Please wait a minute...
Journal of Arid Land
Journal of Arid Land  2021, Vol. 13 Issue (4): 375-387    DOI: 10.1007/s40333-021-0060-y     CSTR: 32276.14.s40333-021-0060-y
Research article     
Water, land, and energy use efficiencies and financial evaluation of air conditioner cooled greenhouses based on field experiments
Ibtihal AL-MANTHRIA1, Abdulrahim M AL-ISMAILIA1,*(), Hemesiri KOTAGAMAB2, Mumtaz KHANC3, L H Janitha JEEWANTHAD4,5
1Department of Soils, Water and Agricultural Engineering, Sultan Qaboos University, Muscat PC123, Oman
2Department of Natural Resource Economics, Sultan Qaboos University, Muscat PC123, Oman
3Department of Plant Science, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat PC123, Oman
4Centre for Future Materials, University of Southern Queensland, Toowoomba QLD 4350, Australia
5School of Mechanical and Electrical Engineering, University of Southern Queensland, Toowoomba QLD 4350, Australia
Download: HTML     PDF(717KB)
Export: BibTeX | EndNote (RIS)      

Abstract  

High temperature and humidity can be controlled in greenhouses by using mechanical refrigeration cooling system such as air conditioner (AC) in warm and humid regions. This study aims to evaluate the techno-financial aspects of the AC-cooled greenhouse as compared to the evaporative cooled (EV-cooled) greenhouse in winter and summer seasons. Two quonset single-span prototype greenhouses were built in the Agriculture Experiment Station of Sultan Qaboos University, Oman, with dimensions of 6.0 m long and 3.0 m wide. The AC-cooled greenhouse was covered by a rockwool insulated polyethylene plastic sheet and light emitting diodes (LED) lights were used as a source of light, while the EV-cooled greenhouse was covered by a transparent polyethylene sheet and sunlight was used as light source. Three cultivars of high-value lettuce were grown for experimentation. To evaluate the technical efficiency of greenhouse performance, we conducted measures on land use efficiency (LUE), water use efficiency (WUE), gross water use efficiency (GWUE) and energy use efficiency (EUE). Financial analysis was conducted to compare the profitability of both greenhouses. The results showed that the LUE in winter were 10.10 and 14.50 kg/m2 for the AC- and EV-cooled greenhouses, respectively. However, the values reduced near to 6.80 kg/m2 in both greenhouses in summer. The WUE of the AC-cooled greenhouse was higher than that of the EV-cooled greenhouse by 3.8% in winter and 26.8% in summer. The GWUE was used to measure the total yield to the total greenhouse water consumption including irrigation and cooling water; it was higher in the AC-cooled greenhouse than in the EV-cooled greenhouse in both summer and winter seasons by almost 98.0%-99.4%. The EUE in the EV-cooled greenhouse was higher in both seasons. Financial analysis showed that in winter, gross return, net return and benefit-to-cost ratio were better in the EV-cooled greenhouse, while in summer, those were higher in the AC-cooled greenhouse. The values of internal rate of return in the AC- and EV-cooled greenhouses were 63.4% and 129.3%, respectively. In both greenhouses, lettuce investment was highly sensitive to changes in price, yield and energy cost. The financial performance of the AC-cooled greenhouse in summer was better than that of the EV-cooled greenhouse and the pattern was opposite in winter. Finally, more studies on the optimum LED light intensity for any particular crop have to be conducted over different growing seasons in order to enhance the yield quantity and quality of crop.



Key words： land use efficiency      energy use efficiency      water use efficiency      gross water use efficiency      financial evaluation      air conditioner cooled greenhouse      evaporative cooled greenhouse     
Received: 15 March 2020      Published: 10 April 2021
Corresponding Authors:
About author: * Abdulrahim M Al-ISMAILIA (E-mail: abdrahim@squ.edu.om)
Service
E-mail this article
Add to my bookshelf
Add to citation manager
E-mail Alert
RSS
Articles by authors
AL-MANTHRIA Ibtihal
M AL-ISMAILIA Abdulrahim
KOTAGAMAB Hemesiri
KHANC Mumtaz
JEEWANTHAD L H Janitha
Cite this article:

Ibtihal AL-MANTHRIA, Abdulrahim M AL-ISMAILIA, Hemesiri KOTAGAMAB, Mumtaz KHANC, L H Janitha JEEWANTHAD. Water, land, and energy use efficiencies and financial evaluation of air conditioner cooled greenhouses based on field experiments. Journal of Arid Land, 2021, 13(4): 375-387.

