3.1. Research Methodology
The Cobb–Douglas production function is a fundamental tool in economic theory, offering insights into production behavior, profit maximization, and cost structure across various industries [
30]. Building upon the quantitative method established by Jungmittag et al. [
12], this study utilized a simple Cobb–Douglas production function to investigate agricultural standardization’s contribution to China’s agricultural development.
To clarify the mechanism by which agricultural patents and standards influence agricultural production, this study introduces them as distinct inputs in the production function. Both represent key dimensions of technological progress, yet they differ in terms of accessibility and application. Agricultural patents protect technological innovations through legal rights, granting exclusive use to inventors for a limited time. In contrast, agricultural standards are public documents, typically developed through consensus among stakeholders and approved by regulatory bodies, facilitating widespread access and adoption [
31].
Patents and standards reach the agricultural sector through different pathways. Patents often lead to the development and commercialization of new agricultural technologies and products, such as water-saving irrigation systems, pest-resistant genetically modified seeds, and intelligent farming machinery. These innovations are transferred to farmers via technology licensing, enterprise-led commercialization, and government-supported extension services. Their application directly enhances agricultural productivity by increasing efficiency, reducing input costs, and improving crop yields. Agricultural standards, on the other hand, focus on the diffusion and standardized application of advanced technologies and best practices. They promote consistent production processes, ensuring quality control, safety compliance, and environmental sustainability. By reducing information asymmetry and transaction costs, standards facilitate large-scale technology dissemination across regions and farming entities. This improves resource allocation efficiency, lowers production risks, and reduces the overall cost of agricultural production.
Although technological progress in agriculture encompasses many aspects—including improvements in production techniques, cultivation methods, pest control, fertilization programs, and farm management practices—these factors are often difficult to quantify and incorporate into empirical research. This study does not explicitly quantify the impact of changes in fertilization or crop protection intensity, which could influence productivity. Future research could explore these effects to provide more comprehensive policy insights. Patents and standards are widely used as measurable and accessible indicators of technological progress. In this study, patents reflect the sector’s capacity for innovation, while standards represent its ability to diffuse and institutionalize technological advancements. Together, they play a crucial role in optimizing resource use, enhancing production efficiency, and promoting sustainable agricultural development.
The Cobb–Douglas production model for agricultural standardization and agricultural development is assumed as follows:
In Equation (1), represents time, where . Among all the variables, “A” simply represents agriculture. represents the output of the agriculture sector, including agriculture, forestry, animal husbandry, and fisheries, in period . The value of agricultural sector output serves as a key indicator of the sector’s overall development over the study period. In this study, is treated as a constant, representing the level of change in agricultural technology during period . represents agricultural capital input, represents agricultural labor input, represents the stock of agricultural standards, and represents the stock of agricultural patents at time . The superscripts , , , and represent the respective production elasticities.
To address heteroskedasticity, we take the natural logarithm of each side of Equation (1) simultaneously and add the regression error term
to the right side. The new regression model is shown in Equation (2):
In Equation (2), the production elasticity coefficient represents the impact of agricultural standardization on agricultural development. Through parameter estimation, the value of can be obtained. If , it indicates that agricultural standardization has a positive impact on agricultural development. Conversely, if , it suggests that agricultural standardization hurts agricultural development. If , it indicates that agricultural standardization does not affect agricultural development. Furthermore, the magnitude of reflects the strength of the effect.
3.2. Variable Selection and Data Processing
- (1)
Indicator of Agricultural Output (ACt)
The output of agriculture is typically measured using the primary sector value added. The primary sector encompasses agriculture, forestry, animal husbandry, and fishery in China’s industrial classification. Therefore, the agricultural added value of these industries is chosen as the measure of agricultural output. However, using calendar year value added presents challenges due to associated data-processing issues, particularly the influence of inflation. The presence of inflation would lead to a biased determination of agricultural output. This ultimately affects the accuracy of the model estimates.
The nominal value added of the primary sector is transformed into constant prices. This transformation can mitigate the effects of inflation and ensures comparability across calendar years. This transformation process involves several steps. Firstly, time-series data of the nominal value added of the primary sector (in billions of yuan) and value-added index (prior year basis, set to 100) for all years from 2003 to 2019 are obtained from the
China Statistical Yearbook. Secondly, the base period, which is set to the year 2003, serves as the reference point for the transformation. The base period price is used as the standard for the transformation. Consequently, the value added of the primary sector at constant prices for the years 2004 to 2019 is calculated using the following formula:
In Equation (3), represents the nominal value added of the primary sector in the base period, which is equivalent to the value added at . denotes the index of value added of the primary sector in period . represents the value added of agriculture, forestry, animal husbandry, and fishery in period at constant prices.
- (2)
Indicator of Agricultural Capital Input (AKt)
In recent research, capital inputs are usually measured by capital stocks. Initially, agricultural capital stock was chosen as the measure of agricultural capital input in this study. However, upon investigation, it was discovered that statistical data on the capital stock by sector of China’s national economy are not readily available. Given the absence of direct statistical data, calculations using the perpetual inventory method were deemed necessary. This approach considers the accumulation of fixed asset investment flows in previous periods as the current capital stock. This stock is extrapolated from data relating to capital formation, investment in fixed assets, and capital depreciation rates.
