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Every autumn an abundance of leaves from various species of shade trees [e.g., oak (Quercus sp.), maple (Acer sp.)] are collected from urban landscapes. In 1988, shade tree leaves were banned from landfills and combustion facilities in New Jersey because it was an unsustainable practice. Composting and mulching leaves and using them as a resource was proposed. The purpose of this review is to summarize studies of mulching and amending soils with shade tree leaves and their potential to benefit agricultural production. Research sponsored by New Jersey Agricultural Experiment Station on soils and crops found that land application of shade tree leaves was beneficial for building soil organic matter content, protecting against erosion, and controlling weeds when used as a mulch. In general, crop yields and quality were improved with leaf mulch. Collected shade tree leaves on average have a relatively high carbon-to-nitrogen (N) ratio and the potential to cause a temporary deficiency of soil N availability. However, with good agronomic practices and well-timed N fertilization, crops perform well after shade tree leaves have been applied without increasing the recommended N fertilizer application rate.

Open Access

The objective of this study was to investigate the effect of high-tunnel production on preharvest losses and harvest quality of two tomato (Solanum lycopersicum) cultivars. Our results indicate that using high tunnels for tomato production can reduce the preharvest food losses for this crop compared with open-field production, as indicated by increased productivity and percent marketability during the span of three production seasons. The tomato harvest quality did not differ in terms of physical attributes. However, open-field–grown tomatoes demonstrated a significantly greater antioxidant capacity when compared with the high-tunnel–grown tomatoes.

Open Access

Substrate stratification is a new research area in which multiple substrates, or the same substrate with differing physical properties, are layered within a container to accomplish a production goal, such as decreasing water use, nutrient leaching, or potentially reducing weed growth. Previous research using stratification with pine (Pinus sp.) bark screened to ≤1/2 or 3/4 inch reduced the growth of bittercress (Cardamine flexuosa) by 80% to 97%, whereas liverwort (Marchantia polymorpha) coverage was reduced by 95% to 99%. The objective of this study was to evaluate substrate stratification with pine bark screened to remove all fine particles as the top strata of the substrate and determine its effect on common nursery weeds and ornamental plants. Stratified treatments consisted of pine bark screened to either 1/8 to 1/4 inch, 1/4 to 1/2 inch, or 3/8 to 3/4 inch, applied at depths of either 1 or 2 inches on top of a standard ≤1/2-inch pine bark substrate. An industry-standard treatment was also included in which the substrate was not stratified but consisted of only ≤1/2-inch pine bark throughout the container. A controlled-release fertilizer was incorporated at the bottom strata in all stratified treatments (no fertilizer in the top 1 or 2 inches of the container media), whereas the industry standard treatment had fertilizer incorporated throughout. Compared with the nonstratified industry standard, substrate stratification decreased spotted spurge (Euphorbia maculata) counts by 30% to 84% and bittercress counts by 57% to 94% after seeding containers. The shoot dry weight of spotted spurge was reduced by 14% to 55%, and bittercress shoot dry weight was reduced by 71% to 93% in stratified treatments. Liverwort coverage was reduced by nearly 100% in all the stratified substrate treatments. Compared with the industry standard substrate, stratified treatments reduced shoot dry weight of ligustrum (Ligustrum japonicum) by up to 20%, but no differences were observed in growth index, nor were any growth differences observed in blue plumbago (Plumbago auriculata).

Open Access

Aeration and sand topdressing are important cultural practices for organic matter management on golf course putting greens. Many golf courses lack the budget for applications of new sand topdressing material. A 2-year study was conducted to investigate the effect of recycling sand from hollow-tine aerification cores on a sand-based creeping bentgrass (Agrostis stolonifera) putting green soil properties and playability. Treatments included traditional [T (cores removed and sand topdressed)], verticut [V (cores broken up with verticutter)], and recycle [R (cores recycled using a core recycler)]. There were no differences in root zone organic matter, bulk density, soil porosity, infiltration rates, percent sand recovered during mowing, surface firmness, and ball roll distance between treatments during the study. Immediately after aerification treatments, T had the highest percent green cover (PGC) (38.3%) compared with V (26.9%) and R (26.8%), indicating that T offered the least sand present on the surface. Seven days after treatments, there was no difference in PGC (85.3% to 90.1%), indicating all treatments recovered similarly. Alternative aerification treatments V and R could be useful techniques to minimize or reduce the amount of sand used for backfilling core aeration holes without compromising the putting green soil properties and playability.

Open Access

Consumers desire low-input turfgrasses that have tolerance to both shade and drought stresses. Several sedges (Carex sp.) and nimblewill (Muhlenbergia schreberi) are native plants prevalent in dry woodland ecosystems in Oklahoma, USA, and may have potential as alternatives to conventional species in dry shaded turfgrass systems. To evaluate selected species for this purpose, a multilocation field trial was conducted in Stillwater and Perkins, OK. Four sedges [gray sedge (Carex amphibola), Leavenworth’s sedge (Carex leavenworthii), ‘Little Midge’ palm sedge (Carex muskingumensis), and Texas sedge (Carex texensis)] and nimblewill were evaluated as alternative turfs for the study. Alternative turfs were compared against two conventional turfgrasses [‘El Toro’ Japanese lawngrass (Zoysia japonica) and ‘Riley’s Super Sport’ bermudagrass (Cynodon dactylon)]. The conventional turfgrasses outperformed each sedge and nimblewill in coverage and turf quality. Leavenworth’s sedge, gray sedge, and Texas sedge persisted well but did not spread quickly enough to achieve a dense canopy by the end of the 2-year trial. In contrast, nimblewill established quickly but declined in coverage over time. This study demonstrated some sedges and nimblewill can be established and maintained as a low-input turf in dry shade, but development of unique management practices is still required for acceptable performance.

