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Open access

Zhenxu Liang, Mingde Sun, Yang Wu, Jun Liu, Yanyan Zhao, Haiqing Tian, Ruirui Du, and Songzhong Liu

To understand the soil nutrient status of pear orchards in Beijing, we investigated their fertilization situation, including the fertilizer type, amount, and period. Furthermore, soil samples were collected at a depth of 0 to 40 cm to determine the contents of soil nitrogen, phosphorus, and potassium. The status of nutrient profits and losses was analyzed. The results showed that 50% of the pear orchards received organic fertilizer as a single nutrient source, and 35.7% of the pear orchards received a combined application of organic fertilizer and chemical fertilizer. Most pear orchards received organic fertilizer in autumn, but the application of chemical fertilizer occurred mainly before germination and during fruit expansion. The average nutrient input to the investigated pear orchards was 569.6 kg/ha for N, 855.0 kg/ha for P2O5, and 448.1 kg/ha for K2O, and the corresponding proportion of organic fertilizer was 76.9%, 88.0%, and 85.8%, respectively. However, the pear orchards had surpluses of nitrogen, phosphorus, and potassium, with average surplus amounts as high as 445.5, 794.3, and 321.4 kg/ha, respectively. Among all pear orchards surveyed, 93.33% faced environmental risks and 37.04% faced leaching risks. The average content of soil phosphorus was 2.23 times its critical value, and 64.29% of the studied pear orchards exceeded the critical value. Most pear orchards had surplus potassium, with 26.92% exceeding 500 kg/ha. This study provides a basis for soil improvement, high-quality production of fruits, and efficient utilization of pear orchards in Beijing.

Open access

Ya Li, Junhai Niu, Shisong Xu, Qingyun Leng, Guangsui Yang, Hernán Ariel López, and Shitao Xu

Bougainvillea (Bougainvillea spp.) belongs to the family Nyctaginaceae and is a native to tropical regions of South America (Roy, 2019). It has many ornamental horticultural advantages, including superabundant and recurring blooms, bright and colorful bracts, strong stress tolerance, and easy propagation and maintenance. Bougainvillea is among the most popular ornamental landscaping and potted plants in tropical and subtropical areas (Roy, 2019).

Bougainvillea have a short history (≈150 years) of domestication and cultivation outside their natural habitats (Ohri, 2013; Zadoo et al., 1975). Breeding practices in the world have given rise

Open access

Jiaqi Lin, Weiyan Xuan, Yanpei Li, Shixiang Xiao, and Dou Feng

Banana (Musa sp.) is one of the world’s most important crops, and a source of extreme economic importance in many countries around the world. However, the height of banana plant poses a significant challenge in both harvesting fruit and their tolerance to extreme weather. Gibberellin (GA) is one of the important endogenous hormones affecting plant height. Copalyl diphosphate synthase (CPS) is the first key enzyme in the GA biosynthesis pathway. In this paper, two full-length coding sequences of CPS genes were cloned from ‘William B6’ dwarf mutant banana and its wild-type parent (Musa AAA group), named CPS-A and CPS-G, respectively. The full-length complementary DNA (cDNA) sequences of CPS-G and CPS-A were both 2163 base pairs (bp), and encoded 720 amino acid residues. There were eight differences between the two speculative amino acid sequences in the alignment analysis. The molecular weights of CPS-G and CPS-A were 82,359.00 and 82,412.15 Da, respectively, and their isoelectric points were 6.17 and 6.03, respectively; there were no signal peptides and transmembrane structures. The banana CPS was mainly located in the cytoplasm by subcellular localization prediction. The results of reverse quantitative real-time polymerase chain reaction showed that CPS gene expression levels in the leaves and false stems of dwarf banana were lower than those of wild banana except for the developmental stage of the 10th leaf. Its expression level in the dwarf banana stem was significantly lower than that of the wild type at the 15th, 20th, and 25th-leaf age, respectively. The results showed that the dwarfism of the ‘Williams B6’ dwarf mutant might be related to the mutation of the CPS sequence and the difference of expression level. This study laid a foundation for further research on functional verification and the genetic regulation mechanism of the CPS gene.

Open access

Koichi Nomura, Eriko Wada, Masahiko Saito, Hiromi Yamasaki, Daisuke Yasutake, Tadashige Iwao, Ikunao Tada, Tomihiro Yamazaki, and Masaharu Kitano

In horticultural leafy vegetable production, continuously monitoring crop size indicators such as the leaf area index (LAI), leaf fresh weight (LFW), and leaf length (LL) is of practical value because these indicators are related to crop yields and harvest timing. The aim of this study was to develop a method that enables the continuous, automatic estimation of the LAI, LFW, and LL of a Chinese chive (Allium tuberosum) canopy by combining timelapse photography with allometric equations. LAI was estimated based on the gap fractions of nadir photographs (i.e., the fractions of nonleaf area), which were retrieved using the deep learning framework DeepLabv3+ with satisfactory accuracy (mean intersection over union, 0.71). This photographically estimated LAI (LAIphoto) corresponded well with the destructively measured LAI (LAIdest) (LAIphoto = 0.96LAIdest, R 2 = 0.87). LAIphoto was then used as the input of allometric regression equations relating LAIphoto with LFW and LL. A power function (y = axb) fit the observed LAIphoto–LFW and LAIphoto–LL relationships well (R 2 = 0.89 and 0.74, respectively). By combining nadir timelapse photography with the allometric equations, changes in the LFW and LL of a Chinese chive canopy were estimated successfully for a 9-month cultivation period. Our approach can replace time-consuming, labor-intensive manual measurements of these crop size indicators for Chinese chive and may be applicable to other crops with different parameter sets.

