 19.44% 2014.07
2 Australia 13 18.06% 2014.31
3 France 6 8.33% 2013.33
4 India 5 6.94% 2014.2
5 England 4 5.56% 2014
6 Italy 4 5.56% 2014.75
7 Belgium 4 5.56% 2013.25
8 Egypt 3 4.17% 2014
9 China 3 4.17% 2014.67
10 Denmark 3 4.17% 2013.67

In terms of core paper publication by country or region, the USA produces the largest number of publications (Table 1.2.9), and the countries with consistently cited papers are the USA and the UK. The Iowa State University, the City University New York (CUNY), and Ohio State University are the dominant institutions (Table 1.2.10). The USA, Czech Republic, China, and Australia have a close cooperation (Figure 1.2.5). The Iowa State University has lesser number of cooperations, whereas the CUNY, Palacký University in Czech Republic, Hungarian Natural History Museum, and Hungarian Academy of Sciences have close cooperation (Figure 1.2.6). The top 3 countries producing the largest number of cited papers are the USA, China, and the Czech Republic (Table 1.2.11). Three universities in the USA—Ohio State University, Iowa State University, and CUNY—and the Palacký University in Czech Republic constitute the  group of institutions with the highest number of cited core papers (Table 1.2.12). China is ranked third in the terms of the number of core papers on this research direction, but the total number of citation frequency is still at a low level. In terms of development potential, China has been ranked second for the number of cited core papers; although the publication of follow-up core papers can be expected, a core research institution has not yet been formed.

《Table 1.2.8 》

Table 1.2.8 Major producing institutions of core papers that are cited by core papers on the engineering research focus “Soil organic car- bon mapping”

No. Institution Number of core papers cited by core papers   Proportion Mean year
1 Univ Sydney 13 12.38% 2014.31
2 Louisiana State Univ 5 4.76% 2013.4
3 Ramakrishna Mission Vivekananda Univ 5 4.76% 2014.2
4 Texas Tech Univ 5 4.76% 2014.4
5 Inst Environm & Sustainabil 4 3.81% 2014.75
6 Joint Res Ctr 4 3.81% 2014.75
7 Catholic Univ Louvain 4 3.81% 2013.25
8 INRA 4 3.81% 2013
9 Univ Wisconsin 3 2.86% 2014.67
10 Aarhus Univ 3 2.86% 2013.67

《Table 1.2.9》

Table 1.2.9 Major producing countries or regions of core papers on the engineering research focus “Healthy growth of livestock and poultry”

No. Country/Region Core papers Proportion of core papers Citation frequency Proportion of citation frequency Average citation frequency Consistently cited papers Patent-cited publications
1 USA 50 55.56% 1017 49.44% 20.34 6 0
2 Czech 14 15.56% 283 13.76% 20.21 1 0
3 China 13 14.44% 184 8.95% 14.15 1 0
4 England 12 13.33% 472 22.95% 39.33 4 0
5 Australia 11 12.22% 356 17.31% 32.36 1 0
6 Hungary 7 7.78% 163 7.92% 23.29 1 0
7 Scotland 5 5.56% 124 6.03% 24.8 1 0
8 New Zealand 5 5.56% 105 5.10% 21 0 0
9 France 5 5.56% 68 3.31% 13.6 0 0
10 Norway 4 4.44% 132 6.42% 33 0 0

《Table 1.2.10》

Table 1.2.10 Major producing institutions of core papers on the engineering research focus “Healthy growth of livestock and poultry”

No. Institution Core papers Proportion of core papers Citation frequency Proportion of citation frequency Average citation frequency Consistently cited papers Patent-cited publications
1 Iowa State Univ 14 15.56% 473 22.99% 33.79 2 0
2 CUNY 14 15.56% 237 11.52% 16.93 2 0
3 Ohio State Univ 14 15.56% 193 9.38% 13.79 1 0
4 Palacky Univ 13 14.44% 265 12.88% 20.38 1 0
5 Univ Cambridge 9 10.00% 417 20.27% 46.33 3 0
6 Australian Natl Univ 6 6.67% 251 12.20% 41.83 1 0
7 Hungarian Nat Hist Museum 6 6.67% 133 6.47% 22.17 1 0
8 Univ Minnesota 6 6.67% 107 5.20% 17.83 0 0
9 Hungarian Acad Sci 5 5.56% 142 6.90% 28.4 1 0
10 Univ Edinburgh 5 5.56% 124 6.03% 24.8 1 0

Note: CUNY stands for the City University of New York.

