Plastic mulches made from nonbiodegradable polymers (e.g., polyethylene) provide an essential service in commercial horticultural production systems by enhancing crop productivity through weed suppression, soil moisture conservation, and moderating soil and canopy temperature conditions. Plastic mulches are particularly important in organic agriculture because weed management options are limited. Nevertheless, there is increasing concern about addressing the negative environmental impacts of plastic mulch waste. Soil-biodegradable plastic mulch (BDM) films that are designed to biodegrade in soils after incorporation are promising alternatives to nonbiodegradable plastic mulch. However, although the US organic standards technically permit the use of BDM films, no commercially available products meet National Organic Program (NOP) requirements for 100% biobased content and 90% degradation after 2 years following soil incorporation (7 Code of Federal Regulations, section 205.2). Other concerns about biodegradable film mulches include high perceived cost, esthetics, and uncertainties regarding the impacts of soil incorporation. New mulch technologies have emerged to diversify sustainable mulch options and overcome barriers associated with BDM film use in organic production. The objective of this study was to provide an overview of alternative and emerging mulch technologies, with an emphasis on biodegradable mulches, including water-based sprayable mulches such as hydromulch and foam mulch, and biobased agrotextiles. Information about how these mulch technologies contribute to organic and sustainable agriculture is provided, along with definitions, opportunities, challenges, and recommended areas for future research.
Breeding programs around the world continually collect data on large numbers of individuals. To be able to combine data collected across regions, years, and experiments, research communities develop standard operating procedures for data collection and measurement. One such method is a crop ontology, or a standardized vocabulary for collecting data on commonly measured traits. The ontology is also computer readable to facilitate the use of data management systems such as databases. Blueberry breeders and researchers across the United States have come together to develop the first standardized crop ontology in blueberry (Vaccinium spp.). We provide an overview and report on the construction of the first blueberry crop ontology and the 178 traits and methods included within. Researchers of Vaccinium species—such as other blueberry species, cranberry, lingonberry, and bilberry—can use the described crop ontology to collect phenotypic data of greater quality and consistency, interoperability, and computer readability. Crop ontologies, as a shared data language, benefit the entire worldwide research community by enabling collaborative meta-analyses that can be used with genomic data for quantitative trait loci, genome-wide association studies, and genomic selection analysis.
Ginger (Zingiber officinale Rosc.) is a valuable sciophyte crop used as a spice or fresh herb in culinary dishes and for treating medical issues such as osteoarthritis, neurological diseases, vomiting, and asthma. The demand for ginger in the United States is remarkably high; it is produced commercially and exclusively in Hawaii but can only meet ∼20% of US demand. Light for ginger growth may be more important than is often assumed, but the roles of light in ginger growth and rhizome yield are not fully understood. We hypothesized that artificial shade would produce the highest yielding ginger compared with no shade. This study evaluated the impact of different shading suited for ginger growth and rhizome yield of different cultivars grown in a high tunnel. There were three levels (0%, 22%, and 40%) of shade using RCBD design. We analyzed the overall yield (weight) of ginger and the specific yield (weight) of different rhizome parts (biological root, edible root, and seed ginger) per plant in addition to plant growth data. Data were analyzed for 2018 and 2019, and shade conditions influenced ginger growth and yield. There was no significant difference between shade conditions or cultivars, but general trends found that data differed between the two growing seasons. In 2018, Chinese White and Hawaii Yellow produced a better (higher) yield under 0% and 40% shade. However, in 2019, Chinese White and Hawaii Yellow produced the highest total yield under 22% shade, but Bubba Blue produced the highest overall yield at 0% shade.
