Evaluating Techno-Economic Efficiency of Irrigation Systems for Guava Orchards and Melon Crops in Punjab, Pakistan: A Beta-Regression Approach ^†

Abstract

Water scarcity is a global phenomenon, and Pakistan is no exception to it. This study aims to assess the techno-economic efficiency of the irrigation system for guava orchard and melon crop in the Hafizabad District of Punjab province in Pakistan. The study has employed efficiency theory for a comparative analysis of modern and high-efficiency irrigation methods in contrast to old traditional methods of irrigation to estimate differentiating impacts on technical efficiency (TE), economic efficiency (EE), water productiveness, and crop yield. The mixed method approach is exercised on data collected from 108 stratified farmers (large, medium and smallholders) using structured surveys and qualitative insights. Beta-regression models using Cauchit link function are applied to translate determinants of TE/EE by taking into account predictor factors such as farming experience, operational costs and water productivity. Results show that solar irrigation systems have significantly better performance than the conventional system by having better TE and EE scores than conventional system performance. Farming experience and water productivity also have positive effects on efficiencies. Results also show that solar systems increase water productivity, lower costs and increase guava and melon productivity to a significant extent, which in turns aid in reducing the effects of salinity and evaporation in arid conditions. The overall finding supports and emphasizes solar’s supremacy for sustainable horticulture. Findings highlight the importance of incentivizing solar adaptation and agrivoltaic integration in Pakistan to ensure sustainable agriculture in water-stressed areas such as Punjab for food security and resource conservation for the production of guava and melons.

1. Introduction

1.1. Global Scarcity Impacting Guava–Melon Yields

Water scarcity is a considerable challenge to the agricultural production of guava and melon among many other factors because of growing pressures resulting from climate change, population growth, overexploitation of water resources, etc. These factors contribute to water scarcity, both green and blue, that are critical for the irrigation of crops and overall agricultural productivity [1,2]. Guava, in particular, has been found sensitive to water stress and salinity with studies finding that the combined effect of high salinity levels with water stress can severely decrease growth, stress tolerance and physiological response, including the amount of chlorophyll content and photosynthesis rates. Guava plants struggle to survive in water-limited conditions where a salinity of more than 20 dS m⁻¹, particularly in water, is detrimental for growth, indicating that guava is only moderately salt-tolerant and needs careful water management to survive [3].

The bigger implications of a lack of water are especially extreme for smallholder farmers in areas such as Asia and Africa, where water availability is already limited in the face of environmental and social stressors. This limits the soundness of expanding irrigated areas and sustainable intensifications accordingly, which impacts the capacity of these farmers to meet increasing food demand [4]. To curb these challenges, innovative water management practices, including micro-irrigation and scheduling of irrigation, are key to emphasizing water use efficiency and guaranteeing the sustainability of guava and melon production in water-deficient lands [1,4].

1.2. Efficient Irrigation Boosting Arid Crop Resilience

Efficient irrigation is paramount in increasing the resilience of guava orchards and melon field production in arid areas through efficient water use, as well as enhancing the yield and quality of the crops under cultivation. Drip irrigation, in particular, has been proved to be highly efficient in increasing the water use efficiency, as well as the yield of guava orchards. The study indicates that the application of 100% crop evapotranspiration ETc through drip irrigation results in the highest guava yield with significant improvements in growth parameters and water productivity compared to furrow irrigation [5]. The strategic placement and discharge rate of drippers are key to obtaining maximum water distribution and root zone wetting, which was proven in guava orchards by optimizing locations and configurations of dripper over several years to improve the yield [6].

On top of that, incorporating soil moisture conservation methods, such as mulching, can further improve water conservation and soil health, resulting in improved guava yields in rain-fed conditions [7]. In melon fields, both the efficient scheduling of irrigation along with the selection of drought-resistant cultivars is of key importance. These practices along with advance technology (such as soil moisture sensors) assist in the precise application of water, thus conserving water and preventing problems such as water loggings [8]. Overall, following the integral approach of improving irrigation facilities, scheduling strategies and practising soil conservation practices can significantly improve the resilience and productivity of guava and melon crops in an arid environment [9].