The data on investment in fixed assets (excluding farm households) in the primary sector which were applied in perpetual inventory method were obtained from the
China Statistical Yearbook. Similar to the method for calculating agricultural output, the perpetual inventory method requires the selection of a base period. Subsequently, the constant value of fixed asset investment (excluding farm households) and a depreciation rate were used to calculate the capital stock. The detailed calculation method is shown as follows:
The effective stock of capital in the base period is estimated as follows:
In Equation (4),
represents the capital stock in period
.
is the capital stock in period
.
denotes the investment in fixed assets in period
, converted to constant prices.
represents the depreciation rate of capital. In previous research focusing on China’s economic development, it has been generally accepted that the capital depreciation rate is a fixed value. Hall and Jones [
32] conducted a study involving 127 countries and found that a depreciation rate of 6% aligns better with reality and yields more accurate results. Therefore, this study adopts a depreciation rate of 6%.
In Equation (5), represents the effective stock of capital in the base period, while denotes the amount of investment in fixed assets in the base period. represents the arithmetic average of the growth rate of annual investment in new fixed assets from year 0 to year t. represents the depreciation rate of the capital stock.
- (3)
Indicator of Agricultural Labor Input (ALt)
This paper takes employment in the primary sector from 2004 to 2019 as a measure of agricultural labor input. The data on employment in the primary sector were directly obtained from the official data query platform “National Data”. This platform, under the purview of the National Bureau of Statistics of China, is tasked with organizing, leading, and coordinating national statistical work. The data provided by this platform are characterized by their truthfulness, accuracy, and timeliness.
- (4)
Indicator of Agricultural Patent Input (APATt)
Patents serve as a significant indicator of technological innovation [
33,
34]. The indicator of agricultural patent input used in the study is represented by the stock of active patents in agriculture over time. This stock is derived from the cumulative number of patents disclosed (published) in period
minus the number of patents that have lapsed in the current period, yielding the effective stock of patents in period
. The study encompassed four categories of patent: invention grant patents, utility model patents, invention application patents, and design patents. However, obtaining comprehensive patent data poses challenges, particularly regarding the amounts of patents disclosed and expired in a calendar year. Only the amount of patents for inventions granted in a calendar year can be obtained from publicly available statistical yearbooks and official data. To overcome these challenges, we decided to use the “Qizhidao” (Enterprise Knowledge) patent search platform operated by a Chinese company. By using the international IPC classification number “A01 (Agriculture)” as the search term, we accessed China’s domestic patent database and retrieved agricultural patents. Through further statistical analysis, we obtained the stock of patents in agriculture.
Preliminary analysis of the types of agricultural patents obtained revealed notable characteristics. Among all valid patents in agriculture in China, agricultural machinery patents accounted for approximately 25%, agricultural pesticides and other agricultural chemical products patents accounted for about 20%, and agricultural breeding and cultivation patents accounted for roughly 39%. These three categories of agricultural patents collectively comprised approximately 84% of all agricultural patents, indicating a concentration of patents across specific categories.
- (5)
Indicator of Agricultural Standard Input (ASTDt)
In China, standards are typically categorized into international standards and domestic standards, with domestic standards further subdivided into five categories: national standards, industry standards, local standards, group standards, and enterprise standards. Among these, national and industry standards hold broader applicability and are the primary focus of research on Chinese domestic standards. The indicator for agricultural standard input can be quantified by the stock of effective standards within a calendar year. This calculation involves subtracting the number of standards repealed or replaced from the cumulative number of standards implemented during the period. The stock of effective agricultural standards only contained national and industry standards. The National Standard Information Public Service Platform is the primary platform for accessing information about Chinese standards. This platform features clear categorization, unique numbering, and detailed publication and revocation dates for standards, ensuring accurate information retrieval. Access to agricultural standards is facilitated through specific selection criteria. Utilizing the International Standard Classification Number (ICS) “65. Agriculture” in the National Standard Catalog allows access to information about national agricultural standards, while information on agricultural industry standards is obtained through China’s industry standard classification number, which is “NY Agriculture”.
A preliminary examination of China’s national agricultural standards reveals notable characteristics. Agricultural and forestry standards constitute approximately 38% of the total, followed by agricultural machinery, tools, and equipment standards at around 21%. Standards for pesticides and other agrochemicals account for about 15%, while feed standards represent approximately 10%, and fertilizer standards comprise only 3%. This distribution highlights an imbalance in agricultural standards, with standards for agriculture and forestry and agricultural machinery, tools, and equipment comprising a significant proportion, almost 60%, of all national agricultural standards. In contrast, other types of standards are relatively scarce.
The initial data collected for this paper are shown in
Table 1. Data for five variables from 2004–2019 are included, and there are no missing values in the data.