Plastic mulch films are widely implemented in horticultural production systems worldwide because the films facilitate increased yields. However, because of their common use, concerns about the long-term sustainability of intensive plastic mulch use have arisen. Two potential ways to alleviate any potential ill effects of long-term plastic mulch use are replacing the fossil-based plastic mulches with biobased and biodegradable plastic mulches or using the same layer of plastic mulch for multiple cropping seasons. This project investigated how biodegradable plastics compare with conventional plastic and the multiseason use of plastic mulch films in comparison with a single season of use. All films in this study produced soil temperatures within a 1.5 degrees C range, and no mulch type was consistently preferable for soil moisture or compaction. The biodegradable mulch films used in this study were less effective at controlling weeds than the plastic mulch films; additionally, unlike the plastic films, they were not able to remain in place for use with multiple crops. The biodegradable films also tended to have fewer mechanical characteristics than the plastic films. However, the biodegradable films produced yields similar to those with the conventional plastic film in both years. The longer the plastic mulch films remained in place, the more compact the soil underneath the mulches; additionally, more residual plastic was found upon film removal, soil moisture was lower, and yields were reduced.

Weather variability in subtropical environmental conditions of the southeastern U.S. impact sweet corn production in the region, which is one of the most important in the country. Understanding sweet corn performance under these environmental conditions is important to help growers with decision making. Thus, the objectives of this study were to evaluate and characterize the performance of ten commercial sweet corn cultivars exposed to several environmental conditions of the southeastern U.S. and to describe impacts of weather variability on cultivar development, yield, and ear quality. Field experiments were conducted in five locations of the southeastern U.S. during the spring and fall of 2020 and 2021. Weather data, biomass accumulation, yield, and ear quality were measured for all cultivar within seasons and locations. Heavy rainfall events created waterlogging conditions for sweet corn development; however, it was the daily air temperature of seasons that mostly impacted yield and ear quality. Daily air temperatures extended the growing season of spring but reduced crop development in the fall. Consequently, biomass accumulation was generally higher in the spring (4243 kg ha−1) compared to the fall (1987 kg ha−1). Biomass accumulation translated into yield, which was thereby higher in the spring compared to the fall. Cultivars with great potential against environmental stresses and best performance for most locations were Affection, GSS1170, Passion, and SCI336 in the spring, and Affection, GSS1170, and SC1136 in the fall. Ultimately, sweet corn yield was strongly correlated with ear dimensions but poorly correlated with number of grains in a kernel, suggesting that breeding programs trying to increase potential yield should be focused on ear diameter and length.

The objectives of this study were to characterize the seed imbibition process of kale seeds, evaluate the effect of three priming techniques on kale seedling production, and identify a priming strategy that increases the emergence, vigor, and growth of kale seedlings. Using three priming agents: water (seeds imbibed for 3, 6, 9, and 12 h), polyethylene glycol 6000 (PEG6000) (seeds imbibed at -0.2, -0.4, -0.6, and -0.8 MPa with kale seeds imbibed for 4, 8, 12, and 16 h), and Progibb((R)) LV; (seeds imbibed at 0.5, 1.0, 1.5, and 2.0 g a.i. L-1 for 15, 30, 45, and 60 min), and three kale cultivars ('Red Russian', 'Blue Ridge', and 'Siberian'), three experiments evaluated kale seedling parameters, including emergence speed index (ESI) and total emergence (TE) in a complete randomized block design (n=4) each. Water imbibition for 3 h provided the highest ESI and TE in the hydropriming experiment. In the hormonal priming experiment, Progibb((R)) LV at 0.5% a.i. imbibed for 15 min provided the highest ESI and TE. In the osmopriming experiment, PEG6000 at 0.2 MPa for 16 h provided the highest ESI and TE. Once the best treatment of each experiment was compared to a control treatment, in which no priming agents were used, only the water imbibition for 3 h presented higher ESI than the control. However, this increment was only 1% higher, indicating that priming agents on kale seedling production should be focused on seedling quality rather than emergence rate.

