Relationship between soil carbon and nitrogen, soil properties, and dryland crop yields

Abstract

Soil organic carbon (SOC) is an important indicator of soil health, but its analysis requires a two-step process of measuring soil total carbon (STC) and inorganic carbon (SIC) in arid and semiarid regions. Determination of STC or soil total nitrogen (STN) for SOC can shorten the analytical process, which may be used for measuring soil health. We related STC, STN, SOC, and SIC to 62 soil properties and mean crop yields across years in two long-term (14-and 36-yr-old) experiments in the northern Great Plains. Treatments were rotations of till-and no-till spring wheat (Triticum aestivum L.)/barley (Hordeum vulgare L.), pea (Pisum sativum L.), and fallow with and without N fertilization. No-till continuous cropping (every year cropping) increased STC, STN, and SOC compared to till and no-till crop-fallow, with limited effect of N fertilization. Treatments had little effect on SIC. The STC correlated to 6, 7, and 28 more soil physical, chemical, biological, and biochemical properties than SOC, STN, and SIC, respectively. A combination of data from both experiments enhanced the relationships among STC, STN, SOC, and selected soil properties. The STC also more strongly related to mean crop yield across years than SOC, STN, and SIC.Because of rapid determination and sensitivity to management practices, STC can be used as a potential soil health indicator to relate to more soil properties and crop yields in dryland cropping systems in the semiarid northern Great Plains. INTRODUCTIONSoil organic carbon (SOC) is an important potential indicator of soil health that affects soil physical, chemical, and Abbreviations: ACEP, autoclaved citrate-extractable protein; CTWF, conventional till spring wheat/barley-fallow; FSTCW, fall and spring till

Soil total carbon and nitrogen under long‐term perennial bioenergy crops receiving various nitrogen fertilization rates

“…The STC and STN stocks at 0–120 cm were calculated by adding stocks from individual depth layers. Because STC related similar to or better than SOC with most soil properties and crop yields (Sainju et al., 2021), we used STC instead of SOC to observe changes in C and N stocks under perennial grasses in the semiarid region. Measurement of STC also saves time and cost of analysis because it requires only one‐step of determination compared to SOC which requires two‐step processes of measuring STC and SIC (Sainju et al., 2021).…”

“…We chose soil total C (STC) instead of SOC to measure C sequestration rates under perennial bioenergy crops in dryland farming in the semiarid climatic condition of the US northern Great Plains because STC was equally sensitive to management practices, associated with more soil properties, and related better with crop yields than SOC (Sainju et al., 2021). As dryland soils contain significant amount of soil inorganic C (SIC) mainly in subsoil layers where the potential for C sequestration is greater, using STC to measure C sequestration rate is more meaningful than using SOC, especially in dryland cropping systems in arid and semiarid regions (FAO, 2004; UNEP, 1991).…”

“…Another reason for using STC instead of SOC is that C sequestration due to management practices occurs both in SOC and SIC and measurement of STC is rapid and as reliable as measurement of SOC in arid and semiarid regions (FAO, 2004; UNEP, 1991). The simplicity and rapidity of measuring STC compared with SOC, which needs measurements of both STC and SIC, also makes STC an inexpensive and palatable measurement of C stocks and C sequestration rates in dryland cropping systems (Sainju et al., 2021).…”

Sustainable Cultivation of Coconut Palms: Soil Fertility Status of Traditional Palm Groves of South India

“…Correlation analysis revealed that SAN positively correlates to FWC, TOC, SAP, and SAK. The positive correlations between SAN with FWC (Zhang and Wienhold 2002) and TOC(Sainju et al 2021) are well known. However, category-wise analysis revealed that such current study, most of the Coconut-growing soils (58%) showed a high level of SAP in the elds.Among the soil orders, Ultisols (77.77%) and Entisols (57.46%) showed a signi cantly increased level of available phosphorus than others.…”