《Figure 1.2.5》

Figure 1.2.5 Collaboration network of the major producing countries or regions of core papers on the engineering research focus “Healthy growth of livestock and poultry”

《Figure 1.2.6 》

Figure 1.2.6 Collaboration network of the major producing institutions of core papers on the engineering research focus “Healthy growth of livestock and poultry”

《Table 1.2.11 》

Table 1.2.11 Major producing countries or regions of core papers that are cited by core papers on the engineering research focus “Healthy growth of livestock and poultry”

No. Country/Region Number of core papers cited by core papers   Proportion Mean year
1 USA 45 33.09% 2014.56
2 China 13 9.56% 2014.77
3 Czech 12 8.82% 2013.42
4 Australia 9 6.62% 2012.67
5 England 8 5.88% 2012.13
6 Hungary 6 4.41% 2013.67
7 Scotland 5 3.68% 2014.2
8 France 4 2.94% 2014.5
9 New Zealand 4 2.94% 2013.5
10 Slovakia 4 2.94% 2012.75

《Table 1.2.12》

Table 1.2.12 Major producing institutions of core papers that are cited by core papers on the engineering research focus “Healthy growth of livestock and poultry” 

No. Institution Number of core papers cited by core papers   Proportion Mean year
1 Ohio State Univ 13 6.57% 2015.23
2 Iowa State Univ 13 6.57% 2014.77
3 CUNY 13 6.57% 2013.54
4 Palacky Univ 11 5.56% 2013.36
5 Univ Minnesota 6 3.03% 2015.17
6 Hungarian Nat Hist Museum 5 2.53% 2014
7 Univ Cambridge 5 2.53% 2011.6
8 Univ Debrecen 5 2.53% 2014
9 Australian Natl Univ 5 2.53% 2012
10 Eotvos Lorand Univ 5 2.53% 2014

Based on supporting data, the researchers of Iowa State University studying porcine epidemic diarrhea virus published a paper titled “Emergence of porcine epidemic diarrhea virus in the USA: clinical signs, lesions, and viral genomic sequences” in 2013 in the Journal of Veterinary Diagnostic Investigation, which has been cited 158 times and shown a profound impact. In 2011, the  researchers at the Palacký University in Czech Republic published “Constraints on host choice: why do parasitic birds have no exploit some common potential hosts?” in the Journal of Animal Ecology” and it is a representative research paper on avian brood parasites.

《2 Engineering development hotspots and engineering development focus》

2 Engineering development hotspots and engineering development focus

《2.1 Development trends of engineering development hotspots》

2.1 Development trends of engineering development hotspots

The top 10 agricultural engineering development hotspots are classified into three categories.

• Ground-breaking development hotspots. They include “Precision irrigation” in agricultural engineering, “Animal stem cells” in veterinary medicine, and “New genetically modified varieties” in agricultural bioengineering.

• Hotspots involving in-depth traditional research. They include “Pesticide pollution and prevention” of plant protection, “Facility agriculture” and “Agricultural machinery improvement” of agricultural engineering, “Animal viral vaccine” in veterinary medicine, “Microbial fertilizer” in agricultural resource science, and “Biomass energy and materials” in forestry engineering.

• Emerging development hotspots. They include “Intelligent agricultural equipment” in agricultural engineering.
The hotspot “Agricultural machinery improvement” has produced a relatively high number of patents (> 600). However, the highest patent citation frequency is found in the hot topic “Animal stem cells” in veterinary medicine (up to 3651 times). The average citation frequency of all hotspots are approximately five times. Among them, the highest and the lowest average citation frequency  of patents are in “Pesticide pollution and prevention” (approximately 10 times) and “New genetically modified species” (less than twice), respectively. The mean year (average publication year) of patents is mainly concentrated from 2012–2013 (Table 2.1.1). The number of patents in the hotspots “Pesticide pollution and prevention” and “New genetically modified varieties” in plant protection has shown a regular downward trend (Table 2.1.2).
Brief descriptions of the top 10 engineering develop- ment hotspots are as follows.

2.1.1 Intelligent agricultural equipment

This is a emerging development hotspots in agricultural engineering. Intelligent agricultural equipment combines the advanced manufacturing, information, and artificial intelligence technologies. It is an important tool for up- grading traditional agricultural machinery manufacturing with the aim of achieving intelligent automation of agri- cultural production processes. Moreover, it has become an important direction for the development of international high-end agricultural equipment manufacturing industry.

