Article Figures & Data
Figures
- Figure 1
Map showing location of sampling sites within the three counties in the Southern High Plains of Texas. Within each county, one long-term (>23 years) Conservation Reserve Program site (CRP; blue points) and one dryland cropland converted from a similar long-term CRP site (C-CRP; green points) were sampled for a total of six sites (note that all points on map not visible due to scaling). Map on the left is an example of one of the counties showing the location of one CRP (green) and one C-CRP (blue) site. Within each site, three 100 m transects (white lines) were placed within the same soil series (e.g., within red outline of the Arvana soil series) and five soil cores were collected approximately every 20 m, split into three depths as shown, and homogenized. Thus, for each site, nine soil samples (three subreplicates from each of the transects × three depths) were collected and analyzed during each of the four sampling years (2012 to 2015).
- Figure 2
Estimated marginal means for the Conservation Reserve Program system (CRP; blue triangles) and the converted CRP to annual cropped system (C-CRP; red circles) for (a to c) soil organic carbon (SOC), (d to f) total nitrogen (TN), (g to i) particulate organic carbon (POM-C), and (j to l) particulate organic matter nitrogen (POM-N) at soil depth profiles of (a, d, g, and j) 0 to 10 cm, (b, e, h, and k) 0 to 30 cm, and (c, f, i, and l) 0 to 50 cm from 2012 to 2015. Different capital letters indicate a significant difference between systems within the same sampling year. Different lowercase letters indicate a significant difference between sampling years within each system. Letters are only shown when there was a significant system by year interaction (α = 0.1). P-values from ANCOVA for main effect of system, year, and their interaction (Int.) are provided (n = 72 for each soil depth profile).
- Figure 3
Estimated marginal means for the Conservation Reserve Program system (CRP; blue triangles) and the converted CRP to annual cropped system (C-CRP; red circles) for (a to c) permanganate oxidizable carbon (POXC), (d to f) microbial biomass carbon (MBC), and (g to i) microbial biomass nitrogen (MBN) at soil depth profiles of (a, d, and g) 0 to 10 cm, (b, e, and h) 0 to 30 cm, and (c, f, and i) 0 to 50 cm from 2012 to 2015. Different capital letters indicate a significant difference (α = 0.1) between systems within the same sampling year. Different lowercase letters indicate a significant difference between sampling years within each system. P-values from ANCOVA for main effect of system, year, and their interaction (Int.) are provided (n = 72 for each soil depth profile).
- Figure 4
Average weather conditions of the research sites from 2011 to 2015 from nearby weather stations. (a) Monthly precipitation, (b) average daily soil temperature, and (c) soil diurnal temperature range (DTR) under bare soil (proxy of C-CRP; red symbols) and vegetated soil (proxy of CRP; blue symbols) at 0 to 10 and 10 to 30 cm. In (a), the numbers before the slash represent the precipitation during the growing season from May to October of each year and the numbers after the slash represent the precipitation of the entire year.
- Figure 5
(a) Average monthly soil carbon dioxide (CO2) efflux rate, (b) cumulative CO2 efflux, and (c) soil volumetric water content (n = 18 replicates for each system and year) for converted Conservation Reserve Program (C-CRP) and CRP. Different capital letters indicate a significant difference between systems within the same sampling month in plots A and B. Letters are only shown when there was a significant system and sampling year/month interaction (α = 0.1).
- Figure 6
Estimated marginal means of soil microbial metabolic quotient (qCO2) in the converted Conservation Reserve Program (C-CRP) and CRP systems. The capital letters indicate the difference between systems (CRP and C-CRP) within the same sampling year. The lowercase letters indicate the difference among different sampling years within each system (n = 72).
Tables
- Table 1
Management history and soil information for each of the six sampling sites (Conservation Reserve Program [CRP] and converted CRP) across the three counties in the Southern High Plains.
- Table 2 The average estimated marginal means of the soil carbon and nitrogen stocks in the Conservation Reserve Program (CRP) and converted CRP (C-CRP) systems from 2012 to 2015 at 0 to 10 cm, 0 to 30 cm, and 0 to 50 cm (n = 72 observations for each depth profile).
2022.00141 Supplementary File
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