1.3. Conventional Systems’ Flaws in Fruit Farming

Conventional irrigation systems used in fruit farming, especially for guava and melons, are characterized by some inefficiencies caused mainly by its inability to perfect the use of water and improve the yield effectively. In guava farming, the traditional furrow irrigation system has been found to decrease water use efficiency (WUE) and provide lower yield as compared to the drip irrigation system. For example, drip irrigation with 100% crop ETc yielded significantly higher guava harvest at 26.64 tons per hectare, while the yield recorded in furrow irrigation with 60% ETc was much less at 17.90 tons per hectare [5]. Drip irrigation also allows a better control over water distribution which is extremely important for optimizing the growth and yield of guava especially in sandy loam soils where the positioning and discharge rate of drippers is extremely important [7]. Moreover, deficit irrigation strategies coupled with mulching have been proven to increase water productivity and fruit quality for guava crop, which is suggestive of conventional systems not taking advantage of such techniques to improve system efficiency [10].

In the case of melons, conventional irrigation systems, especially under conditions of high salinity, are less efficient than the pulse irrigation system, which also better manages the distribution of water and the quality of the fruit [11]. Additionally, advanced irrigation systems that include electronic controls and water distribution barrels can contribute to enhancing water utilization efficiency and stabilizing fruit yield and quality, thereby reducing the limitations of conventional methods in terms of having to cope with the demands of the modern agriculture, highlighting the limitations of conventional methods in coping with the demands of modern agriculture [12]. Overall, these studies highlight the importance of developing more sophisticated methods for irrigation that can address inefficiencies implicit in traditional irrigation methods for farming fruits.

1.4. Solar Power: Optimal for Guava–Melon Efficiency

Agrivoltaic systems, which combine solar panels with agricultural strategies, already had foreshadowed potential as a sustainable strategy to improve both energy and food production, especially for vegetables such as guava and melon. These systems optimize land usage in agro-solar farms by adding both solar energy generation and cropping at the same time, solving the issue of competition for land between agriculture and solar farms [13,14]. The dual-use approach of agrivoltaics not only optimizes the use of land but also provides the beneficial microclimatic conditions that can improve crop yields by minimizing the evaporation of water and keeping plants safe from extreme weather conditions [14]. Studies have revealed that the land productivity of agrivoltaic systems can be as much as 73%, indicating the great potential that exists regarding the ability to increase agricultural production, while also producing a renewable form of energy [13].

However, there are challenges such as a possible reduction in the amount of agricultural production by shading; a well-thought-out recovery plan to balance the energy and the crop yields must be performed. Tailored solutions have to be used, as this can be carried out to adjust the start date of cultivation and shade the rates to mitigate the issues rather than ensure optimal time periods for harvest, ensuring maximum impact in terms of agricultural and energy output [15]. Furthermore, agrivoltaic systems are part of sustainable agriculture, reducing greenhouse gas emissions and enhancing water usage efficiency, which is in line with worldwide sustainability targets [16]. Overall, agrivoltaics provide expansive solutions when looking for viable and innovative methods of energy and food production, especially in areas with limited arable land [16,17].

1.5. Hafizabad’s Guava and Melon Amid Water Risks

Hafizabad, a region of Punjab in Pakistan, is an area where guava is cultivated widely, but it is also faces great problems due to the lack of water. The water footprint in Punjab underlines the importance of water for agriculture with local cause–effect chains pointing to malnutrition and loss of income due to agricultural water deprivation [18]. Guava, being a major crop in the region, is prone to anthracnose, a disease that has negative effects on its yield and quality, and the disease severity in Hafizabad is 46% [19]. The excessive use of groundwater for irrigation is common as a result of poor water distribution from the canal systems, which further the problem of water scarcity [20]. The Indus Basin, supporting the agriculture of Punjab, is under severe water stress, with poor irrigation practices leading to a further threat of water and food security [21].

Strategies like optimum cropping use and modification of irrigation systems with improved technologies like drip and sprinkler irrigation systems could reduce water consumption up to 50%. However, the economic implications of these strategies need to be explored further in order to ensure sustainable water management and agricultural productivity in areas as Hafizabad. The incorporation of all these strategies is essential to sustain the horticultural landscape of Hafizabad, especially for water demand-oriented crops such as guava, considering the accompaniment of water scarcity challenges [21].

