3.1.2. Irrigation and Water Conservation Practices

Grower irrigation practices are summarized in Table 3. Groundwater was the principal source of water for irrigation with 93 percent of respondents identifying it as a source. On average, eight-hundred eighty-nine hectares were irrigated with groundwater with a maximum of 4856 ha relying on that source for irrigation. Surface water was also employed for irrigation including streams and bayous, which are the source for 178 ha on average. The surface sources can also be complemented with OFWS, 11.5 percent of responses, and TWS in 14.2 percent of responses. Some growers built OFWS and TWS capable of fully supplying the irrigation water needs for some of their fields. Producers relying on groundwater from a depletable aquifer were expected to be more inclined to adopt water conservation practices.

The predominant irrigation practice was furrow irrigation for row-crops, which was employed by 86 percent of respondents on an average of 823 ha. Practices that improve the performance of furrow irrigation are deep tilling, employed by 71 percent of the respondents, computerized hole selection (CHS), adopted by 59 percent of growers, and surge irrigation, adopted by 24 percent of farmers in the sample. The last two are considered water-conserving practices for which we sought to find determining adoption factors. Irrigation systems with higher application efficiency are also considered water conservation practices. Micro irrigation was very rare with only 3.4 percent of respondents employing it on an average of 65 ha; while center pivot sprinkler use was more widespread with 60 percent of respondents having used it on an average of 370 ha.

Irrigation scheduling is a crucial component of irrigation water management. The use of Soil Moisture Sensors (SMS) for scheduling has the potential to save as much as 50 percent of total water applied [30]. Agronomic studies in the area showed that SMS could help improve water use efficiency in furrow irrigated soybeans [7] and corn [10] by reducing water use without reductions in yields when compared to conventional farmer-managed scheduling.

Flow-meters at the irrigation wells are another important management tool. Nearly 70 percent of participant growers owned them. A voluntary metering program in Mississippi encourages their use, and participation in NRCS incentive programs makes participation in that program mandatory for their cooperators. Another pump accessory is the pump timer, which allows the irrigation events to be started or stopped automatically. Almost 44 percent of respondents employed pump timers on an average of 11 pumps.

Finally, the energy source for the pump power units varied with most growers having more than one type of energy source. Electricity was the most common energy source with 85 percent of farmers claiming it. Diesel was the second most common source with almost 80 percent of respondents using it. The energy source mix is important in calculating irrigation pumping costs. The average cost of pumping was estimated at USD 0.0538 per megaliter.


**Table 3.** Summary statistics of irrigation practices.

Note: OFWS is On-Farm Water Storage; TWS is Tailwater Recovery System.
