Energy input-output analysis of rice production in Nigeria

Highlights

• Energy input-output energy balance was analysed for rice production in Nigeria.

• Chemical energy input was the major contributor in small, medium and large farms.

• Total energy input for rice production varied from 14067 to 14813 MJ/ha.

• Specific energy ranged from 1.92 to 2.22 MJ/kg paddy rice.

• The energy ratio ranged from 6.58 to 7.62, which suggests efficient use of energy.

Abstract

Energy input-output assessment for crop production processes is becoming increasingly important due to increased energy demand. Efficient use of energy can help achieve an environmentally, economically and socially viable sustainable crop production system now and for the future in general. This paper explores the energy inputs and consumption patterns for rice production system in Nigeria. Energy related data were collected through field surveys, direct measurements, interview with farmers and structured questionnaires for two growing seasons in nine (9) rice farms, comprising of three small, medium and large farms, respectively. Energy requirement for land preparation, planting, crop maintenance (fertilization and weed control), threshing, and harvesting were calculated using standard equations. The average energy input for rice production in small, medium and large farms were 14813, 14543 and 14067 MJ/ha, respectively, while the average yield obtainable were 6695, 7060 and 7364 kg/ha, respectively. There is a significant difference among the three farm categories in respect to input energy and agronomical managements such as transplanting date and land preparation. Energy input in fertilizer application was the highest with 73.80, 75.11 and 76.90% of the total energy input in small, medium and large farm, respectively. The net energy values were 82733, 88321 and 93226 MJ/ha, respectively. Energy ratio in small, medium and large farms were 6.58, 7.07 and 7.62, respectively. Large farms had better energy efficiency due to better management of energy resources. Minimizing input energy through increased level of mechanisation will boost rice production in Nigeria.

Introduction

Crop production requires energy in various forms, such as direct form (human labour, animal power, fuels and electricity), indirect form (machinery, fertilizer and herbicide) and renewable or non-renewable form. Energy consumption in crop production has increased over the years due to increasing demand for food products [1].

Intensive use of energy resources from non-renewable energies such as agricultural machinery, fossil fuel, chemical fertilizers and pesticides has led to some environmental problems such as natural resources depletion and climate change [2]. Therefore, it is important to reduce the energy resources input in agricultural production to ease the environmental problems [3]. Efficient use of energy resources in crop production can mitigate some environmental problems, prevent the destruction of natural resources, and help achieve sustainable production system [4].

Development of energy efficient agricultural production systems with low energy input compared to the output is a means of reducing the greenhouse gas emissions produced from agricultural activity [5]. Energy auditing is a common method of examining energy efficiency and environmental impact of a production system. It empowers the researchers to calculate the input-output ratio, energy use pattern and other relevant indicators in an agricultural production system [6]. An input-output analysis is a reliable approach that provides planners and policy-makers an opportunity to evaluate economic interactions of energy use and its efficiency [7]. Energy budgets for crop production is important for identifying the best production processes in terms of increased efficiency and productivity [8]. Most importantly, it provides alternative forms of energy which can reduce production costs and result in overall increase in agricultural productivity. Evaluating the potential impacts associated with a product or process is also of almost importance, since there is a growing demand for cleaner and sustainable technologies due to environmental issues [9]. Life-Cycle Assessment of a product or process can be carried out through energy analysis using energy efficiency indicators, directed to the characterization and renewability of the crop production system [10].

