Changes in Organic Carbon and Selected Soil Fertility Parameters in Agricultural Soils in Tasmania, Australia

2013 ◽  
Vol 44 (1-4) ◽  
pp. 166-177 ◽  
Author(s):  
Leigh Sparrow ◽  
Bill Cotching ◽  
Jocelyn Parry-Jones ◽  
Garth Oliver ◽  
Eve White ◽  
...  
2021 ◽  
Author(s):  
Caitlin Victoria Santos

Earthworm consumption and egestion of organic materials can increase bioavailable nitrogen in soils. Along with other benefits resulting from their burrowing activities, this process can increase soil fertility. This research investigated whether earthworms were present, and whether a relationship between earthworms and increased ammonium and nitrate levels was seen in the soils of the agricultural green roofs sampled in the greater Toronto area. Earthworms were found at several of the agricultural green roofs, but low soil moisture, low organic carbon, shallow depth, and compactness may have inhibited the establishment of earthworm populations in some soils. Results showed a statistically significant increase in levels of ammonium, but not in nitrate, with the increasing presence of earthworms. Findings indicate that some degree of increased bioavailable nitrogen benefits, resulting from earthworm presence, that are evident in conventional agricultural soils, can also be possible in agricultural green roofs, with attention to management of soil conditions that support earthworm populations.


2021 ◽  
Author(s):  
Caitlin Victoria Santos

Earthworm consumption and egestion of organic materials can increase bioavailable nitrogen in soils. Along with other benefits resulting from their burrowing activities, this process can increase soil fertility. This research investigated whether earthworms were present, and whether a relationship between earthworms and increased ammonium and nitrate levels was seen in the soils of the agricultural green roofs sampled in the greater Toronto area. Earthworms were found at several of the agricultural green roofs, but low soil moisture, low organic carbon, shallow depth, and compactness may have inhibited the establishment of earthworm populations in some soils. Results showed a statistically significant increase in levels of ammonium, but not in nitrate, with the increasing presence of earthworms. Findings indicate that some degree of increased bioavailable nitrogen benefits, resulting from earthworm presence, that are evident in conventional agricultural soils, can also be possible in agricultural green roofs, with attention to management of soil conditions that support earthworm populations.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiao Wang ◽  
Xuexin Wang ◽  
Peng Geng ◽  
Qian Yang ◽  
Kun Chen ◽  
...  

AbstractIn view of the problems of low straw decomposition rates and reduced soil fertility in southern Liaoning, China, we investigated the effects of no-tillage mode (NT), deep loosening + deep rotary tillage mode (PT), rotary tillage mode (RT) and the addition of decomposing agent (the next is called a decomposer) (NT + S, PT + S, RT + S) on the decomposition proportion of straw, respectively, by using the nylon net bag method in combination with 365-day field plot experiments. The decomposition rules of cellulose, hemicellulose and lignin as well as the dynamics of soil organic carbon (SOC), soil microbial biomass carbon (MBC) and soil dissolved organic carbon (DOC) in straw returned to the field for 15, 35, 55, 75, 95, 145 and 365 days were analyzed. The results showed that in the short term, the decomposition of straw was better in both the rotray tillage and deep loosening + deep rotary modes than in the no-tillage mode, and the addition of decomposer significantly promoted the decomposition of straw and the release of carbon from straw, among them, the RT + S treatment had the highest straw decomposition proportion and carbon release proportion in all sampling periods. After a one year experimental cycle, the RT + S treatment showed the highest proportion of cellulose, hemicellulose and lignin decomposition with 35.49%, 84.23% and 85.50%, respectively, and soil SOC, MBC and DOC contents were also higher than the other treatments with an increase of 2.30 g kg−1, 14.22 mg kg−1 and 25.10 mg kg−1, respectively, compared to the pre-experimental soil. Our results show that in the short term, to accelerate the decomposition rate of returned straw and increase the content of various forms of carbon in soil, rotary tillage can be used to return the straw to the field, while also spraying straw decomposer on its surface. This experiment used a new straw decomposer rich in a variety of microorganisms, combined with the comparison of a variety of straw return modes, and in-depth study of straw decomposition effects of cellulose, hemicellulose and lignin. Thus, a scheme that can effectively improve the decomposition rate of straw and the content of various forms of organic carbon in soil within a short period of time was explored to provide theoretical support for the southern Liaoning.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuhua Shan ◽  
Min Lv ◽  
Wengang Zuo ◽  
Zehui Tang ◽  
Cheng Ding ◽  
...  

AbstractThe most important measures for salt-affected mudflat soil reclamation are to reduce salinity and to increase soil organic carbon (OC) content and thus soil fertility. Salinity reduction is often accomplished through costly freshwater irrigation by special engineering measures. Whether fertility enhancement only through one-off application of a great amount of OC can improve soil properties and promote plant growth in salt-affected mudflat soil remains unclear. Therefore, the objective of our indoor pot experiment was to study the effects of OC amendment at 0, 0.5%, 1.0%, 1.5%, and 2.5%, calculated from carbon content, by one-off application of sewage sludge on soil properties, rice yield, and root growth in salt-affected mudflat soil under waterlogged conditions. The results showed that the application of sewage sludge promoted soil fertility by reducing soil pH and increasing content of OC, nitrogen and phosphorus in salt-affected mudflat soil, while soil electric conductivity (EC) increased with increasing sewage sludge (SS) application rates under waterlogged conditions. In this study, the rice growth was not inhibited by the highest EC of 4.43 dS m−1 even at high doses of SS application. The SS application increased yield of rice, promoted root growth, enhanced root activity and root flux activity, and increased the soluble sugar and amino acid content in the bleeding sap of rice plants at the tillering, jointing, and maturity stages. In conclusion, fertility enhancement through organic carbon amendment can “offset” the adverse effects of increased salinity and promote plant growth in salt-affected mudflat soil under waterlogged conditions.


2007 ◽  
Vol 11 (1) ◽  
pp. 61-76 ◽  
Author(s):  
B. Reynolds

Abstract. In the UK, as organo-mineral soils are a significant store of soil organic carbon (SOC), they may become increasingly favoured for the expansion of upland forestry. It is important, therefore, to assess the likely impacts on SOC of this potentially major land use change. Currently, these assessments rely on modelling approaches which assume that afforestation of organo-mineral soils is "carbon neutral". This review evaluates this assumption in two ways. Firstly, UK information from the direct measurement of SOC change following afforestation is examined in the context of international studies. Secondly, UK data on the magnitude and direction of the major fluxes in the carbon cycle of semi-natural upland ecosystems are assessed to identify the likely responses of the fluxes to afforestation of organo-mineral soils. There are few directly relevant measurements of SOC change following afforestation of organo-mineral soils in the UK uplands but there are related studies on peat lands and agricultural soils. Overall, information on the magnitude and direction of change in SOC with afforestation is inconclusive. Data on the accumulation of litter beneath conifer stands have been identified but the extent to which the carbon held in this pool is incorporated into the stable soil carbon reservoir is uncertain. The effect of afforestation on most carbon fluxes is small because the fluxes are either relatively minor or of the same magnitude and direction irrespective of land use. Compared with undisturbed moorland, particulate organic carbon losses increase throughout the forest cycle but the data are exclusively from plantation conifer forests and in many cases pre-date current industry best practice guidelines which aim to reduce such losses. The biggest uncertainty in flux estimates is the relative magnitude of the sink for atmospheric carbon as trees grow and mature compared with that lost during site preparation and harvesting. Given the size of this flux relative to many of the others, this should be a focus for future carbon research on these systems.


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