Irrigation management practices that reduce water use with acceptable impacts on yield are important strategies to cope with diminished water supplies and generate new sources of water to transfer for other agricultural uses, and urban and environmental demands. This study was intended to assess the effects of moderate water deficits, with the goal of maintaining robust alfalfa (Medicago sativa L.) yields, while conserving on-farm water. Data collection and analysis were conducted at four commercial fields over an 18-month period in the Palo Verde Valley, California, from 2018–2020. A range of deficit irrigation strategies, applying 12.5–33% less irrigation water than farmers’ normal irrigation practices was evaluated, by eliminating one to three irrigation events during selected summer periods. The cumulative actual evapotranspiration measured using the residual of energy balance method across the experimental sites, ranged between 2,031 mm and 2.202 mm, over a 517-day period. An average of 1.7 and 1.0 Mg ha−1 dry matter yield reduction was observed under 33% and 22% less applied water, respectively, when compared to the farmers’ normal irrigation practice in silty loam soils. The mean dry matter yield decline varied from 0.4 to 0.9 Mg ha−1 in a clay soil and from 0.3 to 1.0 Mg ha−1 in a sandy loam soil, when irrigation water supply was reduced to 12.5% and 25% of normal irrigation levels, respectively. A wide range of conserved water (83 to 314 mm) was achieved following the deficit irrigation strategies. Salinity assessment indicated that salt buildup could be managed with subsequent normal irrigation practices, following deficit irrigations. Continuous soil moisture sensing verified that soil moisture was moderately depleted under deficit irrigation regimes, suggesting that farmers might confidently refill the soil profile following normal practices. Stand density was not affected by these moderate water deficits. The proposed deficit irrigation strategies could provide a reliable amount of water and sustain the economic viability of alfalfa production. However, data from multiple seasons are required to fully understand the effectiveness as a water conservation tool and the long-term impacts on the resilience of agricultural systems.
We measured the gas exchange parameters of six onion varieties in two photoperiodic regimes. The photoperiods simulated early (long-day) and late (short-day) onion growing seasons of the high desert regions near Lancaster, California. We used six locally grown onion varieties: RedBull (RB), RedWing (RW), Hybrid Cometa (HC), Granero (YG), Hybrid Valero (HV) and Hybrid SR (HS). For both photoperiod regimes, daylength and temperature were changed weekly to represent the natural progression of field growing conditions. The results show that the onion plants grown under short-daylength (SD) and higher temperature regimes exhibited higher leaf photosynthetic rates and stomatal conductance than onion seedlings grown under the long-day (LD) regime. Onion plants also had different functional leaf traits depending on crop growth environment during the onset of bulbing. The higher photosynthetic rate of the short-day plants coincided with bulb initiation. Onion photosynthesis and stomatal conductance increased at bulb initiation, apparently to provide carbohydrates for growth and storage in the bulb.
Alfalfa (Medicago sativa L.) is an important crop for the low desert region of southwestern United States. A field study was conducted to evaluate tolerance of established nondormant conventional alfalfa to saflufenacil applied during the summer slump. Treatments consisted of saflufenacil applied alone at 0.7 or 1.4 oz ac −1 , or saflufenacil at 0.7 oz ac −1 tank-mixed with imazamox, bromoxynil, or metribuzin at 0.8, 6.0, or 16.0 oz ac −1 , respectively. Methylated seed oil (as surfactant) and ammonium sulfate (as adjuvant) were tank-mixed at 1 and 2.5% (v/v), respectively, to each herbicide treatment. At 2 d after treatment, alfalfa injury from saflufenacil at the lower rate was lowest (21%); whereas the injury was highest (48%) from saflufenacil plus bromoxynil treatment. The alfalfa injury progressed for 2 wk after treatment (WAT) and was >36% for all treatments except for saflufenacil at the lower rate. Crop recovery was observed about 2 WAT and minimal injury (<3%) occurred at 4 WAT. Alfalfa height was similar across herbicide treatments and the weed-free (non-treated) control. At 4 WAT, average alfalfa height for all treatments was 11 inches or greater. The alfalfa injury observed during the initial weeks did not translate into biomass yield reduction. Accordingly, there was no significant difference in alfalfa biomass yield among the treatments. Overall, alfalfa biomass yield was 0.57 and 0.47 ton ac −1 or greater at 4 WAT (1st cutting) and 8 WAT (2nd cutting), respectively, after herbicide application. Our results illustrate that saflufenacil and its tank-mix with imazamox, bromoxynil, or metribuzin caused injury to nondormant conventional alfalfa during early weeks, but alfalfa recovered by 2 wk after herbicide application without height and biomass yield reduction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.