Several scientists have been studying the use of energy for agricultural crop production in recent years. Energy expenditure report on crop cultivation include; cassava production [11], plantain production [12], palm kernel oil [13], cashew nut [14], sweet orange production [1] in Nigeria. In addition, there was research on field crops and vegetable production in Turkey [15]; maize cultivation [16,17] and tangerine production in Iran [18], but there is limited information on energy analysis of rice production in Nigeria. Ibrahim and Ibrahim [19] reported that rice production in Nassarawa state of Nigeria consumed an average total energy of 12906.8 MJ/ha, with chemical energy input from herbicide contributing the largest share (53.55%). Human labour had the least contribution (0.74%) of the total energy input used. The energy ratio and energy productivity were 4.1 and 0.3 kg/MJ, respectively. In other part of the world, Alipour et al. [20] in province Guilan, Iran reported higher energy input. The total energy input for rice production reported was 47,600 MJ/ha, while the energy output was 90680 MJ/ha. The highest energy input was related to water (38.84%), electricity (27.78%) and Nitrogen fertilizer (17.5%). Chamsing et al. [21] analysed energy consumption in various regions of Thailand for irrigated and rain-fed rice production. They reported that chemical energy (fertilizer, pesticide and herbicide) contributed the highest energy input, followed by biological energy (seed). Energy inputs reported varied between 1.79-18.49 and 10.09–13.11 GJ/ha for irrigated rice, and rain-fed rice, respectively. Energy ratios for rice production obtained in their study were 4.0 and 2.8, respectively. Eskandari et al. [22] considered the energy consumption and factors affecting rice production in semi-mechanized and traditional systems in province of Mazandaran, Northern Iran. They reported that irrigation and fertilizer energy resources are most consumed in rice production. Iqbal [23] studied the energy inputs requirement for rice production in various categories of farms in Bangladesh and established that small farms (0.61–1.00 ha) had the highest energy ratio (4.14) in comparison with other categories. Kazemi [24] analysed and compared the energy use pattern for rice production in different geographical region of Iran; and reported that there was a significant difference among the three provinces studied in respect to input energy and agronomical managements such as crop rotation, transplanting date and land preparation. The values of energy ratio and productivity as reported varied from 1.39 to 1.67 and 0.064, to 0.070 kg/MJ. Musuda [25] estimated that the energy ratio obtainable in rice production ranged from 0.73 to 0.98 while analysing the effect of increasing the scale of farming on energy efficiency of intensive rice production in Japan. Musuda concluded that increasing the farming scale increases energy efficiency due to greater reduction in the energy consumed by agricultural machinery per unit area. Pirdashti et al. [26] compared energy inputs and outputs from organic rice–duck farming with conventional rice production in the province of Mazandaran, Iran. They established that the total energy input for organic rice–duck production (79,307 MJ/ha) was lower than that of conventional rice (94,377 MJ/ha) and the organic rice–duck farming has more energy efficiency than conventional rice farming.

Rice (Oryza sativa L.) is one of the most important staple food for majority of people in West Africa region, most especially Nigeria. Rice which belongs to the graminae family is valued as the fourth most important cereal crop after sorghum, millet and maize in Nigeria. It is grown and consumed virtually all over the country because of its high nutritional value grown [27]. Rice is consumed as a household food item and by major industrial consumers such as pasta and bread companies; beer and other liquor distilleries and pharmaceutical industries as a raw material in the production of their products [28]. Rice is cultivated on roughly 3.7 million hectares of arable land in Nigeria [29]. Nigeria rice production systems include: upland rice, lowland rice, irrigated rice and mangrove/deep water rice production systems [30]. Rice Farmers Association of Nigeria (RIFAN) reported that the annual rice production in Nigeria has increased to 5.8 million tonnes in 2017 [31]. This increase is attributed to the Central Bank of Nigeria (CBN)’s Anchor borrower intervention fund for rice farmers which had boosted local production of rice and saved the country about $800 million in foreign exchange [32].

Despite been the highest producer of rice in West Africa, Nigeria is still struggling to bridge the gap between supply and the ever-growing demand. The annual consumption rate of rice is estimated at 7.9 million metric tonnes, the gap of about 2.1 million metric tonness is filled through importation [31]. Presently, Nigeria is one of the major importers of rice among countries of the world and the largest rice importer in Africa, importing on average about 2.6 million tonnes per year [33]. This high importation of rice is attributed to the rapid increase in population, improper production methods, scarcity and high cost of inputs, inefficient use of recourses, low-level mechanisation, rudimentary post-harvest and processing methods [34,35].

To become self-sufficient in rice production, the Federal Government of Nigeria in 2006 has initiated policies and incentives for farmers to increase rice production locally. These policies were targeted at reducing import and developing a sustainable rice production system [36,37]. The country can reduce the dependence on imports, ensure stable and sustainable low-prices, improve rice self-sufficiency and create employment if the government recognizes the potential of energy use efficiency policy, large-scale mechanized, irrigated agriculture, improved modern techniques, and promote the expansion of rice production by the private sector [38]. This study was designed to determine the energy inputs and consumption patterns of rice cultivation in Nigeria. The assessment of energy consumption for rice production is required to understand the current situation so as to improve on the use of the resources. It helps to reduce the amount of input in a production system without negatively affecting the output. Efficient use of energy in rice production will help to increased production and productivity, increases rice production profitability and contributes to the nation economy, thus making rice production system sustainable.