《Table 2.1.1》

Table 2.1.1 Top 10 engineering development hotspots in agriculture

No. Engineering development hotspots Published patents Citation frequency Average citation frequency Mean year
1 Intelligent agricultural equipment 142 685 4.82 2013.37
2 Precision irrigation 261 842 3.23 2013.37
3 Pesticide pollution and prevention 160 1481 9.26 2012.11
4 Facility agriculture 226 634 2.81 2012.99
5 Agricultural machinery improvement 606 1326 2.19 2013.49
6 Animal stem cells 473 3651 7.72 2012.26
7 Animal viral vaccine 264 1232 4.67 2012.29
8 Microbial fertilizer 315 1908 6.06 2012.59
9 New genetically modified varieties 105 154 1.47 2012.11
10 Biomass energy and materials 154 806 5.23 2012.75

《Table 2.1.2》

Table 2.1.2 Annual number of core patents belonging to each of the top 10 engineering development hotspots in agriculture

No. Engineering development hotspots 2011 2012 2013 2014 2015 2016
1 Intelligent agricultural equipment 23 19 27 34 33.00 6
2 Precision irrigation 32 52 44 71 45.00 17
3 Pesticide pollution and prevention 46 66 36 9 3.00 0
4 Facility agriculture 48 45 44 44 40.00 5
5 Agricultural machinery improvement 58 99 134 139 155.00 21
6 Animal stem cells 151 162 72 67 18.00 3
7 Animal viral vaccine 81 80 62 30 9.00 2
8 Microbial fertilizer 61 88 100 51 14.00 1
9 New genetically modified varieties 30 37 35 2 1.00 0
10 Biomass energy and materials 36 37 28 35 18.00 0

At present, the intelligent control of agricultural equip- ment focuses on the in-depth exploration of various sen- sors, communication systems, image processing, computer vision, and other information technologies, including the sensors used in vehicle steering control, the level control for the lifting and lowering of ground working parts of ve- hicles, and the electro-hydraulic control of vehicle position with pressure and depth. Furthermore, the focus includes the image sensor monitoring system for plant/crop char- acteristics, such as the maturity of fruits, vegetables, and other agricultural products in addition to equipment in- tegrating image processing and visualizing sensing func- tion (automatic visual monitoring system) for thinning out seedlings and weeding. Further, the focus includes the collaborative control of vision and image processing technology (e.g., stereoscopic vision system) on harvest- ers and transport trucks in a coordinated multi-machine system, the radio load control of harvester grain silos, the improvements in the grain push controllers with control- lable pushing speed, the threshing mechanism combine harvester, and the performance of grain storage container. Intelligent agricultural equipment can meet the different levels of demand. They can be integrated with advanced technologies and information, including intelligent equip- ment, digital design and simulation systems, intelligent equipment testing platform, micro-electromechanical system agricultural sensors, agricultural robots, intelligent navigation control technology, the internet of things, big data, and cloud computing, and cloud service is the main direction of intelligent agricultural equipment research in the future.

2.1.2 Precision irrigation

This is a ground-breaking development hotspot in agricultural engineering. At present, water shortages have become the most important limiting factor in glob-  al agricultural production. In accordance with the crop growth needs, precision irrigation achieves the intelligent monitoring of water, fertilizer, gas, heat, light, and other crop growth factors, and uses water-saving irrigation fa- cilities to provide the most appropriate amount of water supply to crops for achieving the optimal growth status. The application of precision irrigation can significantly improve the yield and quality of agricultural products, and contribute to achieving the water-saving, fertilizer-saving, labor-saving, high yield, and environmental protection goals. In the agricultural productions of Africa, the Mid- dle East, Central Asia, and other arid and semi-arid areas, efficient use of water resources is the primary research topic. Based on the previous technical integration and the degree of mechanization, the performance of the irrigation controller in agricultural precision irrigation technology is more accurate (e.g., on-demand water input, which can be detected and controlled precisely), and the water-saving effect is more significant. E.g., an irrigation controller that automatically adjusts the progress of irrigation wa- ter according to the budget, the irrigation controller that automatically adjusts the water outflow according to the progress of irrigation and the irrigation system based on the theory of evapotranspiration (i.e., control of irrigation water outflow through the information transmitted by evapotranspiration units).

