Dave Franzen

• PhD
• Professor at North Dakota State University

Soybean (Glycine max L.) is a new cash crop grown in north central and northwestern North Dakota (ND). Soils and climate in these new soybean areas differ from current fertilizer guidelines. A three-year study to evaluate soybean fertility best management practices was initiated in the spring of 2016 and concluded in 2018. Each year had two sites a...

Cover crops are an effective way to reduce soil erosion and promote soil health. However, in North Dakota and other northern climates where corn (Zea mays L.) is an important commodity crop, killing frosts generally occur before harvest, leaving little opportunity for cover crop planting. By interseeding cover crops into corn during the growing sea...

As the demand and cultivation of two‐row malting barley (Hordeum vulgare L.) increases in the Northern Great Plains, updated nitrogen (N) recommendations are increasingly necessary. Not only does N play a role in grain yield, but it also impacts grain malting characteristics, including protein and kernel plump. To determine the impacts N rate and a...

North Dakota is a transitional semiarid region with annual precipitation in the eastern part of the state of about 50–55 cm, mostly from rainfall. The moisture demand from interseeding cover crops into standing corn (Zea mays) early in the season has been a concern and is likely why most corn growers do not interseed cover crops. Corn grain yield w...

Plant N concentration (PNC) has been commonly used to guide farmers in assessing maize (Zea mays L.) N status and making in-season N fertilization decisions. However, PNC varies based on the development stage. Therefore, a relationship between biomass and N concentration is needed (i.e., critical N dilution curve; CNDC) to better understand when pl...

Asymbiotic nitrogen fixation (N‐fixation) is a microbial process that may result in the introduction of plant‐available N into the soil. Although the process of N mineralization in soils is mediated by many microorganisms and is related mostly to soil moisture, the soil factors which regulate asymbiotic N‐fixation are relatively unknown and the num...

Plant N concentration (PNC) has been commonly used to guide farmers in assessing maize (Zea mays L.) N status and making in-season N fertilization decisions. However, PNC varies based on the development stage and therefore a relationship between biomass and N concentration is needed (i.e., critical N dilution curves; CNDC) to better understand when...

Improving corn (Zea mays L.) nitrogen (N) rate fertilizer recommendation tools can improve farmers’ profits and mitigate N pollution. Numerous approaches have been tested to improve these tools, but to date improvements for predicting economically optimum N rate (EONR) have been modest. This work's objective was to use ensemble learning to improve...

Numerous studies referred to in this book and in other publications have examined the relationship between a proximal sensor, or remote sensing with crop yield and other attributes of interest to precision agriculture. Combining data from two or more sensors tends to increase the relationship between sensor readings and crop attributes. Crop canopy...

This bulletin covers soil and water properties that impact the suitability of water for irrigation. This publication is an updated and revised version of a publication of the same name published in 2013.

Based on a seminal paper published by Stanford in 1973, many land grant universities adopted N rate guidelines that used expected yield times a factor (such as 1.2 lb N/bu), with adjustments for previous crop, to formulate N rate recommendations for corn. However, discrepancies between yield‐based N rate recommendations and recent N response data l...

Accurate nitrogen (N) diagnosis early in the growing season across diverse soil, weather, and management conditions is challenging. Strategies using multi-source data are hypothesized to perform significantly better than approaches using crop sensing information alone. The objective of this study was to evaluate, across diverse environments, the po...

With the increasing availability of high-resolution digital elevation model (DEM) data, a need has emerged for new processing techniques. Topographic variables such as slope and curvature are relevant on length scales far larger than the pixel resolution of modern DEM data sets. We propose an approach for computing slope and curvature that uses sta...

Development of predictive algorithms accounting for uncertainty in processes underpinning the maize (Zea Mays L.) yield response to nitrogen (N) are needed in order to provide new N fertilization guidelines. The aims of this study were to unravel the relative importance of crop management, soil, and weather factors on both the estimate and the size...

Many endeavours in precision agriculture use some kind of sensor to gain relatively inexpensive information on the spatial and temporal variation in crops, soil, weeds, diseases, and so on. However, information about sensors is scattered throughout the literature. This text fills an important niche by bringing together information on a wide range o...

Maximum genetically possible crop growth and yield are inhibited by abiotic and or biotic stresses. Biotic stresses may include pests, insects or disease infestations whereas abiotic stress includes nutritional deficiencies. Sensors have been developed and are being developed to detect stresses and to assist in crop stress management. Decision supp...