2. Materials and Methods

The research applied mixed-method methodology, combining quantitative and qualitative datasets and analytical methods to assess the techno-economic efficiency of irrigation systems in terms of growing guava orchards and melons in the Hafizabad district of Punjab Pakistan.

2.1. Theoretical Framework

Efficiency Theory

Efficiency theory shows us how efficiently an irrigation system uses resources to obtain optimal horticultural production. This theory is divided in two basic components. First, technical efficiency (TE) is defined as the capacity of an irrigation system to convert inputs (e.g., water, energy) to outputs (e.g., yield of guava or melons). An efficient system is one that reduces resource utilization and maximizes output. For example, according to the available studies, the productivity of water resources is 20–30% more under solar-powered irrigation systems compared to conventional farming systems for guava orchards, which is important in water-scarce areas such as Hafizabad [5]. Technical efficiency is essential in the improvement of horticultural productivity where water shortages are common. Second, economic efficiency (EE) is an assessment of the economic cost-effectiveness of the irrigation systems (in terms of initial investment and operational cost). For example, solar-generated electricity is available at an average cost of $70/MWh, which makes solar irrigation more economical than conventional pumps with internal combustion (diesel) or electric power for melon crops [21]. Economic efficiency—including aspects such as return on investment, net present value and cost–benefit ratios, which are integral stakeholders negatively affected by climate variations—is a key element that guides farmers to make decisions on irrigation practices when it comes to guavas and melons.

2.2. Data-Related Framework

Determining the number of observations that should be sampled is crucial to effective research, and is related to factors such as the size of the population of the research in question, confidence level, margin of error, and data variability. For this study, the population size of targeted people is around 25,000 horticultural farmers at the Hafizabad District with a focus on guava orchards and the cultivation of melon from various categories of land ownership such as large (25+ acres 25% population), medium (12.5–25 acres 35%), and small (less than 25 acre 40%). This population estimate is made from the basis of district agricultural statistics, in which guava is estimated to represent guava production in the area of approximately 1353 acres, while melons (e.g., watermelon) will be grown seasonally over greater areas, amidst a total cultivated land of around 300,000 acres.

$${\displaystyle \frac{\mathrm{N}\times \left({\mathrm{Z}}^2\right)\times \mathrm{p}\times \left(1-\mathrm{p}\right)}{\left({\mathrm{E}}^2\times \left(\mathrm{N}-1\right)+{\mathrm{Z}}^2\times \mathrm{p}\times \left(1-\mathrm{p}\right)\right)}}$$

where n = required sample size, N = population size (25,000), z = 1.96 (95% confidence level), p = 0.5 (estimated proportion), and E = 0.05 (margin of error). This yielded a total sample size of approximately 378 farmers, allocated proportionally across the strata, namely 95 large farmers, 132 medium farmers, and 151 small farmers, using nh = Nh × n/N nh = Nh\times n/N nh = Nh × n/N. Due to time and resource constraints, the sample was narrowed down to 108 farmers. The framework highlights factors affecting the efficiency and adoption of the solar irrigation of guava and melons, providing insights and policy recommendations for promoting sustainable horticultural practices.

Data collection also used a mixed-method approach to ensure the completeness of information. A structured survey was developed for obtaining quantitative and qualitative information, such as demographic data (age, education, farming experience), current irrigation practices (solar/conventional, sources of water: tube well/canal), economic parameters (initial investment, cost of operation) and perception towards solar irrigation (benefits, barriers and willingness to adopt the technology). Surveys were directed at farmers of guava (perennial orchards) and cucumbers (seasonal vines), providing qualitative reflections from local agricultural officials about the effects of the reduced availability of water.

2.3. Data Analysis

The technical efficiency of an irrigation system is explained as the proportion of observed output to the maximum possible output given the inputs. The Stochastic Frontier Analysis (SFA) model is as follows: the technical efficiency of an irrigation system can be explained as a proportion of the observed output to the maximum possible output in the given inputs. The SFA model is as follows:

Y_i = f (X_i, β) · exp(v_i) · exp(u_i)

where Y_i is the actual output, e.g., guava and melon yield per year in tons per acre; X_i represents the inputs, e.g., water use per year in acre-feet per acre, fertilizer applied per annum in units per acre and labor along with other costs per acre. Β represents production technology parameters; f (X_i, β) is the deterministic production frontier. v_i ~ N (0, σ²) shows the random noise and u_i ∼ |N (0, σ²)|is the inefficiency term.

