Percent emergence of kenaf as affected by irrigation regimes and soil surfactant treatments during Expt. 1 at Fort Lauderdale Research and Education Center (FLREC) from 15 Aug to 6 Sep 2023. Irrigation regimes: ED = every day; EOD = every other day; and E4D = every 4 d. Soil surfactant treatments: Yes = one-time application of soil surfactant; No = no soil surfactant application. The same letter above the bars on each date indicates that the data were not significantly different.
Percent emergence of kenaf as affected by irrigation regimes and soil surfactant treatment in Expt. 2 at the Fort Lauderdale Research and Education Center (FLREC) from 8 Dec 2023 to 27 Jan 2024. Irrigation regimes: ED = every day; EOD = every other day; and E4D = every 4 d. Soil surfactant treatments: No = no soil surfactant application; ×1 = label rate of soil surfactant application; and ×2 = double the label rate of soil surfactant application. The same letter above the bars on each date indicates that the data were not significantly different. No letter above the bars indicates P > 0.05.
Effects of irrigation regimes and soil surfactant treatments on the percent volumetric water content of Hallandale fine sand in Expt. 1 at the Fort Lauderdale Research and Education Center (FLREC) from 15 Aug to 6 Sep 2023. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. The same letters above the bars within each category indicate that the data were not significantly different. DAP = days after planting. Irrigation regimes: ED = every day; EOD = every other day; and E4D = every 4 d. Soil surfactant treatments: Yes = one-time application of soil surfactant; No = no soil surfactant application.
Effects of irrigation regime and soil surfactant treatment on the percent volumetric water content of Hallandale fine sand in Expt. 2 at the Fort Lauderdale Research and Education Center (FLREC) from 8 Dec 2023 to 27 Jan 2024. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. The same letters above the bars within each category indicate that data were not significantly different. DAP = days after planting. Irrigation regimes: EDN = every day; − soil surfactant; ED×1 = every day; ×1 soil surfactant; ED×2 = every day; ×2 soil surfactant; EODN = every other day; − soil surfactant; EOD×1 = every other day; ×1 soil surfactant; EOD×2 = every other day; ×2 soil surfactant; E4DN = every 4 d; − soil surfactant; E4D×1 = every 4 d; ×1 soil surfactant; E4D×2 = every 4 d; and ×2 soil surfactant.
The percent volumetric water content in native sand soil during Expt. 1 at the Fort Lauderdale Research and Education Center (FLREC) from 15 Aug to 6 Sep 2023. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. Irrigation regimes: EDN = every day; − soil surfactant; EDS = every day; + soil surfactant; EODN = every other day; − soil surfactant; EODS = every other day; + soil surfactant; E4DN = every 4 d; − soil surfactant; E4DS = every 4 d; and + soil surfactant.
The percent volumetric water content in native sand soil during Expt. 2 at the Fort Lauderdale Research and Education Center (FLREC) from 8 Dec 2023 to 27 Jan 2024. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. Irrigation regimes: EDN = every day; − soil surfactant; ED×1 = every day; ×1 soil surfactant; ED×2 = every day; ×2 soil surfactant; EODN = every other day; − soil surfactant; EOD×1 = every other day; ×1 soil surfactant; EOD×2 = every other day; ×2 soil surfactant; E4DN = every 4 d; − soil surfactant; E4D×1 = every 4 d; ×1 soil surfactant; E4D×2 = every 4 d; and ×2 soil surfactant.
