Soil Organic Carbon and Land Use: Processes and Potential in Ontario’s Long-term Agro-ecosystem Research Sites

Abstract

Soil organic carbon and land use: Processes and potential in Ontario's long-term agro-ecosystem research sites. Can. J. Soil Sci. 94: 317Á336. Soil organic carbon (SOC) is crucial for maintaining a productive agro-ecosystem. Long-term research must be synthesized to understand the effects of land management on SOC storage and to develop best practices to prevent soil degradation. Therefore, this review compiled an inventory of long-term Ontario studies and assessed SOC storage under common Ontario land management regimes via a meta-analysis and literature review. In general, greater SOC storage occurred in no-till (NT) vs. tillage systems, in crop rotation vs. continuous corn, and in N fertilizer vs. no N fertilizer systems; however, soil texture and perhaps drainage class may determine the effects of tillage. The effect on SOC storage was variable when deeper soil depth ranges (0Á45 cm) were considered for NT and rotational cropping, which suggests an unpredictable effect of land management on SOC at depths below the plough layer. Therefore, researchers are encouraged to use the presented inventory of nine long-term research sites and 18 active experiments in Ontario to pursue coordinated studies of long-term land management on SOC at depths extending below the plough layer.

Long-term impact of tillage and crop rotation on soil health at four temperate agroecosystems

“…The nutrients of magnesium, manganese, and zinc represent 'other nutrients', PMN denotes potentially mineralizable N. 15 cm in Ontario. In contrast, many long-term studies in eastern Canada have shown NT increased surface (i.e., 0-10 cm) soil organic C relative to CT (Angers et al, 1997;Deen and Kataki, 2003;Congreves et al, 2014a;Van Eerd et al, 2014). In Iowa USA, 26-30 years of moldboard plowing had the lowest 0-15 cm total organic C concentrations compared to other tillage treatments (i.e., NT) in monoC or C-S rotations (Karlen et al, 2013).…”

“…Therefore, more research is needed to better understand the regional impacts and interactions among soil characteristics, climate, and agricultural management on soil health. There are several field experiments that have been actively maintained for up to 30 years in Ontario (Congreves et al, 2014a), which presents an opportunity to investigate the impact of long-term agricultural production on soil health. An integrated and detailed analysis is required to measure the net impacts of long-term tillage (notillage (NT) vs. conventional tillage (CT)) and crop rotations (monoculture or rotations with and without undersown red clover) on soil quality attributes in Ontario.…”

Agronomic and Economic Benefits of Rotating Corn with Soybean and Spring Wheat under Different Tillage in Eastern Canada

“…The soil organic matter concentration was not significantly affected by soil tillage or rotation system even after 6 yr of study (data not shown). The duration of the experiment might have been too short to see any effect on the soil organic matter concentration (Congreves et al, 2014). In the cold climate of Finland, Sheehy et al (2015) reported no effect after 9 to 11 yr of RT on soil organic matter concentration in the 0‐ to 20‐cm depth in small cereals but a general redistribution of the C pool into macro‐aggregate fractions.…”

Eleven-Year Results on Soft and Durum Wheat Crops Grown in an Organic and in a Conventional Low Input Cropping System

“…The low return of biomass to the soil (Figure 4) and the negative delta N ( Figure 5) recorded for both crops in both systems confirm that wheat-based cropping systems imply a progressive decrease of soil fertility unless appropriate rotation and management of soil N are adopted (Congreves et al, 2014). This means that the C and N pools of the system need to be built during the other rotation phases.…”