Bell Pepper Fruit Yield and Quality as Influenced by Solar Radiation-based Irrigation and Container Media in a Passively Ventilated Greenhouse

Abstract

<jats:p>Frequent fertigation of soilless-grown bell pepper (<jats:italic>Capsicum annuum</jats:italic> 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<jats:sup>−1</jats:sup>·m<jats:sup>−2</jats:sup>, 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<jats:sup>−2</jats:sup> at 5.7 kW·min<jats:sup>−1</jats:sup>·m<jats:sup>−2</jats:sup>. 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<jats:sup>−2</jats:sup>. 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<jats:sup>−1</jats:sup>·m<jats:sup>−2</jats:sup> (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<jats:sup>−1</jats:sup>·m<jats:sup>−2</jats:sup> (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.</jats:p>

Irrigation of Greenhouse Crops

“…However, for rockwool substrate in a free drainage system, Lee [111] recommended accumulated values of 0.8 MJ m −2 with a minimum rest time set (i.e., not irrigated if the target value is reached) between 20 min in bright and 50 min on dark days according to the crop growth phase. Additionally, for bell pepper in container growth with peat mix, perlite, and pine bark media, Jovicich et al [61] indicated that the first-quality fruit weight was enhanced at solar radiation integral levels of 0.34 MJ m −2 , while Lizarraga et al [52] proposed indoor values of 0.81 MJ m −2 for tomatoes grown in perlite in bags of 40 L. In addition, Nikolaou et al [60], working with cucumber in rockwool, indicated a 9% lower drainage amount between high and low irrigation frequency treatments (i.e., accumulated radiation outside greenhouse 1.3 MJ m −2 as opposed to 3 MJ m −2 ), with no negative impact on production.…”

Improvement in Growth, Yield, and Fruit Quality of Three Red Sweet Pepper Cultivars by Foliar Application of Humic and Salicylic Acids

“…Lateral shoots and flowers, just above the cotyledonary node, were also removed. The training system was applied to form a plant structure of two main branches (Alsadon et al, 2013) to form a ''V'' trellising canopy system (Jovicich et al, 2007). When pruning a main branch, only the flower on the branch node and its nearby leaf were left.…”

Changes in electrical conductivity and moisture content of substrate and their subsequent effects on transpiration rate, water use efficiency, and plant growth in the soilless culture of paprika (Capsicum annuum L.)

“…Nutrient solutions were supplied by a drip irrigation system, and the flow rate of the nutrient supply was 30 mL·min -1 per dripper. The plants were pruned to maintain two main stems, which were vertically trellised to a 'V' canopy system (Jovicich et al, 2007), and the additional plant management of pruning and training were carried out every week.…”