A main constraint of hydroponics is the need for high-quality water. This study evaluated the viability of reverse osmosis concentrate backflush, or reject water, as a water source for hydroponic lettuce production. We compared the growth of ‘Casey’ butterhead lettuce produced using nutrient film technique hydroponics with municipal (tap) water (TW), reverse osmosis (RO) water, and reject water from an RO system [wastewater (WW)]. Characterization of water sources showed the following: RO had trace minerals; TW had the greatest potassium (K), calcium (Ca), and magnesium (Mg); and WW had greatest sulfur (S), sodium (Na), and chloride (Cl). No water source had detectable heavy metals. Mineral and heavy metal tissue contents were determined at mid-harvest and end-harvest, and nutrient budgets for nitrogen (N), S, Ca, Mg, Na, and Cl were calculated. Water sources did not impact lettuce growth during the 4-week hydroponic production cycle based on leaf greenness, diameter, fresh weight, or dry weight. In the nutrient reservoirs, Ca and Mg increased over time and were greatest in TW. The Cl and Na levels in WW were 106 and 203 mg·L−1, respectively, and the electrical conductivity (EC) of this treatment increased to 3.5 dS·m−1 after 4 weeks; however, plant water uptake, water use efficiency, and percent moisture loss were unaffected. In shoot tissue, lettuce grown with WW had less Ca at mid-harvest and less Mg at mid-harvest and end-harvest compared with other treatments, suggesting antagonization of uptake by high salt. Tissue S was not different across treatments; however, there were differences in reservoirs of the water sources as S accumulated more from WW. Tissue Na and Cl levels were different among the treatments, and higher amounts in nutrient reservoirs translated to higher uptake by lettuce. Although the heavy metal content in all water sources was <0.01 ppm, arsenic, lead, and chromium were measured in lettuce tissue at levels that exceed recommended limits in most instances. Our results indicated that a water source of RO reject water from municipal feed water is a viable irrigation option for short-term hydroponic production of butterhead lettuce; however, EC reduction in the nutrient solution would be necessary when continuing sequential cropping.
Two common challenges reported by cannabis growers are low yields and small profit margins. Although recent research of cannabis yield has focused on lighting and nutrition, little research has examined how changes in other cultivation practices may be beneficial. The objective of this study was to evaluate the following two techniques to potentially improve yield: fertilizer restriction (FR) to reduce plant size and, thus, increase plant density and shoot number manipulation (SNM) to reduce shoot length and improve biomass partitioning. The FR technique involves leaching the substrate and providing only tap water for 0, 1, or 2 weeks at the start of flower initiation, whereas SNM involves pinching shoot tips 2, 3, or 4 times to produce 4, 8, or 16 shoots/plant, respectively. This study used a full factorial treatment design for a total of nine treatments (three FR × three SNM). Plants were flowered under 12-hour photoperiods for 8 weeks and then destructively harvested for data collection. The results demonstrated that both techniques improve plant productivity in different ways. The FR technique reduced all mass measurements (g/plant) and decreased plant area (m2/plant); therefore, the yield metrics (kg·m−2) increased with the increasing FR treatments. The SNM technique did not affect plant area, but more pinching events resulted in a decrease in reproductive shoot length (cm/shoot) and an increase in inflorescence to trim the dry mass ratio (inflorescence:trim). Shorter shoot lengths are desirable for eliminating trellis support netting, which helps growers reduce material costs and improve labor efficiency during harvest. Increasing the inflorescence:trim may also reduce labor costs related to trimming, which comprise the largest cost of production by many growers. Although both techniques offer advantages, there are trade-offs that must be considered in the context of overall profitability.
