Black Carbon and Its Effect on Carbon Sequestration in Soil

The properties of black carbon (BC) are described very differently in the literature, even when determined by the same methodological procedure. To clarify this discrepancy, BC was investigated in the clay Cambisols of southern Bohemia, Czech Republic, in groups of soils with lower and higher deposition of its atmospheric fallout. The BC determination was performed according to a modified method of Kuhlbusch and Crutzen (1995). The amount of the free light fraction, the occluded light fraction of soil organic matter and its ratio, the amount of heavy soil fraction DF, and its soil organic matter DFOM were determined. Other soil characteristics were identified. It was found that there are two very different types of BC in soils. Historical BC from biomass fires, and new, anthropogenic, from the furnace and transport fumes. Historical BC has a significant effect on the organic matter of the heavy soil fraction, on the ratio of the free and occluded soil organic matter fraction, and the number of water-resistant soil aggregates. Anthropogenic BC does not have this effect. Because this form of BC is not significantly stabilized by the colloidal mineral fraction, it is necessary to take general data on BC’s high stability and resistance to mineralization in the soil with circumspection.

Respons tanaman tebu (Saccharum officinarum L.) terhadap aplikasi konsorsium biostimulan di tiga tipologi lahan

The consortium biostimulant combines several types of biostimulant applied holistically, such as phytohormones to induce physiological processes, humic acid to improve nutrition intake and land fertility, and biofertilizer arbuscular mycorrhizal fungi to improve abiotic stress tolerance. The objectives of this research were to analyze the effect of application consortium biostimulant on the growth and productivity of Bululawang sugarcane variety planted in three land typologies, i.e. irrigated heavy soil with good drainage (BPL), irrigated heavy soil with poor drainage (BPJ), and rainfed light soil with good drainage (RHL). The research was conducted on plant cane (PC) sugarcane areal in Lumajang Regency, East Java, from July 2019 to September 2020. The treatment plot area was 1 ha for each land typologies, and the observation were conducted on 10 m plant row with ten times replications. Each treatment was replicated ten times. The results showed that the application of consortium biostimulant could induce faster growth of sugarcane shoots and better roots at one month after planting (MAP). Stalk height and diameter showed significantly different values between treatment and control at the plant age 6 to 12 MAP. In addition, the sugarcane stalk weight per meter row also increases by 13.72 – 28.57%. The growth performance of sugarcane on a commercial scale increased, also sugarcane productivity increased by 11.08 – 20.36%. The potential sugar yield increased by 15.05% in BPL land typology, 4.9% in BPJ land typology, and 9.7% in RHL land typology. The difference in land typologies affected the effectiveness of the consortium biostimulant application in increasing sugarcane productivity.

Growth Responses of Avicennia germinans and Batis maritima Seedlings to Weathered Light Sweet Crude Oil Applied to Soil and Aboveground Tissues

Oil spills are a significant stressor to coastal and maritime environments worldwide. The growth responses of Batis maritima and Avicennia germinans seedlings to weathered Deepwater Horizon oiling were assessed through a mesocosm study using a factorial arrangement of 4 soil oiling levels (0 L m-2, 1 L m-2, 2 L m-2, 4 L -m-2) x 3 tissue oiling levels (0% of stem height, 50% of stem height, 100% of stem height). Overall, growth metrics of B. maritima displayed much greater sensitivity to both tissue and soil oiling than A. germinans, which exhibited a relatively high tolerance to both routes of oiling exposure. Batis maritima in the 4 L m-2 soil oiling treatment demonstrated significant reductions in cumulative stem height and leaf number, whereas no significant effects of soil oiling on A. germinans were detected. This was reflected in end of the study biomass partitioning, where total aboveground and live aboveground biomass were significantly reduced for B. maritima with 4 L m-2 soil oiling, but no impacts to A. germinans were found. Tissue oiling of 100% did appear to initially reduce B. maritima stem diameter, but no effect of tissue oiling was discerned on biomass partitioning, suggesting that there were no impacts to integrated growth. These findings suggest that B. maritima would be more severely affected by heavy soil oiling than A. germinans.