Strawberries are a very important economic crop; thus, a lot of research has been conducted on several production areas. However, phenological performance is still lacking information, especially when it comes to modeling. Therefore, this study aims to develop a phenological model for flower–fruit development under hydroponic conditions to support growers’ decision-making. Two day-neutral cultivars, ‘Albion’ and ‘San Andreas’, were established in a drip hydroponic system in Auburn, Alabama for the 2022–2023 production season. Phenological data were collected daily on 30 flowers per cultivar for three periods (Oct 25–Dec 16, Dec 27–Feb 21, and Feb 28–Apr 16). Weather data were obtained from a weather station placed in the greenhouse. Growing degree days (GDD) accumulation was calculated for each stage and cycle using a base temperature (Tb) of 3 °C. The Gaussian model was adjusted for each stage and cycle using a non-linear procedure to obtain Gaussian curves. Simulations were made for the model assuming temperature would increase or decrease by 1 °C. Six stages were identified, and their cycle ranged from 43–56 days to be accomplished. ‘Albion’ needed more days to reach maturity, with 51, 56, and 47 days, and ‘San Andreas’ took 43, 54, and 46 days for cycles 1, 2, and 3 respectively. In addition, for cycles 1 and 2, not all the buds reached maturity, as expected. Stage 5 (fruit formation) needed more days than the rest of the stages to be completed. Because of the different starting dates for each cycle, the starting GDD was different as well. A sensitivity analysis simulation of the model showed that if temperature decreases by 1 °C, the GDD accumulated to complete the stages would be less (same dates), and it would be more if the temperature increased by 1 °C. The opposite happened with the days, if the temperature increased by 1 °C, the duration of the stage decreased, and it would increase if the temperature decreased by 1 °C, affecting stages 4, 5, and 6. Overall, ‘San Andreas’ performed better than ‘Albion’ under hydroponic conditions during three productive cycles.

Parsley seeds are known for nonuniform and long germination; consequently, vegetable nurseries commonly use priming techniques to improve the production of parsley seedlings. The objectives of this study were 1) to characterize the imbibition curve of parsley seeds, 2) to evaluate the effect of different priming agents on parsley seedling production, and ultimately 3) to compare priming techniques for emergence and vigor of parsley’s seedlings, thus providing an optimal priming strategy for parsley seedling production. Using three priming agents—water (seeds imbibed for 24, 48, 72, and 96 hours), polyethylene glycol 6000 (PEG6000) (seeds imbibed at –0.5, –1.0, –1.5, and –2.0 MPa for 29, 58, 87, and 116 hours), and gibberellic acid (GA) (seeds imbibed at 0.5, 1.0, 1.5, and 2.0 g·L−1 a.i. of solution for 15, 30, 45, and 60 minutes), and two parsley cultivars (Krausa and Titan), three experiments evaluated parsley seedling parameters, including emergence speed index (ESI) and total emergence (TE) in a complete randomized block design (n = 4) each. In Expt. 1 (hydropriming), increasing water imbibition time (IT) reduced ESI on both parsley cultivars. In addition, the TE quadratically reduced with the increase of water IT. In Expt. 2 (osmopriming), there was no significant main effect or interaction of treatments on ESI. Regardless of PEG6000 concentration, the TE had a linear increase with the increase of IT for cultivar Krausa but not for cultivar Titan. In Expt. 3 (hormonal priming), there was a significant increase in ESI and TE with the increase in GA rate. Ultimately, strategies for analysis of best priming were water at 24 hours of IT, PEG6000 at –2.0 MPa for 116 hours of IT, and GA at 2.0 g·L−1 a.i. of solution for 15 minutes of IT. Once compared with an untreated seeds treatment, priming strategies of water imbibition for 24 hours and PEG6000 at –2.0 MPa for 116 hours had the highest ESI and TE.

A series of experiments was conducted to evaluate variety selection and planting date for spring and fall season extension of tomato (Solanum lycopersicum L. (syn.: Lycoperisicon esculentum Mill.)) production in high tunnels in southeast Alabama. 'BHN 640', 'Florida 91', 'Sun Leaper', and 'Carolina Gold' were evaluated for early spring production in 2004. These varieties did not differ in total yield of marketable fruit; however, 'BHN 640' and 'Sun Leaper' produced higher early yields compared with the other varieties. 'BHN 640' and 'Florida 91' were evaluated for late-season extension in fall 2004. 'BHN 640' produced higher yields of large, medium, total marketable, and unmarketable fruit grades than 'Florida 91'. In a study conducted in early 2005, higher yields of marketable fruit were produced from the first planting date (31 January) compared with the final of four planting date (25 Mar.). In summary, results indicated that season extension of tomato production in high tunnels was possible, with harvests three weeks earlier in the spring and 12 weeks later in the fall compared with typical field harvest dates. These early yields can command prices from $3.30 to $4.40US per kg of fruit.

