Energy balance and economic benefits of two agroforestry systems in northern and southern China

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1 Agriculture, Ecosystems and Environment 116 (2006) Energy balance and economic benefits of two agroforestry systems in northern and southern China Lu Jianbo * Agro-Ecology Institute, College of Life Science, Huajiachi Campus, Zhejiang University, Hangzhou , People s Republic of China Received 14 August 2005; received in revised form 13 February 2006; accepted 28 February 2006 Available online 18 April 2006 Abstract The energy efficiency and economic benefits of agroforestry systems are key issues with respect to their actual sustainability as sound agricultural practices as well as to their potential for further development. Two typical agroforestry systems in China, the Paulownia [Paulownia elongta S.Y. Hu] intercropping system in the north and the Tea [Camellia sinensis O. Ktze] intercropping system in the south were chosen as research subjects. The studies were conducted to establish the energy balance and economic benefits to farmers of these two agroforestry systems in northern and southern China. The objectives were to determine the potential of developing the Paulownia intercropping system in the north and the Tea intercropping system in the south, and their respective sustainability. Two research sites were selected, and two intercropping systems were designed. All the inputs/outputs data of these two agroforestry systems were collected and documented. Input/output analysis and process analysis were conducted. Energy output/input ratio of Paulownia intercropping system was 1.39, of Non-Paulownia intercropping system (traditional cropping system) was 1.27, an increase of 9.45%. Economic output/input ratios of Paulownia and Non-Paulownia intercropping systems were 2.42 and 2.25, respectively, an increase of 7.56%. Ratios under Tea and Non-Tea intercropping systems reflected the same trend. The Tea energy output/input ratio record was 1.12, compared to 0.06 of the Non-Tea intercropping system, i.e. the former is 18.7 times higher than the latter. Economic output/input ratios under Tea intercropping system (2.3) was 64.29% higher than that of the Non-Tea intercropping system (1.4). It was concluded that these two typical agroforestry intercropping systems have a higher energy efficiency and also a better financial benefits to farmers. # 2006 Elsevier B.V. All rights reserved. Keywords: Renewable energy; Energy analysis; Economic analysis; Output/input ratio; Intercropping 1. Introduction and research objectives Agroforestry has a very long history in China (Hsiung et al., 1995). With the rapid growth of population, more and more forestland is converted to agricultural production. Forest coverage in China had been declining from 64% in the year 2000 B.C. to 8.6% in the year Now, however, it is 13.92% (Forestry Society of China, 1996; Forestry Ministry of China, 1996). With its rapidly growing population, China faces pressure to develop and increase food production on limited land resources. Efforts to conserve and protect forest resources and increase forest coverage are urgently being * Tel.: ; fax: address: jianbo.lu@zjuem.zju.edu.cn. intensified. Agroforestry system has good ecological, social and economic benefits in comparison with traditional forestry. These land-use systems provide various products for household and national economies including food and medicinal products for humans and animals, timber for construction and fuel, and cash income. They contribute to the sustainability of soil nutrient and water cycles and act as a buffer to climatic extremes. So they are very important in maintaining sustainability of ecological system and sustainable development of social economic system (Rao and Ong, 2000; Huxley, 1983; Rao and Reyes, 1990; FAO, 1999). There are many types of agroforestry systems in China (Li and Lai, 1994; Lu et al., 2004; Zhao and Lu, 2004), with principal crops such as jujube, Paulownia, metasequoia duck fish system in northern China, and fruit, tea, /$ see front matter # 2006 Elsevier B.V. All rights reserved. doi: /j.agee