URL:

http://jal.xjegi.com/10.1007/s40333-021-0060-y     OR     http://jal.xjegi.com/Y2021/V13/I4/375

Fig. 1 Illustration of evaporative-cooled (EV-cooled) prototype greenhouse (a) and air conditioner-cooled (AC-cooled) prototype greenhouse (b). The EV-cooled greenhouse is equipped with a fan (A)-pad (B) evaporative cooling system, 200 μm? thick polyethylene plastic sheet (C), and two hydroponic irrigation system frames (D); the AC-cooled greenhouse is equipped with an air conditioner (E), 50 mm thick rockwool insulation material sheet and double layers of polyethylene plastic sheets (F), a small fan (G), two hydroponic irrigation system frames (D), and four different height levels red and blue light emitting diodes (LED) lights (H).
Input/output Unit Energy equivalent Reference
per unit input/output (MJ/hm2)
Energy input Human labour h 1.96 Singh et al. (2002)
Rotavator 2.35 Alam et al. (2005)
Knapsack sprayer 1.40 Gezer et al. (2003)
Seed kg 1.00 Taki et al. (2012)
Diesel-oil L 56.31 Singh and Kamal (2012)
Electricity kW·h 3.60 Ozkan et al. (2011)
Water for irrigation/cooling m3 1.02 Yaldiz et al. (1993)
Nitrogen kg 60.60 Singh et al. (2002)
Phosphorus kg 11.10 Singh et al. (2002)
Potassium kg 6.70 Singh et al. (2002)
Sulfate kg 1.12 Mohammadi and Omid (2010)
Calcium kg 1.12 Mohammadi and Omid (2010)
Micro-nutrients kg 120.00 Banaeian et al. (2011)
Farm yard manure kg 0.30 Taki et al. (2012)
Pesticides kg 196.00 Kuswardhani et al. (2013)
Fungicides kg 168.00 Kuswardhani et al. (2013)
Energy output Crop yield (lettuce) kg 1.20 Hatirli et al. (2005)
Table 1 Energy equivalents of different input and output values used in agricultural production
Performance index AC-cooled greenhouse EV-cooled greenhouse
Yield per cultivation period (kg) 151.50 217.50
LUE (kg/m2) 10.10 14.50
WUE (kg/m3) 100.32 96.52
GWUE (kg/m3) 100.32 1.98
EUE 0.08 0.10
Table 2 Performance of the AC-cooled greenhouse and EV-cooled greenhouse in winter
Item Lifetime (a) Initial investment cost (USD) Annualized investment cost (USD)
Hydroponic irrigation
system frames		 20 1664.00 24.18
PVC accessories 20 36.40 0.52
Aluminum door 10 312.00 7.07
Rockwool sheet with double layers of polyethylene sheets 5 299.00 11.83
Water tank 20 55.90 0.81
Foot valve 3 5.72 0.36
Electrical 1.5 mm wires 10 52.00 1.17
Cooling fans 20 156.00 2.26
AC cooling system 10 390.00 6.80
Irrigation pump 5 23.40 0.93
Binding wires 7 5.20 0.16
Electrical panel enclosure 20 52.00 0.75
LED lights 13 1950.00 36.71
Electrical accessories 5 26.00 1.01
Hydroponic irrigation
system		 20 1248.00 18.12
Installation 20 1170.00 17.00
Water meter* 5 39.00 1.53
Thermocouple wires* 10 1916.20 43.40
Watt meter* 5 67.60 2.68
PAR meter* 10 1625.00 36.79
RHT sensor* 10 1235.00 27.98
Anemometer* 20 1326.00 19.27
pH/EC meter 10 156.00 3.53
Total 13810.42** 288.94
Table 3 Initial capital and annualized investments of an AC-cooled greenhouse (18 m2) with lettuce production in winter
Item Lifetime (a) Initial investment cost (USD) Annualized investment cost (USD)
Hydroponic irrigation
system frames		 20 1664.00 24.18
PVC accessories 20 36.40 0.52
Aluminum door 10 312.00 7.07
Polyethylene plastic sheet 5 65.00 2.57
Water tank 20 55.90 0.81
Foot valve 3 5.72 0.36
Electrical 1.5 mm wires 10 52.00 1.17
Two cooling fans 20 312.00 4.52
Cooling pads 5 143.00 5.67
Irrigation pump 5 23.40 0.93
Binding wires 7 5.20 0.16
Electrical panel enclose 20 52.00 0.75
Electrical accessories 5 26.00 1.04