Open Access

Automatic in-field fruit recognition techniques can be used to estimate fruit number, fruit size, fruit skin color, and yield in fruit crops. Fruit color and size represent two of the most important fruit quality parameters in stone fruit (Prunus sp.). This study aimed to evaluate the reliability of a commercial mobile platform, sensors, and artificial intelligence software system for fast estimates of fruit number, fruit size, and fruit skin color in peach (Prunus persica), nectarine (P. persica var. nucipersica), plum (Prunus salicina), and apricot (Prunus armeniaca), and to assess their spatial and temporal variability. An initial calibration was needed to obtain estimates of absolute fruit number per tree and a forecasted yield. However, the technology can also be used to produce fast relative density maps in stone fruit orchards. Fruit number prediction accuracy was ≥90% in all the crops and training systems under study. Overall, predictions of fruit number in two-dimensional training systems were slightly more accurate. Estimates of fruit diameter (FD) and color did not need an initial calibration. The FD predictions had percent standard errors <10% and root mean square error <5 mm under different training systems, row spacing, crops, and fruit position within the canopy. Hue angle, a color attribute previously associated with fruit maturity in peach and nectarine, was the color attribute that was best predicted by the mobile platform. A new color parameter—color development index (CDI), ranging from 0 to 1—was derived from hue angle. The adoption of CDI, which represents the color progression or distance from green, improved the interpretation of color measurements by end-users as opposed to hue angle and generated more robust color estimations in fruit that turn purple when ripe, such as dark plum. Spatial maps of fruit number, FD, and CDI obtained with the mobile platform can be used to inform orchard decisions such as thinning, pruning, spraying, and harvest timing. The importance and application of crop yield and fruit quality real-time assessments and forecasts are discussed.

Open Access

Uniconazole is approved for use as a chemical option on tomato (Solanum lycopersicum) for height control, but research is limited. In this study, 12 tomato cultivars were chosen with three cultivars each of indeterminate, determinate, heirloom, and container types. Plants were sprayed with a one-time application of 0, 2.5, 5, 7.5, or 10 mg⋅L–1 of uniconazole during the two- to four-leaf stage to evaluate height control. Results indicated no significant difference between concentrations for plant height, stem caliper, and plant dry weight. The greatest soil plant analysis development (SPAD) values were observed with the 10-mg⋅L–1 treatment. Flower response in ‘Brandywine’ to a single application of 0, 2.5, or 5 mg⋅L–1 of uniconazole demonstrated a greater number of flowers per plant at 5 mg⋅L–1, whereas no significant difference was shown for the number of flower clusters or the number of flowers per cluster at other treatment levels. Using 2.5 mg⋅L–1 uniconazole was effective for reducing plant height across all cultivars of greenhouse-grown tomato seedlings compared with the control, whereas addition of 5 mg⋅L–1 was shown to increase the number of flowers in the heirloom cultivar Brandywine.

Open Access

Little is known about the adaptability of lychee (Litchi chinensis) to acidic soils high in aluminum (Al). A 2-year greenhouse study was conducted to determine the effects of various levels of soil Al on dry matter production, plant growth, and nutrient concentration in shoots of lychee cultivar rootstock seedlings (maternal half-sibs) of cultivars Brewster, Bostworth-3 (Kwai May Pink), and Kaimana. Soil Al treatments were statistically different for all variables measured in the study but not rootstock seedlings. Total leaf, stem, and root dry weights significantly decreased at soil Al concentrations ranging from 0.42 to 12.69 cmol·kg−1. Increments in soil Al resulted in a significant reduction in the concentration of leaf calcium and phosphorus and a significant increase in leaf Al in cultivar rootstock seedlings. The concentration of leaf potassium, magnesium, iron, zinc, and boron were in the optimum range for lychee, whereas leaf nitrogen and manganese concentrations were above optimum. The results of this study demonstrated no cultivar rootstock seedlings differences for dry matter production in lychee trees grown under Al stress and demonstrate that lychee is highly susceptible to acid soils.

Open Access

Pennsylvania bittercress (Cardamine pensylvanica) and other bittercress (Cardamine) species are among the most common and difficult-to-control weed species in container nurseries, and they have been vouched in most counties in Florida. Preemergence herbicides can provide control, but concerns over potential resistance development, environmental issues, and crop injury problems associated with herbicide use create the need for alternative weed control methods to be explored. Previous studies have shown the potential of mulch materials for controlling weeds in nurseries, but their use along with preemergence herbicides has not been extensively investigated. To compare the effects of different mulch materials and herbicides on Pennsylvania bittercress control, a full factorial designed greenhouse study was conducted. Three mulch treatments including no mulch, pine (Pinus sp.) bark, and rice (Oryza sativa) hulls were evaluated with three herbicide treatments, including water (i.e., no herbicide), isoxaben, and prodiamine applied at label rates. Twenty-five seeds of Pennsylvania bittercress were sown on the surface of each container and emergence (percent), coverage (square centimeters), seedhead number, and biomass (grams) were measured. The results showed that Pennsylvania bittercress in containers mulched with rice hulls had the lowest emergence throughout the experiment. For coverage, seedhead, and biomass parameters, Pennsylvania bittercress seeded in rice hulls treatments had significantly lower coverage, fewer seedheads, and lower biomass compared with those in nonmulched or pine bark treatments, regardless of herbicide treatment. With isoxaben and the water check, nonmulched treatments had the highest coverage/seedhead/biomass, whereas with prodiamine, Pennsylvania bittercress in pine bark mulched containers had the highest coverage/seedhead/biomass. In conclusion, applying rice hulls alone can provide better Pennsylvania bittercress control compared with isoxaben or prodiamine applied alone.

Open Access