2 256 L. Jianbo / Agriculture, Ecosystems and Environment 116 (2006) Chinese fir, oil tea camellia and mulberry-fish in southern China. These agroforestry systems not only increase farmers income and contribute to food security, but also play a role in increasing the vegetation coverage and buffering climatic extremes (Li and Lai, 1994). The Paulownia [Paulownia elongta S.Y. Hu] intercropping system in the north and the Tea [Camellia sinensis O. Ktze] intercropping system in the south are two typical in China. They have been studied by national and international scientists (Yin and Hyde, 2000; Yin and He, 1997; Newman et al., 1997), who reported, on crop yield, rotation period, tree densities, and light and heat distribution. There are few energy and economic studies on Paulownia and Tea intercropping systems. In other regions, scientists have begun to analyze the energy and economic output/input of some agroforestry systems. Ramirez et al. (2001) analyzed economic returns, stability and risk of cacao-plantain-timber agroforestry systems in central America. Rodrigo et al. (2001) conducted financial analysis and sensitivity analysis of immature rubber intercropping system in Sri Lanka. Jian and Singh (2000) reported on economic analysis of industrial agroforestry: poplar (Populus deltoides) in Uttar Pradesh, India. Gajaseni and Gajaseni (1999) studied ecological rationalities of the traditional homegarden system in Chao Phraya Basin in Thailand. Nautiyal et al. (1998) reported economic efficiency and energy output/input analysis of agroforestry systems in the rural landscape in India. Agriculture involves the management of biological systems to optimize the flow of solar energy (either directly or indirectly) toward the output of valuable products, external energy inputs are required to effectively absorb solar energy in agricultural production systems. Research on energy and economic output/input analysis of Paulownia and Tea intercropping systems will benefit not only the evaluation of these two agroforestry systems, but also allows the optimization of their structures, development and wider extension. The specific objectives of this study were: (a) to compare the energy efficiencies of Paulownia and Tea agroforestry systems with traditional cropping systems, and (b) to evaluate the economic viability of Paulownia, Tea, Non-Paulownia and Non-Tea intercropping systems. for wheat and maize production, as well as providing timber (630,000 m 3 ) annually, to prevent sand blowing. Tea intercropping system study site is located in Shexian county ( N, E) of Anhui province in southern China. The average annual rainfall is mm, and average annual temperature is C. This county has 20,000 ha of tea plantation from which about 10,000 t dry tea is harvested annually, ranking it first in terms of tea production in China. Tea intercropping system is typical agroforestry of southern China (Zhao and Lu, 2004), with a large area of tea plantations in the hilly and mountainous region south of Yangtse River. The system has the potential to increase and stabilize farmers cash incomes, contribute to their food security Experimental design for the Paulownia intercropping system One hectare of Paulownia intercropping system field was selected as the experimental field, and 1 ha of Non- Paulownia intercropping system field (traditional cropping system) was selected as a control field. The structure of Paulownia intercropping system is: Paulownia + Wheat [Triticum aestivum Linn] Peanut [Arachis hypogaea Linn]. Paulownia was 4 years old, and the density was 60 tree ha 1. Its structure is illustrated in Fig. 1. The structure of Non- Paulownia intercropping system is: Wheat Peanut. This experiment was carried out from 1996 to Materials and methods 2.1. Site description Study site of the Paulownia intercropping system is located in Lankao county ( N, E and N, E, respectively) of Henan province in the northern China. Lankao county is a key region for Paulownia intercropping system in China. The average annual rainfall is 678 mm, and average annual temperature is 14 8C. It covers 34,700 ha land, with more than 1,800,000 trees of Paulownia. This agroforestry system is importance Fig. 1. The structure of Paulownia intercropping system: (a) from November to June (next year) and (b) from June to November.