Hydroponic irrigation system 20 1248.00 18.12
Installation 20 1170.00 17.00
Water meter 5 39.00 1.53
Thermocouple wires 10 1916.20 43.40
Watt meter 5 67.60 2.68
PAR meter 10 1625.00 36.79
RHT sensor 10 1235.00 27.98
Anemometer 20 1326.00 19.27
pH/EC meter 10 156.00 3.53
Total 11535.42** 220.10
Table 4 Initial capital and annualized investments of an EV-cooled greenhouse with lettuce production in winter
Cost and return components AC-cooled greenhouse EV-cooled greenhouse
Total yield in winter (kg) 780.00 1305.00
Price (USD/kg) 4.68 4.68
Gross value of production (USD) 3650.40 6107.40
Variable cost of production (USD) 959.09 1207.44
Fixed cost of production (USD) 266.94 220.06
Total cost of production (USD) 1226.03 1427.50
Per kilogram cost of production (USD/kg) 1.56 1.09
Gross return (USD) 2691.31 4899.96
Net return (USD) 2424.37 4679.89
Benefit-to-cost ratio 2.98 4.28
Financial productivity (kg/USD) 0.63 0.92
Table 5 Agricultural budgets of the AC- and EV-cooled greenhouses in winter
Performance index AC-cooled greenhouse EV-cooled greenhouse
Yield per cultivation period (kg) 102.00 103.20
LUE (kg/m2) 6.80 6.88
WUE (kg/m3) 41.83 30.61
GWUE (kg/m3) 47.77 0.29
EUE 0.03 0.05
Table 6 Performance of the AC- and EV-cooled greenhouses in summer
Cost and return components AC-cooled greenhouse EV-cooled greenhouse
Total yield in summer (kg) 612.00 619.20
Price (USD/kg) 5.20 5.20
Gross value of production (USD) 3182.40 3219.84
Variable cost of production (USD) 1074.68 1603.68
Fixed cost of production (USD) 266.94 220.06
Total cost of production (USD) 1341.62 1823.74
Per kilogram cost of production (USD/kg) 2.18 2.94
Gross return (USD) 2107.71 1616.16
Net return (USD) 1840.77 1396.10
Benefit-to-cost ratio 2.37 1.77
Financial productivity (kg/USD) 0.46 0.34
Table 7 Agricultural budgets of the AC- and EV-cooled greenhouses in summer
Fig. 2 Relationships of the internal rate of return (IRR) with sale price, yield and electricity cost after subsidy in the AC-cooled greenhouse (a, b and c, respectively) and EV-cooled greenhouse (d, e and f, respectively)
[1]   Al-Busaidi H A, Al-Mulla Y A. 2014. Crop water requirement inside conventional versus seawater greenhouses. Acta Horticulturae, 1054, doi: 10.17660/ActaHortic.2014.1054.7.
doi: 10.17660/ActaHortic.2014.1054.7
[2]   Al-Ismaili A, Al-Mezeini N, Jayasuriya H. 2017. Controlled environment agriculture in Oman: facts and mechanization potentials. Ama, Agricultural Mechanization in Asia, Africa & Latin America, 48(2):75-81.
[3]   Al-Mulla Y A. 2006. Cooling greenhouses in the Arabian Peninsula. Acta Horticulturae, 719:499-506.
[4]   Alam M S, Alam M R, Islam K K. 2005. Energy flow in agriculture: Bangladesh. American Journal of Environmental Sciences, 1(3):213-220.
[5]   Avila M R, Begovich O, Ruiz-León J. 2013. An optimal and intelligent control strategy to ventilate a greenhouse. Cancun: IEEE Congress on Evolutionary Computation, 779-782.
[6]   Baird C D, Bucklin R A, Watson C A, et al. 1993. Evaporative cooling system for aquacultural production. In: Fact Sheet EES-100. Gainesville: University of Florida.
[7]   Banaeian N, Omid M, Ahmadi H. 2011. Energy and economic analysis of greenhouse strawberry production in Tehran Province of Iran. Energy Conversion and Management, 52(2):1020-1025.
[8]   Banik P, Ganguly A. 2017. Performance and economic analysis of a floricultural greenhouse with distributed fan-pad evaporative cooling coupled with solar desiccation. Solar Energy, 147:439-447.