2.1.3 Pesticide pollution and prevention

Pesticide pollution and prevention is a hotspot in the discipline of plant protection, which involves in in- depth traditional research. Pesticide pollution refers to the excessive use of pesticides and improper selection of pesticide type and application time, which lead to exces- sive pesticide residues in agricultural products, thereby causing serious harm to human health. Some natural ene- mies (predators and parasites) of pests are killed, thereby disrupting the balance between pests and their natural enemies, and a rapid pest population growth. Meanwhile, the pollinating insects are killed, which affects the crop yield. Excessive pesticides enter the soil and water owing to rainfall, farmland percolation, and drainage, thereby damaging the ecosystem. The integrated prevention and control technology includes agricultural, biological, chem- ical, physical, and other methods of control. Low toxicity and biological control are the preferred research and de- velopment directions of plant protection.

2.1.4 Facility agriculture

Facility agriculture is a hotspot in agricultural engineer- ing involving in-depth traditional research. Facility agri- culture refers to a modern agricultural approach that uses engineering techniques for efficient production of animals and plants under a relatively controllable condition. Facil- ity agriculture covers facility cultivation, facility breeding, facility-produced edible fungi, etc. Modern greenhouse and plant factory are two important areas of the research on facility agriculture intelligence. Compared with the modern greenhouse, a plant factory that can avoid the field production environment is a higher level of develop- ment of facility agriculture. Among them, the collection and monitoring of environmental and biological informa- tion, intelligent system control platform, biologically stan- dardized and pipelined production management model, and the development of the quality traceability system of agricultural products based on the internet of things will be the core hotspots in future.

2.1.5 Agricultural machinery improvement

This is a hotspot in agricultural engineering involving in-depth traditional research. The focus includes the con- tinuous improvement and manufacturing of advanced agricultural machinery and equipment, with the ultimate aim of improving agricultural production and manage- ment, and continuously enhancing the level of agricultural production technology, economic benefits, and ecological benefits. In addition, the comprehensive integration of the specialization, automation, information technology, and other core technologies of agricultural machinery is an im- portant direction for development.

2.1.6 Animal stem cells

It is a disruptive development hotspot in veterinary medicine. Animal stem cells are cells with an ability of self-replication under certain conditions. They can differ- entiate into a variety of functional cells. According to their developmental stages, the stem cells are divided into em- bryonic stem cells and adult stem cells. According to their developmental potential, stem cells are divided into three categories: totipotent stem cells, pluripotent stem cells, and unipotent stem cells (monopotent stem cells). Stem cells are cells that are immature and not fully differentiated, possess- ing the potential to regenerate living organisms, various tissues, and organs. The animal models that have a close genetic relationship with human, such as cloned pigs, can grow organs and tissues suitable for humans, and cloned macaques can be used to test diabetes and other illnesses.

2.1.7 Animal viral vaccine

This is a hotspot belonging to the discipline of animal husbandry and involving in-depth traditional research. Vaccine refers to a biological agent that is used to inocu- late living organisms, displays antigenicity, and is used   to prevent and control the occurrence of infectious dis- eases. The types of viral vaccines include: (1) traditional vaccines, such as inactivated vaccines, attenuated live vaccines, and subunit vaccines, and (2) new viral vaccines, such as gene-deficient live vaccines, virus-like particles, nucleic acid vaccines, and live viral vectors. The new vi- ruses that are constantly emerging pose a huge challenge for researchers to develop drugs or vaccines.

2.1.8 Microbial fertilizer

This is a hotspot in agricultural resource science involv- ing in-depth traditional research. Microbial fertilizers refer to a type of biological products that use microbial activi- ties for allowing crops to access a specific fertilizer. There are three categories: microbial agents, composite microbial fertilizer, and bioorganic fertilizer. They are used to inhib- it the crop pests and diseases effectively or to provide nu- trients and other growth-promoting substances to crops, to adjust and control the growth, enhance disease resis- tance, and increase the crop yield or crop quality. With the development of organic ecological agriculture, increasing attention will be paid to the use of microbial fertilizers.