Nitrogen fertilizer recommendations in corn (Zea mays L.) that match the economically optimal nitrogen fertilizer rate (EONR) are imperative for profitability and minimizing environmental degradation. However, the amount of soil N available for the crop depends on soil and weather factors, making it difficult to know the EONR from year‐to‐year and...

Improving corn (Zeamays L.) N managementis pertinent to economic andenvironmental objectives. However, there are limited comprehensive data sources to develop and test N fertilizer decision aid tools across a wide geographic range of soil and weather scenarios. Therefore, a public‐industry partnership was formed to conduct standardized corn N rate...

The most common formsof S fertilizers in the northern Great Plains are ammonium sulfate (AS), ammonium thiosulfate (ATS), and elemental S (ES). Among these, AS is preferred over the others because of its readily available SO42– form, and it can be blended with other dry fertilizer granules, but SO42– is prone to leaching. Recently, fertilizer indus...

Reports of sulfur (S) deficiency symptoms in corn (Zea mays L.) fields of the Red River Valley of North Dakota and Minnesota are increasing. Current soil tests cannot predict the availability of S correctly due to the presence of gypsum in soils of this region. Field trials were conducted to determine corn yield and S uptake response to incremental...

Improving corn (Zea mays L.) N fertilizer rate recommendation tools is necessary for improving farmers’ profits and minimizing N pollution. Research has repeatedly shown that weather and soil factors influence available N and crop N need. Adjusting available corn N recommendation tools with soil and weather measurements could improve farmers’ abili...

Maize (Zea Mays L.) yield responsiveness to nitrogen (N) fertilization depends on the yield under non-limiting N supply as well as on the inherent productivity under zero N fertilizer (Y0). Understanding the driving factors and developing predictive algorithms for Y0 will enhance the optimization of N fertilization in maize. Using a random forest a...

The exchangeable fraction of soil potassium (K) has been viewed as the most important source of plant-available K, with other sources playing smaller roles that do not influence the predictive value of a soil test. Thus, as K mass balance changes, the soil test should change correspondingly to be associated with greater or reduced plant availabilit...

Placement strategies can be a key determinant of efficient use of applied fertilizer potassium (K), given the relative immobility of K in all except the lightest textured soils or high rainfall environments. Limitations to K accessibility by plants caused by immobility in the soil are further compounded by the general lack of K-stimulated root prol...

Splitting the N application into two or more timings may improve corn (Zea mays L.) grain yield and N recovery relative to a single‐N application. A 49 site‐year study across eight U.S. Midwestern states compared the effect of an at‐planting (single‐N application) and two split‐N applications [45 (45+SD) or 90 kg N ha⁻¹ (90+SD) at planting with the...

Anaerobic potentially mineralizable nitrogen (PMN) combined with preplant nitrate test (PPNT) or pre‐sidedress nitrate test (PSNT) may improve corn (Zea mays L.) N management. Forty‐nine corn N response studies were conducted across the U.S. Midwest to evaluate the capacity of PPNT and PSNT to predict grain yield, N uptake, and economic optimal N r...

Supply of adequate P is critical at the early growth stages of corn (Zea mays L.), particularly under a cold environment like the northern Great Plains. The mutualistic relationship between arbuscular mycorrhizal fungi (AMF) and corn roots is responsible for supplying P. However, colonies of AMF drastically decline when corn follows a non‐host crop...

Soil microbes drive biological functions that mediate chemical and physical processes necessary for plants to sustain growth. Laboratory soil respiration has been proposed as one universal soil health indicator representing these functions, potentially informing crop and soil management decisions. Research is needed to test the premise that soil re...

The anaerobic potentially mineralizable N (PMN) test combined with the preplant (PPNT) and presidedress (PSNT) nitrate tests may improve corn (Zea mays L.) N fertilization predictions. Forty‐nine corn N response experiments (mostly corn following soybean [Glycine max (L.) Merr.]) were conducted in the U.S. Midwest from 2014–2016 to evaluate the abi...

Understanding the variables that affect the anaerobic potentially mineralizable N (PMNan) test should lead to a standard procedure of sample collection and incubation length, improving PMNan as a tool in corn (Zea mays L.) N management. We evaluated the effect of soil sample timing (preplant and V5 corn development stage [V5]), N fertilization (0 a...

The commonly accepted belief of crop and soil scientists and practitioners is that the tie‐up or release of N from cover crops is based largely on carbon‐to‐nitrogen ratios (C:N). Recent research in Wisconsin and North Dakota challenge this long‐held belief. Earn 0.5 CEUs in Nutrient Management by reading this article and taking the quiz at www.cer...