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Kenaf (Hibiscus cannabinus) is a fiber crop that grows well in tropical climates and has numerous potential industrial and environmental benefits. However, like many crops, it may be limited by sensitivity to water stress, particularly at the seedling stage. Soil surfactants are frequently used as soil amendments to increase the volumetric water content (VWC), particularly under deficit irrigation. Two greenhouse experiments were conducted to determine the emergence and growth response of kenaf to three irrigation regimes and a one-time soil surfactant application. Kenaf seeds were planted in native Margate fine sand soil (siliceous, hyperthermic Mollic Psamnaquent) and sprayed with a nonionic surfactant at 3 quarts/acre (7.5 L/ha) (1×) and subjected to three irrigation regimes of 3.5 ounces (100 mL) of water applied every day (ED), every other day (EOD), or every 4 days (E4D). In Expt. 2, an additional surfactant treatment applied at 6 quarts/acre (15 L/ha) (2×) was included. The percent emergence, plant height, postexperiment biomass, and volumetric water content data were collected. During Expt. 1, kenaf emergence was significantly inhibited by ED irrigation with 1× when compared with E4D with 1×. In Expt. 2, seed treated with the 2× rate emerged faster and had better overall emergence under all irrigation regimes when compared with no soil surfactant. There was a trend for better kenaf emergence when less water was applied. The ED irrigation increased biomass in both experiments; however, in Expt. 2, the 2× rate doubled the biomass in the ED irrigation regime, and both 1× and 2× rates increased biomass in the EOD and E4D irrigation regimes. Soil surfactant treatment significantly increased the VWC in ED in Expt. 1 on four dates; however, in Expt. 2, both surfactant treatments increased the VWC in E4D irrigation until 35 days after planting. The results of this experiment suggest that a one-time soil surfactant treatment did not inhibit kenaf emergence under any irrigation regime. Kenaf emergence and biomass was greater and VWC was lower when a 2× rate of soil surfactant was applied to soil. In hydrophilic disturbed native sand soils, a one-time soil surfactant application increased kenaf emergence under deficit irrigation and the 2× rate of soil surfactant increased biomass under every irrigation regime. To maximize water savings, this study indicated that kenaf seed could withstand four-times less water to improve emergence. To maximize biomass, ED irrigation with a 2× soil surfactant treatment was significantly better.
Kenaf (Hibiscus cannabinus) is a tropical, fibrous crop that belongs to the Malvaceae family. Initially, kenaf was of interest to the United States government for rope and cordage during World War II. Subsequently, government-funded research evaluated kenaf for paper pulp production because of its fast growth, low lignin content, and naturally white paper production. Globally, kenaf has been used for paper pulp production (Ang et al. 2010), engineered wood (Anyanwu et al. 2019), plastic composites (Akil et al. 2011; Deng et al. 2013; Saba et al. 2015), a high protein food source (Robinson 1988), livestock feed (Webber 1993), and textile production (Lips and van Dam 2013). Despite its versatility, most kenaf is grown predominantly in India or China. However, kenaf has been grown successfully in the United States as far north as Massachusetts.
Environmentally, kenaf can improve soil health as well as sequester greenhouse gases. Researchers in Japan found that kenaf, when planted densely (220,000–500,000 plants/ha), fixed twice as much carbon dioxide as that fixed by trees in a tropical rainforest (Lam et al. 2003). Kenaf plants can also hyperaccumulate cadmium, lead, chromium, and arsenic from a variety of contaminated soils (Ding et al. 2016; Guo et al. 2023; Mun et al. 2008; Nizam et al. 2016). As a warm-season crop, kenaf is known to thrive in tropical climates. Francois et al. (1992) found that kenaf is salt-tolerant with sodium sequestered in the woody tissue and chloride in the leaves. During a drought tolerance experiment, kenaf survived under extensive drought stress and 3- to 4-week intervals of no irrigation, but biomass accumulation was reduced (Ogbonnaya et al. 1998). Tolerance to drought and salinity also makes kenaf an ideal crop for water-limited croplands or those with low water quality. However, when water is not limited, kenaf will use water uptake via greater stomatal conductance and transpiration, thus making kenaf an ideal option for areas that periodically receive rainfall or irrigation (Scordia et al. 2013). The versatility of kenaf is well-documented.
