*2.6. Data Analysis*

All statistical analyses were conducted using SAS [35]. The data were analyzed using Tukey-Kramer test for comparing pair wise differences of means [36]. Variables compared included water applied (mm), crop yield (kg/ha), soil moisture (%vol.), LAI, above ground biomass (kg/ha) and economic productivity of water (US\$/ha-cm). The economic productivity of water was calculated using the income (I, \$) from crop yield and volume of water applied (ha-cm, irrigation plus rainfall) [37] as:

$$Economic\ productivity\ of\ water = \frac{I(\\$)}{Water\ applied\ (\text{Ha}-\text{cm})}$$

Average farm gate paddy price of 550 Tanzanian Shillings TZS/kg [38] and prevailing exchange rate (1 US\$ = 1600 TZS) during 2013 was used to calculate the income (I).