3 L. Jianbo / Agriculture, Ecosystems and Environment 116 (2006) included: labor, electricity, fuel, chemical fertilizer, pesticide, agricultural machinery, seed and seeding. The economic output of these systems included: agricultural products (food), forestry and agroforestry products and byproducts. All prices of input and output were market prices (average prices of years ). The economic benefits analysis focuses on the structure of input and output, marginal profit, ratio of output and input, and economic feasibility. Fig. 2. The structure of Tea intercropping system Experiment design for Tea intercropping system Four hectares of Tea intercropping system field was selected as the study field, and 4 ha of Non-Tea intercropping system field (traditional tea farming system) was selected as a control field. The experiment field is upland at an elevation of 500 m. Its structure is: Tea + Maize [Zea mays L.] Red Mung Bean [Vigna rabiata (Linn) Baker] Green Manure [Astragalus sinicus Linn], as illustrated in Fig. 2. Tea was planted in two to three rows per terrace at the inter-row spacing of m. Seeding rates were: maize 22.5 kg ha 1, red mung bean 3.75 kg ha 1 and green manure 7.5 kg ha 1. Tea was cultivated according to organic tea (organic agriculture) production standards, using 32,100 kg ha 1 organic manure. Under traditional tea farming, only tea crop was cultivated no other crops were planted. This experiment was carried out from 1996 to Method of energy balance analysis The methodologies of energy analysis are: statistical analysis; input/output analysis; process analysis (Jones, 1989). Input/output analysis and process analysis were applied in this research. Firstly, the system boundary was defined, with 1 ha as the basic unit for energy flow analysis. Secondly, the main components of the system and their relationships were analyzed, trees and crops were the key components of the two agroforestry systems. Thirdly, input and output of the systems were determined. Energy input included (apart from solar energy): (1) industrial energy: fossil fuels, electricity, agricultural machinery, chemical fertilizer, pesticide, etc.; (2) biological energy: labor, animal power, organic manure, crop straw, etc. Energy output included: main agricultural products (food), forestry and agroforestry products and by-products (crop straw, etc.). Lastly, the quantities of input and output were computed into energy flow with the energy accounting coefficients Method of economic benefits analysis The input/output analysis was also applied in economic benefits analysis. The process was similar with energy balance analysis. One hectare of experiment field was the basic unit for analysis. The economic input of these systems 3. Results 3.1. Energy balance in the Paulownia intercropping system Energy input and output status of Paulownia and Non- Paulownia intercropping systems is shown in Table 1. Comparing the energy input types of Paulownia intercropping system (PIS) with those of Non-Paulownia intercropping system (NPIS), we find only three types that are different, with the rest being the same. Labor input for PIS is 120 h ha 1 more than that for NPIS, pesticide input for PIS is 1.5 kg ha 1 more than that for NPIS, and Paulownia seeding of PIS is 7.5 kg ha 1. Consequently, total energy input for PIS is 145,455 kcal higher than that for NPIS, which is an increase of 0.3% in comparison with total energy input of NPIS. There is 73,530 kcal additional industrial energy input of the total energy utilized under PIS, representing 50.55% of the total additional energy input. The remainder of the total extra energy employed under PIS is taken up by biological energy which is 71,925 kcal amounting to 49.45% of the total additional energy input. The results also show that three output energy types have different values between PIS and NPIS: PIS wheat yield increased by 135 kg ha 1 over NPIS with additional harvests of 2100 kg ha 1 of timber and twig and leaves per year giving an important energy output of 6,177,600 kcal ha 1. This represents an increase of 9.95% in comparison with energy output under NPIS. The ratio of the energy output to the energy input under PIS is 1.39, and that for NPIS is 1.27, showing that the ratio for PIS is 9.45% higher than that for NPIS. Comparing the additional energy output to the additional energy input we obtain a ratio of If this ratio is compared to total output/ input ratio (1.39) of the whole PIS, it can be seen that it is 30 times higher. Output/input ratios of PIS and NPIS are shown in Fig. 3. In Fig. 3, B-PIS represents the ratio of energy output to biological energy input of PIS, B-NPIS represents the ratio of energy output to biological energy input of NPIS, I-PIS represents the ratio of energy output to industrial energy input of PIS and I-NPIS represents the rate of energy output to industrial energy input of NPIS. All the ratios of PIS are higher than those of NPIS, which means that in PIS both biological energy efficiency and industrial energy efficiency are higher.