Soil surfactants can be used to improve germination and establishment of crops under deficit irrigation. Soil surfactants can improve the wettability of the soil by first mitigating soil water repellence, and then by improving the soil volumetric water content (VWC) distribution (Kostka et al. 2007). Leinauer et al. (2001) reported significant increases in water retention with an application of a nonionic soil surfactant in a sand-based soil column. Soil surfactants increased the soil water content by 5% in potato hills and increased potato yield (Cooley et al. 2009). Similarly, the soil surfactant application increased the total dry matter and grain yield in corn (Chaichi et al. 2015). Soil surfactants may be directly applied via spray application to the soil before or after planting, or they may be applied as a seed coating (Madsen et al. 2016).
Seed tolerance to soil surfactant applications varies widely. Onion (Allium cepa) germination and lettuce (Lactuca sativa) germination have been shown to be affected by the rates and chemistry of applied soil surfactants (Gálvez et al. 2019). A rate titration effect was found when sodium dodecyl sulfate soil surfactant was applied to wheat seedlings (Triticum aestivum). The higher the rate, the more seed germination that was inhibited (Chang et al. 2015). Alternatively, direct application of a nonionic soil surfactant to cool-season grasses, tall fescue (Schedonorus arundinaceus), and perennial ryegrass (Lolium perenne) enhanced turfgrass germination and establishment under deficit irrigation (Madsen et al. 2016). Soil surfactant chemistry and rates play a key role in seed germination, emergence, and plant establishment.
Although germination rates of kenaf have been found to be inhibited by low soil temperatures (Curtis and Läuchli 1985), kenaf was relatively immune to saline conditions during germination. Kenaf emergence after soil surfactant application, under deficit irrigation, and under high temperatures is not known. The objective of this research was to determine whether the emergence and establishment of kenaf under deficit irrigation and high temperatures could benefit from the one-time application of a nonionic soil surfactant.
Two greenhouse experiments were conducted at the University of Florida’s Institute of Food and Agricultural Sciences, Fort Lauderdale Research and Education Center (FLREC), Davie, FL, USA. Expt. 1 and Expt. 2 were conducted from 15 Aug 2023 to 6 Sep 2023 and from 8 Dec 2023 to 27 Jan 2024, respectively. Both experiments were conducted until plants exhibited nutrient deficiency. Kenaf (Hibiscus cannabinus, var. “Whitten”) seeds were sown in 5-inch (12.7-cm)-diameter plastic pots filled with native Margate fine sand soil (siliceous, hyperthermic Mollic Psamnaquent) and watered to field capacity 1 d before seeding. Kenaf seeds were planted at three seeds/pot at a 0.5-inch (1.25-cm) depth and lightly top-dressed with native soil. Pots that received a soil surfactant application were sprayed with Quickin™ (Precision Laboratories, Chicago, IL, USA). Quickin™ irrigation soil surfactant is a multipurpose nonionic soil surfactant that significantly reduces the surface tension of water and improves the movement of rainfall and irrigation into agricultural soils. It is a combination of primary alcohol ethoxylate soil surfactant and alkyl aryl sulfonate. Soil surfactant rates were applied at 1× [3 quarts/acre (7.5 L/ha), high label rate] or 2× [6 quarts/acre (15 L/ha)] delivered in a water volume of 4 gal/1000 ft2 (180 mL/m2) using a CO2 spray boom assembly with one nozzle (Tee Jet 8006 ceramic tip). The surfactant application rate of Expt. 1 was 1× only. All pots, including those with the surfactant treatment, received a water-only spray applied as a delivery rate of 4 gal/1000 ft2 (180 mL/m2) to move surfactant into the soil. Irrigation frequency treatments were initiated the following day. Based on the evapotranspiration (ET) replacement over 4 d, a 3.5-ounce (100-mL) volume was imposed for all irrigation regimes. In Expt. 1, six treatments were performed as follows: 100 mL every day + soil surfactant (EDS); 100 mL ED − soil surfactant irrigation (EDN); 100 mL every other day + soil surfactant; 100 mL every other day – soil surfactant (EON); 100 mL every 4 d + soil surfactant; and 100 mL every 4 d − soil surfactant (E4N). In Expt. 2, a 2× rate of surfactant was added, but the irrigation rates and frequency remained the same (ED2×, EO2×, E42×), for a total of nine treatments. Both Expt. 1 and Expt. 2 were completely randomized designs with four replications. Greenhouse temperature and relative humidity were collected daily. The percent emergence was monitored daily until no further emergence was observed for 3 d. The percent VWC was measured at a 1.5-inch (3.8-cm) depth after kenaf had emerged using a Spectrum TDR150 (Spectrum Technologies, Inc., Aurora, IL, USA). The experiments were ended after plants exhibited signs of nutrient stress (discoloration). Deconstruction included plant height (cm), root dry biomass (g), and leaf dry biomass (g) after 3 d in a 60 °C oven. All data were subject to a statistical analysis, and significant means were identified using Tukey’s honestly significant difference test (SAS version 9.4; SAS Institute Inc., Cary, NC, USA; SAS Institute 1989).
