*3.2. Tuber Yield*

A common yield value for the Hermes cultivar in the Arava region is approximately 40 ton ha−<sup>1</sup> [14]. The potato yield from this study (3rd year) attained that value and was similar to the results obtained from the study two years earlier. This supports the evidence that the yield under low-discharge drip irrigation is similar to that reported for sprinkler irrigation and ranges from 30 to 50 ton ha−<sup>1</sup> [11,35,36]. In Figure 2, the results obtained for the total tuber yield as a function of nitrogen (F0, 50 100%) and water doses (W40, 60, 80, 100%) are presented. For a given nitrogen treatment, no significant differences for tuber yield were found between the irrigation doses, excluding the F0% treatment where tuber yield under the W80% irrigation dose was found to be significantly higher than the lower (i.e., W40% and W60%) and higher (i.e., W100%) irrigation doses. A possible explanation for this observation may be attributed to the nitrogen availability. Specifically, since the only source of nitrogen in the F0% treatment is from the applied compost, the rate and extent of its release from the solid compost to the soil solution will govern its availability. In this regard, an irrigation dose lower than W80% may not be sufficient while the higher irrigation dose (i.e., W100%) may leach the available nitrogen from the root zone. Figure 2 suggests that some saving of water and fertilizer are possible. However, additional parameters should be considered in order to conclude the optimal irrigation and fertigation regime.

**Figure 2.** Potato tuber yield (ton ha<sup>−</sup>1) as a function of irrigation and fertigation regime. Values with the same letter are not significantly different (*p* < 0.05).
