scholarly journals Soil Organic Carbon Changes for Croplands across China from 1991 to 2012

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1433
Author(s):  
Wentian He ◽  
Ping He ◽  
Rong Jiang ◽  
Jingyi Yang ◽  
Craig F. Drury ◽  
...  

Accurate estimates of soil organic carbon (SOC) are critical for evaluating the impacts of crop and nutrient management practices on soil sustainability and global climate change. Temporal and spatial variations in topsoil (0–0.20 m) SOC were analyzed using 43,743 soil samples in China’s croplands. The soil database in our study was collected from the International Plant Nutrition Institute (IPNI) China Program. The results showed an increasing trend in SOC density (SOCD) for both grain and cash crops from 1991 to 2012. The average SOCD increased by 16.8, 17.4, 11.8 and 8.7% in the north central, northwest, southeast and southwest regions, respectively, whereas average SOCD decreased by 1.3% for the northeast region between the 1991–2001 and 2002–2012 periods. For both grain and cash crops, the SOCD frequency distribution (%) increased in the ranges of 10–20, 20–30 and 30–40 Mg C ha−1 from the 1991–2001 to the 2002–2012, but decreased in the ranges of 0–10 and 50–60 Mg C ha−1. Additionally, SOCD increased in most major soil types across China’s cropland regions, except in phaeozems, chernozems and umbrisols, where it decreased by 8.6–18.7% mainly due to water runoff, soil erosion, and low C input. The overall SOC stock (SOCS) in China’s cropland increased by 260 Tg C (23.7 Tg C yr−1) from 1991–2001 to 2002–2012, which was partially due to the increased crop residue return, improved fertilization and adopted conservation tillage over the period. This SOC increase represents a potential offset in carbon dioxide (CO2) emissions that could help reduce the overall net CO2 emissions in China.

Author(s):  
Sumit Mukati ◽  
Y. M. Kool ◽  
Deepak Thakur ◽  
Deepak Singune

Present field experiment was conducted at farmer’s field in Ringondiya village, Madhya Pradesh during rabi season 2018-19 to study the effect of integrated nutrient management practices on performance of chickpea, basic soil properties and nutrient availability. The performance of chickpea (cv. JG-322) was evaluated under seven treatments viz., T1-Control, T2-100% N:P:K (20:50:20), T3-50% N:P:K + FYM @5 t ha-1, T4-50% N:P:K + vermicomposting @2 t ha-1, T5-50% N:P:K + PSB @4 kg ha-1, T6-50% N:P:K + FYM @5 t ha-1 + PSB @4 kg ha-1 and T7-50% N:P:K + vermicomposting @2 t ha-1 +PSB @4 kg ha-1 replicated thrice in a randomized block design. The grain yield, straw yield and harvest index of chickpea were determined at harvest. Similarly, the soil pH, electrical conductivity, soil organic carbon and soil available nutrients (N, P and K) were also determined in post harvest soil samples. The results revealed that the integrated nutrient management practice significantly improved the performance of chickpea. The soil organic carbon and available nutrients were also found increased under INM practices.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 650
Author(s):  
Jesús Aguilera-Huertas ◽  
Beatriz Lozano-García ◽  
Manuel González-Rosado ◽  
Luis Parras-Alcántara

The short- and medium—long-term effects of management and hillside position on soil organic carbon (SOC) changes were studied in a centenary Mediterranean rainfed olive grove. One way to measure these changes is to analyze the soil quality, as it assesses soil degradation degree and attempts to identify management practices for sustainable soil use. In this context, the SOC stratification index (SR-COS) is one of the best indicators of soil quality to assess the degradation degree from SOC content without analyzing other soil properties. The SR-SOC was calculated in soil profiles (horizon-by-horizon) to identify the best soil management practices for sustainable use. The following time periods and soil management combinations were tested: (i) in the medium‒long-term (17 years) from conventional tillage (CT) to no-tillage (NT), (ii) in the short-term (2 years) from CT to no-tillage with cover crops (NT-CC), and (iii) the effect in the short-term (from CT to NT-CC) of different topographic positions along a hillside. The results indicate that the SR-SOC increased with depth for all management practices. The SR-SOC ranged from 1.21 to 1.73 in CT0, from 1.48 to 3.01 in CT1, from 1.15 to 2.48 in CT2, from 1.22 to 2.39 in NT-CC and from 0.98 to 4.16 in NT; therefore, the soil quality from the SR-SOC index was not directly linked to the increase or loss of SOC along the soil profile. This demonstrates the time-variability of SR-SOC and that NT improves soil quality in the long-term.