Pumpkin (Cucurbita moschata Duch.) is a versatile crop with strong stress resistance and promising growth potential. Widely cultivated in various regions of China, it ranks among the top crops globally in terms of both planting area and consumption. Known for its pleasant taste and high nutritional value, pumpkin pulp is rich in essential trace elements for the human body. Even after harvest, pumpkin fruit remains metabolically active, requiring its own nutrients to complete the postripening process. Failure to provide proper postharvest storage conditions can lead to excessive water loss and rapid nutrient depletion, resulting in rough, shriveled, and even rotten peel, ultimately diminishing the economic value of the pumpkin. This study aimed to investigate the changes in pumpkin quality and physiological indicators during storage to provide insights to determine optimal consumption and processing periods of pumpkins. The pumpkins were stored at a temperature of 16 ± 2 °C and 60% to 80% humidity during the experiment. The dynamic changes in fruit quality, hardness, respiration rate, malondialdehyde content, level of antioxidant enzymes, and other indicators of two pumpkin cultivars (BM5 and JQ) were assessed during storage, and the correlation among these indicators was evaluated. The results indicated a decrease in the vitamin C content and pulp hardness, whereas the superoxide dismutase and catalase contents initially increased and then decreased, and malondialdehyde and weight loss rates increased over the storage period. The weight loss rate exhibited significant positive and negative correlations with the malondialdehyde content (P < 0.01) of the two cultivars, whereas the vitamin C content showed a significant positive correlation with pulp hardness (P < 0.01). The findings indicate that optimal fruit quality was maintained within 40 days of postharvest storage. This study provides valuable insights into the selection of storable pumpkin cultivars.
Bulk density (Db) and subsequent physical properties are determined by the substrate and packing method. Packing method is the way one fills and compresses a substrate within a given volume. Bulk density produced in the laboratory may not align with “expected” published ranges due to variations in packing. Additionally, it is unknown if ranges identified as “typical” using a small volume sample ring reflect Db occurring in larger production size containers packed using commercial potting practices. Therefore, our objectives were to 1) emulate nursery practices and document the Db associated with a potted 2.8-L (#1) container, 2) develop and test the new “shim and compression” method to determine if it consistently packs sample rings to a Db commensurate with that of a 2.8-L nursery container, and 3) demonstrate how static physical properties are affected by the new “shim and compression” sample ring packing method compared with the traditional bench top tap method. When emulating nursery potting practices with 100% pine bark, coir, and peat, and blends of each, Db ranged from 0.08 g⋅cm−3 (coconut coir) to 0.17 g⋅cm−3 (pine bark). We used an espresso tamp and shims to pack the aforementioned substrates in sample rings. The Db achieved using a range in number of presses and discs was largely dependent on the substrate, but the desired Db was consistently achieved for each substrate. There was no effect of disc number on Db (P = 1.000) for any substrate. There was no effect of tamp number (P ≥ 0.0602) for all substrates except peat-amended, for which five tamps yielded a greater Db than one tamp (P = 0.0324). In an experiment in which a different technician who was accustomed to the conventional benchtop tap packing method performed both methods, method influenced Db (P < 0.0001), and the conventional method more closely attained the target Db. To our knowledge, this is the only report of Db observed in commercial container production facilities (i.e., “native”).
The limited availability of peat-based substrates, a nonrenewable resource, and the negative environmental impacts associated with their extraction require the conservation of this resource. We assessed the use of cattle dung compost as a stand-alone nursery substrate, replacing peat substrate for the production of lettuce (Lactuca sativa L.) seedlings. A completely randomized design was employed, using cattle dung compost (C) and commercial peat (P, control treatment) in various combinations (100% P; 25% C/75% P; 50% C/50% P; 75% C/25% P; 100% C) to assess their effects on different growth parameters of lettuce. Twenty-eight parameters (e.g., seed germination, seedling survival, diameter, height, biomass growth) were assessed, corresponding to the time when the seedlings are transplanted. All treatments achieved 100% seed germination and seedling survival; indicating the successful establishment of lettuce seedlings across all tested substrates. However, seedling growth was found to be significantly influenced by substrate type. Seedling diameter was significantly increased by 10.8% in the 50% C/50% P substrate, while seedling height was significantly increased by 7.7, 6.8, and nearly 10%, respectively, within the 25% C/75% P, 50% C/50% P and 100% C substrates, relative to the control. Other substrate treatments were not significant. Similar or significantly higher values than the control were also observed for biomass growth under the tested substrates, indicating the beneficial effect of cattle dung on the initial growth of plants during the nursery phase. Cattle dung compost, used as a growing substrate, demonstrated similar or superior results to commercial peat, suggesting its potential as a viable alternative potting medium for sustainable horticulture.