Flowering responses of Heliconia psittacorum L.f. × H. spathocircinata Aristeguieta `Golden Torch' to temperature and photosynthetic photon flux (PPF) were determined in controlled-environment conditions using a 2 × 2 factorial combination of temperature (32C day/20C night and 24C day/20C night) and PPF (475 and 710 μmol·m–2·s–1). Temperature had no significant effect on new shoot production, with an average of 9.3 shoots per plant being produced over the 248 days of treatment. More shoots, however, were produced at the higher PPF level (10.1 compared with 8.3 shoots). The proportion of shoots that initiated flowers (85%) was similar in all treatments. The duration from shoot until inflorescence emergence was significantly less at 32C day/20C night than at 24C day/20C night (140 and 146 days, respectively) and was unaffected by PPF. This duration also was significantly affected by the interacting effects of order of shoot appearance and the number of leaves subtending the inflorescence. The second shoots to emerge had the shortest duration from shoot emergence to inflorescence emergence. The number of leaves subtending the inflorescence increased at the higher temperature and decreased as shoot order increased but was unaffected by PPF. Temperature and PPF levels influenced total leaf area at flowering, with highest areas being achieved in the high temperature–low PPF combination. Acceptable flower quality with at least two, opened, well-formed, well-colored bracts was obtained in all treatments, although flower stems were taller and thicker at 32C day/20C night and these dimensions increased further with increasing order of shoot appearance. Stem diameters tended to be thinner at the lower PPF level. Overall, temperature was more dominant than light in influencing production and quality of flowers, but developmental factors associated with the order of shoot appearance also played a significant role. Flower production of `Golden Torch' should be feasible in temperature-controlled glasshouses in temperate regions where mean air temperatures can be maintained at ≈20C.
Frequent fertigation of soilless-grown bell pepper (Capsicum annuum L.) can increase fruit production, but development of fruit disorders may offset the increase in yield of first-quality (blemish-free) fruit in greenhouses with minimal environmental control. Fruit yield and quality were studied as affected by water volumes and nutrient concentration levels, delivered with irrigation events initiated after determined cumulative solar radiation levels, in ‘HA3378’ bell pepper from October to May in north–central Florida. Irrigation events occurred after solar radiation integral levels (SRI; ±SD) 1.7 ± 0.42, 3.7 ± 0.42, 5.7 ± 0.42, 7.7 ± 0.42, and 9.7 ± 0.42 kW·min−1·m−2, which led to mean number of daily irrigation events of 61 ± 31, 26 ± 12, 17 ± 8, 12 ± 5, and 10 ± 4 respectively. In peat mix, perlite, and pine bark media, volume per irrigation event and concentration levels of the nutrient solution were, in the first experiment, 74 mL standard (74-s), and in a second concurrent experiment, 74 mL half-standard (74-½s) or 3) 37 mL standard (37-s). In both studies, combined marketable fruit yields of first quality and second quality (minor cracking patterns and yellow spots) increased linearly with decreasing SRI (increased events per day). First-quality fruit weight with 74-s was unaffected by media and, in a quadratic response to SRI, reached 5.4 kg·m−2 at 5.7 kW·min−1·m−2. First-quality weight with 74-½s and 37-s did not differ. Weight was unaffected by SRI in peat mix and perlite, and a quadratic response was recorded in pine bark, with yields of ≤3.6 kg·m−2. Fruit cracking incidence decreased with increased SRI, and was generally greater in pine bark. Incidence of yellow spots doubled with 74-½s compared with 37-s, and decreased linearly with increased SRI; the disorder was minor with 74-s. Compared with 37-s, 74-½s decreased fruit with blossom-end rot by 14%, increased marketable fruit weight by 10% in media with the lowest water-holding capacity (perlite, pine bark), and increased nutrient use efficiency. With any media used, the SRI set point of 5.7 kW·min−1·m−2 (daily mean of 17 irrigation events) and 74 mL, at standard nutrient concentration levels, appeared to produce greater blemish-free fruit yield than delivering 37 mL/event or half-concentrated 74 mL/event within the range of SRI means of 1.7 to 9.7 kW·min−1·m−2 (61–10 irrigation events/day). Disorder-tolerant pepper cultivars, better temperature control, and August plantings are additional suggestions for irrigation management to increase first-quality fruit yield.
