Use Of Marginal Soils Research Articles

Screening of Salt-Tolerant Thinopyrum ponticum Under Two Coastal Region Salinity Stress Levels.

To accelerate the exploitation and use of marginal soils and develop salt-tolerant forage germplasm suitable for the coastal regions of China, seven lines of decaploid tall wheatgrass [Thinopyrum ponticum (Podp.) Barkworth and D. R. Dewey, 2n = 10x = 70] were transplanted under low (.3%) and high (.5%) salt conditions for a comprehensive analysis at the adult-plant stage. Differences were observed among these materials, especially in terms of grass yield, agronomic characteristics, and physiological and biochemical indices. Line C2 grew best with the highest shoot total fresh and dry weights under all conditions except for the milk-ripe stage in Dongying in 2019. The total membership value of C2 also reflected its excellent performance after transplanting. As superior germplasm, its relatively high antioxidant enzyme activities and chlorophyll a/b ratio suggested C2 may maintain normal metabolic and physiological functions under saline conditions. Furthermore, decaploid tall wheatgrass as a forage grass species has a high nutritive value beneficial for animal husbandry. Accordingly, line C2 may be used as excellent germplasm to develop salt-tolerant cultivars in the Circum-Bohai sea.

Switchgrass as an alternative biomass for ethanol production in a biorefinery: Perspectives on technology, economics and environmental sustainability

The production of biofuels from lignocellulosic biomass is not economically viable unless it is co-produced with other marketable high value bio-based compounds using a biorefinery strategy. Advanced cellulosic biofuels derived from agricultural and forestry residues, non-food/feed energy crops or organic waste, could overcome concerns associated with conventional biofuels (impact on food prices, use of land for agricultural and forest products) and achieve large greenhouse gases emissions savings. The main obstacles to the use of advanced biofuels are availability and price of feedstocks, efficiency in conversion, reliability of the technology involved, stability of national polices, level of subsidy and mixing requirements. Switchgrass is a dedicated lignocellulosic energy crop that has great potential for bioethanol production due to its ease of adaptation to the soil in different geographical regions (use of marginal soils), its high yields, poor soil erosion, low incidence of pests and diseases, and low water and nutrient requirements. This review discusses several switchgrass-to-ethanol conversion pathways, considering different aspects of the feedstock, research on the cultivar, yield, and characteristics that have driven research to develop the perennial crop for biofuel. A comprehensive gathering of literature on alternative pretreatment methods, fermentation processes and microorganisms, co-products synthesized when fractionating multiple sugars, and biorefinery economics are presented. Meta-data about pretreatment and fermentation experimental work and how these studies have informed techno-economic analysis of bio-ethanol conversion are reported. Environmental life cycle assessment studies and to a lesser extent, socio-economic and social aspects of biofuels and dedicated energy crops like switchgrass are also reviewed.

Influence of coir fiber reinforcement on shear strength parameters of cement modified marginal soil mixed with fly ash

In the context of paucity for suitable granular soils at various work sites, it has become inevitable for the use of marginal soils (low quality soils) and has been being used for different types of constructions. With the advent of reinforcing soil, a wide variety of materials such as geosynthetics are used for reinforcement. Apart from geosynthetics, coir fiber is also been used for soil strength improvement for their engineering practice. Coir fiber is randomly distributed in soil mass for the purpose of reinforcement. Fly ash has been used at several work sites due to its abundant availability as a waste material. The effective use of Fly ash has an advantage over saving and preserving natural resources, leading in the reduction in cost of the project. Apart from various other techniques of soil modification such as chemical stabilization, lime stabilization etc; the cement modification has got prominence. In the present study, the marginal soil is treated with 3% cement that could able to make it non–plastic. An attempt was made to investigate the effectiveness of coir fiber as reinforcement for locally available cement modified marginal soil and mixed with Fly ash. The intention of the work is to study the effectiveness of coir fiber as a randomly distributed reinforcement on shear strength and strength characteristics of cement modified marginal soil mixed with Fly ash. A series of laboratory tests such as direct shear and unconfined compressive strength tests were conducted using marginal soil. The shear strength of this marginal soil reinforced with 2% coir and mixed with 10% Fly ash was 1.5 to 2 times the shear strength of plain marginal soil. Hence, the experimental study provides an approximate solution for enhancement of shear strength of marginal soil, that marginal soil could be used in construction of reinforced soil structures.