[9]   Barbosa G L, Gadelha F D A, Kublik N, et al. 2015. Comparison of land, water, and energy requirements of lettuce grown using hydroponic vs. conventional agricultural methods. International Journal of Environmental Research and Public Health, 12:6879-6891.
[10]   Brechner M, Both A J, CEA (Controlled Environment Agriculture) Staff. 2013. Hydroponic lettuce handbook. Ithaca: Cornell University.
[11]   Castilla N, Baeza E. 2013. Greenhouse site selection. In: Duffy R. Good Agricultural Practices for Greenhouse Vegetable Crops Principles for Mediterranean Climate Areas. Rome: the Food and Agriculture Organization of the United Nations, 21-34.
[12]   Choi H G, Moon B Y, Kang N J. 2015. Effects of LED light on the production of strawberry during cultivation in a plastic greenhouse and in a growth chamber. Scientia Horticulturae, 189:22-31.
[13]   Fadel M A, AlMekhmary M, Mousa M. 2014. Water and energy use efficiencies of organic tomatoes production in a typical greenhouse under UAE weather conditions. Acta Horticulturae, 1054:81-88.
[14]   Fan Y B, Wang C G, Nan Z B. 2014. Comparative evaluation of crop water use efficiency, economic analysis and net household profit simulation in arid Northwest China. Agricultural Water Management, 146:335-345.
[15]   Fang W. 1995. Greenhouse cooling in subtropical regions. Acta Horticulturae, 399:37-48.
[16]   Fath H E S, Abdelrahman K. 2005. Micro-climatic environmental conditions inside a greenhouse with a built-in solar distillation system. Desalination, 171(3):267-287.
[17]   Fernández M D, González A M, Carreño J, et al. 2007. Analysis of on-farm irrigation performance in Mediterranean greenhouses. Agricultural Water Management, 89(3):251-260.
[18]   Fogg L W, Rauhala K R, Satterfield E H, et al. 1979. Controlled environment agriculture facility and method for its operation. America, US4163342. [2020-01-21]. https://www.freepatentsonline.com/4163342.html.
[19]   Folta K M, Childers K S. 2008. Light as a growth regulator: controlling plant biology with narrow-bandwidth solid-state lighting systems. HortScience, 43(7):1957-1964.
[20]   Gezer I, Acaroǧlu M, Haciseferoǧullari H. 2003. Use of energy and labour in apricot agriculture in Turkey. Biomass and Bioenergy, 24(3):215-219.
[21]   Hartz T K, Johnstone P R, Williams E, et al. 2007. Establishing lettuce leaf nutrient optimum ranges through DRIS analysis. HortScience, 42(1):143-146.
[22]   Hasan O, Atilgan A, Buyuktas K, et al. 2009. The efficiency of fan-pad cooling system in greenhouse and building up of internal greenhouse temperature map. African Journal of Biotechnology, 8(20):5436-5444.
[23]   Hatirli S A, Ozkan B, Fert C. 2005. An econometric analysis of energy input-output in Turkish agriculture. Renewable and Sustainable Energy Reviews, 9(6):608-623.
[24]   Heidari M D, Omid M. 2011. Energy use patterns and econometric models of major greenhouse vegetable productions in Iran. Energy, 36(1):220-225.
[25]   Hood K, Snyder R, Walden C. 2005. Budget for greenhouse tomatoes. In: Extension Publication 2257. Mississippi Oxford: Mississippi State University.
[26]   Ioslovich I, Seginer I, Gutman P O, et al. 1995. Sub-optimal CO2 enrichment of greenhouses. Journal of Agricultural Engineering Research, 60(2):117-136.
[27]   Jayasuriya H P W, Al-Ismaili A M, Al-Shukaili T. 2017. Farming systems in Oman and mechanization potentials. Ama, Agricultural Mechanization in Asia, Africa & Latin America, 48(2):66-75.
[28]   Kiyumi K S M. 2009. Greenhouse cucumber production systems in Oman: A study on the effects of cultivation practices on crop diseases and crop yields. PhD Dissertation. Reading: University of Reading.
[29]   Kuswardhani N, Soni P, Shivakoti G P. 2013. Comparative energy input-output and financial analyses of greenhouse and open field vegetables production in West Java, Indonesia. Energy, 53(1):83-92.
[30]   Li F G N, Smith A Z P, Biddulph P, et al. 2015. Solid-wall U-values: heat flux measurements compared with standard assumptions. Building Research & Information, 43(2):238-252.