Similarly, the technical efficiency is as follows:

$$\mathrm{T}{\mathrm{E}}_{\mathrm{i}}=\exp \left(-{\mathrm{u}}_{\mathrm{i}}\right)={\mathrm{Y}}_{\mathrm{i}}/\mathrm{f}\left({\mathrm{X}}_{\mathrm{i}},\mathsf{\beta }\right)·\exp \left({\mathrm{v}}_{\mathrm{i}}\right)$$

Here, a Cobb–Douglas production function is utilized as follows:

ln(Yfrontier,i) = β0 + β1 ln(wtr use_pa) + β2 ln(Fertilizer_pa) + β3 ln(Other Op Costs_pa)

where inputs were generated, e.g., water use per year adapted for guava (typically 1.2–1.8 acre-feet/acre under drip), inputs were calculated, e.g., water use per year, noise vi and inefficiency u_i were drawn, with small farmers having higher u_i; TE was calculated as exp(−u_i) and yields were derived: _yld_pa_i = max_p os_yld_pa_i.

3. Results and Discussion

This section shows the results and discussion of the research, which seeks to run be-ta-regression models to show the technical and economic efficiencies in detail and demonstrate the dependency of the efficiencies on various factors and variables. The results are categorized in an inclusive table format, and the discussion interprets these objective results in an extensive way, relating these results with farming practices of guava orchard and melon crops in the Hafizabad District of Punjab, Pakistan. The analysis underlines the superiority of solar-powered irrigation systems over conventional techniques, which prove to have high-efficiency scores, lower operational costs and improved water productivity in water-scarce environments. Beta-regression with Cauchit link function was chosen as the best model according to model fit statistics (i.e., AIC and BIC lower than alternatives such as logit, probit, loglog and clogging), which is particularly favorable to the bounded efficiency data (0–1), showing asymmetry typical of horticultural product yields for perennial guava trees and seasonal melon vines.

To interpret the determinants of technical efficiency (TE) and economic efficiency (EE), beta-regression models were estimated using farming experience (Exp_yrs), operational irrigation cost per acre (est_op_co_pa), and water productivity (wtr_prod) as predictors. The Cauchit link function was employed for the mean model, as it provided the best fit with the lowest AIC and BIC values among tested links (logit, probit, loglog, cloglog, and Cauchit). This link is particularly effective for handling the heavy-tailed distributions observed in efficiency scores for guava and melon farming, where outliers from variable seasonal water availability and orchard maturity can skew results. The precision parameter (phi) was modeled with an identity link. The results for TE and EE are presented in

Table 1. Technical efficiency in the horticultural context (author’s own work).

Variable	Estimate	Standard Error	z Value	Pr (>|z|)
Mean Model
Intercept	−0.6550	0.08049	−8.138	4.03 × 10−16 ***
Experience in Years	0.02263	0.002784	8.129	4.32 × 10−16 ***
Estimated Operational Cost per Annum	−1.228 × 10−5	1.772 × 10−5	−6.931	4.17 × 10−12 ***
Water Productivity	2.750	0.9140	3.009	0.00262 **
Precision Model
(phi)	66.144	8.699	7.604	2.87 × 10−14

Note: Log-likelihood = 160.9; Pseudo R² = 0.5911; AIC = 311.8272; BIC = −298.1462. Significance codes: *** p < 0.001; ** p < 0.01.

and

Table 2. Economic efficiency in the horticultural context (author’s own work).

Variable	Estimate	Standard Error	z Value	Pr (>|z|)
Mean Model
Intercept	−0.8351	0.08338	−10.015	<2 × 10−−16 ***
Experience in Years	0.02416	0.002878	8.393	<2 × 10−16 ***
Estimated Operational Cost per Annum	−1.268 × 10−5	1.846 × 10−6	−6.868	6.49 × 10−12 ***
Water Productivity	3.051	0.9425	3.237	0.00121 **
Precision Model
(phi)	66.227	8.708	7.605	2.85 × 10−14 ***

Note: Log-likelihood = 159.2; Pseudo R² = 0.5997; AIC = −3083379; BIC = −294.6569. Significance codes: *** p < 0.001; ** p < 0.01.

