April Ulery

Integrated organic–inorganic soil amendments have been proposed as a strategy to improve soil fertility while maintaining crop productivity, yet their effects on seasonal nutrient dynamics and chile (Capsicum annuum L.) performance remain unclear. Two chile cultivars (‘NuMex Odyssey’, ‘NuMex Sandia Select’) were tested to evaluate the effects of organic and inorganic amendments on soil nutrient dynamics, chile vegetative growth, and fruit yield and dimensions across key growth stages. The amendments included an unamended control (CK), half-rate (CF) and full-rate (CFCF) chemical fertilizer, and three integrated amendments consisting of composted manure–biochar blend (CFMB), composted manure (CFM), and pea residues (CFP) applied at a 1:1 ratio with chemical fertilizer on a plant-available nitrogen (PAN) basis. CFCF produced the highest early-season availability of N, P, and K, whereas CFP and CFM provided a more gradual nutrient release pattern, maintaining PAN comparable to CFCF through flowering and sustaining P and K availability through harvest. ‘NuMex Sandia Select’ exhibited greater yield responsiveness to soil amendments, while ‘NuMex Odyssey’ produced fewer but higher dimension fruits. CFP maintained fruit yields comparable to CFCF while producing lower vegetative biomass. Correlation analyses showed that significant nutrient–plant relationships were concentrated at harvest, with soil NO₃⁻-N associated with fruit number and NH₄⁺-N with fruit dimensions. These findings indicate that partial substitution of mineral fertilizer with organic amendments may sustain nutrient availability and chile productivity while providing a more gradual nutrient release throughout the growing season.

Nitrogen (N) is essential for all land plants, but crops use only ∼50% of the fertilizer N, the rest being lost to the environment. Accurate estimation of soil N and optimizing N fertilizer management are critical for enhancing agricultural sustainability and profitability. This study compared the performance of five extraction methods: distilled water (DW) at room temperature (25°C), and 1 and 2 M potassium chloride (KCl) extractions conducted either cold (25°C) or hot (100°C for 4 h) to evaluate their performance in estimating inorganic N. The most practical methods identified through this comparison were then used to assess inorganic N responses to eight cover crop treatments, including single species, binary mixtures, and multispecies combinations with two compost levels (0 and 16.8 Mg ha ⁻¹ ) in a semiarid agroecosystem. Results revealed that all KCl‐based methods extracted significantly more inorganic N than DW. In January samples (before compost application), no difference was observed between 1 M cold and hot KCl. However, during the July sampling, 1 M hot KCl extracted significantly more inorganic N, ranging from 25% to 440% higher than 1 M cold KCl in compost‐amended soils. No significant differences were observed among cover crop treatments. While 1 M cold KCl remained effective in early season, 1 M hot KCl better captured compost‐enhanced N availability later. Compost consistently improved inorganic N, underscoring its role in nutrient management. Tailoring extraction methods to management practice and seasonal timing can enhance N assessment and support sustainable nutrient management.

Concerning rising salinity and declining freshwater supply in the U.S. Southern Great Plains, alternative crop production choices using marginal saline irrigation water are irresistible. The study investigated plant traits related to salt tolerance in greenhouse canola (Brassica napus L.) in 2022 and 2023. Spring and winter canola, including ten genotypes each, were evaluated at six salinity levels (0; control, 2, 4, 6, 8, and 8 dS m⁻¹ EC). Plant height, stem mass, leaf area, and specific leaf area (SLA) showed a negative linear response, while quadratic relationships were observed in biomass and leaf mass with increased salinity levels. Substantial negative salinity impacts on plant traits occurred at ≥6 dS m⁻¹ EC (p ≤ 0.01) except for SLA. Overall, winter canola genotypes: Athena, Ericka, CP320WRR, CP115W, and CP225WRR, and spring genotypes: Empire, Monarch, Profit, and Westar, were relatively more salt-tolerant than others. Spring canola showed greater salinity tolerance than winter canola. Salinity stress resulted in differential responses of greater leaf mass in winter canola but more efficient leaf area production in spring canola. SLA and stem mass were highly correlated with most parameters. Findings indicate SLA and stem mass are potential salt tolerance traits in canola and warrant further investigations and validation.

Heavy metals and metalloids (HMs) are environmental pollutants, most notably cadmium, lead, arsenic, mercury, and chromium. When HMs accumulate to toxic levels in agricultural soils, these non-biodegradable elements adversely affect crop health and productivity. The toxicity of HMs on crops depends upon factors including crop type, growth condition, and developmental stage; nature of toxicity of the specific elements involved; soil physical and chemical properties; occurrence and bioavailability of HM ions in the soil solution; and soil rhizosphere chemistry. HMs can disrupt the normal structure and function of cellular components and impede various metabolic and developmental processes. This review evaluates: (1) HM contamination in arable lands through agricultural practices, particularly due to chemical fertilizers, pesticides, livestock manures and compost, sewage-sludge-based biosolids, and irrigation; (2) factors affecting the bioavailability of HM elements in the soil solution, and their absorption, translocation, and bioaccumulation in crop plants; (3) mechanisms by which HM elements directly interfere with the physiological, biochemical, and molecular processes in plants, with particular emphasis on the generation of oxidative stress, the inhibition of photosynthetic phosphorylation, enzyme/protein inactivation, genetic modifications, and hormonal deregulation, and indirectly through the inhibition of soil microbial growth, proliferation, and diversity; and (4) visual symptoms of highly toxic non-essential HM elements in plants, with an emphasis on crop plants. Finally, suggestions and recommendations are made to minimize crop losses from suspected HM contamination in agricultural soils.

