Jennifer R Reeve

Utah State University | USU · Plants Soils and Climate

Quantifying changes in soil organic carbon (SOC) is essential for understanding the effect of managements on carbon (C) sequestration, especially in cultivated marginal lands. The objectives of this study were to determine the short- (<3 yr) and long-term (>24 yr) effects of a one-time compost application on soil organic matter (SOM) pools and stoc...

Organic amendments are applied in organic farming systems to provide nutrients for crop uptake and to improve soil health. Compost is often favored over fresh manure for food safety reasons, while fresh manure can be a valuable source of readily available nitrogen (N). However, the potential for fresh versus composted manure to differentially affec...

Nitrogen‐fixing legumes such as alfalfa (Medicago sativa L.) and sainfoin (Onobrychis viciifolia Scop.) may benefit agricultural systems. In addition to quality forage, both legumes contain secondary metabolites that play important roles in agroecological systems. Alfalfa contains triterpenes (saponins), and sainfoin contains phenolic compounds (ta...

Organic dryland wheat (Triticum aestivum L.) is an important crop in Utah and the Intermountain Western United States; however, growers face numerous challenges maintaining yield, grain quality, soil fertility, and health. Wheat yields in the West are severely constrained by lack of rainfall, so dryland organic wheat farmers generally do not grow c...

Grazed pastures are susceptible to N loss from urine/manure additions, which increases eutrophication, affecting the global N cycle. Plant secondary metabolites (PSM), such as condensed tannins (CT) and terpenes, influence silviculture soil dynamics by generally decreasing N mineralization. We investigated whether cattle‐grazed pastures of non‐trad...

Dual‐use cover/green manure (CGM) crops and animal manure are used to supply N and P to organically grown field crops. A comprehensive review of previous research was conducted to identify how CGM crops and animal manure have been used to meet N and P needs of organic field crops, and to identify knowledge gaps to direct future research efforts. Re...

Standard commercial soil tests typically quantify nitrogen, phosphorus, potassium, pH, and salinity. These factors alone are not sufficient to predict the long-term effects of management on soil health. The goal of this study was to assess the effectiveness and use of simple physical, biological, and chemical soil health indicator tests that can be...

Maintaining nutrient availability in organic orchards presents challenges. Diverse litter sources may increase nutrient cycling and the efficiency by which microbes utilize carbon (C). Two tree-row treatments: ‘straw-mulch’ (Triticum aestivum L.) and ‘living-mulch’ (Lobularia maritima (L.) Desv.), and two alleyway groundcovers: ‘grass’ (Festuca rub...

Including drought-tolerant crops, such as quinoa (Chenopodium quinoa Willd.), in rotation could benefit growers facing increased water shortages in the western United States. Yet, there are limited varieties available and varietal response to irrigation rate has not been described. To address this, a line-source irrigation trial was conducted with...

Quinoa (Chenpodium quinoa Willd.) could provide a high value crop for organic cropping systems in the Intermountain Western US. This study evaluated quinoa in three cover cropping systems [strip crop (SC), undersown clover (UC), or winter cover crop and tillage (T)] with and without compost (+C or −C) in a split-plot with blocks design. Quinoa prod...

Organic farming systems receive organic amendments to maintain soil fertility and supply nutrients for plant growth. This study investigated the effect of organic fertilizers (no amendment as control, compost, and manure), and their interaction with cover crops (millet, buckwheat, and black turtle bean) on soil enzyme activities, N transformation r...

Treerow vegetation abundance and biodiversity were measured in response to six orchard floor management strategies in organic peach in northern Utah for three growing seasons. A total of 32 weed species were observed in the treerow; the most common were field bindweed, dandelion, perennial grasses (e.g., red fescue and ryegrass), clovers, and prick...

Onion thrips, Thrips tabaci Lindeman, a primary insect pest of onions, Allium cepa L., worldwide, reduces yield and transmits a devastating Tospovirus, Iris yellow spot virus. Costly and frequent insecticide application and increased resistance of onion thrips to insecticide prompted interest in alternative pest management options. Three trap crops...

Adequate weed control and nutrient supply are critical for successful establishment of fruit trees. This is of particular concern in organic orchard establishment. In order to determine the best approach for establishing peach trees (Prunus persica L.) organically in climates characterized by hot dry summers and cold winters such as the North Ameri...