2.1.9 New genetically modified varieties

This is a disruptive development hotspot in agricultural bioengineering. To obtain new genetically modified variet- ies, the useful target gene is isolated from donor organisms and introduced into the recipient animals and plants di- rectly or through DNA recombination and genetic transfor- mation. After screening, the genetically modified organism with a stable expression is obtained, and it can be produced by testing and selective breeding. In recent years, the ge- netic characteristics of organisms have been altered by pro- cesses such as gene knockout, and silence of genes to obtain the desired traits and breed new varieties. A large number of new cotton, corn, soybeans, and other crop varieties are reported from abroad; in addition, transgenic research on pigs, cattle, sheep, and other animals has been reported. The application of transgenic technology and the breeding of new varieties are the most popular and advanced re- search and development fields in the world.

2.1.10 Biomass energy and materials

This is a hotspot in forestry engineering involving in- depth traditional research. Biomass energy is the form of energy, in which the solar energy is stored as chemical energy, i.e., the biomass acts as the energy carrier. It is derived directly or indirectly from the photosynthesis of green plants and can be converted into conventional solid, liquid, and gaseous fuel. Biomass energy devel- opment technology is currently focusing on gasification, compressed fuel, combustion power generation, and the production of fuel ethanol and biodiesel. Among them, biomass gasification fuel and biomass compression mold- ing techniques have matured from the traditional re- search content. In terms of combustion power generation, high-efficiency direct-fired power generation is consid- ered the most viable way of biomass utilization and is an important future development direction. The current con- version efficiency in the production of fuel ethanol with forest waste as raw material is still low; this technique is still in the experimental stage, and the development of ethanol production technique using lignocellulose as raw material will be the focus of future research and devel- opment. The extraction of biodiesel from tree seeds with high oil content is still in the exploratory stage, and it is too early for industrial production. However, it is one of the key directions of future research and development.

《2.2 Understanding of engineering development focus》

2.2 Understanding of engineering development focus

2.2.1 Intelligent agricultural equipment

The focus of intelligent control technology for agricul- tural equipment is the in-depth explorations of various sensors, communication systems, image processing, com- puter vision, and other information technologies.

The countries or regions producing the core patents are China and the USA (Table 2.2.1). The number of core pat- ents of China and the USA account for approximately 75%

《Table 2.2.1》

Table 2.2.1 Major producing countries or regions of core patents on the engineering development focus “Intelligent agricultural equipment”

No. Country/Region Published patents Proportion of published patents Citation frequency Proportion of citation frequency Average citation frequency
1 China 107 75.35% 456 66.57% 4.26
2 USA 28 19.72% 210 30.66% 7.5
3 Korea 3 2.11% 14 2.04% 4.67
4 Canada 1 0.70% 3 0.44% 3
5 UK 1 0.70% 2 0.29% 2
6 Israel 1 0.70% 1 0.15% 1
7 Italy 1 0.70% 0 0.00% 0
8 New Zealand 1 0.70% 2 0.29% 2

《Table 2.2.2》

Table 2.2.2 Major producing institutions of core patents on the engineering development focus “Intelligent agricultural equipment”

No. Institution Published patents Proportion of published patents Citation frequency Proportion of citation frequency Average citation frequency
1 Hunter Ind 5 3.52% 51 7.45% 10.2
2 Skydrop LLC 3 2.11% 5 0.73% 1.67
3 China Agric Univ 3 2.11% 18 2.63% 6
4 Kunming Univ Sci & Technol 3 2.11% 6 0.88% 2
5 Shandong Agric Univ 3 2.11% 8 1.17% 2.67
6 Valmont Ind Inc. 3 2.11% 7 1.02% 2.33
7 Beijing Res Cent Intelligent Equip Agric 2 1.41% 7 1.02% 3.5
8 Jiangsu Guanjia Water Conservancy 2 1.41% 6 0.88% 3
9 Nat Diversified Sales Inc. 2 1.41% 9 1.31% 4.5
10 Rain Bird Corp 2 1.41% 24 3.50% 12

and less than 20%, respectively. However, the opposite situation is observed in the average citation frequency of core patents, with the USA and China accounting for 7.50 and 4.26, respectively. These findings indicate that the patents of the USA are low in a number, but influential. Hunter Ind. and Rain Bird Corp. in the USA, and China Agricultural University have a high core patent citation frequency and show a significant impact (Table 2.2.2). The USA and Canada have some cooperation, but no cooper- ation is observed among the top 10 research institutions (Figure 2.2.1 and Figure 2.2.2).

