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Biochar offers several benefits as a soil amendment, including increased soil fertility, carbon sequestration, and water-holding capacity in nutrient-poor soils. In this study, soil samples with and without biochar additives were collected for two consecutive years from an experimental field plot to examine its effect on the microbial community structure and functions in sandy soils under peach-trees (Prunus persica). The four treatments evaluated consisted of two different rates of biochar incorporated into the soil (5%, and 10%, v/v), one “dynamic” surface application of biochar, and a 0% biochar control. Fatty acid methyl ester (FAME) analysis was used to assess the microbial community structure, and enzyme activities involved in C, N, P, and S nutrient cycling were used as a means of assessing soil functionality. Total FAME and bacterial indicators increased by 18% and 12%, respectively, in the 10% incorporated and 5% surface applied treatments. Biochar applications increased β-glucosaminidase and arylsulfatase activities, 5–30% and 12–46%, respectively. β-glucosidase and acid phosphatase activities decreased by approximately 18–35% and 5–22% in the 0–15 cm soils. The overall results suggest that biochar’s addition to the sandy soils stimulated microbial activity, contributing to the increased mean weight diameter (MWD), C sequestration, and consequential soil health. The changes in microbial community structure and functions may be useful predictors of modifications in soil organic matter (SOM) dynamics due to the long-term application of pine biochar in these systems.

Biochar may enhance soil health in sandy soils under peach [Prunus persica (L.) Batsch] tree production. A study was initiated in the Sandhills of North Carolina by applying pine‐biochar at two different rates (5 and 10%, v/v) and types of application (incorporation to 30 cm [‐Inc] and surface [‐Sur]) in 2017. Soil organic matter (SOM) dynamics was assessed via soil organic carbon (SOC), total nitrogen (TN), permanganate‐oxidizable carbon (POXC), aggregate fractions (macro‐, micro‐aggregates, and clay + silt particles), and enzyme activities (CNPS activity) at 0–15 and 15–30 cm in 2018 and 2019. After the first year of pine‐biochar application, POXC decreased in all biochar treatments, SOC was higher in the 10%‐Inc treatment, whereas CNPS activities and macroaggregates were highest in the 5%‐Sur compared with the non‐treated control. These results suggest early changes in SOM dynamics and biogeochemical cycling and have the potential to guide producers with the long‐term application of pine‐biochar to sandy soils.

With the registration of 1-methylcyclopropene (1-MCP) in the USA and large scale use on apples, the question was posed of how effective the product would be in maintaining the flesh firmness of tree ripened peaches. In NC where peaches are sold primarily through retail outlets immediately after harvest, high quality tree-ripened peaches are expected. However, to meet this expectation peaches are picked at a more advanced stage of maturity and they are softer with a reduced shelf life. Six peach (Prunus persica L. Batsch) cultivars and one nectarine cultivar were harvested at tree-ripe maturity. The cultivars were selected to represent a range of maturity from early to late season. The cultivars included in this study were: 'Candor', 'Goldprince', 'Carolina Red', 'Redhaven', 'Contender', 'China Pearl', and 'Big Red'. After harvest the fruit were cooled overnight to remove field heat and then treated with 1-MCP for 24 h at 5°C. After treatment with one µL/L 1-MCP the fruit were held at 21°C for up to 8 days to simulate retail and consumer conditions after purchase. Treatment with 1-MCP resulted in fruit with higher flesh firmness, particularly during the first 5 days at 21°C, compared to untreated fruit. Treated fruit were significantly firmer than the untreated fruit after approximately seven days, but this was somewhat dependent on harvest maturity. On fruit harvested at a later stage of maturity that had significantly softened, 1-MCP had little effect. One µl/L reduced the respiration rate of the fruit. Effect on soluble solid concentration was not consistent. It was concluded that use of 1-MCP would allow a tree-ripened peach to maintain slightly greater flesh firmness for a longer period of time when held under room temperature conditions. However, the commercial economics of this treatment need to be determined.

