Evaluation of Soil Test Phosphorus Extractants in Idaho Soils

Soil P testing is critical to ensure the accuracy of fertilizer recommendations and to optimize crop yield while minimizing negative environmental consequences. Olsen-P is the most commonly used soil P test for alkaline calcareous soils found in Idaho and the western United States. The Bray- 1 test is commonly used in the Pacific Northwest on neutral to acidic soils but underestimates P in alkaline calcareous soils. Mehlich-3 has been evaluated throughout various regions in the United States. Few data evaluating Mehlich-3 exist for soils in the western United States. Additionally, the comparatively newly developed Haney–Haney–Hossner–Arnold (H3A) test, a component of the soil health tool, has not been widely evaluated on alkaline calcareous soils. Soil samples from the 0- to 30-cm depth were collected from agricultural fields throughout Idaho and analyzed with Bray-1, H3A, Mehlich-3, and Olsen-P extractants. The results indicate that Olsen-P was correlated with Mehlich-3, whereas Bray-1 and H3A were not correlated with Olsen-P. Both Bray-1 and H3A resulted in lower values of extractable P than the Olsen-P test, whereas Mehlich-3 resulted in greater values. A threshold point in CaCO3 (i.e., inorganic C) of 6.7 and 5.1 mg kg-1 for the Bray-1 and H3A was obtained, respectively, which indicated that inorganic C concentrations at or above these levels resulted in a reduction in extractable soil P. Thus Mehlich-3 could be evaluated for use in alkaline calcareous soils, whereas Bray-1 and H3A have notable issues that would limit their applicability

Evaluation of soil test phosphorus extractants in Idaho soils

Evaluation of soil-phosphorus (P) tests is critical to ensure the accuracy of fertilizer recommendations to optimize crop yield while minimizing negative environmental consequences. Olsen-P is the most commonly used soil-P test for alkaline calcareous soils found in Idaho and the Western United States. The Bray-1 test is commonly used in the Pacific Northwest (PNW) on neutral to acidic soils but underestimates P in alkaline calcareous soils. Mehlich-3 has been evaluated throughout various regions in the United States. Little data evaluating the test exists on soils in the Western United States. Additionally, the comparatively newly developed H3A test, a component of the soil health tool, has not been widely evaluated on alkaline calcareous soils. Soil samples from the 0- to 30-cm depth were collected from agricultural fields throughout Idaho and analyzed using Bray-1, H3A, Mehlich-3, and Olsen P extractants. Results suggested that Olsen P was strongly correlated with Mehlich-3, while Bray-1 and H3A were not correlated with Olsen P. Both the Bray-1 and H3A test underestimated extractable P when compared with the Olsen P test, whereas the Mehlich-3 overestimated. A threshold point in calcium carbonate (i.e., inorganic carbon (IC)) of 6.7 and 5.1 mg kg-1 for the Bray-1 and H3A was obtained, respectively, that indicated inorganic carbon concentrations at or above these levels result in underestimation of extractable soil P. Thus, Mehlich-3 was very strongly correlated to Olsen P and could be evaluated for use in alkaline calcareous soils whereas Bray-1 and H3A have notable issues that would limit their applicability

Evaluation of Soil Test Phosphorus Extractants in Idaho Soils

Soil P testing is critical to ensure the accuracy of fertilizer recommendations and to optimize crop yield while minimizing negative environmental consequences. Olsen-P is the most commonly used soil P test for alkaline calcareous soils found in Idaho and the western United States. The Bray- 1 test is commonly used in the Pacific Northwest on neutral to acidic soils but underestimates P in alkaline calcareous soils. Mehlich-3 has been evaluated throughout various regions in the United States. Few data evaluating Mehlich-3 exist for soils in the western United States. Additionally, the comparatively newly developed Haney–Haney–Hossner–Arnold (H3A) test, a component of the soil health tool, has not been widely evaluated on alkaline calcareous soils. Soil samples from the 0- to 30-cm depth were collected from agricultural fields throughout Idaho and analyzed with Bray-1, H3A, Mehlich-3, and Olsen-P extractants. The results indicate that Olsen-P was correlated with Mehlich-3, whereas Bray-1 and H3A were not correlated with Olsen-P. Both Bray-1 and H3A resulted in lower values of extractable P than the Olsen-P test, whereas Mehlich-3 resulted in greater values. A threshold point in CaCO3 (i.e., inorganic C) of 6.7 and 5.1 mg kg-1 for the Bray-1 and H3A was obtained, respectively, which indicated that inorganic C concentrations at or above these levels resulted in a reduction in extractable soil P. Thus Mehlich-3 could be evaluated for use in alkaline calcareous soils, whereas Bray-1 and H3A have notable issues that would limit their applicability

