The most significant impacts of the vineyard floor treatments were of the cover-crop treatments on soil parameters in the middles. Soil organic matter in cover-cropped middles was higher than in bare middles each year . Cover crops affected key soil nutrients in the middles; for instance, cover crops greatly reduced nitrate-nitrogen , and to a lesser extent, extractable phosphorus , which may be beneficial in reducing loss of these nutrients in runoff during winter storms, but which also may have reduced the phosphorus content in the vines. In addition, cover crops in the middles also significantly reduced soil boron , extractable sodium and pH , and increased chloride and zinc when compared to bare soil.Soil microbial biomass. Microbial biomass varied as a result of both the cover-crop and weed control treatments. In both the middles and vine rows, microbial biomass was higher in rye cover-crop plots compared to bare plots . These results confirm earlier observations by Ingels et al. that microbial biomass carbon was higher in cover-cropped middles compared to bare middles. In the vine rows, microbial biomass was greater in plots adjacent to rye cover-cropped plots compared to bare plots. The effect of cover crops grown in the middles on soil in the vine rows may be due to cover-crop roots or tops extending into the vine rows and their subsequent decomposition, providing a food source for soil microbes.
Microbial biomass varied between the weed treatments in the vine rows but not middles . In the vine rows, stackable planters microbial biomass was significantly higher in the cultivation plots compared to the pre-emergence weed control plots . The most likely explanation is the incorporation of greater amounts of weed-derived carbon into the surface soil of the cultivated plots. Mycorrhizae. AMF can benefit grapevines by improving the nutritional 35 30 25 20 15 10 5 0 Cultivation Post-emergence Pre-emergence herbicide herbicide Bare ground Merced rye Trios 102 status of the plant and producing a highly branched root system. We quantified AMF reproductive structures in grapevine roots to determine if the weed control treatments in the rows and/or cover-crop treatments in the middles had significant effects on mycorrhizal colonization from 2003 through 2005. Based on ANOVA, the effects of weed control on colonization were not consistent among covercrop treatments . Grapevines adjacent to ‘Merced’ rye had higher colonization compared to those adjacent to ‘Trios 102’ triticale or bare ground, in both the cultivation and pre-emergence treatments . In contrast, grapevines in the post emergence treatment had the lowest colonization when adjacent to ‘Merced’ rye. These findings were consistent in each study year, based on the absence of significant main or interactive effects of time . It is possible that low colonization of grapevines in the post-emergence-by-‘Merced’ rye treatment is associated with this treatment’s weed community. Indeed, weed species vary in their ability to host AMF , so their presence or absence may affect mycorrhizal colonization of grapevines. Indeed, reports on the influence of plant community composition on AMF suggest that plant diversity has a strong effect on AMF diversity , and this may affect the colonization of individual plant species. All yield, fruit quality and vine growth parameters varied by year, and this was the only significant effect for these parameters, with the exception of berry weight and titratable acidity . No differences in crop yield or fruit composition were observed from 2001 to 2005 due to weed control treatments . Cover-crop treatments also had no significant effect on yield or fruit composition, although in 2001 and 2004, there was a reduction in berry size in the ‘Trios 102’ triticale treatment. Weed control treatments also had no effect on vine growth , based on shoot counts and pruning weights taken at dormancy. Cover-crop treatments had no significant effect on vine growth when averaged over 5 years, although in 2001 and 2005 the ‘Trios 102’ triticale treatment significantly reduced pruning weights. The trend for lower pruning weights may be related to the greater decline in soil moisture in the middles where this cover crop was used. It appears that vine growth, yield and grape quality are more significantly affected by annual precipitation than by vineyard floor management practices. In low rainfall areas the choice of cover crop is critical because of its effect on available soil moisture. We observed that late-maturing ‘Trios 102’ used more soil moisture during the vine growing season; if irrigation water does not compensate for water used by the cover crop, reduced vine growth and yield losses may result. The clear benefits of cover crops were increased organic matter in the middles and reduced sediment loss. Microbial biomass was increased in cover-cropped middles and there were indications that this effect extended to under the vines. Although there were no negative impacts of weed control treatments on vine productivity, we observed increased compaction over time from the use of cultivation. This study indicated that the choice of weed control strategy and cover crop must be carefully considered to maximize the benefits and minimize negative impacts of the practices. The benefits of cover crops are concentrated in the middles,and future research should focus on evaluating practices that improve the quality of soil under the vines.Elderberry is a part of the Viburnaceae family and grows all over the world, including Europe, North America, and Asia. Due to the vast geographic and morphological variety within Sambucus, there have historically been many species within the genus. However, a reorganization by Bolli reclassified some of the most common species under Sambucus into subspecies of S. nigra. More recently, elderberry was moved out of the Adoxoaceae family, which had already been changed before when elderberry was taken out of the Caprifoliaceae family. These changes have impacted the three subspecies most of interest in this work: the European elderberry S. nigra ssp. nigra; the American elderberry S. nigra ssp. canadensis; and the blue elderberry S. nigra ssp. cerulea . However, due to wide acceptance of this naming scheme for the subspecies, it will be used through this work to align with the current naming, but previous works cited may use the former