2003 ◽  
Vol 83 (4) ◽  
pp. 363-380 ◽  
Author(s):  
A. J. VandenBygaart ◽  
E. G. Gregorich ◽  
D. A. Angers

To fulfill commitments under the Kyoto Protocol, Canada is required to provide verifiable estimates and uncertainties for soil organic carbon (SOC) stocks, and for changes in those stocks over time. Estimates and uncertainties for agricultural soils can be derived from long-term studies that have measured differences in SOC between different management practices. We compiled published data from long-term studies in Canada to assess the effect of agricultural management on SOC. A total of 62 studies were compiled, in which the difference in SOC was determined for conversion from native land to cropland, and for different tillage, crop rotation and fertilizer management practices. There was a loss of 24 ± 6% of the SOC after native land was converted to agricultural land. No-till (NT) increased the storage of SOC in western Canada by 2.9 ± 1.3 Mg ha-1; however, in eastern Canada conversion to NT did not increase SOC. In general, the potential to store SOC when NT was adopted decreased with increasing background levels of SOC. Using no-tillage, reducing summer fallow, including hay in rotation with wheat (Triticum aestivum L.), plowing green manures into the soil, and applying N and organic fertilizers were the practices that tended to show the most consistent in creases in SOC storage. By relating treatment SOC levels to those in the control treatments, SOC stock change factors and their levels of uncertainty were derived for use in empirical models, such as the United Nations Intergovernmental Panel on Climate Change (IPCC). Guidelines model for C stock changes. However, we must be careful when attempting to extrapolate research plot data to farmers’ fields since the history of soil and crop management has a significant influence on existing and future SOC stocks. Key words: C sequestration, tillage, crop rotations, fertilizer, cropping intensity, Canada


2014 ◽  
Vol 6 (1) ◽  
pp. 619-655
Author(s):  
S. Zubrzycki ◽  
L. Kutzbach ◽  
E.-M. Pfeiffer

Abstract. Permafrost-affected soils have accumulated enormous pools of organic matter during the Quaternary Period. The area occupied by these soils amounts to more than 8.6 million km2, which is about 27% of all land areas north of 50° N. Therefore, permafrost-affected soils are considered to be one of the most important cryosphere elements within the climate system. Due to the cryopedogenic processes that form these particular soils and the overlying vegetation that is adapted to the arctic climate, organic matter has accumulated to the present extent of up to 1024 Pg (1 Pg = 1015 g = 1 Gt) of soil organic carbon stored within the uppermost three meters of ground. Considering the observed progressive climate change and the projected polar amplification, permafrost-affected soils will undergo fundamental property changes. Higher turnover and mineralization rates of the organic matter are consequences of these changes, which are expected to result in an increased release of climate-relevant trace gases into the atmosphere. As a result, permafrost regions with their distinctive soils are likely to trigger an important tipping point within the global climate system, with additional political and social implications. The controversy of whether permafrost regions continue accumulating carbon or already function as a carbon source remains open until today. An increased focus on this subject matter, especially in underrepresented Siberian regions, could contribute to a more robust estimation of the soil organic carbon pool of permafrost regions and at the same time improve the understanding of the carbon sink and source functions of permafrost-affected soils.


2021 ◽  
Vol 19 (1) ◽  
pp. e1102
Author(s):  
Maroua Dachraoui ◽  
Aurora Sombrero

Aim of study: To evaluate the effects of conventional tillage (CT) and no tillage (NT) systems on the soil organic carbon (SOC) changes, CO2 emissions and their relation with soil temperature and grain yield in a monoculture of irrigated maize during six years.Area of study: In Zamadueñas experimental field in the Spanish province of Valladolid, from 2011 to 2017.Material and methods: The SOC content was determined by collecting soil samples up to 30 cm in November at two years interval. Short-term CO2 emissions were measured simultaneously with soil temperature using a respiration chamber and a hand-held probe immediately before, after every tillage operation and during the maize cycle.Main results: The SOC stock of the top 30 cm soil layers was 13% greater under NT than CT. Short-term CO2 emissions were significantly higher under CT ranging from 0.8 to 3.4 g CO2 m-2 h-1 immediately after tillage while under NT system, soil CO2 fluxes were low and stable during this study period. During the first 48 h following tillage, cumulative CO2 emissions ranged from 0.6 to 2.4 Mg CO2 ha-1 and from 0.2 to 0.3 Mg CO2 ha-1 under CT and NT systems, respectively. Soil temperature did not show significant correlation with CO2 emissions; however, it depended mostly on the time of measurement.Research highlights: No tillage increased the SOC accumulation in the topsoil layer, reduced CO2 emissions without decreasing maize grain yield and minimized the impact on climate change compared to CT system.


2021 ◽  
Author(s):  
Cong He ◽  
Jia‐Rui Niu ◽  
Cheng‐Tang Xu ◽  
Shou‐Wei Han ◽  
Wei Bai ◽  
...  

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