Many of the apples (Malus ×domestica) grown in the southeastern United States are sold to consumers through direct farm markets and roadside stands. Fruit in these markets may be exposed to high temperatures (>68 °F), which cause the fruit to ripen quickly, limiting their shelf life and consumer appeal and increasing their susceptibility to decay pathogens. Studies were undertaken in 2009 and 2010 to determine the effects of a 1-μL·L−1 postharvest 1-methylcyclopropene (1-MCP) treatment on the maintenance of flesh firmness and the incidence of rots in fruit held at elevated temperatures for up to 8 weeks. 1-MCP-treated fruit of three apple cultivars (Ginger Gold, Gala, and Golden Delicious) held in three retail farm markets in the southeastern United States maintained their firmness for 3 to 5 weeks. The firmness of non-treated ‘Ginger Gold’ fruit declined to less than 12 lbf after 1 week in each market, whereas the firmness of treated fruit remained greater than 16 lbf after 3 weeks. Treated ‘Gala’ fruit maintained their firmness at 14 lbf during 4 weeks in each farm market, whereas the firmness of non-treated fruit declined to less than 12 lbf after 2 weeks. The firmness of non-treated ‘Golden Delicious’ fruit declined to less than 12 lbf after 1 week in each farm market, whereas treated fruit maintained their firmness for up to 4 weeks. ‘Golden Delicious’ fruit treated with 1-MCP exhibited almost no loss of firmness during 4 weeks at 32, 50, or 70 °F, or even up to 8 weeks at 32 or 50 °F. The incidence of fruit rots increased with temperature, and 1-MCP reduced the incidence of fruit rots after 4 weeks at 70 °F in 2009 or after 8 weeks at 70 °F in 2010. These data show that 1-MCP may be of great benefit to producers who sell their fruit directly to the consumer by delaying the loss in firmness and reducing the incidence of rots in fruit kept at elevated temperatures.

Experiments were conducted to compare the effects of different preharvest and postharvest 1-methylcyclopropene (1-MCP) treatment combinations on ‘Law Rome’ and ‘Golden Delicious’ apple fruit. Preharvest 1-MCP sprays had minimal effects on maturity as determined by flesh firmness, starch index, internal ethylene concentration, and soluble solids concentration. Fruit internal ethylene concentration and firmness loss after 30- to 40-days storage at 0 °C plus 7 days at 20 °C were reduced by preharvest and postharvest 1-MCP treatments. The positive effects of preharvest 1-MCP on postharvest quality of ‘Law Rome’ declined in fruit that were harvested 3 days or more after spraying, whereas preharvest 1-MCP continued to have a positive effect on postharvest fruit quality of ‘Golden Delicious’ that were harvested up to 9 days after spraying. The loss in postharvest effects of preharvest 1-MCP treatment on ‘Law Rome’ at delayed harvests was reinstated by exposing fruit to gaseous 1-MCP on the day of harvest. These findings suggest that attached apple fruit of some cultivars may be capable of rapidly generating new ethylene receptors.

Three experiments were undertaken to evaluate the effects of different preharvest 1-methylcyclopropene (1-MCP) spray treatments on apple (Malus × domestica Borkh.) fruit maturity at harvest and quality after long-term storage in a regular atmosphere or controlled atmosphere (CA). Trees were sprayed within 7 days of the anticipated harvest date (H) and fruit for long-term storage were sampled at either H in the case of ‘Law Rome’ or at harvest dates that were delayed by up to 21 days (H + 21) in the case of ‘Golden Delicious’ and ‘Law Rome’. Preharvest 1-MCP sprays within 7 days of H reduced fruit drop, internal ethylene concentration, and starch index and reduced firmness loss during long-term storage of fruit at delayed harvest dates but had only minor effects on fruit maturity at H. Preharvest 1-MCP sprays reduced the incidence of superficial scald on ‘Law Rome’ apples more effectively than either diphenylamine or CA storage. Application of 1-MCP within 7 days of H may be used to delay harvest date, thereby allowing continued fruit growth without a concomitant advance in fruit maturity and to reduce firmness loss and superficial scald during long-term storage both for normal and delayed harvests.

