Sugar beet crown and root rot caused by Rhizoctonia solani is a major yield constraint. Root rot is highly increased when R. solani and Leuconostoc mesenteroides co-infect roots. We hypothesized that the absence of plant cell-wall-degrading enzymes in L. mesenteroides and their supply by R. solani during close contact, causes increased damage. In planta root inoculation with or without cell-wall-degrading enzymes showed greater rot when L. mesenteroides was combined with cellulase (22 mm rot), polygalacturonase (47 mm), and pectin lyase (57 mm) versus these enzymes (0–26 mm), R. solani (20 mm), and L. mesenteroides (13 mm) individually. Carbohydrate analysis revealed increased simpler carbohydrates (namely glucose + galactose, and fructose) in the infected roots versus mock control, possibly due to the degradation of complex cell wall carbohydrates. Expression of R. solani cellulase, polygalacturonase, and pectin lyase genes during root infection corroborated well with the enzyme data. Global mRNAseq analysis identified candidate genes and highly co-expressed gene modules in all three organisms that might be critical in host plant defense and pathogenesis. Targeting R. solani cell-wall-degrading enzymes in the future could be an effective strategy to mitigate root damage during its interaction with L. mesenteroides.

Core Ideas: Bray‐1, Mehlich‐3, Haney–Haney–Hossner–Arnold, and Olsen‐P were compared on primarily alkaline calcareous soils. Mehlich‐3 was correlated with the Olsen‐P extractant regardless of pH or inorganic C content. 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 CaCO ₃ (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.

Core Ideas: Multinutrient extractants were correlated to standard tests on alkaline calcareous soils For the tested nutrients Mehlich‐3 generally extracted greater and H3A less than the common tests used in the Western United States Mehlich‐3 extracted large amounts of Ca when inorganic‐C as CaCO₃ was greater than 3.3 g kg⁻¹ resulting in poor correlation with the ammonium acetate test Soil fertility and nutrient management programs across Idaho and the western United States should consider the effective comparison of various extractants for nutrient analyses. Common extractants for K, Ca, Mg, S, and micronutrients (Zn, Cu, Mn, Fe, B, Na) vary (e.g., ammonium acetate [AA], Olsen, etc.). The desire to develop effective correlation equations among common tests in the region and those of multinutrient extractants used or proposed in other geographical regions (i.e., Mehlich‐3 [M‐3] and Haney, Haney, Hossner, Arnold [H3A]) has increased due to the interest in nutrient management planning and in relation to soil health measurements. To investigate these multinutrient tests, 46 primarily alkaline soils were sampled from the 0‐ to 30‐cm depth in agricultural fields in Idaho. Linear regressions between AA and Olsen K and both M‐3 and H3A resulted in a significant positive fit (R² = 0.69–0.90). Notable issues with increased Ca concentrations occurred in soils with large amounts of inorganic C. Removal of these samples improved the relationship between standard and multinutrient soil tests. Specific micronutrient regressions were problematic when both alkaline and acidic soils were analyzed but improved when separated. Mehlich‐3 and H3A extractants were generally well correlated, with the exceptions noted above, to common extractants used in western soils. Thus, this research provides specific correlation equations that could be used for comparison among tests as well as provides evidence of the potential suitability of multinutrient extractants in the region.

Determination of soil organic carbon (SOC) is highly desirable for assessing fertility and carbon sequestration; however, numerous methods of determination warrant study of method agreement. Recently, a novel method was developed following dichromate oxidation using a microplate spectrophotometer. This novel method was compared with (a) total C by dry combustion − soil inorganic carbon (DC _{w/o pretreatment} –pressure calcimater [Pcal]); (b) traditional Walkley–Black titration (WBTIT) and (c) loss on ignition (LOI _360°C ) in calcareous soils of south‐central Idaho ( n = 75) in conjunction with North American Proficiency Testing program soils ( n = 10). A two‐way ANOVA was fit with soils as a blocking factor to identify any difference between methods; means were separated using Tukey's honestly significant difference test (α = .05). Additional comparisons were made for all soils ( n = 85) and for soils in the lower 75th percentile of SOC determined by WBTIT ( n = 56) using regression analysis. Only the WBTIT and LOI _360°C methods were statistically equivalent nevertheless there was high agreement (Lin's concordance coefficients > .90) between all methods ( n = 85). Under low SOC soils ( n = 56) the agreement between all methods decreased, but the Walkley–Black spectrophotometric method (WBSPEC) method fit other methods comparatively well r ²  = .71, .74, and .78 for LOI _360°C , DC _{w/o pretreatment} –Pcal, and WBTIT respectively. The WBSPEC method provided estimates of SOC between the methods currently used in the region while reducing hazardous waste generation over traditional WBTIT and sample handling over LOI _360°C and DC _{w/o pretreatment} –Pcal methods, positioning it as a sensible option for SOC determination in low SOC calcareous soils of south‐central Idaho.

Total dry matter (TDM) and nutrient accumulation, nutrient partitioning, and cumulative growing degree days at the time of maximum nutrient accumulation for two‐row spring barley (Hordeum vulgare L.) are not well quantified under high‐yielding irrigated conditions common in the semi‐arid western United States. Thus, five cultivars of barley were grown under irrigated conditions on a loam soil in the 2015 and 2016 growth seasons to determine these factors. Total nutrient accumulation was greatest at either the soft dough or maturity stage where specific nutrients were greater at one stage as compared to the other. Mean N accumulation was greatest at the soft dough stage (256 kg ha⁻¹) where the regression model accounted for 80% of the variation in the data. Additionally, spike N increased from 91 to 105 kg ha⁻¹ from soft dough to maturity. Specific nutrients (e.g., K) had significantly greater plant (i.e., culms plus leaves) accumulation between soft dough and maturity, 253 and 172 kg ha⁻¹, respectively, where the spike at the same growth stages had an accumulation of 37 and 42 kg ha⁻¹, respectively. In contrast, other nutrients (e.g., P) were remobilized to the spike as noted by the increase from 14 kg ha⁻¹ at soft dough to 26 kg ha⁻¹ at maturity. In addition to nutrient partitioning, linear regressions resulted in well‐correlated models between TDM and total nutrient accumulation (R² = 0.35–0.88) for measured nutrients. Results from the current study provide critical data on nutrient accumulation as well as regression models for two‐row barley under high‐yielding conditions. This information can be used to improve harvest decisions as well as more accurately predict nutrient cycling in barley cropping systems.