Determining which corn (Zea mays L.) N fertilizer rate recommendation tools best predict crop N need would be valuable for maximizing profits and minimizing environmental consequences. Simultaneous comparisons of multiple tools across various environmental conditions have been limited. The objectives of this research were to evaluate the performanc...

Estimates of mineralizable N with the anaerobic potentially mineralizable N (PMNan) test could improve predictions of corn (Zea mays L.) economic optimal N rate (EONR). A study across eight US midwestern states was conducted to quantify the predictability of EONR for single and split N applications by PMNan. Treatment factors included different soi...

Nitrogen provided to crops through mineralization is an important factor in N management guidelines. Understanding of the interactive effects of soil and weather conditions on N mineralization needs to be improved. Relationships between anaerobic potentially mineralizable N (PMNan) and soil and weather conditions were evaluated under the contrastin...

In the Northern Great Plains, sugarbeet (Beta vulgaris L.) harvesting is stretched out from August to October. Sensors mounted on unmanned aerial vehicles (UAVs) may provide the information needed to identify sugarbeet approaching an optimum harvesting date that maximizes the recoverable sugar yield. The objective of this study was to relate the ve...

The recent incidence and severity of sulfur (S) deficiency due to a decrease in atmospheric S deposition and greater S removal by crops requires reevaluating current S recommendation for corn (Zea mays L.). Ten on‐farm field trials were conducted to evaluate corn response to S additions at sites in the Red River Valley of North Dakota and Minnesota...

Successful adoption of drone‐based remote sensing depends on changes in sensitivity over vegetation indices (VIs) and growth stage(s). During 2017–2018, experiments were conducted to relate between vegetation indices and corn (Zea mays L.) and sugarbeet (Beta vulgaris L.) yields in western Minnesota. Aerial images were collected using an unmanned a...

Nitrogen (N) fertilizer recommendation tools could be improved for estimating corn (Zea mays L.) N needs by incorporating site-specific soil and weather information. However, an evaluation of analytical methods is needed to determine the success of incorporating this information. The objectives of this research were to evaluate statistical and mach...

A series of N‐rate experiments previously conducted in spring wheat, corn, and sunflower in North Dakota indicated that less N was required when fields were in six years or more continuous no‐till compared to conventional till. The objective of this study was to determine whether part of the reason for the decreased requirement for N was the greate...

Core Ideas Use of dry soil K soil test was most predictive of corn response in North Dakota. Consideration of clay chemistry increased the prediction of yield response by the K soil test. A smectite/illite ratio of 3.5 separated the sites into one requiring a higher critical K soil test value and one with a lower critical K value. Due to initially...

Topographic features impact biomass and other agriculturally relevant observables. However, conventional tools for processing digital elevation model (DEM) data in geographic information systems have severe limitations. Typically, 3-by-3 window sizes are used for evaluating the slope, aspect and curvature. As a consequence, high resolution DEMs hav...

Core Ideas Confection sunflower yield was related to active optical sensor readings. Oilseed sunflower yield was not related to active optical sensor readings. Oilseed sunflower yield was related to crop height measurements. Active‐optical (AO) sensors have been used in several crops as a yield‐prediction tool for N management, but not in sunflowe...

A series of N-rate experiments was previously conducted in spring wheat, corn and sunflower in North Dakota indicated that less N was required when fields were in 6-years or more continuous no-till compared to conventional till. The objective of this study was to determine whether part of the reason for the decreased requirement for N was the great...

Nitrogen, phosphorus and potassium are the most critical of these nutrients. This publication outlines some basic information about phosphorus and its interaction in the Northern Plains environment.

Core Ideas Canopy sensor performance improved using site‐specific information. Evenness of early‐season rainfall is crucial for adjusting N recommendations. Adjusting N recommendations using measured vs. USDA mapped soil data performed alike Active‐optical reflectance sensors (AORS) use light reflectance characteristics from a crop canopy as an in...

Core Ideas A Machine Learning approach was innovatively used to predict corn EONR. Two features were created to approximate hydrological conditions for modeling EONR. Soil hydrology conditions were found essential in successful modeling in‐season EONR. Determination of in‐season N requirement for corn ( Zea mays L.) is challenging due to interacti...

Core Ideas Active‐optical reflectance sensor algorithms perform poorly outside the area for which they were originally developed. The red edge waveband is more sensitive to N stress than the red waveband. Some active‐optical reflectance algorithms are dependent on the sensor for which they were developed. Uncertainty exists with corn ( Zea mays L....

