Rooftop gardening and economic benefits

Covid-19, a pandemic, which won’t allow us to go out of house due to lockdown. At this time, we can work in some sorts on our roofs to supply the nutrient sources for daily requirements. All we can get is healthy, fresh and unpolluted fruits and plant products. A survey conducted by Thapa et al. ((Thapa et al., 2020)) during covid-19 period reported that all of the respondents from dhulikhel has positive response towards rooftop gardening. The ease of rooftop farming can be presented as use of plastic bins and plastic bags and some bottles to plant vegetables and flowers which is easily available in our own kitchen.

Next, second step telephone survey was conducted from Kathmandu to know about the status of rooftop garden. There we reported that 7% of the roof was covered by rooftop garden and if we compare to rural setting 10-15% of the land is covered by home garden used to supply for daily food requirement. The much more benefit than table requirement of rooftop farming are ecosystem services.

Ecosystem services includes all of those components from food supply to environmental settings. Something new to Nepal and most probably very secondly presented article which is in press now has dealt a lot about ecosystem services which includes food production value, carbon sequestration value, air quality and storm water retention. All of these will be expressed in terms of monetary value. A strong methodology was adopted while conducting survey as proposed by (Tomalty et al., 2010) cited from (Kumar et al., 2019; Safayet et al., 2017). Details of the calculation are:

Food production value (b)= P×g× a

Where p=productivity ($2 per square meter per month and for lettuces, herbs, and flowers (high case scenario) $20 per square meter per month)       

g= duration of growing; as crops were grown all the year so it is taken as 12 month

a= area of the roof covered by a garden in M²

Strom water retention (b)= (R+E) ×C× a

R= retention basin, $20.13 for pond and highest value 1059.44/m³

E= Value of erosion mitigation i.e. $13.66/ m³

C= retention capacity, $42.7/m²

a= area of rooftop garden in m²

Air Quality (b)= (g /months) [H­­­_sg ×a_sg + H_tg× a_tg × H_d× a_d]

Where,

H­­­_sg, H_tg, H_d represents the health benefit for short grass pollution absorption (0.0521 US$/m2), for tall herbaceous plant pollution absorption(0.0673 US$/m2), and for deciduous plant pollution absorption (0.0839 US$/m2) per year respectively.

a_sg = area covered by short grasses

a_tg = area covered by tall herbaceous cops

a_d = area covered by deciduous plants

Carbon Sequestration Value (b)= S_d× a_d + S_g× a_g + S_f ×a_f

Where, S_d, S_g, and S_f represents the value of carbon sequestration by deciduous plants ($39.11/ha,), by grasses ($28.46/ha), and by productive agriculture ($28.59/ha),

a_d= area covered by deciduous crops

a_g= area covered by grasses

a_f= area covered by productive agriculture

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#socialscience survey
#ecosystemservices
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#gokuleshwor agriculture and animal science college
#preprintreview
#foodquality

#mendeley citations

Anyone interested in survey fell free to contact for research design, statistical analysis, research methodology and social science survey design.

Email: sand.thapa.2056@gmail.com

References

Kumar, J.R., Natasha, B., Suraj, K., Kumar, S.A., Manahar, K., 2019. Rooftop Farming: an Alternative To Conventional Farming for Urban Sustainability. Malaysian J. Sustain. Agric. 3, 39–43. https://doi.org/10.26480/mjsa.01.2019.39.43

Safayet, M., Arefin, M.F., Hasan, M.M.U., 2017. Present practice and future prospect of rooftop farming in Dhaka city: A step towards urban sustainability. J. Urban Manag. 6, 56–65. https://doi.org/10.1016/j.jum.2017.12.001

Thapa, S., Bhandari, R., Nainabasti, A., 2020. Survey on people’s attitudes and constraints of rooftop gardening in Dhulikhel Municipality, Nepal. Ecofeminism Clim. Chang. J. https://doi.org/10.1108/EFCC-04-2020-0008

Tomalty, R., Komorowski, B., Doiron, D., 2010. The monetary value of the soft benefits of green roofs. Final Rep.