[31]   MAF (Ministry of Agriculture and Fisheries). 2013. Soilless Agriculture in Greenhouses. Kingston: MAF.
[32]   Mazid A. 2011. Assessing returns from investments in two agricultural development projects (protected agriculture and modern irrigation systems) in the Sultanate of Oman. Muscat: International Centre for Agricultural Research in the Dry Areas.
[33]   Mohammadi A, Omid M. 2010. Economical analysis and relation between energy inputs and yield of greenhouse cucumber production in Iran. Applied Energy, 87(1):191-196.
[34]   Ozkan B, Ceylan R F, Kizilay H. 2011. Comparison of energy inputs in glasshouse double crop (fall and summer crops) tomato production. Renewable Energy, 36(5):1639-1644.
doi: 10.1016/j.renene.2010.11.022
[35]   Salih A R S, Aydrous A E. 2015. Compilation and evaluation of wind energy resources in Jebel Awlia area, South Khartoum. International Journal of Life Science and Engineering, 1(3):97-100.
[36]   Singh A K, Kamal S. 2012. Effect of black plastic mulch on soil temperature and tomato yield in mid hills of Garhwal Himalayas. Journal of Horticulture and Forestry, 4(4):78-80.
[37]   Singh D, Basu C, Meinhardt-Wollweber M, et al. 2015. LEDs for energy efficient greenhouse lighting. Renewable and Sustainable Energy Reviews, 49:139-147.
[38]   Singh H, Mishra D, Nahar N M. 2002. Energy use pattern in production agriculture of a typical village in arid zone, India—part I. Energy Conversion and Management, 43(16):2275-2286.
[39]   Tabook S M, Al-Ismaili A M. 2016. Evaluation of greenhouse cropping systems in Oman. International Journal of Tropical Agriculture, 34(3):715-720.
[40]   Tabook S M. 2017. Evaluating the performance of greenhouse cucumber production in Barka. MSc Thesis. Muscat: Sultan Qaboos University.
[41]   Taki M, Ajabshirchi Y, Mahmoudi A. 2012. Application of parametric and non-parametric method to analyzing of energy consumption for cucumber production in Iran. Modern Applied Science, 6(1):75-87.
[42]   Tawfiq A. 2009. The guidelines for techniques of the protected agriculture in Oman. Muscat: The State of Plant Genetic Resources for Food and Agriculture in Oman.
[43]   Touliatos D, Dodd I C, McAinsh M. 2016. Vertical farming increases lettuce yield per unit area compared to conventional horizontal hydroponics. Food and Energy Security, 5(3):184-191.
[44]   Ünlükara A, Cemek B, Karaman S, et al. 2008. Response of lettuce (Lactuca sativa var. crispa) to salinity of irrigation water. New Zealand Journal of Crop and Horticultural Science, 36(4):265-273.
[45]   Vox G, Teitel M, Pardossi A, et al. 2010. Sustainable greenhouse systems. In: Salazar A, Rios I. Sustainable Agriculture: Technology, Planning and Management. New York: Nova Science Publishers, Inc., 1-79.
[46]   Ward W A. 1997. Cost-Benefit Analysis: Techniques and Applications—with Emphasis upon Energy Sector Applications. Washington D.C.: Economic Development Institute of the World Bank.
[47]   Xu J, Li Y, Wang R Z, et al. 2015. Experimental performance of evaporative cooling pad systems in greenhouses in humid subtropical climates. Applied Energy, 138:291-301.
[48]   Yaldiz O, Ozturk H H, Zeren Y, et al. 1993. Energy usage in production of field crops in Turkey. In: The Fifth International Congress on Mechanization and Energy in Agriculture. Izmir, Turkey:527-536.
[49]   Yoshioka K, Otani M. 2002. Natural feathered fiber insulator. America, US20020034637. [2020-01-15]. https://www.freepatentsonline.com/y2002/0034637.html.
[1] Teame G KEBEDE, Emiru BIRHANE, Kiros-Meles AYIMUT, Yemane G EGZIABHER. Arbuscular mycorrhizal fungi improve biomass, photosynthesis, and water use efficiency of Opuntia ficus-indica (L.) Miller under different water levels[J]. Journal of Arid Land, 2023, 15(8): 975-988.