2.2.2 Precision irrigation

Owing to previous technical integration and the degree of mechanization, the performance of the irrigation

《Figure 2.2.1》

Figure 2.2.1 Collaboration network of the major producing countries or regions of core patents on the engineering development focus “Intelligent agricultural equipment”

《Figure 2.2.2》

Figure 2.2.2 Collaboration network of the major producing institutions of core patents on the engineering development focus “Intelligent agricultural equipment”

controller in agricultural precision irrigation technology (e.g., on-demand water input is more accurate, and the water-saving effect is more significant. Examples include the irrigation controller that automatically adjusts the progress of irrigation water according to the budget, the irrigation controller that automatically adjusts the water outflow according to the progress  of irrigation, and the irrigation system based on the theory of evapotranspiration (i.e., control of irrigation water outflow based on the information transmitted by evapotranspiration units).
In this research area, China has the  highest number of core patents and is dominant (Table 2.2.3). Japan, Germany, and the USA have only a few patents, but a high average citation frequency. The average citation frequency of the Japanese patents is 4.79 times, whereas that of the Chinese patents is 3.17 times. The Nanjing Research Institution for Agricultural Mechanization (NRIAM) of the National Ministry of Agriculture and seven other Chinese institutions are among the top 10 organizations, and the other two organizations are a Jap- anese and an Austrian company (Table 2.2.4). Among the top 10 countries or regions, only Germany and Den- mark have cooperation; among institutions, only Qing- dao Agricultural University and a company in Qingdao (Qingdao Hongsheng Auto Fittings Co. Ltd.) have some cooperation (Figure 2.2.3 and Figure 2.2.4).

2.2.3 Pesticide pollution and prevention

The prevention and control techniques for pesticide

《Table 2.2.3》

Table 2.2.3 Major producing countries or regions of core patents on the engineering development focus “Precision irrigation”

No. Country/Region Published patents Proportion of published patents Citation frequency Proportion of citation frequency Average citation frequency
1 China 208 79.69% 659 78.27% 3.17
2 Japan 19 7.28% 91 10.81% 4.79
3 Germany 6 2.30% 18 2.14% 3
4 USA 6 2.30% 22 2.61% 3.67
5 Korea 5 1.92% 10 1.19% 2
6 Austria 4 1.53% 10 1.19% 2.5
7 Russia 4 1.53% 5 0.59% 1.25
8 France 2 0.77% 7 0.83% 3.5
9 Belgium 1 0.38% 5 0.59% 5
10 Denmark 1 0.38% 2 0.24% 2

《Table 2.2.4》

Table 2.2.4 Major producing institutions of core patents on the engineering development focus “Precision irrigation”

No. Institution Published patents Proportion of published patents Citation frequency Proportion of citation frequency Average citation frequency
1 Min Agric Nanjing Res Inst Agric Machinery 6 2.30% 18 2.14% 3
2 Qinghai Agric & Husbandry Machinery Mfg 6 2.30% 19 2.26% 3.17
3 Kubota Corp 5 1.92% 21 2.49% 4.2
4 Shandong Changlin Agric Equip Co., Ltd. 5 1.92% 19 2.26% 3.8
5 Qingdao Agric Univ 5 1.92% 11 1.31% 2.2
6 Alois Pöttinger Maschinenfabrik GmbH 4 1.53% 10 1.19% 2.5
7 Qingdao Hongsheng Auto Fittings Co., Ltd. 4 1.53% 21 2.49% 5.25
8 Henan Univ Sci & Technol 4 1.53% 13 1.54% 3.25
9 Chery Heavy Industry Co., Ltd. 3 1.15% 6 0.71% 2
10 Chongqing Standard Machinery Mfr Co., Ltd. 3 1.15% 6 0.71% 2

《Figure 2.2.3》

Figure 2.2.3 Collaboration network of the major producing countries or regions of core patents on the engineering development focus “Precision irrigation”

《Figure 2.2.4 》

Figure 2.2.4 Collaboration network of the major producing institutions of core patents on the engineering development focus “Precision irrigation”

pollution include the following aspects: (1) Agricultural control—the use of crop rotation, selection of new pest and disease resistant varieties, and reasonable control of fertilizer and water to improve crop resistance to pests and diseases; (2) Biological control—the use of natural enemies for pest control, the use of insects, bacteria, animals and plants, and other organisms for weed control, and the use of biological pesticides for pest control; (3) Chemical control—the disease, insect, and weed forecasts, achieving timely control, and reasonable mix  and  alternate use  of  less-persistent pesticides; (4) Physical control—the use of mechanical or hand control, syrup and light trapping, manual weeding, mechanical weeding, etc. At present, the use of low toxicity and less-persistent pesticides is the dominant control technique.

