Dan Long

United States Department of Agriculture | USDA · Agricultural Research Service (ARS)

Brassicaceae oilseed crops have proven potential as vegetable oil feedstock for biofuels and food uses. However, meeting a growing demand for vegetable oils for food and industrial uses will require identifying oilseed species that are best suited for various growing environments within a particular region. The objective of this study was to compar...

Precision nitrogen (N) application methods have been developed for dryland wheat that utilize site‐specific measurements of grain protein concentration (GPC) to determine N fertilizer recommendations for the next season. The objectives of this study were to determine the critical protein level and N equivalent to a unit change in GPC from relations...

Some producers in the inland Pacific Northwest (PNW) are interested in diversifying the traditional 2‐yr sequence of winter wheat (Triticum aestivum L.) (WW)–summer fallow (SF) with oilseed crops to capture break crop effects. The objective of this study was to compare production costs and economic returns of 2‐yr sequences with those of intensifie...

Weed maps created late in the growing season are potentially useful in regions where late maturing weeds are problematic and need to be controlled before they produce seed. The objectives of this study were to (1) spatially characterize the population dynamics of predominant weed species and apply this information into quantifying the effect of tre...

A combine harvester provides unique capabilities as a mobile sensing platform. This chapter aims to contribute to the advancement of on-combine sensor use for obtaining site-specific crop data by trying to convince potential users in the agricultural community of its value and accessibility. Today, mass/volume flow and electrical capacitance sensor...

Monitoring crop phenology is crucial for making site‐specific management decisions for crop protection and nutrition. The prominent yellow bloom associated with canola (Brassica napus L.) and similar yellow‐flowering plants can provide cues about spatial differences as well as timing of crop input requirements. The objective of this study was to re...

An on-combine, near infrared (NIR) spectrometer is now commercially available for mapping grain protein concentration (GPC) within farm fields. Costing > US$20,000, this specialized instrument may not be affordable for all producers. The objective of this study was to adapt and evaluate a moderately priced reflectance spectrometer (<US$5500, Avante...

A lack of plant available water limits the ability to intensify the summer fallow-winter wheat (SF-WW) rotation in low precipitation (<350 mm) areas of the inland Pacific Northwest (PNW). The objective of this study was to compare crop yield, water use efficiency, precipitation capture, and soil water storage between conventional-tillage SF and red...

Brassicaceae oilseed crops can provide rotation benefits to dryland wheat (Triticum aestivum L.) and supply feedstock for biofuel production. However, growers face decisions about what oilseed crop is best suited for an environment. The objective of this study was to determine how varying production environments affect the agronomic performance of...

Tillage alters the soil environment and microbial communities responsible for decomposition and nutrient cycling. This study aimed to evaluate the effects of tillage intensity (minimum vs. conventional) on the soil chemical and microbial properties of a winter wheat (Triticum aestivum L.)–fallow rotation in the low‐precipitation zone of the Pacific...

Downy brome (Bromus tectorum L.) is a problematic weed for the conventional fallow/winter wheat (F/W) production system in the low precipitation-region (< 350mm yr−1) of the Pacific Northwest. A 4-yr field experiment was conducted to determine if incorporating spring barley (B, Hordeum vulgare L.) or spring carinata (C, Brassica carinata A. Braun)...

Core Ideas Soil attributes can be improved by intensifying crop rotations in combination with reduced tillage. There was weak evidence that intensifying wheat systems with oilseed crops improves aggregate stability. Reduced tillage produces fewer small class size aggregates that impede infiltration. Improving soil aggregation in the semiarid inlan...

Core Ideas Nitrogen removal maps combined with the fertilizer N equivalent are useful for precision N management. More N is needed to change spring wheat protein in Pacific Northwest than in northern Plains. The fertilizer N equivalent is generalizable among spring wheat cultivars. Growers can use yield and protein maps to implement the N replaceme...

Prominent yellow flowers that are present in a Brassica oilseed crop such as canola require careful consideration when selecting a spectral index for yield estimation. This study evaluated spectral indices for multispectral sensors that correlate with the seed yield of Brassica oilseed crops. A small-plot experiment was conducted near Adams, Oregon...

Meeting the goals set by the Energy Independence and Security Act requires evaluation of all potential feedstock sources including arid and semi-arid portions of the western United States (U.S.). The objective of this study was to assess the lignocellulosic feedstock potential in stream buffers of the inland Pacific Northwest. A 3-yr (2010–2012) ex...