Open access

Jeff B. Million and Thomas H. Yeager

Fabric containers (FAB), due to their root-pruning properties, can be used as an alternative to conventional plastic containers (PLA) in container nurseries. Because sidewall evaporation in FAB has been shown to reduce container substrate temperatures, our objective was to determine if FAB would reduce the release rate of controlled-release fertilizer (CRF), resulting in less leachate loss of nitrogen (N) and phosphorus (P) and greater CRF longevity. Dwarf Burford holly were grown in 36-cm-diameter (18-L substrate) FAB or PLA in a bark-peat substrate with incorporated CRF. Spray stake irrigation was routinely adjusted to a target leaching fraction of 25%. Maximum daily substrate temperature, measured 3 cm from southwest-facing container wall, averaged 6 °C lower in FAB than in PLA. For two 31-week experiments where leachate was continuously collected and sampled weekly, FAB reduced leachate N loss by 30% and P loss by 47% despite requiring 66% more irrigation water and collecting 31% more leachate than with PLA. FAB reduced average N loss from 114 to 78 kg·ha−1 and average P loss from 16.0 to 8.6 kg·ha−1. FAB increased plant size by 8% and shoot dry weight by 12% for one experiment but had no effect in the other. We concluded that compared with PLA, the use of FAB can decrease leachate loss of N and P but require considerably more irrigation water to offset water loss via sidewall evaporation.

Open access

Azeezahmed Shaik and Sukhbir Singh

Recent studies suggest that arbuscular mycorrhizal fungi (AMF) have the potential to improve the growth and yield of eggplant (Solanum melongena L.) under soil-based organic production systems. However, the application of AMF in organic soilless vegetable production in a greenhouse has not been well studied, creating an important knowledge gap. Therefore, two greenhouse experiments [Experiment 1 (E1) and Experiment 2 (E2)] were conducted to investigate the effect of AMF (Glomus spp.) on the growth, gaseous exchange, and yield of eggplant fertilized with various liquid organic fertilizers (OFs) and inorganic fertilizers (IFs) in a soilless greenhouse production system. The experiment was conducted in a split-plot design with four replications in which liquid OFs [OF1 (5N–1P–1K), OF2 (0N–5P–5K and 3N–3P–3K), OF3 (3N–1P–1K), OF4 (5N–1P–2K), OF5 (3.7N–2.7P–3.7K), and OF6 (3N–3P–5K)], and IFs [IF1 (6N–4P–4K) and IF2 (4N–0P–1K and 1N–3P–5K)] were randomized as main plot factor, and AMF [inoculated and uninoculated (control)] as a subplot factor. Results indicate that AMF inoculation had no significant effect on the growth, gaseous exchange, and yield parameters of eggplant. Among different OFs, the eggplant fertilized with OF6 resulted in a 4.3% and 3% reduction of leaf area compared with top-performing IF1 treatment in E1 and E2, respectively. Further, the OF6 treatment resulted in a 12% and 15% reduction in total yield per plant compared with IF1 in E1 and E2, respectively. The differences in plant gaseous exchange parameters were also nonsignificant for eggplants fertilized with different OF and IF treatments in both E1 and E2. These results conclude that Glomus spp. were not associated with a significant increase in the yield of eggplant in the soilless production system. However, OFs were performing similar to IFs in terms of growth and yield, which could be due to a higher nutrient availability of these OFs, which are highly useful for the production of eggplant in greenhouse soilless production systems.

Open access

S. Alan Walters and Bryan G. Young

Preemergence (PRE) herbicides are an important part of the overall weed management plan in no-till (NT) pumpkin (Cucurbita pepo) production. A field evaluation was conducted in an NT production system using PRE herbicides labeled for pumpkins to determine the benefits of specific herbicide combinations and the economic returns on investment associated with their use. The PRE herbicide treatments evaluated were 1) s-metolachlor (1360 g⋅ha–1 a.i.), 2) clomazone (350 g⋅ha–1 a.i.) and ethalfluralin premix (1120 g⋅ha–1 a.i.), 3) s-metolachlor + clomazone and ethalfluralin premix, 4) s-metolachlor + halosulfuron (35 g⋅ha–1 a.i.), 5) clomazone and ethalfluralin premix + halosulfuron, and 6) none. The primary weed species present were tall waterhemp (Amaranthus tuberculatus), redroot pigweed (Amaranthus retroflexus), giant foxtail (Setaria faberi), and large crabgrass (Digitaria sanguinalis). The best weed control option for full-season broadleaf and grass weed control was s-metolachlor + clomazone and ethalfluralin. This herbicide combination also provided the greatest economic return on investment, ranging from a 20% to 40% improvement (depending on the year) compared with the next closest PRE herbicide treatment. Those with the lowest returns on investment were s-metolachlor combined with halosulfuron, and clomazone and ethalfluralin combined with halosulfuron. Besides providing the highest returns on investment, the PRE application of s-metolachlor with clomazone and ethalfluralin also produced the largest pumpkin fruit for the weed species present. Although growers often look for ways to reduce input costs in NT pumpkin production systems, the proper selection of PRE herbicides that considers the weed species present is clearly an important investment that improves pumpkin yields and revenues.

Open access

Leynar Leyton Naranjo and Carol D. Robacker

Abelia R. Brown is an important genus of flowering landscape shrubs. Native to China, the genus is characterized by evergreen or semievergreen shrubs with a flowering period from spring to frost; white or pink flowers; and yellow-green, gold, red, or dark-green foliage, depending on the season (Dirr, 2011). Abelia is disease, pest, and deer resistant; heat and drought tolerant (Scheiber and Robacker, 2003); nontoxic to humans; attractive to a variety of pollinators (Mach, 2018); and a noninvasive species that rarely sets seeds naturally, make Abelia an important genus for