Assessment of In‐Season Soil Nitrogen Tests for Corn Planted into Winter Annual Cover Crops

Abstract

Core Ideas The Solvita 1‐d CO2 mineralization test could be a new tool to improve in‐season N rate recommendations for corn. Solvita and soil NO3–N tests may be useful for predicting the level of early‐season N mineralization from winter cover crops (WCCs). Soil NO3–N collected at the V4 growth stage of corn at 0 to 15 cm was positively correlated (R2 = 0.45) with corn check yield. Neither the Solvita nor the presidedress nitrate test detected WCC N mineralization consistently enough to use them in rate recommendations. Environmental and economic goals encourage the use of soil N tests to improve fertilizer N (FN) management in corn (Zea mays L.). Recently, the Solvita 1‐d CO2 burst test, which proposes to estimate soil potentially mineralizable N (PMN), has been promoted as a tool for FN recommendations. We aimed to compare the Solvita test with the established presidedress nitrate test (PSNT) for estimating optimum sidedressed FN rates in a typical corn crop rotation in the Mid‐Atlantic United States that includes winter annual cover crops (WCCs). Research was conducted at eight locations from 2012 to 2014. Three WCC treatments [cereal rye (Secale cereale L.), hairy vetch (Vicia villosa Roth ssp. villosa) or a cereal rye–hairy vetch mix] were the main plots and 10 FN rates were the subplots. The WCCs affected preplanting (PP) Solvita results at one location, V4 NO3–N at 0 to 15 cm (PSNT15) at four locations, and V4 NO3–N at 0 to 30 cm (PSNT30) at two locations. Correlations between soil N test parameters and relative corn yields ranged from 0.31 to 0.13. Values for PSNT15 and PSNT30 correlated positively with corn check yields (r = 0.41 and 0.39 respectively). Solvita did not provide additional information to PSNT for predicting preplanting PMN, V4 PMN, or corn check yields. The advantages of the Solvita test were its simplicity, speed of analysis, and lower coefficient of variation relative to the PSNT. Neither method was consistently effective for predicting WCC effects on soil N or relative corn yield.

Agroecosystem management responses to Haney soil health test in the southeastern United States

“…Other studies also reported a lack of strong response of Nmin estimated from HSHT parameters to agromanagement practices (Castro Bustamante & Hartz, 2016; Dick & Culman, 2016; Tu, 2016; Moore, Guillard, Morris, & Brinton, 2019). In addition, some studies discussed the limited applicability of using Nmin in predicting crop N fertilizer requirement due to the requirement of advanced yield estimation, high measurement variability of HSHT indicators, and region‐specific calibration and validation of such predictions (Norris, Chim, Evanylo, Reiter, & Thomason, 2018; Stahl, Fernández, & Kaiser, 2016).…”

Predicting Cool‐Season Turfgrass Response with Solvita Soil Tests, Part 2: CO2–Burst Carbon Concentrations

“…The SSCB test has been reported to distinguish CO 2 respiration differences between various treatment effects in cropped and noncropped situations (Goupil and Nkongolo. 2014; Sadeghpour et al, 2016; Sciarappa et al, 2017; Mureva and Ward, 2017; Ward et al, 2017; Chahal and van Eerd, 2018; Norris et al, 2018). As a predictor of plant growth or crop yield, though, the SSCB test has not been reliable or consistent in the few published peer‐reviewed field studies that used this test (Castro Bustamante and Hartz, 2016; Ward et al, 2017; Chahal and van Eerd, 2018; Bamber et al, 2018; Norris et al, 2018).…”

“…As an assessment of soil CO 2 respiration, the SSCB test has been evaluated in various crop and grassland systems (Goupil and Nkongolo, 2014; McDonald et al, 2014; Castro Bustamante and Hartz, 2016; Sadeghpour et al, 2016; Sciarappa et al, 2017; Mureva and Ward, 2017; Ward et al, 2017; Bamber et al, 2018; Chahal and van Eerd, 2018; Norris et al, 2018). The SSCB test is positively and significantly ( P < 0.05) correlated with SOM (McDonald et al, 2014; Castro Bustamante and Hartz, 2016; Sadeghpour et al, 2016; Rogers et al, 2018), soil total organic C and N (Haney et al, 2012; McDonald et al, 2014), soil N mineralization (Haney et al, 2008b; McDonald et al, 2014; Castro Bustamante and Hartz, 2016; Rogers et al, 2018), plant‐mineralizable N (Norris et al, 2018), soil water‐extractable organic C and N (Haney et al, 2012; Castro Bustamante and Hartz, 2016), soil P mineralization (Haney et al, 2008b), and chloroform fumigation extraction microbial biomass C (Chatterjee and Acharya, 2018).…”

“…No correlation or consistent trend between marketable crop yields and the SSCB test was observed in annual cropping systems in California or Ontario (Castro Bustamante and Hartz, 2016; Chahal and van Eerd, 2018) or between SSCB–C concentrations and aboveground primary productivity in South African perennial grasslands (Ward et al, 2017). Across different locations in the Virginia Coastal Plain, SSCB–C concentrations were positively, but weakly, correlated to relative maize ( Zea mays L.) yields (Norris et al, 2018) and wheat grain yields in the 0‐kg N ha −1 fertilization treatment (Bamber et al, 2018). To date, there have been no peer‐reviewed reports of evaluating the SSCB test in turfgrass systems, but it has been evaluated in grassland soils in Ireland (McDonald et al, 2014) and in South African grasslands (Mureva and Ward, 2017; Ward et al, 2017).…”

Talking SMAAC: A New Tool to Measure Soil Respiration and Microbial Activity

“…Finally, both spot and integrated samples can be analyzed using colorimetric techniques. For spot samples, colorimetric tubes can be used (Patil et al, 2010), while colorimetric paddles can provide integrated flux measurements (Sciarappa et al, 2016;Norris et al, 2018). Micro-respiration measurements, which quantify soil respiration and microbial community physiological profiles using indicator dyes in agar gel, also use colorimetric techniques (Campbell et al, 2003;Renault et al, 2013).…”