|SIMPSON, CATHERINE - Texas A&M University|
|KING, STEPHEN - Millican Farms, Llc Tx|
|VOLDER, ASTRID - University Of California, Davis|
Submitted to: Sustainability
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2018
Publication Date: 3/1/2018
Citation: Simpson, C.R., Franco Jr, J.G., King, S.R., Volder, A. 2018. Intercropping halophytes to mitigate salinity stress in watermelon. Sustainability. 10(3):681. https://doi.org/10.3390/su1003068.
Interpretive Summary: Halophytes are plants that can potentially take up salts that have built-up in soils where saline irrigation water is used. This is important in dry farming regions that rely heavily on irrigation. Yields of high-value crops such as watermelon can be reduced under salty conditions. Intercropping, growing two or more crops together, can be a way to reduce stress on cash crops. In this study, we identified two halophytic plants, garden orache and purslane, that could be intercropped with watermelon under field production conditions. Intercropping with garden orache resulted in yields comparable or higher than watermelon grown alone. In addition, salinity or intercropping did not harm watermelon growth or fruit quality. This suggests intercropping watermelon with garden orache adds value for producers interested in diversifying production. This result is important to producers and water management officials, showing a way to increase overall crop production under salty conditions.
Technical Abstract: Regional water resources throughout the U.S. and in semi-arid and arid regions throughout the world are declining in both quantity and quality. Irrigation with water high in salts can lead to the buildup of salts within the soil profile and in crop yield declines. Halophytic plants are known to accumulate excess salts in tissues, removing them from the immediate environment. This two-phase experiment explored the feasibility of intercropping watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus] with halophytic or semi-halophytic plant species as a way of mitigating the negative effects of saline irrigation water while providing a value-added crop. In the first experiment, six species were grown in the greenhouse and irrigated with water that was either deionized (0 dS m-1) or contained 3 or 6 dS m-1 of salts for 41 days and screened for their ability to remove salts from soil and accumulate them in tissues. Based on results from the first phase, two halophytes were selected to be additively intercropped with watermelon under field conditions and irrigated with the same saline irrigation levels as the first experiment. Results from phase one indicated that garden orache (Atriplex hortensis L.) exhibited the highest growth rates and purslane (Portulaca oleracea) accumulated high amounts of sodium (Na) in plant tissues under saline irrigation. In addition, while other species also exhibited good growth rates and accumulation of salts, is was believed these two species would be more competitive with watermelon under field conditions. Results from the field experiment showed that watermelon yields were not affected by saline irrigation; however, the watermelon/orache (W/O) intercropping treatment had significantly higher yields. Furthermore, salinity and intercropping treatment had no effect on fruit quality or water potential. These results indicate that intercropping with halophytes has the potential to contribute a value added crop without reducing watermelon yields.