That the health of soils, plants, animals, and people are linked is an ancient idea that still resonates. Growing evidence links farm management, soil health, and plant health but relationships among soil health, food crop nutritional quality, and human health are less understood. Numerous studies compare organic with conventional farming in order...

Agricultural developments over the previous half-century have highly increased food, feed and fiber production. Yet, global food output and distribution still falls short of feeding the world with unintended harm to the environment and society. Agriculture requires new approaches that meet the challenges of sustainable and equitable food production...

In the majority of agricultural soils, ammonium (NH4+) is rapidly converted to nitrate (NO3−) in the biological ammonia and nitrite oxidation processes known as nitrification. The often rate-limiting step of ammonia oxidation to nitrite is mediated by ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA). The response of AOA and AOB...

Compost plays a central role in organic soil fertility plans but is bulky and costly to apply. Determining compost carryover is therefore important for cost-effective soil fertility planning. This study investigated two aspects of nutritive carryover [nitrogen and phosphorus (P)], and an indicator of non-nutritive carryover [soil organic matter (SO...

Birdsfoot trefoil (BFT, Lotus corniculatus L.) is a nonbloating perennial forage legume well suited to ruminant production on pastures. It is persistent under irrigation in cool, dry western US climates, and has been found to increase meat and milk production compared with other forages. The establishment of BFT pastures was evaluated on five comme...

Effects of onion landscape effects, inlcuding other crops and weeds, crop rotation and nitrogen management on Thrips tabaci and incidence of Iris yellow spot virus.

Soil quality problems such as erosion, depleted soil organic matter, nutrient reserves and reduced water holding capacity are of increasing concern to farmers in the Intermountain West. Marginal soils require more amendments and fertilizers to meet crop needs. As input costs rise and water resources are increasingly limited, effective methods of ev...

The economic importance of the European earwig Forficula auricularia L. in Utah peach orchards has been recognized but remains ambiguous due to the insect’s dynamic feeding behaviors (i.e., beneficial predator and pest herbivore). Local growers are requesting appropriate integrated pest management (IPM) programs that either promote or discourage ea...

Onion thrips and Iris yellow spot virus (IYSV) are two primary yield reducing factors in onion production worldwide. Current management practices rely on heavy use of insecticides and fertilizers, threatening the sustainability of onion systems. Little is known about how cultural practices such as reduced fertility, soil biostimulants, and crop rot...

The European earwig, Forficula auricularia L., is of interest in peach systems due to its abundance and diverse functional role; it is both a frugivorous pest and beneficial predator. The justification and protocol for earwig pest management in organic peach systems has not been established, and is a potential limitation to adoption of organic prac...

Adequate nutrient supply and weed control is critical for the successful establishment of fruit trees. A lack of available N and inadequate weed control is of particular concern in organic tree fruit establishment, especially when a short growing season and shallow alkaline soils limit natural fertility and use of nitrogen fixing winter cover crops...

Fruit production in Utah and throughout the US Intermountain West has come under increasing pressure due to rising input costs, diminishing water supplies, loss of export markets, and urban encroachment. These challenges also present considerable opportunity in the form of increased local and value-added marketing potential. Organic production may...

Interest in unheated plastic film-covered high tunnels to extend the growing season of high-value fruits and vegetables is growing rapidly, but sustainable soil management in intensively managed high tunnels is challenging. Yields, fruit quality, and soil quality in transition organic and conventional tomato were measured over the course of three g...

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Current commercial orchard floor practices in the U.S. Intermountain West consist of a grass alleyway and a vegetation-free strip in the tree row. Leguminous cover crops in the alleyway may provide the orchard with additional nitrogen inputs. Alleyway treatments of alfalfa (Medicago saliva L.), alfalfa-clover mix (Trifolium fragiferum L., and T rep...

Research has established that soil health benefits result from adopting organic farming practices. However, the relationship between the soil health benefits derived from organic farming methods and food quality is poorly understood. A multi-state coordinating committee was formed in 2010 to foster improved coordination among scientists working on...

Overreliance on fossil fuel based inputs, and transport of inputs and products is seen by many as a threat to long-term agricultural and food system sustainability. Many organic, biodynamic, and low-input farmers limit off-farm inputs, attempting instead to farm within the carrying capacity of their land or local environment. These farmers often ac...

[This corrects the article on p. e12346 in vol. 5.].