In‐line, optical sensing has been developed for on‐combine measurement and mapping of grain protein concentration (GPC). The objective of this study was to estimate changes in costs and net returns from using this technology for segregation of the dark northern spring (DNS) subclass of hard red wheat ( Triticum aestivum L.) by GPC. Site‐specific GP...

Hydrotreated renewable jet fuel (HRJ) derived from crop oils has been commercially demonstrated, but full-scale production has been hindered by feedstock costs that make it more costly than petroleum-based fuels. Maintaining low feedstock costs while developing crops attractive to growers will be key to producing affordable HRJ and creating a depen...

Reproductive growth, such as flowers, may contribute to a canopy-level signal yet there are not currently any indices that measure variation in flowering. This study was conducted to determine how flowers influence the overall canopy signal and what bands of light may be useful for estimating variation in flower density and leaf area index (LAI). T...

Agricultural producers can use variable-rate application technology to vary N fertilizer within fields. ­ is study was conducted toestimate changes in net returns from implementation of variable-rate N management (VNM) on hard red spring wheat (Triticumaestivum L.) in a summer-fallow region in northern Montana. Net return from uniform N management...

On-combine yield monitors are widely used in precision agriculture for locating areas within fields where yields are reduced. However, the crop yield variability may be better interpreted by utilizing grain protein maps to reveal the factors limiting yield. The objective of this study was to develop an on-combine multi-sensor system for obtaining s...

Cellulosic ethanol commercialization promises to produce energy from agricultural biomass. Available biomass depends on plant net primary productivity (NPP) and crop type, which maintain total soil organic carbon (TOC). Effect of crop-type, residue removal, and NPP on ethanol yield and TOC levels were assessed by means of a three-pool C model deriv...

The winter wheat (Triticum aestivum L.)/summer fallow rotation typically practiced in the intermediate precipitation zone (300 to 450 mm [12 to 18 in]) of the inland Pacific Northwest has proven to be economically stable for producers in this region. However, multiple tillage operations are used to control weeds and retain seed-zone soil moisture,...

Grain segregation by grain protein concentration (GPC) may help growers maximize revenues in markets that offer protein premiums. Our objective was to develop an on-combine system for automatically segregating wheat (Triticum aestivum L.) by GPC during harvest. A multispectral optical sensor scans the grain as it is conveyed by the combine's grain...

This research compares three different classification algorithms for mapping crops in Pinal County, Arizona, using both present and historical image data. The study area lacked past crop maps, and farmers were dealing with the risk of evolution of resistance ...

Producers in the northern plains are diversifying and intensifying traditional wheat (Triticum aestivum L.)-based cropping systems by reducing summer fallow and including legume and oilseed crops. This study examined the influence of diversification and intensification on spring wheat yield and quality and associated insects, diseases, and weeds. R...

By ignoring spatial variability in grain quality, conventional harvesting systems may increase the likelihood that growers will not capture price premiums for high-quality grain found within fields. The Grain Segregation Profit Calculator was developed to calculate the cutoff value to use for segregating wheat (Triticum aestivum L.) into two lots o...

Growers are becoming interested in producing canola (Brassica napusor B. rapa) in the dryland, wheat-fallow region of the Pacific Northwest. Currently, agronomic research for spring canola in this region has not been initiated. This study evaluated the effect of no-till planting methods on stand establishment, crop yield, and seed oil quantity of s...

Multiple plant stresses can affect the health, esthetic condition, and timber harvest value of conifer forests. To monitor spatial and temporal dynamic forest stress conditions, timely, accurate, and cost-effective information is needed that could be provided by remote sensing. Recently, satellite imagery has become available via the RapidEye satel...

Foliar biochemistry provides important information about the physiological status of plants. Several different tools and techniques have been developed to infer plant biochemistry (such as state and change of foliar nitrogen (N) and chlorophyll) using remote sensing. However, few techniques allow accurate mapping of foliar biochemistry in 3-dimensi...

Contour seeding has long been recommended as a means of detaining water on hillslopes, increasing infiltration, and reducing runoff and soil erosion. Highly undulated landscapes with complex slopes such as those found in the inland Pacific Northwest have stymied application of this practice. This study investigated the potential usefulness of using...