[2] Mohamed K EL-GHANNAM, Fatma WASSAR, Sabah MORSY, Mohamed HAFEZ, Chiter M PARIHAR, Kent O BURKEY, Ahmed M ABDALLAH. Controlled drainage in the Nile River delta of Egypt: a promising approach for decreasing drainage off-site effects and enhancing yield and water use efficiency of wheat[J]. Journal of Arid Land, 2023, 15(4): 460-476.
[3] HAN Mengxue, ZHANG Lin, LIU Xiaoqiang. Subsurface irrigation with ceramic emitters improves wolfberry yield and economic benefits on the Tibetan Plateau, China[J]. Journal of Arid Land, 2023, 15(11): 1376-1390.
[4] Halimeh PIRI, Amir NASERIN, Ammar A ALBALASMEH. Interactive effects of deficit irrigation and vermicompost on yield, quality, and irrigation water use efficiency of greenhouse cucumber[J]. Journal of Arid Land, 2022, 14(11): 1274-1292.
[5] JIA Hao, WANG Zhenhua, ZHANG Jinzhu, LI Wenhao, REN Zuoli, JIA Zhecheng, WANG Qin. Effects of biodegradable mulch on soil water and heat conditions, yield and quality of processing tomatoes by drip irrigation[J]. Journal of Arid Land, 2020, 12(5): 819-836.
[6] PEI Yanwu, HUANG Laiming, SHAO Ming'an, ZHANG Yinglong. Responses of Amygdalus pedunculata Pall. in the sandy and loamy soils to water stress[J]. Journal of Arid Land, 2020, 12(5): 791-805.
[7] ZHOU Honghua, CHEN Yaning, ZHU Chenggang, YANG Yuhai, YE Zhaoxia. Water transport and water use efficiency differ among Populus euphratica Oliv. saplings exposed to saline water irrigation[J]. Journal of Arid Land, 2019, 11(6): 866-879.
[8] Shanshan JIN, Youke WANG, Xing WANG, Yonghong BAI, Leigang SHI. Effect of pruning intensity on soil moisture and water use efficiency in jujube (Ziziphus jujube Mill.) plantations in the hilly Loess Plateau Region, China[J]. Journal of Arid Land, 2019, 11(3): 446-460.
[9] RUDIKOVSKII Alexandr, RUDIKOVSKAYA Elena, DUDAREVA Lyubov. Impact of air drought on photosynthesis efficiency of the Siberian crabapple (Malus baccata L. Borkh.) in the forest-steppe zone of Transbaikalia, Russia[J]. Journal of Arid Land, 2019, 11(2): 255-266.
[10] Jing ZHENG, Junliang FAN, Fucang ZHANG, Shicheng YAN, Jinjin GUO, Dongfeng CHEN, Zhijun LI. Mulching mode and planting density affect canopy interception loss of rainfall and water use efficiency of dryland maize on the Loess Plateau of China[J]. Journal of Arid Land, 2018, 10(5): 794-808.
[11] Xiaobing LI, Qi HUANG, Xue MI, Yunxiao BAI, Meng ZHANG, Xu LI. Grazing every month minimizes size but boosts photosynthesis in Stipa grandis in the steppe of Inner Mongolia, China[J]. Journal of Arid Land, 2018, 10(4): 601-611.
[12] Xiaotao HUANG, Geping LUO, Feipeng YE, Qifei HAN. Effects of grazing on net primary productivity, evapotranspiration and water use efficiency in the grasslands of Xinjiang, China[J]. Journal of Arid Land, 2018, 10(4): 588-600.
[13] Xuelian JIANG, Ling TONG, Shaozhong KANG, Fusheng LI, Donghao LI, Yonghui QIN, Rongchao SHI, Jianbing LI. Planting density affected biomass and grain yield of maize for seed production in an arid region of Northwest China[J]. Journal of Arid Land, 2018, 10(2): 292-303.
[14] Hui RAN, Shaozhong KANG, Fusheng LI, Taisheng DU, Risheng DING, Sien LI, Ling TONG. Responses of water productivity to irrigation and N supply for hybrid maize seed production in an arid region of Northwest China[J]. Journal of Arid Land, 2017, 9(4): 504-514.
[15] Jie BAI, Jin WANG, Xi CHEN, GePing LUO, Hao SHI, LongHui LI, JunLi LI. Seasonal and inter-annual variations in carbon fluxes and evapotranspiration over cotton field under drip irrigation with plastic mulch in an arid region of Northwest China[J]. Journal of Arid Land, 2015, 7(2): 272-284.