Evaluation of CO2 emission from rice husk biochar and cowdung manure co-compost preparation

Composting of animal manure had been considered a sustainable alternative method for recycling organic waste. However the process involved had been associated with greenhouse gas emission (CO2, N2O and CH4) which play an active role in global warming. This study evaluated CO2 emissions from biochar-manure co-compost production. Biochar (from rice husk) and manure were mixed in a ratio of 3:1 v/v to achieve a range of different co-compost mixtures. The treatments and controls in triplicates of 18 units were arranged in a complete randomize design. All treatments were incubated at around 28 oC and turned every two days for 2 weeks, and later five days for 39 days. CO2 production in the compost bins was measured by trapping the evolved gas in 5M NaOH. Total CO2 emissions varied over time with higher rates at the beginning of the composting process. Within the first 7 days, total CO2 emissions (587 mg/m2) from cow dung alone was not significantly different from cow dung plus biochar (506 mg/m2). At the latter stages of the composting process, CO2 emission from cowdung and biochar mixture was less than from the other treatments

Soil and crop residue CO2-C emission under tillage systems in sugarcane-producing areas of southern Brazil

Appropriate management of agricultural crop residues could result in increases on soil organic carbon (SOC) and help to mitigate gas effect. To distinguish the contributions of SOC and sugarcane (Saccharum spp.) residues to the short-term CO2-C loss, we studied the influence of several tillage systems: heavy offset disk harrow (HO), chisel plow (CP), rotary tiller (RT), and sugarcane mill tiller (SM) in 2008, and CP, RT, SM, moldboard (MP), and subsoiler (SUB) in 2009, with and without sugarcane residues relative to no-till (NT) in the sugarcane producing region of Brazil. Soil CO2-C emissions were measured daily for two weeks after tillage using portable soil respiration systems. Daily CO2-C emissions declined after tillage regardless of tillage system. In 2008, total CO2-C from SOC and/or residue decomposition was greater for RT and lowest for CP. In 2009, emission was greatest for MP and CP with residues, and smallest for NT. SOC and residue contributed 47 % and 41 %, respectively, to total CO2-C emissions. Regarding the estimated emissions from sugarcane residue and SOC decomposition within the measurement period, CO2-C factor was similar to sugarcane residue and soil organic carbon decomposition, depending on the tillage system applied. Our approach may define new emission factors that are associated to tillage operations on bare or sugarcane-residue-covered soils to estimate the total carbon loss

Soil respiration in cucumber field under crop rotation in solar greenhouse

Crop residues are the primary source of carbon input in the soil carbon pool. Crop rotation can impact the plant biomass returned to the soil, and influence soil respiration. To study the effect of previous crops on soil respiration in cucumber (Cucumis statirus L.) fields in solar greenhouses, soil respiration, plant height, leaf area and yield were measured during the growing season (from the end of Sept to the beginning of Jun the following year) from 2007 to 2010. The cucumber was grown following fallow (CK), kidney bean (KB), cowpea (CP), maize for green manure (MGM), black bean for green manure (BGM), tomato (TM), bok choy (BC). As compared with CK, KB, CP, MGM and BGM may increase soil respiration, while TM and BC may decrease soil respiration at full fruit stage in cucumber fields. Thus attention to the previous crop arrangement is a possible way of mitigating soil respiration in vegetable fields. Plant height, leaf area and yield had similar variation trends under seven previous crop treatments. The ratio of yield to soil respiration revealed that MGM is the crop of choice previous to cucumber when compared with CK, KB, CP, BGM, TM and BC

Virtual Visualization System for Growth of Tobacco Root

International audienceVisualization study on the growth of virtual plant roots is of great significance to enhance the overall level of research on virtual plant growth. In this study, with the tobacco root as the object, its growth was divided by systematic analysis into three stages: root emergence, root growth, and root branching. Through the quantitative analysis of the morphological data of the tobacco root and in combination with results of previous studies, the tobacco root growth, branching and other models were established, and parameter values of the models were extracted. On this basis, computer graphics technology was applied to establish a virtual visualization system for tobacco root growth that should be capable of simulating root growth and computing indicators of roots including the number, length, density, etc. Results indicated that this system can do a better job of simulating the morphological features for the tobacco root and virtually displaying the process of tobacco root growth in a more realistic way

Simulation of Sandsage-Bluestem Forage Growth Under Varying Stocking Rates

The effect of stocking rate on forage growth has attracted much research attention in forage science. Findings show that forage growth may be affected by stocking rate, and there is a consensus that high stocking rates lead to soil compaction, which could also in turn affect forage growth because of the changing soil hydrology and increased soil impedance to forage root penetration. In this study we used a modeling approach to investigate the effect of stocking rates on the growth of sand-bluestem forage at Fort Supply, Oklahoma. The GPFARM-Range model, which was originally developed and validated for Cheyenne, Wyoming, was recalibrated and enhanced to simulate soil compaction effects on forage growth at Fort Supply. Simulations without the consideration of soil compaction effects overestimated the forage growth under high stocking rate conditions (mean bias [MBE]= –591 kg ha-1), and the agreement between the simulated and observed forage growth was poor (Willmott’s d=0.47). The implementation in the model of soil compaction effects associated with high stocking rates reduced the bias (MBE= –222 kg ha-1) and improved the overall agreement between the observed and the simulated forage growth (d = 0.68). It was concluded that forage growth under increasing soil compaction could be predicted provided such sensitivities are included in forage growth models. The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202