4 258 L. Jianbo / Agriculture, Ecosystems and Environment 116 (2006) Table 1 Comparison of energy input and output of Paulownia and Non-Paulownia intercropping systems (per year) Energy category Paulownia + Wheat Peanut Wheat Peanut Quantity Energy coefficient a Energy (kcal) Quantity Energy coefficient a Energy (kcal) Input Labor (h ha 1 ) Electricity (kwh ha 1 ) Diesel oil (kg ha 1 ) Organic manure (kg ha 1 ) Urea (kg ha 1 ) Phosphate fertilizer (kg ha 1 ) Pesticide (kg ha 1 ) Farm implement b (kg ha 1 ) Machinery (kg ha 1 ) Paulownia seedling (kg ha 1 ) Seed of wheat and peanut (kg ha 1 ) Total input Output Wheat (kg ha 1 ) Peanut (kg ha 1 ) Paulownia (kg ha 1 ) Crop straw (kg ha 1 ) Paulownia twig and leaf (kg ha 1 ) Total output Ratio of energy output/input a Energy coefficient means the heat energy (kcal) changed by 1 kg material, the values are from the book Agro-Ecology edited by Luo Shiming (2001, Chinese Agricultural Press, Beijing, Appendix 4, pp ). b Farm implement means small farm tools, such as hoe, plough, cutting knife. The energy output/input rates of these two systems range from 1.2 to 1.4. These values correspond with the average for agricultural production in China (Wen and Pimentel, 1984a,b) Energy balance in the Tea intercropping system The results of the energy balance under the Tea and Non- Tea intercropping systems are shown in Table 2. Fig. 3. Energy output and input ratios of Paulownia and Non-Paulownia intercropping systems at different cases. *PIS: Paulownia intercropping system; NPIS: Non-Paulownia intercropping system; B-PIS: energy output to biological energy input of PIS; B-NPIS: energy output to biological energy input of NPIS; I-PIS: energy output to industrial energy input of PIS; I-NPIS: energy output to industrial energy input of NPIS. The ratios of the energy output to input under TIS is 1.12, which is much higher than that of NTIS, whose ratio is only 0.06, indicating that TIS s ratio is 18.7 times that of NTIS. Analyze the energy input items, and we can find that because the Tea intercropping system is an organic tea production system, no industrial energy such as chemical fertilizer and pesticide is put into the system. Instead, much biological energy such as cake, animal manure, human manure and crop seed is applied. The total energy input of TIS is higher than that of NTIS, with the additional energy input is kcal ha 1. It is 54.17% of total energy input of NTIS. On the energy output, apart from tea, which is the sole product from the NTIS, other agricultural products are also harvested from the TIS, making the energy output of TIS much higher than that of NTIS. The figure is times. The additional energy output is 3.08 times that of the additional energy input in TIS. Its efficiency is about three times that of itself. Comparison of different ratios of different types of output and inputs is shown in Table 3. B-TIS represents the ratio of output and biological energy input in TIS; B-NTIS represents the ratio of output and biological energy input in NTIS; I-TIS is the ratio of output and industrial energy input under TIS; I-NTIS represents the ratio of output and industrial energy input under NTIS. All the ratios in TIS are much higher than those in NTIS, which means that the biological and industrial energy efficiencies are both increased in TIS. The main energy input of TIS is biological energy, and therefore the ratio of energy output