Evaluation of soil test phosphorus extractants in Idaho soils

Evaluation of soil-phosphorus (P) tests is critical to ensure the accuracy of fertilizer recommendations to optimize crop yield while minimizing negative environmental consequences. Olsen-P is the most commonly used soil-P test for alkaline calcareous soils found in Idaho and the Western United States. The Bray-1 test is commonly used in the Pacific Northwest (PNW) on neutral to acidic soils but underestimates P in alkaline calcareous soils. Mehlich-3 has been evaluated throughout various regions in the United States. Little data evaluating the test exists on soils in the Western United States. Additionally, the comparatively newly developed H3A test, a component of the soil health tool, has not been widely evaluated on alkaline calcareous soils. Soil samples from the 0- to 30-cm depth were collected from agricultural fields throughout Idaho and analyzed using Bray-1, H3A, Mehlich-3, and Olsen P extractants. Results suggested that Olsen P was strongly correlated with Mehlich-3, while Bray-1 and H3A were not correlated with Olsen P. Both the Bray-1 and H3A test underestimated extractable P when compared with the Olsen P test, whereas the Mehlich-3 overestimated. A threshold point in calcium carbonate (i.e., inorganic carbon (IC)) of 6.7 and 5.1 mg kg-1 for the Bray-1 and H3A was obtained, respectively, that indicated inorganic carbon concentrations at or above these levels result in underestimation of extractable soil P. Thus, Mehlich-3 was very strongly correlated to Olsen P and could be evaluated for use in alkaline calcareous soils whereas Bray-1 and H3A have notable issues that would limit their applicability

Evaluation of residue management practices on barley residue decomposition.

Optimizing barley (hordeum vulgare L.) production in Idaho and other parts of the Pacific Northwest (PNW) should focus on farm resource management. The effect of post-harvest residue management on barley residue decomposition has not been adequately studied. Thus, the objective of this study was to determine the effect of residue placement (surface vs. incorporated), residue size (chopped vs. ground-sieved) and soil type (sand and sandy loam) on barley residue decomposition. A 50-day(d) laboratory incubation experiment was conducted at a temperature of 25°C at the Aberdeen Research and Extension Center, Aberdeen, Idaho, USA. Following the study, a Markov-Chain Monte Carlo (MCMC) modeling approach was applied to investigate the first-order decay kinetics of barley residue. An accelerated initial flush of residue carbon(C)-mineralization was measured for the sieved (Day 1) compared to chopped (Day 3 to 5) residues for both surface incorporated applications. The highest evolution of carbon dioxide (CO2)-C of 8.3 g kg-1 dry residue was observed on Day 1 from the incorporated-sieved application for both soils. The highest and lowest amount of cumulative CO2-C released and percentage residue decomposed over 50-d was observed for surface-chopped (107 g kg-1 dry residue and 27%, respectively) and incorporated-sieved (69 g kg-1 dry residue and 18%, respectively) residues, respectively. There were no significant differences in C-mineralization from barley residue based on soil type or its interactions with residue placement and size (p >0.05). The largest decay constant k of 0.0083 d-1 was calculated for surface-chopped residue where the predicted half-life was 80 d, which did not differ from surface sieved or incorporated chopped. In contrast, incorporated-sieved treatments only resulted in a k of 0.0054 d-1 and would need an additional 48 d to decompose 50% of the residue. Future residue decomposition studies under field conditions are warranted to verify the residue C-mineralization and its impact on residue management

Per- and Polyfluoroalkyl Substances (PFAS) in Integrated Crop–Livestock Systems: Environmental Exposure and Human Health Risks

Per- and polyfluoroalkyl substances (PFAS) are highly persistent synthetic organic contaminants that can cause serious human health concerns such as obesity, liver damage, kidney cancer, hypertension, immunotoxicity and other human health issues. Integrated crop–livestock systems combine agricultural crop production with milk and/or meat production and processing. Key sources of PFAS in these systems include firefighting foams near military bases, wastewater sludge and industrial discharge. Per- and polyfluoroalkyl substances regularly move from soils to nearby surface water and/or groundwater because of their high mobility and persistence. Irrigating crops or managing livestock for milk and meat production using adjacent waters can be detrimental to human health. The presence of PFAS in both groundwater and milk have been reported in dairy production states (e.g., Wisconsin and New Mexico) across the United States. Although there is a limit of 70 parts per trillion of PFAS in drinking water by the U.S. EPA, there are not yet regional screening guidelines for conducting risk assessments of livestock watering as well as the soil and plant matrix. This systematic review includes (i) the sources, impacts and challenges of PFAS in integrated crop–livestock systems, (ii) safety measures and protocols for sampling soil, water and plants for determining PFAS concentration in exposed integrated crop–livestock systems and (iii) the assessment, measurement and evaluation of human health risks related to PFAS exposure

Biochar in the Agroecosystem–Climate-Change–Sustainability Nexus

Interest in the use of biochar in agriculture has increased exponentially during the past decade. Biochar, when applied to soils is reported to enhance soil carbon sequestration and provide other soil productivity benefits such as reduction of bulk density, enhancement of water-holding capacity and nutrient retention, stabilization of soil organic matter, improvement of microbial activities, and heavy-metal sequestration. Furthermore, biochar application could enhance phosphorus availability in highly weathered tropical soils. Converting the locally available feedstocks and farm wastes to biochar could be important under smallholder farming systems as well, and biochar use may have applications in tree nursery production and specialty-crop management. Thus, biochar can contribute substantially to sustainable agriculture. While these benefits and opportunities look attractive, several problems, and bottlenecks remain to be addressed before widespread production and use of biochar becomes popular. The current state of knowledge is based largely on limited small-scale studies under laboratory and greenhouse conditions. Properties of biochar vary with both the feedstock from which it is produced and the method of production. The availability of feedstock as well as the economic merits, energy needs, and environmental risks—if any—of its large-scale production and use remain to be investigated. Nevertheless, available indications suggest that biochar could play a significant role in facing the challenges posed by climate change and threats to agroecosystem sustainability