In-season, spatially variable nitrogen (N) fertilizer applications in agricultural systems can help to maximize crop N use efficiency and minimize N losses via hydrological leaching, runoff, and atmospheric volatilization. N fertilizer management often relies upon measurements of crop spectral reflectance using ground-based optical on-the-go sensor...

Total chlorophyll a and b content (Chlab) of leaves is an important indicator of the photosynthetic capacity, nutritional condition, and health status of plants. Developing low-cost, easily accessible methods for estimating foliar Chlab of needleleaf species would enable a broad range of forestry applications. We evaluated data acquired using an of...

Leaf chlorophyll content (mu g cm(-2)) is an important variable for agricultural remote sensing because of its close relationship to leaf N content. The objectives of this study were to develop and test a new index, based on red, green and blue bands, that is sensitive to differences in leaf chlorophyll content at leaf and canopy scales. We propose...

Greater capacity in field experimental research could be achieved by equipment that harvests high-yielding biomass energy crops within small plots. Versatility and cost-effectiveness would be enhanced if the harvester were adaptable to currently available equipment. A narrow-width biomass harvester for experimental plots was constructed to meet the...

In the intermediate annual precipitation zone (14 to 18 inches) of northeastern Oregon, there is interest in increasing the intensity of cropping with spring crops. Mechanical tillage remains popular for seedbed preparation and weed control, but contributes to environmental problems and high labor and fuel cost. No-tillage (NT) crop production can...

Plant structure and chlorophyll content strongly affect rates of photosynthesis. Rapid, objective, and repeatable methods are needed to measure these vegetative parameters to advance our understanding and modeling of plant ecophysiological processes. Terrestrial laser scanners (TLS) can be used to measure structural and potentially chemical propert...

Practices that combine GPS-based guidance for terrain contouring and tillage for runoff detention have potential to increase water infiltration and reduce runoff. The objective of this study was to investigate contour planting as a means to reduce soil erosion on steep slopes of the Columbia Plateau dryland wheat region. An exploratory field study...

Active ground optical remote sensing (AGORS) devices mounted on overhead irrigation booms could help to improve seedling quality by autonomously monitoring seedling stress. In contrast to traditionally used passive optical sensors, AGORS devices operate independently of ambient light conditions and do not require spectral reference readings. Beside...

Spectral indices (SI) derived from crop reflectance data are sensitive to chlorophyll a and b content (Chl). However, the SI-Chl relationship might be confounded by variation in leaf area index (LAI) and soil background reflectance, especially in semiarid environments where water determines crop growth. This study evaluated the sensitivity of SI to...

Harvesting wheat (Triticium aestivum L.) for forage or leaving it for grain is the main decision uncertainty growers face in semi-arid regions during mid-season. To facilitate decision-making, a decision support system (DSS) has recently been proposed that requires information about crop water and nutritional status during spike emergence. Though r...

Conservation tillage systems that reduce soil erosion and maintain or increase soil carbon offer long-term benefits for producers in the inland Pacific Northwestern United States but could result in reduced grain yields due to increased pressure from weeds, disease, and insect pests. Our objective was to compare runoff, soil erosion, and crop yield...

Ground-based, active light sensing relies upon the Normalized Difference Vegetation Index (NDVI) for assessing crop N response and applying N fertilizer. However, NDVI may not work well in semiarid environments where biomass and yields depend upon plant available water. This study evaluated the Canopy Chlorophyll Content Index (CCCI) for predicting...

Spectral indices are useful for estimating crop yield potential and basing in-season N fertilizer applications. The normalized difference vegetation index (NDVI) is positively related to crop N status and leaf area index (LAI) under N limited conditions. However, under water limited conditions, variations in LAI may be driven by soil moisture rathe...

The advent of near infrared (NIR) on‐combine sensors gives growers the opportunity to measure the grain protein concentration of wheat ( Triticum aestivum L.) during harvest. A study consisting of three sequential experiments (laboratory bench, combine test stand, and field) was conducted to evaluate the performance of an in‐line, NIR reflectance s...

The advent of near infrared (NIR) on-combine sensors gives growers the opportunity to measure the grain protein concentration of wheat (Triticum aestivum L.) during harvest. A study consisting of three sequential experiments (laboratory bench, combine test stand, and field) was conducted to evaluate the performance of an in-line, NIR reflectance sp...