Heavy metals and metalloids (HMs) are environmental pollutants, most notably cadmium, lead, arsenic, mercury, and chromium. When HMs accumulate to toxic levels in agricultural soils, these non-biodegradable elements adversely affect crop health and productivity. The toxicity of HMs on crops depends upon factors including crop type, growth condition, and developmental stage; nature of toxicity of the specific elements involved; soil physical and chemical properties; occurrence and bioavailability of HM ions in the soil solution; and soil rhizosphere chemistry. HMs can disrupt normal structure and function of cellular components and impede various metabolic and developmental processes. This review evaluates: (1) HM contamination in arable lands through agricultural practices, particularly due to chemical fertilizers, pesticides, livestock manures and compost, sewage-sludge based biosolids, and irrigation; (2) factors affecting the bioavailability of HM elements in the soil solution, and their absorption, translocation, and bioaccumulation in crop plants; (3) mechanisms by which HM elements directly interfere with the physiological, biochemical, and molecular processes in plants with particular emphasis on the generation of oxidative stress, inhibition of photosynthetic phosphorylation, enzyme/protein inactivation, genetic modifications, and hormonal deregulation, and indirectly through inhibition of soil microbial growth, proliferation, and diversity; and (4) visual symptoms of highly toxic non-essential HM elements in plants with an emphasis on crop plants. Finally, suggestions and recommendations are made to minimize crop losses from suspected HM contamination in agricultural soils.

A two-year field study was conducted in sandy loam soil to evaluate the impacts of biochar on soil quality and the growth and yields of pinto bean (Phaseolus vulgaris) and sorghum–Sudan (Sorghum × drummondii). A wood-derived commercial biochar was applied at three rates to pinto bean (PB) and sorghum–Sudan (SS) plots. The biochar application rates applied annually for two years to PB plots were 0, 2.2, and 11.2 Mg ha⁻¹, whereas the rates for SS plots were 0, 3.4, and 6.7 Mg ha⁻¹. Crop growth and harvest parameters were evaluated. Assessed soil measurements included pH, electrical conductivity, available nutrients, soil organic matter (SOM), permanganate oxidizable carbon (POXC), soil aggregates, and volumetric soil moisture content. The results showed no significant differences in plant growth parameters and yields over the two growing seasons for both PB and SS. Compared to the control treatment, the biochar at 11.2 Mg ha⁻¹ in PB plots improved soil moisture retention after irrigation by 19% in the first year and 25% in the second year. The SOM in the SS plot at 6.7 Mg ha⁻¹ biochar rate was higher (1.02%) compared to the control plot (0.82%), whereas a similar increase was not observed in the PB plot. Although biochar rates did not affect most of the soil measurements, there were significant changes in soil properties over time, regardless of biochar treatments: POXC increased in the PB and SS plots; SOM increased in the SS plot; and electrical conductivity, sodium adsorption ratio, and most soil micronutrients decreased. This research was conducted over two years; the effects of biochar can persist for much longer, indicating the need for longer-term biochar field studies in arid agroecosystems.

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In this study, an inexpensive Nix Pro (Nix Sensor Ltd.) color sensor was used to develop prediction models for soil iron (Fe) content. Thirty‐eight soil samples were collected from five agricultural fields across the Animas watershed to develop and validate soil Fe prediction models. We used color space models to develop three different parameter sets for Fe prediction with Nix Pro. The different color space sets were used to develop three new predictive models for Nix Pro‐based Fe content against the lab‐based inductively coupled plasma analyzed Fe content. The model performances were assessed using the coefficient of determination, root mean square error, and model p‐value. Three models (International Commission on Illumination's lightness, ±a axis (redness to greenness), and ± b axis (yellowness to blueness) [CIEL*a*b]; red, green, blue [RGB]; and cyan, magenta, yellow, key [black] [CMYK]) were significant in predicting the Fe content using colorimetric variables with R² ranging from 0.79 to 0.81. The mean square prediction error (MSPE) and Kling–Gupta efficiency (KGE) Index were calculated to validate models and CMYK was predicted to be a better model (MSPE = 0.13; KGE = 0.601) than CIEL*a*b and RGB models. The results suggest Nix Pro is useful in predicting soil Fe content.