The countries mainly producing the core patents on this focus are China, the USA, and Germany (Table 2.2.5). China has the largest proportion of published pat- ents and has approximately the same average citation frequency as other countries have. Among the major organizations owning the core patents (Table 2.2.6), six institutions in Guangxi and Guangdong of  China have  a high number of patents, and one institution each from Germany, the USA, France, and Switzerland is among the top 10 organizations. The USA and France remain the main cooperating countries, and China mainly co- operates with Germany (Figure 2.2.5). However, there is no cooperation mechanism among the top 10 research institutions (Figure 2.2.6).

《Table 2.2.5 》

Table 2.2.5 Major producing countries or regions of core patents on the engineering development focus “Pesticide pollution and prevention”

No. Country/Region Published patents Proportion of published patents Citation frequency Proportion of citation frequency Average citation frequency
1 China 121 75.63% 1148 77.52% 9.49
2 USA 22 13.75% 177 11.95% 8.05
3 Germany 15 9.38% 153 10.33% 10.2
4 Switzerland 6 3.75% 60 4.05% 10
5 France 6 3.75% 46 3.11% 7.67
6 Canada 3 1.88% 24 1.62% 8
7 UK 3 1.88% 29 1.96% 9.67
8 Italy 2 1.25% 7 0.47% 3.5
9 Belgium 1 0.63% 6 0.41% 6
10 Finland 1 0.63% 12 0.81% 12

《Table 2.2.6》

Table 2.2.6 Major producing institutions of core patents on the engineering development focus “Pesticide pollution and prevention”

No. Institution Published patents Proportion of published patents Citation frequency Proportion of citation frequency Average citation frequency
1 Guangxi Idyllic Biochemistry Co., Ltd. 20 12.50% 277 18.70% 13.85
2 BASF SE 13 8.13% 122 8.24% 9.38
3 Guangdong Zhongxun Agric Sci Co., Ltd. 7 4.38% 55 3.71% 7.86
4 Dow Agrosciences LLC 6 3.75% 57 3.85% 9.5
5 Nanning Defengfu Chem Co., Ltd. 5 3.13% 42 2.84% 8.4
6 HSP Crop Technology Co., Ltd. 4 2.50% 27 1.82% 6.75
7 Nantong Liannong Pesticide Preparation 4 2.50% 45 3.04% 11.25
8 Hebei Bojia Agric Co., Ltd. 3 1.88% 45 3.04% 15
9 Rhodia Operations 3 1.88% 12 0.81% 4
10 Syngenta Participations AG 3 1.88% 36 2.43% 12

《Figure 2.2.5》

Figure 2.2.5 Collaboration network of the major producing countries or regions of core patents on the engineering development focus “Pesticide pollution and prevention”

《Figure 2.2.6》

Figure 2.2.6 Collaboration network of the major producing institutions of core patents on the engineering development focus “Pesticide pollution and prevention”

 

 

Project Participants

Members of the Field Group

Leaders of the Field Group:

KANG Shaozhong, LI Zhaohu, DENG Xiuxin

Other Members:

LIU Xu, ZHAO Yaofeng, HUANG Haitao, ZHANG Wentao, WANG Qing, WEN Danyan, XU Jianxiang, YUAN Wenye, LI Chenying, SHI Lijuan, YANG Aidong, WANG Yan, XING Lu

 

Report Writers

KANG Shaozhong, YUAN Wenye, SHI Lijuan, XU Jianxiang, YANG Aidong, WANG Yan, XING Lu
 

《Acknowledgments》

Acknowledgments

This report was completed with the support from the project “Strategic Consulting and Research of Global Engineering Focus” in the Chinese Academy of Engineering, under the guidance and help of the project integration group. The data were processed and provided by Clarivate Analytics (Beijing). QIAN Xuhong, ZHENG Wenjiang, and MU Zhirui from the project integration group, and JIANG Zhiqiang, ZHOU Weixing, JI Jiuming, and other teachers from the East China University of Science and Technology helped in report writing, chart plotting, etc. Further, we thank the members from the Standing Committee of Agriculture Faculty of Chinese Academy of Engineering, and the academicians and experts of the relevant fields in the selection of hotspots and focus.