In Expt. 1, the maximum greenhouse temperature was over 54 °C (130 °F), with an average of 49 °C (120 °F). In south Florida, in August, kenaf emerged in all treatments 4 d after planting (DAP). Significantly higher emergence (60%) occurred in EODN and E4DS compared with that in EDS (Fig. 1). Seeds watered EOD with or without a soil surfactant and seeds that received water every 4 d with a soil surfactant had the highest percent emergence compared with that of all other treatments and significantly more than that of EDS. In Expt. 1, soil treated with soil surfactant and irrigated four-times less (E4DS) had nearly twice (33.3%) and six-times (13.3%) greater emergence than that irrigated every day with or without soil surfactant, respectively. The EOD irrigation regimes received 2× more water than E4DS but had a similar emergence. This suggested that too much water hinders kenaf emergence; however, if water conservation is important to the grower, then watering every 4 d and treating one time with soil surfactant would improve emergence in low water-holding soils. Vayabari et al. (2023) reported that kenaf seedlings are particularly susceptible to standing water, and that kenaf is better adapted to well-drained soil, which may explain the lower germination rates in ED irrigation regimes.
Citation: HortTechnology 35, 1; 10.21273/HORTTECH05537-24
Expt. 2 was initiated in December, when the maximum temperature was 41 °C (106 °F), with an average temperature of 34 °C (94 °F). In Expt. 2, maximum emergence was reached for all treatments within 6 DAP in a sand-based soil with less than 2% organic matter (Fig. 2). At 4 DAP, emergence was significantly faster in E4D2× (73.3%) compared with that in EDN (26.7%), ED1× (20.0%), EODN (13.3%), and EOD1× (26.7%). Doubling the rate of surfactant improved emergence under ED and E4D. Both experiments suggested that under severe water restrictions and when seeds were planted in soils with low water-holding capacity, a one-time application of a soil surfactant may improve kenaf emergence. The 2× rate of surfactant may also improve emergence in overirrigated or heavy rainfall situations. As suggested by Almaz et al. (2023) and Ou and Latin (2018), the soil surfactant at a higher rate may allow for more uniform distribution of water and better water penetration in the soil, leading to homogenization of water distribution in the root zone. However, additional studies should be conducted to confirm the effect of the high rate of soil surfactant on kenaf emergence. The optimum emergence temperatures for kenaf were determined to be 35 °C and 45 °C; however, with temperatures over 40 °C, hypocotyl and radical elongation were reduced (Carberry and Abrecht 1990). These data also suggested that kenaf, a tropical crop that thrives in areas of high rainfall and solar radiation, may be an ideal crop for south Florida because of enhanced emergence during warmer months in locations that include water restrictions, but also because of its preference for well-drained soils that predominate in south Florida. Irrigation requirements are crop-use specific. Falasca et al. (2014) determined that if kenaf is grown for fiber or food, then supplementary irrigation would be required; however, for biofuel production, no additional irrigation is necessary. In either case, a one-time soil surfactant application improved kenaf emergence and, despite high greenhouse temperatures and deficit irrigation, 80% emergence suggests that kenaf might be ideal for addressing alternative crop strategies under increasing global temperatures. Soil surfactant treatment hindered emergence in ED at the 1× rate, suggesting that higher soil surfactant rates might be ideal for this crop to improve emergence under both high irrigation and deficit irrigation.
