Agricultural production process requires, except of optimal use and combination of inputs, also the effective utilization of other aspects such as technological innovations, the experience and ability of those employed in the agricultural sector, but also the consideration of elements related to the economic circumstance that characterize economies both individually and globally. Moreover, a list of unprecedented economic, social and environmental conditions, such as financial crisis phenomena, farmers and consumers income inequalities and climate change, have shaped a complex environment for agricultural production. Based on the above, decisions are made regarding the use of the appropriate quantities, but also the type of production factors, with the ultimate goal of economic efficiency of the agricultural sector. These choices on production factors are not just technical decisions, but refer to the adaptation of agriculture to ever-changing challenges. As farmers face extensive changes in market conditions, technological capabilities offered and political regulations, the selection of production factors must be performed, considering their interaction.
In this context, capital is a decisive factor for agricultural production, performing a dual role as a source of financing and as a shaper of production processes. Technological progress and innovation require frequent investments in fixed capital, such as equipment and machinery, with the aim of improving efficiency along with the use of sustainable production methods (Crespi & Zuniga, 2012; Gann, 2000) in the most sectors, hence also in agriculture. Moreover, labor productivity, is also a crucial factor for the efficient implementation of agricultural activities, affecting the output quantity and quality but also production costs, which are besides affected by the nature of materials used (Akram, 2019), such as fertilizers, pesticides and seeds, costs of renting land, wages of dependent labor (Jayachandran, 2006) and intermediate consumption elements in general. Nevertheless, the selection of the amount of labor and variable inputs used in the production process is carried out on the basis of the given potential provided by the existing fixed capital, creating a relationship of interaction with it.
The Cobb-Douglas production function is considered as a useful tool for modeling the interaction between factors of production as it expresses the relationship between the quantity of production outputs and the inputs used in it. The efficiency of the Cobb-Douglas function is based on the fact that it can provide a reliable representation of the production process by estimating the contribution of each input to the total output produced, the corresponding returns to scale, the marginal productivity of production factors used and their marginal rate of substitution (Fuss & McFadden, 1978). The application of the Cobb-Douglas production function to agricultural production has been a subject of intense academic research in exploring the relationship between inputs and agriculture output, as is one of the most widespread production functions in economic logic, as it offers simplicity and flexibility in the econometric modelling.
Within this framework, Armagan and Ozden (2007) argued that the Cobb-Douglas production function estimation is suitable for the efficient analysis of agricultural activities, as it is characterized by ease of calculations and capability of statistical testing of production flexibilities, pointing that this approach addresses the concept of productivity and efficient use of inputs through the integration of the output function based on the inputs used. This particular methodology was enthusiastically supported in a recent article by Faruq-Uz-Zaman (2021), who also highlights the advantage that it provides for the calculation of marginal productivity in production. Based on this and using data set related to crop production in Bangladesh, used land area coverage under cultivation, the proportion of the population engaged in agriculture, household spending as a proxy for capital input, the amount of fertilizer used per hectare of land, and the total cultivated land area under irrigation as inputs, in order to estimate its impacts on agriculture output. Their results showed a particular inefficiency of the use of inputs, noting negative returns on the scale with elasticity equal to -0.977, which is mainly due to the negative marginal productivity of cultivated land and labor, emphasizing the non-rational use of those production factors.
In fact, the negative effect of labor growth on agricultural production was clearly confirmed by Echevarria (1998), who used data for the period 1971 to 1991 for Canada and Cobb-Douglas equation, comparing the agricultural sector with those of services and industry, as she determines the less need of the agricultural sector for labor and the particular importance of using technological innovations, as they positively affect productivity. Similarly, Mundlak et al. (1999) use panel data of the period 1967 to 1992 for 57 countries, suggesting that agriculture production should rely to a greater extent on its extensive industrialization as output is relatively less influenced by changes in labor compared to capital used, indicating also that adopting more efficient production methods is linked to a reduction in labor, signifying a shift towards technology that reduces the need for labor.
Yuan (2011), uses data from 1999 to 2008 for Hebei Province China by estimating a Cobb-Douglas production function, where independent variables consist of cultivated land area, effective irrigation area, chemical fertilizer usage, agricultural machinery power, rural electricity consumption, and manpower. Effective irrigation area appears as the most influential factor on agricultural production, followed by chemical fertilizer usage and farm labor, with cultivated land area, electricity consumption, and farm machinery power showing less but also positive impact on output and overall input elasticity indicating decreasing returns to scale, with a value of 0.56.