, respectively.

In the case of EE, the situation was not different: Experience in years (estimate = 0.02416, p = 0.001) and water production (estimate = 3.051, p = 0.00121) had a positive effect on efficiency but estopco_pa (estimate = −1.268 × 10⁻⁵, p = 0.001) had a negative effect. The model had a variance of 59.97 (Pseudo R2 = 0.5997) and residuals ranging between −2.6242 and 2.0784. The Cauchit link was faster than others (e.g., cloglog AIC TE = −308.5 greater than Cauchit −311.8) and thus better suited to the modeling of efficacy in guava and melon systems, where data defined-ness and asymmetry (e.g., due to odd melon harvests) are strong.

The analysis identifies salient factors in the efficiency of farmers in growing guava orchards, and melon. The experienced farmers with higher experience in years are better at controlling irrigation time, use of fertilizers, and the pests, resulting in optimal yields. In the case of guava, which is a year-round watering perennial crop (guideline of 800–1000 mm/year), farmers with extensive experience who use solar drip irrigation achieve up to 30% TE reduction by eliminating effects of water stress and salinity [22]. Experience depends on timely action in proactive melon fields, which are seasonal and prone to overwatering, leading to waste reduction and improved health of vines [13].

Water productivity develops as a forceful positive driver (TE: 2.750, EE: 3.051), which highlights the significance of it to Hafizabad’s arid environment. Solar irrigation also increases water production by 25–40% by spacing out irrigation precision, including IoT-based drip system systems that react to soil moisture; and they required only 30–50% of the amount of water than traditional flooding [5,6]. In the case of guava, it means 20–26 tons per hectare with solar versus 15–18 tons per hectare with conventional production, and evaporation in orchards is also reduced [7]. The same applies to melons, where pulse or deficit irrigation under a solar system ensures the quality of fruits is maintained, yields reach between 15 and 20 tons per acre, and salinity is reduced [11]. These profits are essential in the context of the groundwater depletion of Hafizabad, where traditional over-pumping only worsens the situation [21].

The negative effect of operational costs on efficiency is that an increase in costs due to diesel pumps or inefficient tube wells puts pressure on the smallholders. Solar systems reduce this to approximately PKR 10,000–15,000/acre/year (vs. PKR 20,000–30,000/acre/year with conventional), which will pay back within 2–3 years in terms of energy savings [22]. Solar with mulching lowers the expenses used in guava farming by 35% and enhances EE [10]. In the case of melons, the consistency of solar over the summertime prevents the failure of crops, which improves the returns of these crops despite the initial investment.

The strong Pseudo R² values (TE: 0.5911, EE: 0.5997) indicate that the models explain performance well, even without variables like extension services or cooperative membership. The Cauchit link’s superior fit (lowest AIC/BIC) suits the limited efficiency range in horticulture, where guava’s long maturation (3–5 years) and melon’s variability create non-normal distributions. Logit, probit, and cauchit links were tested but rejected for higher AIC; cloglog was close but Cauchit better handled tails.

More so, the models emphasize the overall advantage of solar: on average, TE/EE scores of solar users were 0.75–0.85 with a conventional 0.45–0.60 according to survey data collected from 108 farmers (e.g., the yield of guava was 12–15 tons/acre using solar and 8–10 using conventional). It is consistent with agrivoltaic conceptions, wherein the solar panels shadow guava trees, which decreases evaporation by a factor of 20 and increases the efficiency of dual use [2,16]. There should be additions such as education, or access to credit to improve models; however, the existing findings would justify policy changes toward subsidizing solar in Hafizabad to boost exports of guavas to 1353 acres, as well as melon exports.

4. Conclusions

• The findings support the techno-economic benefits of solar irrigation on guava and melon orchards, which enable water-risk regions to be more sustainable with optimal production.
• The initial costs as well as the operating costs of installing and using the solar system have reduced to a great extent, which helps farmers to use this advanced and efficient mode of energy to reduce their cost of production.
• Technical efficiency is far better when using the solar mode of energy as compared to traditional modes.
• Government subsidies in acquiring solar systems for orchard farmers can aid in the progressive and sustainable usage of this mode of energy.
• Lastly, water productivity also improved when using the solar mode of energy.