Feasibility analysis of substituting gutters in NFT system network for horticulture production with corrugated roof sheet

Abstract

Hydroponic cultivation with nutrient film technique (NFT) is an alternative solution for problems in horticulture production, especially those related with land limitations and climate problems. However, high investment requirements often become obstacles in applying the technique. This paper discusses the feasibility analysis of substituting the commonly used gutters in NFT system network for horticulture production with corrugated roof sheet, i.e. tarpaulin-covered corrugated asbestos roof sheet. The technical feasibility analysis was carried out based on a number of parameters, i.e. the uniformity of nutrients solution flow rate at the inlet and outlet, the uniformity of nutrients solution depth in the NFT network, the uniformity of nutrients solution concentration in the network, and the uniformity of produced plant weights. Meanwhile the financial feasibility analysis was carried out by Net Present Value (NPV) analysis, Net B/C analysis, and Internal Rate of Return (IRR) analysis of horticulture production. The results of the analysis were compared with those of NFT network system using gutters. The results indicated that uniformity of flow rate, the uniformity of nutrients solution concentration in terms of electrical conductivity and degrees of acidity, the uniformity of depth of flow and plant weight were close to 90%. This means that the proposed hydroponic technique can be applied. Using assumptions derived from productivity of tested horticulture commodities and the actual market prices of inputs as well as output, hydroponic techniques with NFT networks using tarpaulin-covered corrugated asbestos roof sheet was also financially feasible.