Farmer Mentoring in Determining Fertilization Dosage of Corn Plants (Zea Mays L.) Using Soil Test Equipment

Amirrullah J, Hutapea Y, Ratmini NPS, Prabowo A. 2020. Farmer mentoring in determining fertilization dosage of corn plants (Zea mays L.) using soil test equipment. Jurnal Lahan Suboptimal: Journal of Suboptimal Lands 9(1): 102-108.Balanced fertilization is very important to do in marginal soils. The constraints in the use of marginal soils are physical, chemical and biological soil characteristics which do not support planting growth. Determination of fertilizer dosage for corn commodity in one region can be different depending on the available nutrient content that testing needs to be carried out. This study aimed to mentor farmers in taking appropriate soil samples and determined fertilizer doses according to location specifications and application of fertilizers on target using the Dry Soil Test Kit (Perangkat Uji Tanah Kering). This activity was carried out in Fajar Jaya Village, Ogan Komering Ulu District in February 2019. The results of the soil analysis of the location used as a demonstration plot derived from the results of low soil fertility analysis with soil acidity at pH 4-5 with acid crystals, moderate P, K and C-organic nutrients were relatively low. The recommended fertilizer is as follows: urea 325 kg/ha given 3 times, one-third the dose, carried out 1 MST, 4 MST and 6 MST; TSP 200 kg/ha; KCl 125 kg/ha; 5,000 kg/ha of compost and 1,000 kg/ha of lime stocked during tillage 1 week before planting. Fertilization application method applied by farmers is not in accordance with the recommendations; consequently, it is necessary to fertilize to increase nutrient content.

Utilization and Improvement of Marginal Soils for Agricultural Development in Indonesia

Indonesia is a humid tropical country that has very intensive weathering of soils resulting acidic soils such as Oxisols and Ultisols. In swampy ecosystems, organic matters accumulated become peat soils or Histosols. Reclamation of shallow peat for agricultural land will induce the forming of acid sulfate soils (Sulfaquept and Sulfaquent). Due to low fertility soils, the three of above soils are classified as marginal soils and now they are used for agricultural activities and some of them are still in forests. The use of marginal soils should refer to land suitability whether it is retained as a forest or used as agricultural land. The development of agricultural commodities on marginal soils must consider soil characteristics and agro-climate conditions. Oxisols and Ultisols have characteristics of low pH, low organic C, low macro and micro nutrients. In areas where rainfall is higher than 2,000 mm/year and evenly distributed throughout the year, oil palm plantations can be well developed. Meanwhile in the rainfall between 1,750-2,000 mm/year, rubber, cacao, coffee plants can be cultivated. Agricultural development in acidic soils need to be followed by the addition of soil amendments such as organic materials, humic substances, lime, fly ash, steel slag as well as fertilizers. Acid sulfate soils have a pH value of around 3 due to pyrite oxidation and usually low macro and micro nutrient content. Acacia mangium plants as raw material for pulp and oil palm plantation can grow quite well if followed by application of fertilizers and appropriate soil amendments. Peat soils are very fragile ecosystem so that in the upstream area and peat dome, they must be retained as forests. Peat can be developed for Acacia crassicarpa, oil palm, and rubber plants with good water and fertilizer management. Thin peat underneath mineral soil from river sediments can be developed rice field.

Study of vertical water flows contribution to the crop water consumption in suka kollus using a mixed drainage system