5 L. Jianbo / Agriculture, Ecosystems and Environment 116 (2006) Table 2 Comparison of energy input and output of Tea and Non-Tea intercropping systems (per year) Energy category Tea + Maize Red Mung Bean Green Manure (TIS) Tea (NTIS) Quantity Energy coefficient Energy (kcal) Quantity Energy coefficient Energy (kcal) Input Labor (h ha 1 ) Animal manure (kg ha 1 ) Vegetable manure (kg ha 1 ) Human organic wastes (kg ha 1 ) Ammonium hydrogen carbonate (kg ha 1 ) Urea (kg ha 1 ) Pesticide (kg ha 1 ) Machinery (kg ha 1 ) Electricity (kwh ha 1 ) Fuel (fire wood) (kg ha 1 ) Maize seed (kg ha 1 ) Red mung bean seed (kg ha 1 ) Green manure seed (kg ha 1 ) Total input Output Tea (kg ha 1 ) Maize (kg ha 1 ) Red mung bean (kg ha 1 ) Maize straw a (kg ha 1 ) Bean straw a (kg ha 1 ) Green manure a (kg ha 1 ) Crop root a (kg ha 1 ) Total output Ratio of energy output/input a Fresh weight. and industrial input is very high. It proves that few industrial energy input can get high energy efficiency in biological farming system Economic benefits of the Paulownia intercropping system Economic input and output status of the Paulownia and Non-Paulownia intercropping systems is shown in Table 4. The study results also indicate total economic input of PIS to be a little higher than that of NPIS, and is equivalent to 180 Yuan ha 1, representing an increase of 2.24%. The main economic input types responsible for this increase are labor, pesticides and Paulownia seeding. There was an increase of 210 Yuan ha 1 in output value from wheat under PIS over NPIS. In addition, the value of Paulownia and its byproducts was 1590 Yuan; therefore, the total increase in output value was 1800 Yuan ha 1, which is 9.95% higher than that of NPIS. The ratios of the economic output to input of PIS and NPIS are 2.42 and 2.25, respectively. It can be seen that the ratio of PIS is 7.56% higher than that of NPIS. The ratio of additional output to additional input is 10, which is much higher than that of total output/input ratio of the PIS itself Economic benefits of the Tea intercropping system Table 5 shows a comparison between the economic inputs and outputs in the Tea and Non-Tea intercropping systems. The input categories of the economy are the same as the energy input types in the two systems. The labor and fertilizer application inputs recorded large differences between the two farming systems. Labor input under TIS was much higher than that under NTIS. Fertilizer application Table 3 Comparison of different ratios of energy output/input in respective types of TIS and NTIS Respective types TIS NTIS B-TIS B-NTIS I-TIS I-NTIS Ratio of output and input TIS: Tea intercropping system; NTIS: Non-Tea intercropping system; B-TIS energy output to biological energy input of TIS; B-NTIS: energy output to biological energy input of NPIS; I-TIS: energy output to industrial energy input of TIS; I-NTIS: energy output to industrial energy input of NTIS.

6 260 L. Jianbo / Agriculture, Ecosystems and Environment 116 (2006) Table 4 Comparison of economy input and output of Paulownia and Non-Paulownia intercropping systems (per year) Economic category Paulownia + Wheat Peanut Wheat Peanut Quantity Value (Yuan) a Quantity Value (Yuan) a Input Labor (h ha 1 ) Electricity (kwh ha 1 ) Diesel oil (kg ha 1 ) Organic manure (kg ha 1 ) Urea (kg ha 1 ) Phosphate fertilizer (kg ha 1 ) Pesticide (kg ha 1 ) Farm implement (kg ha 1 ) Machinery (kg ha 1 ) Paulownia seedling (kg ha 1 ) Seed of wheat and peanut (kg ha 1 ) Total input Output Wheat (kg ha 1 ) Peanut (kg ha 1 ) Paulownia (m 3 ha 1 ) Crop straw (kg ha 1 ) Paulownia twig and leaf (kg ha 1 ) Total output Ratio of economic output/input a US$ 1 = 8.2 Chinese Yuan. Table 5 Comparison of economic input and output of Tea and Non-Tea intercropping systems (per year) Economic category Tea + Maize Red Mung Bean Green Manure Tea Quantity Value (Yuan) a Quantity Value (Yuan) b Input Labor (h ha 1 ) Animal manure (kg ha 1 ) Vegetable manure (kg ha 1 ) Human manure (kg ha 1 ) Ammonium carbon (kg ha 1 ) 1500 Urea (kg ha 1 ) Pesticide (kg ha 1 ) Machinery (kg ha 1 ) Electricity (kwh ha 1 ) Fuel (fire wood) (kg ha 1 ) Maize seed (kg ha 1 ) Red mung bean seed (kg ha 1 ) Green manure seed (kg ha 1 ) Total input Output Tea (kg ha 1 ) Maize (kg ha 1 ) Red mung bean (kg ha 1 ) Maize straw a (kg ha 1 ) Bean straw a (kg ha 1 ) Green manure a (kg ha 1 ) Crop root a (kg ha 1 ) Total output Ratio of economic output/input a Fresh weight. US$ 1 = 8.2 Chinese Yuan.