Slope computations in Geographic Information Systems are typically done over windows of sizes as small as 3×3 pixels, and the algorithms that are used do not scale to very large windows. Considering the abundance of high-resolution Digital Elevation Model (DEM) data, these algorithms are inadequate for providing high-quality processed data efficien...

Use and development of soil biological tests for estimating soil nitrogen (N) availability and subsequently corn (Zea mays L.) fertilizer N recommendations is garnering considerable interest.The objective of this research was to evaluate relationships between the Haney Soil Health Test (HSHT), also known as the Soil Health Tool or Haney test, and t...

Single fertilizer nitrogen rate of 146 kg N ha ⁻¹ for sugarbeet is outdated. Sugarbeet–fertilizer nitrogen recommendation should consider soil characteristics. Sugarbeet yield and sugar content was optimized at 112 kg N ha ⁻¹ . In‐season soil nitrogen and red‐edge normalized difference vegetative index can predict yield response to nitrogen. Econom...

Optical sensors are commonly used by the researchers to improve yield estimated in commercial crops. This study was carried out in two states in two different crops, corn and potatoes, 2011–2013 and 2017, respectively. The objectives of the study were to evaluate ground based optical sensors to predict yield potential across multiple locations, soi...

Ground-based active optical sensors (GBAOS) have been successfully used in agriculture to predict crop yield potential (YP) early in the season and to improvise N rates for optimal crop yield. However, the models were found weak or inconsistent due to environmental variation especially rainfall. The objectives of the study were to evaluate if GBAOS...

Core Ideas Nitrogen availability and fertilization can increase sunflower see yield. Nitrogen fertilization may decrease oil concentration of oilseed sunflower. Nitrogen fertilization increases sunflower lodging risk in windy regions. The N and P recommendations for sunflowers growers in North Dakota have not been changed in 30 yr. Twenty‐two N an...

This is a paper that compares the effect of single near planting nitrogen fertilizer applications and splitting up the nitrogen fertilizer application on soil nitrate-nitrogen content and corn grain yield

Reclamation of sodic soils is proving increasingly vital as greater land area becomes salt-affected in the northern Great Plains of the United States. Flue gas desulfurization gypsum (FGDG) can be an agriculturally important resource for increasing land productivity through the ameliorating of sodic soils. Biochar is also considered as an aid in re...

Core Ideas The geographic scope, scale, and unique collaborative arrangement warrant documenting details of this work. The purpose of this article is to describe how the research was undertaken, reasons for the research methods, and the project's potential value. The project generated a valuable dataset across a wide array of weather and soils that...

Concerns for environmental sustainability are leading to a growing interest understanding geospatial data. At the same time, the availability of high-resolution imagery from satellites and unmanned air systems is increasing rapidly. However, the processing techniques that are available within geographic information systems are not yet adapted to bi...

This paper evaluates the use of the anaerobic potentially mineralizable nitrogen test as an index for nitrogen mineralization and its use to estimate N fertilizer needs of corn.

The demand for improved decision‐making products for cereal production systems has placed added emphasis on using plant sensors in‐season, and that incorporate real‐time, site specific, growing environments. The objectives of this work were to describe validated in‐season sensor‐based algorithms presently being used in cereal grain production syste...

Prediction of S deficiency is difficult due to poor soil test relationship to crop response. The purpose of this article is to provide evidence that the use of an N‐sufficient area established for use as a standard for active‐optical (AO) sensor directed in‐season N application could also serve to detect S deficiency in corn ( Zea mays L.). Nitroge...

Corn height measured manually has shown promising results in improving the relationship between active-optical (AO) sensor readings and crop yield. Manual measurement of corn height is not practical in US commercial corn production, so an alternative automatic method must be found in order to capture the benefit of including canopy height into in-s...

Potassium (K) fertilizer recommendations are mainly based on air -dried soil samples which can lead to over- or under-estimation of plant available soil K. Three on-farm trials were conducted in North Dakota and Minnesota to determine the variation of soil test-K between air-dried (KDry) and field moist (KMoist) soil samples. The differences betwee...

Yield prediction in sugar beet (Beta vulgaris L.) is important as a basis for in‐season N application. Active optical sensors have been researched in sugar beet for yield estimation. A common field method for using active‐optical sensors is to establish an N non‐limiting area, and compare the yield predicted from sensor readings with readings from...

Core Ideas Satellite imagery could be used to predict yield the study crops. Satellite imagery could be used to screen fields for in‐season N application. Obtaining satellite imagery early enough in the season to screen fields for in‐season N is a problem. Algorithms using active‐optical (AO) sensors have been developed to direct in‐season N appli...

