European Borage (Borago officinalis L.) Yield and Profitability under Different Irrigation Systems
European borage (Borago officinalis L.) is a cultivated medicinal plant in Iran, but common agronomic practices about profitable cultivation are mostly unknown. A 2-yr field experiment (2013 and 2014) was conducted in Guilan Province of northern Iran to evaluate European borage yield and profitability under irrigation with surface and drip irrigation systems. Treatments included (i) rainfed production (I0, control), (ii) single irrigation (I1) applied with surface irrigation alone and drip irrigation alone, and (iii) two irrigations (I2) applied with surface irrigation alone and drip irrigation alone. In 2013, I1 increased flower dry weight by 41.0% and seed weight by 7.1% compared with rainfed European borage, while with I2, the increases in those traits were 23.4% and 0.6%, respectively. In 2014, I1 increased flower dry weight by 78.0% and seed weight by 21.3% compared with rainfed European borage, while the respective increases were 51.8% and 17.3% with I2. On average, drip irrigation provided higher flower dry weight and seed weight by 39.3% and 12.6%, respectively, compared with surface irrigation. Drip irrigation increased variable costs by 165.2% compared with surface irrigation but resulted in increased gross income by 23.2%. Partial budgeting showed that I1 with drip irrigation provided the maximum net profit in both years. Based on the final rate of return, investing in the treatment I1 with drip irrigation was better than investing in the other treatments. Moreover, I1 with drip irrigation showed the highest value of economic water productivity and could be considered for improving the net income of European borage farmers.