A gronomy J our n al • Volume 10 9, I ssue 3 • 2 017 M icronutrients are essential for plant growth because these trace elements perform important biological functions. Defi ciencies of micronutrients in soils can signifi cantly reduce crop yield, quality, and economic return (Marschner, 2002). Soybean is an important cash crop in Minnesota being grown on 3.05 million ha in 2015 (USDA, 2016). Th ere has been increased pressure for farmers in Minnesota in the recent years to apply micronutrients to soybean due to a perception that defi ciencies have increased. Soybean response to fertilizer B has been reported in many areas in the United States. In Arkansas, Ross et al. (2006) found that soil-applied B increased soybean grain yield by 4 to 130% and increased trifoliate and grain B concentration. Application of 0.28 to 1.12 kg B ha-1 was suffi cient to produce maximum grain yield. Research in Georgia found that soil, leaf, and grain B concentration were signifi cantly increased with increasing rates of soil-applied B (Touchton et al., 1980). In 3 of the 9 yr, soybean yield increased when fertilizer B was applied. In a separate study, foliar application of 0.56 kg B ha-1 was found to be the optimal rate for increasing the number of pods per branch but application of 1.12 kg B ha-1 promoted the highest seed yield per plant due to increase in seed size (Schon and Blevins, 1990). In the Midwest, Oplinger et al. (1993) summarized 29 trials across Illinois, Ohio, Missouri, and Wisconsin and reported yield increase only in four sites on B-suffi cient soils. Chlorine plays an important role in gas exchange, photosynthesis, and disease resistance in crops. Defi ciency of Cl can negatively impact a crop's normal growth and reduce grain yield if aff ected by disease. In Minnesota, Cl defi ciency has not been reported for major fi eld crops. Chlorine defi ciency is unlikely because most agricultural fi elds in Minnesota routinely receive KCl fertilizer to prevent K defi ciency, which is 50% Cl by mass. Chlorine toxicity is a serious yield-limiting factor for soybean in the southern states of the United States. Toxicity of Cl is caused by accumulation of Cl in the upper soil profi le (Rupe et al., 2000). Chlorine accumulation occurs in poorly drained soils and with limited precipitation because these two factors promote soil Cl retention (Yang and Blanchar, 1993). Soybean grown in the poorly drained Flatwoods soils (fi ne, mixed, semiactive, mesic Aquic Hapludults) of Georgia which received Cl-containing fertilizer exhibited leaf scorching consistent with

Abstract:In north-central Oklahoma eastern redcedar (Juniperus virginiana), encroachment into grassland is widespread and is suspected of reducing streamflow, but the effects of this encroachment on soil hydraulic properties are unknown. This knowledge gap creates uncertainty in understanding the hydrologic effects of eastern redcedar encroachment and obstructs fact-based management of encroached systems. The objective of this study was to quantify the effects of eastern redcedar encroachment into tallgrass prairie on soil hydraulic properties. Leaf litter depth, soil organic matter, soil water repellency, soil water content, sorptivity, and unsaturated hydraulic conductivity were measured near Stillwater, OK, along 12 radial transects from eastern redcedar trunks to the center of the grassy intercanopy space. Eastern redcedar encroachment in the second half of the 20th century caused the accumulation of 3 cm of hydrophobic leaf litter near the trunks of eastern redcedar trees. This leaf litter was associated with increased soil organic matter in the upper 6 cm of soil under eastern redcedar trees (5.96% by mass) relative to the grass-dominated intercanopy area (3.99% by mass). Water repellency was more prevalent under eastern redcedar than under grass, and sorptivity under eastern redcedar was 0.10 mm s À1/2, one seventh the sorptivity under adjacent prairie grasses (0.68 mm s À1/2 ). Median unsaturated hydraulic conductivity under grass was 2.52 cm h À1, four times greater than under eastern redcedar canopies (0.57 cm h À1 ). Lower sorptivity and unsaturated hydraulic conductivity would tend to decrease infiltration and increase runoff, but other factors such as rainfall interception by the eastern redcedar canopy and litter layer, and preferential flow induced by hydrophobicity must be examined before the effects of encroachment on streamflow can be predicted.

Core Ideas Nitrogen and sulfur can interact within the plant and affect the concentration of each other in corn plant tissue. Nitrogen concentration in plant tissue has a greater impact on the N/S ratio than S which was found to not affect the N/S ratio in corn ear leaf tissue and grain. Individual sufficiency of N and S in plant tissue is a better predictor of corn yield response versus the ratio of N/S in the plant tissue. The accumulation of nitrate–N in the base of the corn stalk assessed at maturity is decreased when sulfur fertilizer is applied. Excess sulfate can accumulate in the base of the plant at maturity but the amount of sulfate–S cannot be used to predict the sufficiency of S. Nitrogen and S can interact within the corn (Zea mays L.) plant. The objectives of this study were to evaluate in corn (i) the effect of N and S on nutrient uptake and grain yield, (ii) use of tissue total N/S ratio to predict grain yield, and (iii) the impact of applied SO4–S on basal stalk NO3–N concentration. Treatments were applied as a factorial design. Factor 1 consisted of 0 or 28 kg S ha‐1. Factor 2 consisted of 0, 56, 112, 168, 224, and 280 kg N ha‐1. Fertilizer N increased the concentration of N and S in corn R1 leaf tissue, N concentration in grain, relative grain yield, grain removal of N and S, and NO3–N in the basal stalk. Fertilizer S increased R1 leaf N and S concentration, decreased basal stalk NO3–N, and increased corn grain yield when N was applied at a rate that maximized corn grain yield. The total N/S ratio in corn R1 leaf and harvested grain were affected by N application but not by S addition. Basal stalk N/S ratio was affected by both N and S. A critical N/S ratio could not be identified to predict corn grain yield response. While the data support a general effect of N and S on the uptake of each other, fertilization with N or S should be based on potential for increased grain yield from either nutrient. Based on results, optimal N rates for corn are not affected if S is also applied.

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Nitrogen and phosphorus are key limiting nutrients in teff [Eragrostis tef (Zucc.) Trotter] production. The crop is particularly sensitive to N fertilization, and as a result forage and grain yields are influenced. We conducted four site‐year studies to determine N and P requirement of teff grown under a dryland production system. Studies were located in central Oklahoma. Treatments included nine N and P combinations. Commonly grown varieties ‘Quick‐E’ and ‘Tiffany’ were used in 2009 and 2010, respectively. Experiments were arranged in a randomized complete block design with three replications. Data were subject to statistical analysis using Statistical Analysis Software (SAS). Analysis of variance (ANOVA), orthogonal polynomial or paired contrasts and non‐linear regressions were used to determine the effect of treatments on teff forage and grain yields and quality. Results showed that for central Oklahoma, optimum fertilizer N rate was 67 kg/ha which corresponded with a 1.1 Mg/ha yield goal. Forage crude protein increased with N rate. In addition, N and P influenced some teff mineral and forage quality parameters such as Ca, Fe, acid detergent fiber, and crude protein. Recommendations provided here will serve as a benchmark for N and P fertility guidelines for producers in Oklahoma and semi‐arid regions who want to grow teff in a niche market.