Estimation of rice production function parameters
The estimation of rice production function parameters for 2018-2021 is presented in Table 2.
In addition to the estimated parameters shown in Table 2, the reliability of the Stochastic Frontier Analysis (SFA) model is evaluated through goodness-of-fit indicators. The Likelihood Ratio test (LR test) shows that the frontier model is significantly superior to the ordinary least squares (OLS) model, indicating that output variations do not only come from random disturbances, but are also influenced by technical inefficiencies. Furthermore, the obtained value of the gamma parameter (g) is close to 1, which confirms that the most significant proportion of the output variation is caused by technical inefficiency and not noise. This confirms the appropriateness of using the frontier approach in analyzing the efficiency of Indonesian rice farming during the pre-crisis period. Thus, these results strengthen the interpretation of the parameters presented and ensure that the model used has statistical credibility, allowing it to clearly separate production inefficiencies from random factors in the rice production system.
Table 2 shows that the harvested area coefficient ranges from 1.17 to 1.28 and is statistically significant (t-ratio > t-table in all years). This suggests that increasing the land area directly increases rice yields. This finding is consistent with studies by
Muhardi and Effendy (2021) and
Tondi et al., (2025), which state that land is the dominant input in food crop production. The variations of coefficients from 2018 to 2021 suggest that the influence of harvested area on rice production is not stable and may be conditioned by multiple factors. Variability in the efficacy of harvested area may arise from changes in weather patterns and irrigation availability, as well as the mobilization of new agricultural technologies between years
(Silfiani et al., 2024). Moreover, extreme changes in governmental policies, such as land use, subsidies and market access, may have contributed to the uncoupling of harvested area and rice yield
(Urrutia et al., 2017).
ZA fertilizer increases rice yield, as indicated by its positive coefficient in the rice production function from 2018 to 2021. This reflects the importance of nitrogen in rice production
(Dhakal et al., 2019). The interannual variability in the impact of ZA fertilizer can be attributed to several environmental and management factors
(Mirza et al., 2022; Vasuki et al., 2024). Soil conditions, weather patterns and water availability can influence the effectiveness of ZA fertilizer (
Devi and Sivakumar, 2022). Additionally, the timing and method of fertilizer application as well as the rice variety cultivated can also influence the crop’s response to ZA fertilizer
(Elekhtyar et al., 2023).
The positive impact of NPK fertilizer was consistently observed throughout. It is an NPK fertilizer, in which N stands for nitrogen, P stands for phosphorus and K stands for potassium. Changes in the coefficients over time interfere with the fertilizer management. These differences would be attributed to the contributing factors of soil fertility status, climate variation and crop management measures on the efficacy of NPK fertilizers
(Mirza et al., 2022; Devi and Sivakumar, 2022). The fertilizer applications (rates, timing and methods) can be adapted according to these factors
(Elekhtyar et al., 2023), resulting in high nutrient use efficiency of rice and maximizing its output with minimal environmental footprint.
The high coefficient of granular organic fertilizers reflects that they have a significant positive effect on rice yield
(Mirza et al., 2022). Soil structure, water retention and nutrient availability are enhanced by organic fertilizers, promoting optimal environmental conditions for rice plant development. Organic fertilizers that enhance soil physical, chemical and biological fertility levels have been proposed as the most suitable option to improve the long-term productivity of rice cropping systems (
Devi and Sivakumar, 2022). Moreover, application of organic fertilizers decreases the dependency on synthetic inputs and thus reduces environmental impacts (
e.g., GHG emission and water pollution)
(Elekhtyar et al., 2023; Ekaria et al., 2025).
The positive sign of the informal labor coefficient reflects its contribution to rice production (
Alam and Effendy, 2017). Informal labor, which includes family members and locally hired labor, is utilized to undertake a range of labor-intensive activities in rice production, such as planting, weeding, harvesting and post-harvest processing. Since the coefficient value is positive, increasing informal labor can enhance rice crop yield. In many regions with little advanced machinery, this non-capitalized labor is critical to conduct farming activities that are closely related to rice yield and productivity (
Liu and Li, 2023). The findings regarding the significant contribution of informal labor to productivity increases indicate that the rural labor structure remains a crucial factor in Indonesia’s rice production system. Therefore, this research can inform the government’s design of inclusive mechanization policies-for example, by providing agricultural machinery and training to enhance the technical competence of informal labor and support gradual agricultural transformation (
Custodio, 2025;
Chandra and Walia, 2025). Evidence from Vietnam suggests that farmer efficiency (technical/profitability) improves when financial constraints and business shock risks are addressed simultaneously with the adoption of variety and technology-a finding relevant for intervention design in Indonesia
(Nguyen et al., 2023). In Vietnam, a combination of small mechanization and training has also been found to increase the productivity of smallholder farmers. Thailand, on its part, has adopted strategies that promote public-private sector partnerships to enhance access to technology and market linkage. This comparison suggests that providing training programs and access to more affordable farm implements may be considered as potential strategies for improving the technical efficiency of rice production in Indonesia.
Impact of rice farming size on technical efficiency
The size of rice farming, expressed in terms of harvested area and technical efficiency, is presented in Table 3. The highest efficiency occurs in agricultural land with a harvested area of 1,214,851.23-1,822,088.90 ha. Rice farming with a larger harvested area has higher technical efficiency.
Table 3 shows that technical efficiency increases alongside land area, from 0.842 to 0.915. This supports the theory of “returns to scale”, where farmers with larger land areas have better access to technology, information and more efficient management (
Muhardi and Effendy, 2021;
Tondi et al., 2025). In contrast, small-scale farmers typically have limited access to essential agricultural inputs, including improved seeds, high-quality fertilizers and modern production tools (
Olubunmi-Ajayi, 2024). Financial constraints and restricted access to credit hinder them from investing in productive technologies.
Impact of rice farming area on technical efficiency
The technical efficiency of rice farming by region is presented in Table 4.
The variation of technical efficiency in rice production and harvesting among the regions in Indonesia is presented in Table 4. High Technical Efficiency Regions: DKI Jakarta: Despite the province having relatively limited agricultural areas, rice production is maintained efficiently through its urban farming program and increasing land use density
(Erissanti et al., 2021). Bali: The developed stage of the Subak system is a key factor in its success, as it incorporates local wisdom with modern agricultural systems, enabling sustainable water management and resource distribution (
Arisena and Dewi, 2017). Gorontalo has a good climate and fertile soil for growing rice (
Iskandar and Jamhari, 2020).
Areas of Low TE
West Kalimantan and Central Kalimantan face marginality, poor soil fertility, limited infrastructure and sociocultural constraints that result in inefficient agricultural cropping systems
(Mustapa et al., 2019). The observation of such a discrepancy suggests that other factors may be influencing or hindering efficacy in each region. High-efficiency areas were more likely to be the product of agricultural practice, infrastructure and policy development. Concerning low-productive areas, it is expected that farmers will have restricted access to technologies, inputs, capital and information.
Dynamic analysis: Development of technical efficiency of the rice farming business in 2018-2021
A dynamic analysis of the technical efficiency of the rice farming business is presented in Fig 1.
As shown in Fig 1, technical efficiency increased in some areas between 2018 and 2021, but decreased in others. This is representative of the variegated agro-climate and praxis within the archipelago
(Sumaryanto et al., 2023). Various factors, including rainfall distribution, soil type, temperature range, pests and disease pressure, influence rice productivity and the efficiency of resource utilization. Furthermore, efficiency can also be improved by the adoption of new technologies, growing practices and stronger policy support
(Liu et al., 2020; Tondi et al., 2025).