Raw data for all slides. (2.98 MB CSV)

Normalized data by functional groups. (0.00 MB CSV)

Normalized data for diversity analysis. (0.00 MB CSV)

Two gene sequences endemic to conventionally managed field soils and 233 sequences endemic to organically managed field soils, and the organisms from which probes were designed. (0.15 MB DOC)

Agrichemical inputs (insecticides, fungicides, herbicides, molluscides, adjuvants, fumigants, and fertilizers) applied to 26 strawberry fields during the 2004 and 2005 growing seasons. (0.05 MB DOC)

Fruit, leaf, and sensory properties (mean ± standard error) for ‘Diamante’ and ‘San Juan’ strawberry cultivars from organic (ORG) and conventional (CON) farms in June and September 2004 and April, June, and September 2005. (0.32 MB DOC)

Data by functional groups (SNR>2.0). (1.14 MB CSV)

Strawberry varieties, soil sampling dates, soil types, and soil classification for field pairs in the study. (0.05 MB DOC)

Soil properties (mean ± standard error) at two depths (0–10 cm and 20–30 cm) from organic and conventional strawberry farms in June 2004 and June 2005. (0.09 MB DOC)

Sale of organic foods is one of the fastest growing market segments within the global food industry. People often buy organic food because they believe organic farms produce more nutritious and better tasting food from healthier soils. Here we tested if there are significant differences in fruit and soil quality from 13 pairs of commercial organic...

EVALUATING THE EFFECTS OF NITROGEN, CROP ROTATION AND TRAP CROPS ON ONION THRIPS, IRIS YELLOW SPOT VIRUS AND CROP YIELD Kristie Buckland1, Jennifer Reeve1, Daniel Drost1, and Diane Alston2 Utah State University 1Department of Plants, Soils and Climate, 4820 Old Main Hill, Logan, UT 2Department of Biology, 5305 Old Main Hill, Logan, UT Onion pro...

Current guidelines for the use of compost in organic agriculture are based on nutrient targets, which represent the conditions needed for maximum yield. Due to the high cost of inputs, however, a maximum-yield strategy may be far from economically optimal in some organic cropping systems. In this article we formulate a theory of economically optima...

Relationships between soil microbial diversity and soil function are the subject of much debate. Process-level analyses have shown that microbial function varies with soil type and responds to soil management. However, such measurements cannot determine the role of community structure and diversity in soil function. The goal of this study was to in...

For organic farmers who use manure or compost to maintain soil fertility, a pressing question is how much should be applied. Although many factors influence this decision, an important consideration is that manure and compost continue to fertilize for many years after their application. In conventional agriculture, the carry-over effects of manure...

Root distribution was compared among Prunus rootstocks budded to 'Montmorency' tart cherry (Prunus cerasus L.) and Redhaven' peach (Prunus persica [L.] Batsch) and grown at the Kaysville, Utah location oldie multi-site NC-140 Regional Rootstock Research Project. Sampling was carried out on replicate trees with the rootstocks selected based on indus...

Plants take up nitrogen principally in the form of nitrate and ammonium; however, evidence is growing that they can also use organic N in the form of amino acids. Selecting varieties that better use organic N could be important in maximizing productivity in organic and low-input systems because these varieties may access a wider pool of available n...

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) is a serious virus pathogen in onion bulb and seed crops in the United States and several parts of the world (1). The virus is exclusively transmitted by onion thrips (Thrips tabaci). Besides onion and other susceptible crops such as garlic, leek, chives, and several ornamentals,...

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) continues to be an economically important pathogen affecting onion bulb and seed production in several parts of the world and the United States (1). Several weeds were reported naturally infected with IYSV (1,2,4). Leaves of Atriplex micrantha Ledeb. (synonym A. heterosperma Bunge...

Evidence is growing that amino acids can be an important source of plant N in nutrient limited natural ecosystems, but relatively little is known about the effect of agricultural management on soil amino acid pools and turnover. Organic management in particular relies on slow-release organic inputs as fertilizer, which could result in greater pools...

Wines produced from biodynamically grown grapes have received increasing attention. Similar to organic agriculture, biodynamics eliminates synthetic chemical fertilizers and pesticides. The primary difference between the two farming systems is that biodynamics uses a series of soil and plant amendments, called preparations, said to stimulate the so...

Goals/Specific Aims: * Develop molecular tools to examine genes encoding N mineralization and immobilization enzymes through data-mining and bioinformatic analysis of existing resources. Extend the database of genes encoding the enzymes of N mineralization and immobilization for agricultural soil environments. * Analyze genomic information from...