This study assessed whether vegetation indices derived from broadband RapidEye™ data containing the red edge region (690–730 nm) equal those computed from narrow band data in predicting nitrogen (N) status of spring wheat (Triticum aestivum L.). Various single and combined indices were computed from in‐situ spectroradiometer data and simulated Rapi...

The use of grain protein as a post-harvest index of N fertility status has been promoted for spring wheat (Triticum aestivium L.) through the establishment of critical levels for segregating wheat into N deficient vs. N sufficient classes. The objectives of this study were to evaluate this concept for winter wheat in the northern Great Plains; and...

The objective of this study was to evaluate an on-combine optical sensor for measuring and mapping the grain protein concentration in soft white winter wheat. Protein concentration was measured in reference samples of grain collected by hand from the combine during harvest. These reference measurements were statistically compared with sensor measur...

Unlike other measurement methods discussed in this special issue, time domain reflectometry (TDR) has the ability to measure both water content (θ) and apparent electrical conductivity (ECa) of soils. From simultaneous knowledge of θ and ECa, the soil solution electrical conductivity (ECs) and even the concentration of specific ionic constituents s...

The objective of this study was to evaluate a new optical near infrared transmitter analyzer for automatically sensing the protein concentration of wheat on the combine during actual harvest. In 2004, the Zeltex AccuHarvest Analyzer was mounted on the clean grain elevator of a Case IH combine harvester and linked with the GPS. The protein content o...

Site-specific measurements of grain protein concentration, in addition to grain yield, are potentially useful for assessing spatial variability in cereal crop production as needed in precision agriculture. This study investigated an on-combine spectroscopic sensor for mapping grain protein levels within farm fields. The optical, near-infrared senso...

grain yield using ratios of 1.3 and 1.6, respectively. One problem with this approach for estimating straw yield Accurate estimates of straw production for spring wheat (Triticum is that straw/grain ratios in wheat are not constant as aestivum L.) are important in the Great Plains for conservation plan- ning, nutrient cycling, and fertilizer recomm...

Variable-rate fertilizer application requires knowledge of the spatial distribution of soil nutrients within fields. Grid soil sampling might be used for acquiring this information, but is often too expensive for resolving spatial patterns in soil nutrients at the scale of precision fertilizer application. The objective of this study was to determi...

Mapping soil water content for site-specific management of farm fields is commonly achieved through grid soil sampling. This effort frequently requires intensive soil coring, which is destructive and time consuming. Precision farming and research can be facilitated if sampling techniques are improved and made cost effective. We designed and constru...

Mapping soil water content for site-specific management of farm fields is commonly achieved through grid soil sampling. This effort frequently requires intensive soil coring, which is destructive and time consuming. Precision farming and research can be facilitated if sampling techniques are improved and made cost effective. We designed and constru...

The impact of interactions between water and N stress on 13C isotopic discrimination (Δ) is not well understood. The objective of this study was to determine the impact of N on Δ in wheat (Triticum aestivum L.) grown under low, moderate, and high water stress. In a field study located near Havre, Montana, USA (48° 30′ N lat. and 109° 22′ W long.),...

By accounting for spatial variation in soil N levels, variable-rate fertilizer application may improve crop yield and quality, and N use efficiency within fields. The main purpose of this study was to demonstrate how site-specific wheat yield and protein data, and a geographic information system may be used in developing precision N-recommendations...

Wheat (Triticum aestivum L.) fields in the semi-arid Northern Great Plains are spatially variable in soil N fertility and crop productivity. Consequently, there is interest in applying variable, rather than uniform rates of fertilizer N across the landscape. Intensive soil sampling as a basis for variable-rate fertilizer management is too costly wh...

This paper illustrates spatial autoregressive response modeling applied to estimating the relationship between site-specific wheat yield and selected terrain variables within a dryland production field in Montana. Yield values for numerous irregularly spaced areal units are obtained with a mass flow yield sensor. Kriging is used to compute spatiall...

The predominant dryland cropping system in the low (

Combine yield monitors are increasingly being used by production agriculturalists across the world. A portion of the data acquired from yield monitors is erroneous. Erroneous data can result from rapid speed changes, extraneous vibration resulting from crossing bumps in the field, not cutting a full header width, erroneous position information and...