White clover is a weed in apple orchards that competes with the crop; also, flowers of this weed are unwanted attractants of honey bees at times when insecticides, which are harmful to these pollinators, are being applied. In 1997 and 1998, white clover flower head and plant control by clopyralid alone and with 2,4-D and apple tolerance to these herbicides were determined. Treatments consisted of clopyralid at 0.10 and 0.21 kg ae/ha, 2,4-D at 1.1 kg ae/ha, and 2,4-D at 1.1 kg ae/ha plus 0.03 or 0.05 kg ae/ha clopyralid, which were applied 2 wk before full apple bloom and 2 wk after full apple bloom, and a nontreated check. No crop injury occurred with any treatment. All herbicide treatments provided some white clover control and flower head suppression. No differences in white clover bloom reduction were observed through May among treatments containing clopyralid. As summer progressed, the effect of clopyralid rate became more apparent. Clopyralid at 0.21, regardless of application time, provided 99% vegetative control and 100% flower head reduction through July. Clopyralid plus 2,4-D controlled white clover better than 2,4-D alone. However, vegetative control and flower head reduction with clopyralid at reduced rates (0.03 or 0.05 kg ae/ha) plus 2,4-D were not acceptable (76% or less and 78% or less, respectively). Thus, clopyralid at 0.10 and 0.21 kg ae/ha will be necessary for acceptable white clover vegetation control and flower head reduction.

A problem facing the peach industry is the ability to harvest field-ripened peaches and get them to market without significant softening or damage. However, getting mature peaches into marketing channels before significant softening occurs is a challenge. Our objectives were to evaluate two growth regulators to determine the effect on fruit quality and softening at harvest and after 1, 2, or 3 weeks in cold storage and to evaluate the effect on harvest date. The two products evaluated in this study were ReTain (aminoethoxyvinylglycine (AVG)—Abbott Labs) and EthylBloc (1-methylcyclopropene (MCP)—Biotechnologies for Horticulture). ReTain is a growth regulator that inhibits ethylene production and is used in commercial apple production to delay harvest. EthylBloc is applied as a gas and attaches to ethylene receptor sites which inhibits ethylene effects. A trial with preharvest foliar applications of ReTain and postharvest gassing with EthylBloc was initiated in July 1998 on `Contender' peaches. ReTain applications were made at 3-day intervals beginning 19 days before first harvest at the rate of 50 g a.i./acre. Applications 3 days before harvest resulted in increased flesh firmness at harvest and decreased ethylene evolution, which continued for up to 3 weeks in cold storage. Fruit were also gassed with 1 μl•L-1 (1ppm) EthylBloc in the laboratory the day following harvest for 24 h. Fruit treated with ReTain and EthylBloc had twice the flesh firmness of peaches that were not treated after 1 week in storage. ReTain applied 3 days before harvest delayed maturity. Further evaluation will be conducted in 1999.

Thinning peach fruit in the spring of the year is one of the most labor- and capital-intensive operations for peach growers in the southeast. In addition, fruit size can be negatively affected if peach thinning is delayed. The objective of this study was to evaluate the application of gibberellic acid (4% GA3, Ralex—Abbott Labs) in June to reduce peach bloom the following spring. Ralex was applied in June 1995 and 1996 to `Contender' peaches. Bloom density was evaluated in Spring 1996 and 1997 from long and short shoots from the higher and lower portions of the tree's canopy. Applications in 1995 were to trees with a crop load while applications in 1996 were to trees without a crop due to a spring freeze. Bloom densities in 1997 were 300% greater than bloom densities in 1996. The five rates of material evaluated were 0, 59, 79, 99, and 119 g/ha. In 1996, bloom density was significantly reduced with Ralex applications with the greatest reduction with the 99 and 119 g/ha application rates. However, in 1997 only slight differences were detected between all treatments with no difference between the control and 79-g/ha rate.

Saccharomyces cerevisiae a cells secrete an extracellular protein, called "barrier" activity, that acts as an antagonist of alpha factor, the peptide mating pheromone produced by mating-type alpha cells. We report here the DNA sequence of BAR1, the structural gene for barrier activity. The deduced primary translation product of 587 amino acids has a putative signal peptide, nine potential asparagine-linked glycosylation sites, and marked sequence similarity of the first two-thirds of the protein with pepsin-like proteases. Barrier activity was abolished by in vitro mutation of an aspartic acid predicted from this sequence homology to be in the active site. Therefore, barrier protein is probably a protease that cleaves alpha factor. The sequence similarity suggests that the first two-thirds of the barrier protein is organized into two distinct structural domains like those of the pepsin-like proteases. However, the BAR1 gene product has a third carboxyl-terminal domain of unknown function; deletion of at least 166 of the 191 amino acids of this region has no significant effect on barrier activity.