Thirty field experiments were conducted in North Dakota during 2011 and 2012 to compare two ground-based active-optical sensors for their relationship between sensor readings and INSEY (in-season estimate of yield). The experimental design at each site was a randomized complete block with four replications and six nitrogen (N)rate treatments: contr...

Active-optical sensor readings from an N non-limiting area standard established within a farm field are used to predict yield in the standard. Lower yield predictions from sensor readings obtained from other parts of the field outside of the N non-limiting standard area indicate a need for supplemental N. Active-optical sensor algorithms for predic...

Nitrogen management for corn (Zea mays L.) may be improved by applying a portion of N in-season. This investigation was conducted to evaluate crop modeling (Maize-N) and active crop canopy sensing approaches for recommending in-season N fertilizer rates. These approaches were evaluated during 2012-2013 on 11 field sites, in Missouri, Nebraska, and...

The traditional response of crop to N graph is a linear/plateau model, which has some problems. In contrast, most N rate studies result in a quadratic model. Economists are familiar with the quadratic input rate response and call it “the law of diminishing returns.” New research‐based N rate calculation tools in North Dakota and Montana are based o...

Saturated paste derived sodium adsorption ratio (SARe) is not a routine procedure for soil testing laboratories in the northern Great Plains. The objective of this study was to determine the relationship between SARe, a solution-phase only extraction, and percentage of Na (%Na; Na/(Na+Ca+Mg+K), a solution phase plus exchange phase value using 1M am...

The soil potassium (K) test methodology is under increased evaluation due to the soil sample drying effect, temporal variations of test results and inconsistent crop response to applied K fertilizers. Ten on-farm trials were conducted in 2014 in eastern North Dakota to determine the corn response to different K-fertilizer rates and to assess the va...

Active optical light sensors have been available for agricultural use for about 20 years. People are most familiar with passive light sensors. A passive light sensor can detect visible light and other electro-magnetic radiation originally emitted by the sun or another light source. The instrument senses the reflection of the light. Examples of pass...

Early in-season loss of N continues to be a problem in corn (Zea mays L.). One method to improve N use efficiency is fertilizing based on in-season crop foliage sensors. The objective of this study was to evaluate two ground-based, active-optical (GBAO) sensors and explore the use of corn height with sensor readings for improving relationships with...

Corn has been a crop in North Dakota for at least 100 years. However, the acres under corn grain production have been relatively small, compared with small-grain crops, until about 20 years ago. Today, corn consistently is planted on more than 3 million acres each year, with most North Dakota counties having signifi cant acreage. The surge in acrea...

Yield prediction is important for making in-season agronomic input decisions and for greater logistical decisions. In predicting the crop yield based on ground-based active optical sensing data, the ordinary statistical unweighted linear or nonlinear regression models are the most popular choices. However, these unweighted models may not be accurat...

A series of nitrogen rate experiments were established in sugar beet (Beta vulgaris, L), sunflower (Helianthus annuus, L), and spring wheat (Triticum aestivum, L) in 2012. Two active-optical sensors were used in sugar beet and sunflower at the 6 leaf stage and again about two weeks after the first reading. The sensors were used at flag leaf (Zadoks...

Nitrogen Nodulation Although the atmosphere is 78 percent nitrogen gas, plants cannot use it directly. Plants can use only ammonium-N or nitrate-N. Soybean is a legume and normally should provide itself N through a symbiotic relationship with N-fi xing bacteria of the species Bradyrhizobium japonicum. In this symbiotic relationship, carbohydrates a...

Textural features extracted from LANDSAT satellite image and non-imagery information like soil electrical conductivity, crop yield, topography, and crop dry residue matter etc., were used to develop residual soil nitrate prediction models using three neural networks; back propagation, modular, and radial basis function architectures. Statistical pa...

A four-year study was conducted from 2000 to 2004 at eight field sites in Montana, North Dakota and western Minnesota. Five of these sites were in North Dakota, two were in Montana and one was in Minnesota. The sites were diverse in their cropping systems. The objectives of the study were to (1) evaluate data from aerial photographs, satellite imag...

Reports supporting folklore beliefs that buckwheat (BW) can significantly contribute solubilized phosphorus (P) from sparingly soluble soil P to subsequent crops remain anecdotal. To quantify P solubilized by BW from five inorganic and three organic pools in a Fargo silty clay, spring wheat (Triticum aestivum L.) (WHT) was grown as a reference crop...