Citation: HortTechnology 35, 1; 10.21273/HORTTECH05537-24
Plant height was collected when kenaf began to exhibit discoloration because of a lack of fertilizer. In Expt. 1, this occurred at 40 DAP (Table 1). Soil surfactant treatment did not influence plant height. Pots that received 100 mL of water ED had significantly taller plants compared with those that received EOD and E4D irrigation regimes. In Expt. 2 (Table 2), plant height was collected at 52 DAP. Significantly taller plants were found in ED2× compared with those in EODN. Soil surfactant treatment did not influence shoot and root biomass in Expt. 1, but the irrigation regime did significantly increase root biomass and shoot biomass in ED compared with those of all other treatments. Root and shoot biomass was greater in E4D when treated with a soil surfactant, but this was not the case in EOD. In Expt. 2, kenaf shoot biomass was significantly greater in ED2× compared with that in all other irrigation regimes. There was a trend for greater shoot mass in all soil surfactant treatments compared with that in soils that did not receive a one-time soil surfactant treatment. Root biomass was significantly greater under ED irrigation compared with that under other irrigation regimes. Root biomass was four-times greater when kenaf was watered every day compared with EOD and E4D. However, although not statistically significant, the 2× rate of soil surfactant nearly doubled root biomass under every irrigation regime, even ED. Despite the poor emergence of kenaf in the ED irrigation regime, the ED treatment did outperform the other treatments in terms of biomass production which would make it an ideal crop for south Florida in the summer during the wet season. This experiment indicated that a high rate of surfactant would be ideal under either irrigation regime.
There was a clear trend for significantly greater VWC in surfactant treated soils compared with untreated soil in ED and E4D, in Expt. 1 and Expt. 2, respectively (Figs. 3 and 4). The ED irrigation regime increased VWC to 10-times greater water content compared with E4D at the beginning of the experiment. However, at 12, 21, 23, and 40 DAP, soil surfactant treatment significantly increased VWC in EDS compared with that in all other treatments (Fig. 3). The ED treatment significantly increased VWC compared with that in all other irrigation regimes. At 12 and 23 DAP, EODS increased VWC compared with that in both E4D irrigation regimes with and without soil surfactant. After 21 and 40 DAP, no treatment differences were significant between EOD and E4D irrigation regimes. The percent VWC treatment differences were apparent between pots that received ED and EOD compared with E4D. The percent VWC in these sandy soils under ED irrigation was, on average, more than 15%. However, in pots that received water EOD and E4D, the percent VWC was typically less than 10%, particularly after day 27 (Fig. 5). In Expt. 2, at 14, 18, 19, 21, 35, and 47 DAP, treatment differences were significant (Fig. 4). At 14 DAP, only E4D2× significantly increased the VWC compared with that in E4DN. At 18, 19, and 21 DAP, both surfactant treatments significantly increased the percent VWC compared with that in E4DN. At 35 DAP, EOD2× significantly increased the VWC compared with that in EOD1X, but not that in EODN. At 47 DAP, EOD2× significantly increased the VWC compared with that in EODN. There was no treatment separation between ED irrigation regimes throughout Expt. 2, but there was a clear separation between ED and EOD compared with the E4D water content (Fig. 6). Soil-applied soil surfactants typically are efficacious for 30 d, and these data suggest that this may be the case when treatment separation ended under the E4D irrigation regime at 35 DAP. It should be noted that the Quickin™ label recommends reapplication at 3 to 4 weeks. The lack of separation in ED and EOD may indicate that irrigation may have leached the soil surfactant from the soil, but treatment differences were maintained because of surface tension reduction.