Shipment to the U.S. Cut alstroemeria, carnation, gerbera, and rose were transported via commercial carriers from Bogotá, Colombia, to the U.S. on a monthly basis for 1 year using a 7-day conventional distribution system with temperature controls and 3-day
responses of nutrient accumulation, as discussed subsequently. Fig. 1. Cellular membrane stability, expressed as percentage of electrolyte leakage (EL), in kentucky bluegrass ( A ) and bermudagrass ( B ) under optimal temperature (control) and heat
Controlled-release fertilizer (CRF) use is a best management practice that may reduce nitrogen (N) loss to the environment. Several factors affect CRF nutrient release; therefore, including CRF in a fertilization program may have challenges. Thus, the study objective was to evaluate the effects of CRF N rate, source, release duration, and placement on seepage-irrigated marketable tomato (Solanum lycopersicum L.) yield, leaf tissue N (LTN) concentration, post-season soil N content, and postharvest fruit firmness and color. There were two soluble fertilizer (SF) controls [University of Florida/Institute of Food and Agriculture Sciences (UF/IFAS) (224 kg·ha−1) and grower standard (280 kg·ha−1)] and six and seven CRF treatments (alone or in combination with SF) in Fall 2011 and 2012, respectively. Cumulative rainfall totaled 31.4 and 37.4 cm during the 2011 and 2012 seasons with average air temperatures of 22.4 and 22.1 °C, respectively. Soil temperatures ranged from 14.2 to 40.6 °C in 2011 and 11.1 to 36.6 °C in 2012 with a strong correlation (r = 0.95) to air temperature. Controlled-release urea resulted in 7.5% to 17.9% plant mortality in 2011 and reduced yields in 2012 compared with CRF N–phosphorus–potassium (NPK) at a similar N rate. LTN concentrations were above or within the sufficiency range for all treatments. In 2011, using CRF-urea at 190 kg·ha−1 N produced similar marketable tomato yield in all fruit categories except season total large tomatoes, which produced significantly fewer marketable tomatoes with 13.5 Mg·ha−1 compared with UF/IFAS and grower standard with 17.9 and 14.2 Mg·ha−1, respectively. In 2012, CRF-NPK (168 kg·ha−1 N) significantly reduced first and second harvest combined large and season total large and total marketable yields compared with the UF/IFAS rate and grower standard treatments. Marketable yield was not significantly affected by CRF (urea or NPK) release duration, but CRF-NPK 180-day release duration significantly increased residual soil N in 2012 compared with CRF-NPK 120-day release with 74.2 and 34.3 kg·ha−1 N, respectively. Rototilling CRF-urea into the bed, which was only evaluated in 2011, significantly increased total season yields compared with CRF-urea broadcast in row before bedding (BIR) with 43.0 and 46.5 Mg·ha−1, respectively. There were no significant yield differences when 50% or 75% of the total N was CRF placed in the hybrid fertilizer system, which is a system with CRF placed BIR with the remaining N as SF-N banded on the bed shoulders. No significant differences among treatments were found for total residual soil N in 2011; however, higher soil N remained in CRF (NPK and urea) treatments compared with SF treatments in 2012, except for Treatment 9. No significant differences were found among treatments for fruit firmness or color in 2011 or 2012. CRF-NPK at 190 to 224 kg·ha−1 N with a 120-day release may be recommended as a result of similar or greater first harvest and total season marketable yields compared with IFAS-recommended rates and low residual soil N. Further research must be conducted to explore CRF placement and percentage urea composition, although use of the hybrid system or rototilling may be recommended.
handles a biologic, physical, or environmental control task. Next to a component for dynamic temperature control, other climatic control components for, e.g., pests ( Jakobsen et al., 2005 ), diseases ( Körner and Holst, 2005 ), or supplementary
; altitude 1 200 m.a.s.l). A temperature-controlled plastic tunnel was used equipped with a pad and fan (2 × 1.1-kW fans, 1300 mm in diameter) cooling system. Ambient temperature in the tunnel during 2011–12 and 2012–13 ranged from 13 to 35 °C and 11.6 to 36
followed, the proper healing chamber is critical to ensure that complete union has formed. With the case of the tongue approach grafting, this means only an adequate greenhouse with temperatures controls. However, for the other three methods described, a
fertigation while applying foliar fertilizer on mini-cucumber grown in sawdust growing medium. Materials and Methods Trial location. The experiment was carried out during Nov. 2014 to Mar. 2015 (Summer/Autumn season) in a non-temperature controlled plastic
temperature-controlled chamber set at 29 °C. After 48 h, the seeds were moved to the greenhouse. Seeding was performed 12 d before grafting. Seedlings were subirrigated with water as needed and once with the same nutrient solution before grafting. In addition