7 L. Jianbo / Agriculture, Ecosystems and Environment 116 (2006) under TIS was purely of organic manure, whereas under NTIS only chemical fertilizers were applied. Tea produced under TIS was organic tea. In general, the total economic input of TIS was 4334 Yuan ha 1 higher than that of NTIS, representing an increment of 30.37%. This increase in input was compensated for by a massive % increment in economic output under TIS, because not only good quality tea, which can fetch a high price at the international market, was harvested from the system but also other products like maize, bean and green manure were produced. The economic output and input ratios of TIS and NTIS are 2.3 and 1.4, respectively, which means the former was 64.29% higher than the later. 4. Discussion The agroforestry system, however, has the added benefits of providing fuel wood and improving soil quality by preventing soil erosion. Most modern, industrialized agricultural systems that depends on fossil fuels are energy-inefficient and in the longer term, unsustainable. In addition to conserving fossil energy, sound agricultural practices must place priority on using renewable energy, and conserving soil, water and biological resources (Pimentel and Pimentel, 2005). Farmer can get more economic benefits from PIS. Here 1800 Yuan ha 1 is the marginal profit and a direct benefit. In addition, wood of Paulownia can be processed and farmer will get more profits. Furthermore, sand can be effectively retained and wind erosion prevented, and microclimate of crop field can be improved leading to ecological benefits. A larger crop diversity is a consequence of TIS. The solar energy can be more effectively used. Mung bean crop and green manure are incorporated into the system, so that soil fertility is enhanced and tea yields are increased. In general, sustainability of TIS becomes better than that of NTIS. TIS is an agroforestry system of high efficiency and stability. Additional research may lead to even further increases in energy output and income of these two innovative agroforestry systems. Only energy balance and economic benefits of these two typical agroforestry systems were analyzed, which the value of their ecosystem services was not included in the current study. An analysis of the social and environmental benefits of agroforestry production systems and an assessment of the value of their contribution to ecosystem health would contribute to a profound understanding of the social, economic and environmental benefits of agroforestry systems. 5. Conclusion The study concludes that agroforestry systems can effectively employ solar energy, heat and water resources, and land resource. Intercropping in agroforestry systems can increase the energy flow, especially when the biological energy input is added. The benefits to farmers from these systems are significant and there are important ecological benefits as well. Intercropping in agroforestry brings higher high energy efficiencies, and also good economic returns to farmers, thus making them appropriate for extension in suitable regions across China. Acknowledgements This research was supported by National Chinese Ecological Agriculture Counties Construction Project, which was financed and coordinated by Agricultural Ministry of China. The author wishes to thank the two County Offices of Ecological Agriculture Construction for data collection. The author would like to thank Ms. Xia Li, Lecturer of English of Zhejiang Sci-Tech University, China, for English improving during the first revision stage, and Prof. Dr. Frits Penning de Vries, Director of MAIRS-IPO (International Project Office of Monsoon Asia Integrated Regional Study), China, for English improving during the last revision stage. 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