Citation: HortTechnology 35, 1; 10.21273/HORTTECH05537-24
Citation: HortTechnology 35, 1; 10.21273/HORTTECH05537-24
Citation: HortTechnology 35, 1; 10.21273/HORTTECH05537-24
Citation: HortTechnology 35, 1; 10.21273/HORTTECH05537-24
In conclusion, a one-time soil surfactant treatment did not hinder kenaf emergence under any irrigation regime. Applying this soil surfactant at the 2× rate under deficit irrigation will not only save water but also significantly improve emergence compared with all other treatments. To maximize biomass, the optimum method comprised the application of irrigation every day and the 2× soil surfactant rate. However, areas under significant water restrictions may not have that option. Additional studies need to be conducted to replicate the data from the 2× rate. Kenaf emergence and establishment under high greenhouse temperatures and deficit irrigation suggest that this plant could have potential in the ever-changing global climate.
Percent emergence of kenaf as affected by irrigation regimes and soil surfactant treatments during Expt. 1 at Fort Lauderdale Research and Education Center (FLREC) from 15 Aug to 6 Sep 2023. Irrigation regimes: ED = every day; EOD = every other day; and E4D = every 4 d. Soil surfactant treatments: Yes = one-time application of soil surfactant; No = no soil surfactant application. The same letter above the bars on each date indicates that the data were not significantly different.
Percent emergence of kenaf as affected by irrigation regimes and soil surfactant treatment in Expt. 2 at the Fort Lauderdale Research and Education Center (FLREC) from 8 Dec 2023 to 27 Jan 2024. Irrigation regimes: ED = every day; EOD = every other day; and E4D = every 4 d. Soil surfactant treatments: No = no soil surfactant application; ×1 = label rate of soil surfactant application; and ×2 = double the label rate of soil surfactant application. The same letter above the bars on each date indicates that the data were not significantly different. No letter above the bars indicates P > 0.05.
Effects of irrigation regimes and soil surfactant treatments on the percent volumetric water content of Hallandale fine sand in Expt. 1 at the Fort Lauderdale Research and Education Center (FLREC) from 15 Aug to 6 Sep 2023. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. The same letters above the bars within each category indicate that the data were not significantly different. DAP = days after planting. Irrigation regimes: ED = every day; EOD = every other day; and E4D = every 4 d. Soil surfactant treatments: Yes = one-time application of soil surfactant; No = no soil surfactant application.
Effects of irrigation regime and soil surfactant treatment on the percent volumetric water content of Hallandale fine sand in Expt. 2 at the Fort Lauderdale Research and Education Center (FLREC) from 8 Dec 2023 to 27 Jan 2024. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. The same letters above the bars within each category indicate that data were not significantly different. DAP = days after planting. Irrigation regimes: EDN = every day; − soil surfactant; ED×1 = every day; ×1 soil surfactant; ED×2 = every day; ×2 soil surfactant; EODN = every other day; − soil surfactant; EOD×1 = every other day; ×1 soil surfactant; EOD×2 = every other day; ×2 soil surfactant; E4DN = every 4 d; − soil surfactant; E4D×1 = every 4 d; ×1 soil surfactant; E4D×2 = every 4 d; and ×2 soil surfactant.
The percent volumetric water content in native sand soil during Expt. 1 at the Fort Lauderdale Research and Education Center (FLREC) from 15 Aug to 6 Sep 2023. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. Irrigation regimes: EDN = every day; − soil surfactant; EDS = every day; + soil surfactant; EODN = every other day; − soil surfactant; EODS = every other day; + soil surfactant; E4DN = every 4 d; − soil surfactant; E4DS = every 4 d; and + soil surfactant.
The percent volumetric water content in native sand soil during Expt. 2 at the Fort Lauderdale Research and Education Center (FLREC) from 8 Dec 2023 to 27 Jan 2024. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. Irrigation regimes: EDN = every day; − soil surfactant; ED×1 = every day; ×1 soil surfactant; ED×2 = every day; ×2 soil surfactant; EODN = every other day; − soil surfactant; EOD×1 = every other day; ×1 soil surfactant; EOD×2 = every other day; ×2 soil surfactant; E4DN = every 4 d; − soil surfactant; E4D×1 = every 4 d; ×1 soil surfactant; E4D×2 = every 4 d; and ×2 soil surfactant.