species names. Furthermore, some sources refer to the entire plant as an “elder”, while others refer to the plant as “elderberry”, which is also used to denote the fruit of the plant. In this work, “elderberry” is used to discuss the plant as well as the fruit. “Elderflower” is used to refer to the blossoms of the plant. European elderberry is the most well-studied and widely used subspecies of elderberry in the market. This subspecies grows throughout the European continent, including countries such as Slovenia, Portugal, and Austria. The fruit and flower have been studied for decades for their composition and bio-activity, and while elderberry and elder flower are not new ingredients to the market, they have garnered more attention in the last several years as consumers look for more natural remedies and supplements to support their health. This has been especially true during the COVID-19 pandemic, in which elderberry became a popular ingredient in immunity-supporting supplements. Thus, investigating other elderberry subspecies like the blue elderberry, the focus of future chapters, allows for farmers in the United States to capitalize on this demand, but more information is needed on this particular plant if it is going to be used in consumer products.There is a long, rich history of the use of different parts of the elderberry plant by many cultures. For example, the wood has been used for kindling and musical instruments. Indeed, stackable flower pots the name of the plant is derived from various ancient words related to instruments. The flowers and berries have been used in a variety of beverages, foods, and other herbal supplements. Folklore has many stories about the healing power of the elderberry and elder flower. The plant itself has been revered by many cultures, with a story about the “Elder Mother” living within the plant would protect those near the plant. It was even expected to ask the Elder Mother for the berries or flowers before taking them; without permission, she may seek revenge. The leaves, branches, flowers, and berries were believed to have protective powers for a home and the leaves were also used during burial rituals by some Celtic people. The personification and deep reverence for the elderberry show the importance of the plant through generations. Hippocrates and Pliny the Elder both wrote about elderberry and its medicinal properties. Tribes indigenous to North America used flowers and fruit for medicinal and beverages. Berries were also used as a natural dye for baskets and branches were used to make musical instruments. Elderberry is a perennial, deciduous plant native to many regions of the northern hemisphere. Elderberry plants are neither tree nor bush, as the plant sends new canes up each season, which without pruning, can lead to a large, shrub-like plant that can be several meters tall and wide. They prefer to grow in sunny, riparian climates with moist, well-drained soil, though subspecies in North America can be drought-tolerant. While pruning even down to the ground level of the elderberry can improve yield and accessibility for harvesting, there is a limitation on pruning of the blue elderberry in the Central Valley of California. Due to the threatened status of the Valley Elderberry Longhorn Beetle , which lives only in the elderberry, branches larger than one inch in protected areas should not be pruned or removed from a growing site. Elderberry shrubs typically produce small white flowers with five petals in the spring, though the elder flowers of the blue elderberry are a creamy yellow color. Small, dark blue-purple berries ripen in the summer in large clusters called umbels or cymes, though there are examples of subspecies that have some variation to these morphologies, such as the blue elderberry that has a white bloom on the berries, causing the berries to look blue, and S. racemosa, which are red. Variation can also occur within a subspecies due to growing conditions, such as soil type, precipitation, and temperatures, as well as a key differentiation tool: cultivars or genotypes. There are established cultivars or genotypes of the European subspecies , such as Sambu or Haschberg, as well as of the American subspecies , like Bob Gordon or Wylewood. Cultivars can have more consistent growing patterns, such as blooming or ripening all at once, and desired chemical compositions, such as increased anthocyanins, thus are more desirable to use in large scale growing of elderberry for commercial use. Blue elderberry does not have any established genotypes to date. If commercial interest in this subspecies continues to expand, effort should be made to develop cultivars with consistent quality and improved harvest ability, which is hampered right now due to flowers and berries ripening throughout a season, instead of a smaller window of time like the American and European subspecies. Indeed, starting this work can help increase the commercial interest viability of the blue elderberry. A primary driver in interest in the composition of elderberry and elder flower is for their potential health benefits. Several reviews have recently been published on this topic; thus, it will not be explored in depth here. European elderberry has been studied for its antioxidant, antimicrobial, anti-inflammatory, anticancer, immunomodulatory, and antidiabetic properties, as well as neuroprotection and cardiovascular protection in vitro and in vivo. These activities have been mainly attributed to the phenolic compounds like cyanidin 3-glucoside and cyanidin 3- sambubioside, but some other compounds have been shown to be bioactive as well, including terpenes, lectins, pectin, peptides, and malic acid. Using data from randomized, controlled clinical trials, a recent review found that elderberry could reduce symptoms from upper respiratory viral infections, providing support for the use of elderberry supplements by consumers to combat colds and flus without the use of antibiotic medicine. In a more unique application, elderberry and elder flower extracts have both shown to be effect in combatting gingival inflammation using a topical herbal patch and elder flower tea, respectively. A study of the mechanism of cyanidin 3-glucoside to treat against the influenza virus showed that elderberry extract had some inhibitory effect during the early stages of virus cycle with stronger impacts during post-infection.