Carrot Yield and Shape Altered by Seeding Rate and Raised Beds in Clay-loam Soil

Carrots (Daucus carota L. var sativus) in the midwestern United States are generally raised commercially on sandy-loam or muck soils. Some smaller growers may not have the luxury of an ideal soil type, so raised beds are often recommended to improve taproot growth. To determine specific yield and shape responses of carrots to raised-bed culture in heavy soil, three hybrids (‘Cupar’, ‘Envy’, and ‘Naval’) were grown in 2019 and 2020 on raised or flat beds in clay-loam soil. In addition, two seeding rates (high or low) were incorporated into the split-split plot design. ‘Cupar’ was larger and less misshapen than the other hybrids, but total marketable yields were similar among all three. ‘Naval’ was the most cylindrical. High seeding rate generally resulted in more numerous but smaller marketable roots and no change in total marketable weight. Raised beds caused a 10.6% increase in total marketable weight by allowing more marketable roots classified as “short” (between 76 and 127 mm long, diameter >25 mm) to grow to lengths more than 127 mm long. The average taproot cylindricity was increased and diameter decreased by growing on raised beds. Soil penetration resistance at 7.6 cm was correlated with many of the measured responses.

Diversity of reductive dechlorinating bacteria and archaea in herbicide/dioxin-contaminated soils from Bien Hoa airbase using metagenomic approach

Heavy herbicide/dioxin contamination of soil was derived a negative effect on the microbial biodiversity, soil quality, animal and human health in Central and South of Vietnam. This is the first time, the application metagenomic tools investigated soil microbial structural community of undetoxified (C - 21,605 ng TEQ/kg dry soil) and bioremediated (BHR - 13.2 ng TEQ/kg dry soil) which could not only help us to explore the potential risks associated with contaminated soils but also provide insights into possible soil bioremediation technology by stimulating indigenous microbes. Four methanogen genera, Methanosarcina (24 - 322 OTUs respectively C – BHR samples), Methanocella (13 - 63 OTUs), Methanosaeta (7 - 42 OTUs) and Methanococcus (6 - 69 OTUs) have been dominantly detected in both two metagenomes. Twenty genera of archaea belonging to the phylum Euryarchaeota were found. They could be clustered within 14 different families and nine archaeal genera including unclassified archaea (17 OTUs – C; 145 OTUs - BHR). In metagenome C and BHR, 12 genera of sulfate reducing bacteria (SRB) with different number (2 - 77; 61 - 904 OTUs) respectively were presented. Four SRB genera are dominated in C metagenome, it is linear also in BHR. The highest number is genus Desulfovibrio detected in both examined metagenomes. However, the relationship features of these bacterial groups need deeply investigation for understanding their role of reductive dechlorination, anaerobic degradation in herbicide/dioxin contaminated heavy soil and sediment. These results provide additional evidence to explain why heavy herbicide/dioxin contaminated soil was detoxified successfully at Bien Hoa airbase, Vietnam.

Cropping Systems of Fenugreek with Faba Bean to Reduce Broomrape Infestation

Background: Broomrape (Orobanche crenata Forsk.) is a major threat to faba bean and an important danger parasite. An intercropping is a necessity to curb the spread and progress of the parasite before it leads to much more economic losses. The current study was aimed to evaluate intercropping of fenugreek with faba bean under two plant densities of both crops on broomrape incidence to increase faba bean yield, land usage and economic return in heavy soil infestation of broomrape.Methods: This study was carried out at Giza Agricultural Research Station (Lat. 30°002 303 N, Long. 31°122 433 E, 26 m a.s.l), Agricultural Research Center, Giza, Egypt. During the winter season of 2017/2018 and 2018/2019 seasons, sixteen treatments were the combinations between two ridge widths (60 “narrow” and 120 cm “wide”) and six cropping systems (50% faba bean + 50% fenugreek, 100% faba bean + 50% fenugreek, 50% faba bean + 100% fenugreek, 100% faba bean + 100% fenugreek, 50% sole faba bean and 100% sole faba bean), as well as sole plantings of fenugreek under heavy soil infestation of broomrape. A split-plot design with three replicates was used. Ridge widths were assigned in the main plots and cropping systems were arranged in sub plots. Result: Growing faba bean plants in wide ridges had physical barriers with stamping of the vascular system against the parasite. 50% faba bean + 100% fenugreek had higher soil total phenols in faba bean rhizosphere than the others. Growing 50% faba bean + 100% fenugreek in wide ridges had lower number of spikes per m2 and spikes dry weight per m2, meanwhile, growing 100% faba bean + 100% fenugreek in wide ridges had higher seed yields of both crops per ha, land usage and economic return. Growing two rows of faba bean (100% of sole cropping) in both sides of wide ridge (120 cm width) with four rows of fenugreek (100% of sole cropping) in middle of the ridge could be an integrated control strategy to increase faba bean productivity, land usage and economic return under heavily soil infested of broomrape.