Contributor Notes
M.M. is the corresponding author. E-mail: mica.mcmillan@ufl.edu.
Percent emergence of kenaf as affected by irrigation regimes and soil surfactant treatments during Expt. 1 at Fort Lauderdale Research and Education Center (FLREC) from 15 Aug to 6 Sep 2023. Irrigation regimes: ED = every day; EOD = every other day; and E4D = every 4 d. Soil surfactant treatments: Yes = one-time application of soil surfactant; No = no soil surfactant application. The same letter above the bars on each date indicates that the data were not significantly different.
Percent emergence of kenaf as affected by irrigation regimes and soil surfactant treatment in Expt. 2 at the Fort Lauderdale Research and Education Center (FLREC) from 8 Dec 2023 to 27 Jan 2024. Irrigation regimes: ED = every day; EOD = every other day; and E4D = every 4 d. Soil surfactant treatments: No = no soil surfactant application; ×1 = label rate of soil surfactant application; and ×2 = double the label rate of soil surfactant application. The same letter above the bars on each date indicates that the data were not significantly different. No letter above the bars indicates P > 0.05.
Effects of irrigation regimes and soil surfactant treatments on the percent volumetric water content of Hallandale fine sand in Expt. 1 at the Fort Lauderdale Research and Education Center (FLREC) from 15 Aug to 6 Sep 2023. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. The same letters above the bars within each category indicate that the data were not significantly different. DAP = days after planting. Irrigation regimes: ED = every day; EOD = every other day; and E4D = every 4 d. Soil surfactant treatments: Yes = one-time application of soil surfactant; No = no soil surfactant application.
Effects of irrigation regime and soil surfactant treatment on the percent volumetric water content of Hallandale fine sand in Expt. 2 at the Fort Lauderdale Research and Education Center (FLREC) from 8 Dec 2023 to 27 Jan 2024. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. The same letters above the bars within each category indicate that data were not significantly different. DAP = days after planting. Irrigation regimes: EDN = every day; − soil surfactant; ED×1 = every day; ×1 soil surfactant; ED×2 = every day; ×2 soil surfactant; EODN = every other day; − soil surfactant; EOD×1 = every other day; ×1 soil surfactant; EOD×2 = every other day; ×2 soil surfactant; E4DN = every 4 d; − soil surfactant; E4D×1 = every 4 d; ×1 soil surfactant; E4D×2 = every 4 d; and ×2 soil surfactant.
The percent volumetric water content in native sand soil during Expt. 1 at the Fort Lauderdale Research and Education Center (FLREC) from 15 Aug to 6 Sep 2023. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. Irrigation regimes: EDN = every day; − soil surfactant; EDS = every day; + soil surfactant; EODN = every other day; − soil surfactant; EODS = every other day; + soil surfactant; E4DN = every 4 d; − soil surfactant; E4DS = every 4 d; and + soil surfactant.
The percent volumetric water content in native sand soil during Expt. 2 at the Fort Lauderdale Research and Education Center (FLREC) from 8 Dec 2023 to 27 Jan 2024. ns, +, *, **, and *** represent P > 0.10, P < 0.10, P < 0.05, P < 0.01, and P < 0.001, respectively. Irrigation regimes: EDN = every day; − soil surfactant; ED×1 = every day; ×1 soil surfactant; ED×2 = every day; ×2 soil surfactant; EODN = every other day; − soil surfactant; EOD×1 = every other day; ×1 soil surfactant; EOD×2 = every other day; ×2 soil surfactant; E4DN = every 4 d; − soil surfactant; E4D×1 = every 4 d; ×1 soil surfactant; E4D×2 = every 4 d; and ×2 soil surfactant.