Dawson and Lingard (1982), investigate the relationship between various input factors and total revenue in agricultural output, using a Cobb-Douglas production function. The study employs Ordinary Least Squares and covariance analysis to estimate the elasticities and marginal productivity of labor, total wage-bill, machinery costs, livestock costs, crop costs, general farming costs, rent, and land area which are set as independent variables, using total revenue as dependent variable. The results emphasize the special role of labor, but also of raw materials, as their increase leads to increased productivity, while a similar but less important is the effect of investments in fixed capital. Nevertheless, decreasing returns on the scale of variable inputs are observed, and thus a relatively reduced efficiency of the use of production factors is signaled.
A study by Ghoshal and Goswami (2017), referring to efficiency of agricultural production in regions of India, using Stochastic Frontier Analysis with the help of Cobb-Douglas production function, in panel data for the period 2005 to 2014, found matching results. The average annual efficiency ranged from 0.376 to 0.882, for the different regions of the country, also indicating inefficiency in the use of production inputs, with the variable inputs of the amount of fertilizers and pesticides being the most important in increasing output, which it is also positively affected by the presence of an extensive network of public infrastructure, such as total state road length per unit of cultivated area. In fact, this particular element was also observed by Mamatzakis (2003), who used data concerning the Greek agricultural sector for the period 1960 to 1995, estimating with the use of the I3SLS method a translog cost function. The study, fount that the improvements in public infrastructure reduce marginal variable costs, while on the contrary there is a positive impact of public infrastructure on the advancement of productivity in the Greek agricultural sector.
Competitiveness and Productivity Challenges in Greek Agriculture
Greece's accession to the European Union in 1981, had a catalytic impact on the subsequent evolution of Greek agriculture. The full integration and implementation of the Common Agricultural Policy created the conditions, through measures such as price guarantees and the application of structural policies, for the transition of the rural economy from primitive self-sustaining engagement to modern entrepreneurial agricultural economy. Tangible outcomes for farmers were already noticeable during the adjustment period in 1978 and onwards. Today, agriculture is fully governed by the rules of the CAP, shaping and controlling the entire framework of operation and activity in the agricultural sector. Over approximately four decades of CAP implementation, significant changes have been observed in the Greek rural economy. The most noteworthy of these changes concern employment, production structure, prices, and rural incomes. The implementation of CAP resulted in substantial improvements in producer incomes through subsidies and played a key role in development in rural areas of the country. However, the periodic revisions of CAP had a significant impact on the Greek economy, often imposing limitations on the external trade of agricultural and livestock products, while simultaneously redirecting production away from market demands.
According to Hellenic Statistics Authority data, the 1980s represent the most prosperous decade for Greek agriculture in terms of real producer prices and agricultural production value. During the 1990s, production volume stabilized, while real prices progressively declined. Labor productivity during the 1980s increased at an annual rate of 4.9%, and in the 1990s, it stabilized at slightly higher levels despite a significant reduction in the workforce, which decreased from 31.6% of the total workforce in Greece in 1980 to 18% in 2000. After 2000 until 2010, employment and Gross Value Added in the Greek agricultural sector exhibited a steady decline, resulting in a significant reduction in agricultural GDP. Simultaneously, the 2007 crisis, coupled with the decrease in private investments in agriculture, resulted in low overall performance and competitiveness of the primary sector (Kassimis & Papadopoulos, 2013). These challenges have persisted in the long term, leading the country to exhibit a deficit in the trade balance of agricultural products throughout the 2010s and up to date. As a result, today, Greek agriculture contributes only 3.6% to the country's national GDP, with the total value of Greek agricultural production amounting to 12 billion euros, indicating that it lags behind in competitiveness in the international market.
Hence, enhancing competitiveness and productivity in the agricultural sector remain key challenges for the future of Greek agriculture, as they determine its ability to penetrate international markets. However, as producer prices generally show a downward trend and considering the departure of a significant portion of the workforce from the agricultural sector, the further contraction of production is not unlikely unless there are drastic improvements in the productive structures of the Greek agricultural sector and the modernization of all other factors involved in the production and marketing of agricultural products.