Productivity of Drought-Tolerant Alternative Crops Subjected to Water-Limiting Conditions in West Texas

The declining water availability from the Ogallala aquifer and erratic drought events are posing serious threats to the economic stability of agriculture in West Texas. Adoption of water-conserving strategies such as growing low-input and drought-tolerant alternative crops together with high-value crops is a possible solution in improving agricultural productivity and farmers’ profitability. A field experiment was conducted in 2017 at New Deal, Lubbock, Texas to evaluate the productivity of cotton and six alternative crops (guar, pearl millet, safflower, sesame, sorghum, and sunflower) grown under four different levels of deficit irrigation (DI: extreme - 51 mm, severe - 127 mm, moderate - 203 mm, and mild- 279 mm) based on physiological responses to available water, soil water extraction patterns, and agronomic yield. An economic analysis was also performed to determine DI treatment profitability based on revenues above variable costs per hectare. Results showed that the crops’ adaptations to deficit irrigation conditions were associated to an extension of rooting depths to extract water deeper in the soil, regulated water loss from the leaves, and restricted transpiring area. Among deficit irrigation treatments, the yield losses for each crop were minimized. Harvest index and water use efficiency were affected by varying deficit irrigation levels, however, the differences were not substantial. For all crops except sorghum and sunflower, the economic analysis showed that in 2017 growing season, on a per hectare basis, it was economically justifiable to use irrigation amounts lower than mild DI in growing these crops, particularly when water supplies are limited. Under deficit irrigation conditions, the revenues above variable costs per hectare generated from pearl millet, sesame, and sorghum showed that these crops could be grown together with cotton in the same field, with the possibility of more economic return and less income risk than growing cotton alone.

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