Preemergence (PRE) herbicide applications through drip-irrigation is a novel approach for controlling nutsedge spp. under low-density polyethylene (LDPE) mulch. However, achieving acceptable movement of PRE herbicides under LDPE mulch is difficult. Nonionic surfactants are used in agriculture to enhance the dispersion, spreading, sticking and penetration of pesticides. With this in mind, field experiments were conducted to evaluate nonionic surfactants applied with PRE herbicides through drip-irrigation on yellow nutsedge ( Cyperus esculentus L.) punctures in LDPE-mulched beds. The objective of this experiment was to increase herbicide movement under the mulch thus improving nutsedge control. The experiment was a factorial treatment arrangement of the nonionic surfactants Integrate TM 20 (2.8 kg ai ha -1 ), Tween ® 20 (2.8 kgha -1 ) and no surfactant, and the PRE-applied herbicides halosulfuron (54 gha -1 ), S -metolachlor (1.4 gha -1 ), and fomesafen (280 gha -1 ). A non-treated control (LDPE mulch alone) was included for comparison. Tween ® 20 and Integrate TM 20 nonionic surfactants applied with fomesafen, halosulfuron, and S -metolachlor through drip-irrigation did not reduce nutsedge punctures through LDPE mulch compared to application of these herbicides without surfactants. Combinations of nonionic surfactants and PRE herbicides not evaluated in this experiment may elicit different results and warrant further investigation.

Raised bed production trials were conducted to evaluate the effectiveness of effluent from a biofloc-style recirculating aquaculture system producing nile tilapia (Oreochromis niloticus) as nutrient-rich irrigation water for fall ‘Celebrity’ tomato (Solanum lycopersicum) production. The objective of this study was to provide baseline vegetable production data and justification for using aquaculture effluent as a water and nutrient resource. The experiment was a split-plot, randomized block design with three treatments: aquaculture effluent, granular fertilizer, and fertigation. Tomato seeds were sown in June, transplanted in August, and grown until Oct. 2019 in nine replicated raised beds. Conventional field tomato production practices were followed throughout the trial, and data were collected for tomato fruit yield, market quality, size, leaf greenness (SPAD), and foliar nutrient analysis. Fruit yield was similar between fertigated and aquaculture effluent treatments, with granular fertilizer resulting in yield that was significantly lower (P ≤ 0.033). SPAD measurements were similar among treatments. All nutrients met or exceeded sufficiency ranges. Foliar nutrient analysis revealed no significant difference for nitrogen, phosphorus, potassium, magnesium, calcium, boron, zinc, manganese, and iron among treatments. Sulfur and copper levels were significantly lower (P < 0.05) with aquaculture effluent treatment as compared with the granular and fertigated treatments. Overall, tomato production using aquaculture effluent as a water and nutrient supplement produced similar yields to commercial practices, making it potentially viable for producers.

An experiment was conducted to determine the effects of banded phosphorus (P) applications at differing rates in irrigated and nonirrigated pecan ( Carya illinoinensis ) plots on P movement within the soil, P uptake and movement within pecan trees, and the yield and quality of nuts. On 20 Mar. 2015, P applications of 0 kg·ha −1 (0×), 19.6 kg·ha −1 (1×), 39.2 kg·ha −1 (2×), and 78.5 kg·ha −1 (4×) were administered to bands of triple superphosphate to randomly selected trees in nonirrigated and irrigated plots of a ‘Desirable’ orchard bordered by ‘Elliot’ trees. When P was applied at the 2× and 4× rates, the total soil test P decreased linearly by 35% and 54%, respectively, in nonirrigated plots and by 41% and 59%, respectively, in irrigated plots over the course of the experiment. There was no change in soil test P over time at the 0× rate for either irrigation regimen; however, at the 1× rate, soil test P decreased 44% in the irrigated plot but did not change in the nonirrigated plot. The largest linear decrease of the soil test P from the start of the experiment to the end of the experiment occurred in the top 0 to 7.6 cm. In contrast, soil test P at a depth of 15.2 to 22.9 cm decreased linearly by 23% in the nonirrigated plot, but it did not decrease over time in the irrigated plot. Increasing the P application rate increased foliar P quadratically in the nonirrigated plot, but only the 4× application rate increased foliar P compared with the 0× control. In the irrigated plot, foliar P concentrations decreased linearly from 2015 to 2017, and foliar P concentrations were not influenced by the P application rate. No differences in pecan yield or quality were observed in either irrigated or nonirrigated plots. Overall, P banding may not be the most sustainable way to increase foliar concentrations of P quickly or to maintain concentrations of the nutrient in the long term.