Do Crop Rotations in Rice Reduce Weed and Echinochloa spp. Infestations? Recommendations for Integrated Weed Control

The species belonging to the genus Echinochloa represent the main weeds in rice fields worldwide. Heavy soils are especially appropriate for this crop that is often grown in monoculture. A drought period in 2012 impeded farmers from sowing rice in some parts of the region of Aragon (northeastern Spain) and, unusually, they seeded alternative crops such as winter cereal, fescue (Festuca arundinacea), ryegrass (Lolium multiflorum) and lucerne (Medicago sativa). A total of 20 fields were selected, in which rice had been grown in monocrop until 2011 and several crop sequences were established afterwards; weed vegetation was recorded in spring, summer and autumn 2014-16 to find out if the crop rotations reduced weed infestations. Winter cereal and fescue were the crops with the highest soil cover; ryegrass and lucerne had difficulties in installation probably due to the heavy soil textures. Echinochloa spp. plants were found in the winter cereal stubble after having grown fescue for the previous two years and rice before that; in the forage fields, small plants of earing Echinochloa spp. adapted to mowing were detected. Recommendations for Integrated Weed Management that arise from the observations are ploughing the winter cereal stubble before seed shed of the emerged Echinochloa plants, assuring a high density of the forage crops, and efficient herbicide control in rice fields.

Sustainability of Machinery Traffic in Vineyard

Viticulture involves significant levels of machinery traffic, causing heavy soil compaction. In particular, the compaction of the subsoil is increased; a deep tillage could certainly solve the problem, but the risk of damage to the plants’ root system is high. The aim of this study was to investigate the trend of both the top- and the sub-soil compaction in a hillside vineyard located in Tuscany (Italy), investigating different machine-implement combinations, i.e., self-propelled machinery or narrow tractor coupled to implements. The tests were repeated periodically along the entire growing season, approximately every 6–8 weeks (end of May, end of July and first decade of October). A single test included at least 50 sample measurements, recorded randomly along each inter-row investigated. In the surveyed field, the inter-rows were alternatively covered with grass, or tilled in the top layer during the previous wintertime. Two experimental test sets were developed: the first involved the use of two implements (a sprayer and a grape harvester) towed by narrow tractors, while in the second the pesticide distribution and the harvesting were performed with a properly equipped self-propelled tool carrier. All the other farming operations were executed using the same implements in both cases. Balanced use of the self-propelled tool carrier and the traditional tractor-implement combination allows a better distribution of the soil compaction (in particular in the top-soil), thus improving the root-growing efficiency.

Design and Evaluation of the Key Units in a Rapeseed Direct Seeder Integrated with Plowing-Rotating Combined Tillage

HighlightsThe seeder combined the plowing and rotating tillage to overcome the heavy soil and a large amount of straws.The plow could lift and turn the soil and straw before rotary tillage.The optimal working parameters of the seeder were obtained by orthogonal field experiments.Abstract. Rapeseed, one of the most important oil crops in China, is mainly planted in the mid-lower reaches of the Yangtze River. However, limited by the special long-term rice-rapeseed rotation, rotary tillage is applied in most of the planted areas apply instead of plow tillage, leading to a shallow arable layer. On the other hand, maintaining a high-quality seedbed for rapeseed becomes a challenge because a large amount of straw remains buried in the soil. As a solution, a rapeseed direct seeder that combines plow tillage and rotary tillage was designed. The structure of the plowing unit, whose key components were a lifting-turning plow and symmetrical plow, was analyzed based on the forming principle of the plow. Furthermore, a mechanical soil throwing model of the rotary tillage blade was built to determine the structural parameters. Then, the interaction between the rotary tillage unit and the lift-turning plow was analyzed. Finally, the performance and optimal parameters were evaluated by orthogonal field experiments. The seedbed after the operations indicated that the seeder could achieve the function of turning the soil and straw first and then rotating the soil with good passability, mixing the straw and the soil, flattening the surface of the seed bed, and stabilizing the tillage depth. Orthogonal experiments showed that the optimal working parameters of the seeder were as follows: the tillage depth was 180 mm, the equipment forward speed was 2.1 km/h, and the speed of the rotary tillage blade was 250 r/min. Under the optimal parameter combination, the power consumption of the seeder, the thickness of the tillage layer, the crop residue burial efficiency, the soil breakage efficiency, and the flatness of the seed bed surface were 30.48 kW, 231 mm, 90.88%, 93.26%, and 21.15 mm, respectively. The working performance of the seeder could meet the tillage requirements of rapeseed planting. Keywords: Direct seeder, Evaluation, Plow, Plowing-rotating combined tillage, Rapeseed.