ABSTRACTGrowing interest in curcumin from turmeric (Curcuma longa L.) for medical and health purposes has led to interest in turmeric cultivation in the United States. The warm growing season in Alabama is short relative to tropical environments where the plant is normally grown, and research on cultural practices is lacking. A split‐split‐plot experiment was performed in Alabama to assess the effects of shade (40% shade vs. no shade), establishment method (early establishment in greenhouse over heat vs. direct seeding), and variety on rhizome yield and curcumin content. Canonical discriminant analysis revealed distinctive trends based on varietal differences, establishment methods, and presence or absence of shade. Extending the growing season by early establishment in the greenhouse increased rhizome and curcumin yield, as well as curcumin concentration in lateral rhizomes. Shade increased plant height, leaf size, and fresh weight of rhizomes, but an apparent increase in rhizome dry weight was not significant. Shade decreased curcumin concentration and yield in mother rhizomes but had little effect on curcumin concentration in lateral rhizomes. An apparent increase in curcumin yield in lateral rhizomes with shade was not significant. Significant differences among varieties were observed for rhizome yield and curcumin concentration and yield. Cultivation of turmeric in Alabama is feasible by extending the growing season and selection of short‐season varieties high in curcumin.

AbstractProduction of quality greenhouse and nursery crops is dependent on high quality and quantities of water. At present, in some regions, insufficient water supply is a growing concern. This study was conducted to evaluate growth of New Guinea impatiens (Impatiens hawkerii 'Celebrate Salmon'), when watered with a polyoxyethylenesorbitan monolaurate (C58H114O26) solution commercially known as Tween 20, at differing irrigation levels compared with a conventional water regimen without the surfactant, and also to determine how Tween 20 would affect photosynthesis and transpiration. The treatment design was a 3 by 6 complete factorial design plus a control. The two factors were irrigation and Tween 20. Irrigation levels of 20%, 40%, or 60% of the full crop evapotranspiration (ET) requirements were used in combination with Tween 20 concentrations of either 0, 25, 50, 75, 100, or 125 mg·L−1 (0, 0.003338, 0.00668, 0.0100145, 0.01335, or 0.01669 oz per gallon). The control group was watered with tap water to container capacity with about 30% leachate. Evapotranspiration was determined as the difference of the applied water amount minus the leachate of the control. Plants irrigated with Tween 20 from 25 to 125 mg·L−1 (0.003338 to 0.01669 oz per gallon) at the 40% or 60% irrigation level had the same height and growth index as plants in the control after three months of growth. Plant fresh and dry weights were not different between the control and the treatments of Tween 20 from 50 to 125 mg·L−1 (0.00668 to 0.01669 oz per gallon) at the 60% irrigation level or the treatment of Tween 20 at 100 mg·L−1 (0.01335 oz per gallon) at the 40% irrigation level. Tween 20 had no effect on net photosynthetic rate. Tween 20 decreased the amount of transpired water of New Guinea impatiens 'Celebrate Salmon'. When the Tween 20 concentration increased from 0 to 100 mg·L−1 (0 to 0.01335 oz per gallon) at the 60% irrigation level, the transpiration rate and stomatal conductance decreased markedly by 43% and 47%, respectively, and water use efficiency was increased by 47%. Results from this study suggest that Tween 20 is able to increase plant water use efficiency through regulation of stomatal conductance or transpiration under deficit irrigation.Index words: irrigation management, chemigation, source-sink physiology, deficit irrigation, wetting agent, Tween 20, adjuvant.Species used in this study: New Guinea Impatiens (Impatiens hawkerii W. Bull. 'Celebrate Salmon').Chemicals used in this study: Tween 20 (polyoxyethylenesorbitan monolaurate). (aka: polysorbate 20, polyoxyethylene (20) sorbitan monolaurate)