The suka kollus, considered among the most important hydraulic structures of ancestral Andean technology, are used as a technique for crop production in flood-prone soils, enabling subsurface irrigation of crops by means of drainage channels. They also generate a thermoregulatory effect depending on the channel/ridge ratio and the total size of the infrastructure. They could be a valuable way of making use of marginal soils if some of the drainage channels are replaced by underground drains to increase the area of cultivation. This work was therefore undertaken to study the flow of water under a “mixed” drainage system (surface and subsurface drainage) adapted to the suka kollus system.The work was carried out in marginals in the Kallutaca area, La Paz, Bolivia. The potato cultivar ‘Imilla negra’ (Solanum tuberosum ssp. andigena) was used in four treatments with different platform widths: T1 (control), the traditional system in which all drainage was via open channels; and T2, T3 and T4, where one, two and three channels were, respectively, replaced by drains. The study describes the comparison between T1 treatment, with open drains at a depth of 1 m and platform width of 6.5 m (T1) with the other treatments, i.e. subsurface pipe drains at a depth of 1.2 m and a platform widths of respectively 12 m (T2, where one channel was replaced by a drain), 18 m (T3, where two channels were replaced by drains) and 25 m (T4, where three channels were replaced by drains)The results showed that the distance of 6.5 m between drainage channels, commonly used in traditional suka kollus, was less than the calculated distances. As such, it was possible to expand the area of the platforms by setting the drainage channels between 10 and 14 m apart. Crops yield in the T2 and T3 treatments (10.67–11.35 Mg/ha, respectively) are significantly higher compared to the traditional open drainage system, T1 (8.33 Mg/ha) and the wider platform width of 25 m, T4 (7.3 Mg/ha) due to the higher height of plants and the greater number of tubers per plant, compared to the control. Likewise, the high clay percentage of the second stratum of the T3 treatment could be beneficial in terms of greater retention of water at the root level, mainly for periods of water deficit. The crop water requirements were covered by the upward flows from the water table and by precipitation, demonstrating that the suka kollus system is sustainable under current climatic conditions.

Effect of Geocomposite Layers on Slope Stability Under Rainfall Condition

Slope instability and associated loss of matric suction under rainfall condition is a serious global issue, and deserves special attention. The objective of the present paper is to investigate the effect of inclusion of a special variety of geosynthetic material, referred to as geocomposite (or dual-function hybrid geosynthetic) within slopes subjected to rainfall. In this regard, centrifuge based physical modelling was performed on a model silty-sand slope having 7.2 m height (prototype scale) and 2V:1H inclination at 30 gravities using the 4.5 m radius centrifuge facility available at IIT Bombay, India. A rainfall simulating assembly was designed and developed for the above study, capable of producing fine mist at a uniform rate during in-flight testing using specially designed pneumatic nozzles (intensity range: 2 mm/h to as high as 80 mm/h). The surface settlements, displacement profile, strain experienced by reinforcement layers, and pore water pressure profiles developed during rainfall were investigated in the unreinforced and reinforced slope models. It was observed that, the unreinforced slope model experienced excessive settlement and increasing phreatic levels with rainfall, leading to catastrophic failure. On the contrary, the geocomposite reinforced slope was stable under rainfall condition, and experienced negligible deformation with progress of rainfall, the maximum peak strain value being as low as 8.01%. Further, the inclusion of geocomposite layers provided preferential drainage channels within the slope, and resulted in reduction of pore water pressure values by almost 47%, thereby indicating the importance of coupling the functions of reinforcement and drainage simultaneously within low-permeability slopes subjected to rainfall. The above finding facilitates the use of locally available low-permeable soils in construction of reinforced soil walls/slopes, thereby economizing the project. Further, use of marginal soils in combination with geocomposites (or hybrid geosynthetics) can prevent the unsustainable mining of natural sand deposits for construction purposes, while catering to the problem of scarcity of good quality permeable granular materials in recent times.

Soil nutritional survey for soybean production in Uruguay

The recent changes in the agriculture in Uruguay, by the adoption of no-tillage planting systems, have included the use of marginal soils for crop production, being the soybean the main crop that allowed those changes. Several questions have arisen about the sustainability of the intensive soil use of these new production systems. The objective of this work was to detect situations with greater probability of nutrient defi ciencies, using soybean as indicator crop. During crop seasons 2009/10 and 2010/11 a nutritional soil survey of soybean crops was conducted, collecting soil and leaf samples of 178 commercial fi elds widely distributed around the country, at the R1-R2 soybean growth stage. In half of the sites soybean was the main crop, and in the other half soybean was planted following winter crops. Soybean yield ranged from 511 to 5435 kg ha-1. In 34% of the fi elds pH was below 5.3, even in the traditional agricultural zone. In 54% of fi elds available P was below 12 mg kg-1 of P Bray-1, and 23% of the cases were below 0.30 cmolc kg-1 of exchangeable K. The concentrations of macronutrients in leaves for all the samples were: 3.88 (±0.66) % N; 0.26 (± 0.08) % P; 2.03 (±0.53) % K; 1.14 (±0.23) % Ca; 0.36 (±0.10) % Mg; and 0.29 (±0.07) % S. The micronutrient concentration means were 9, 77, 61, and 30 mg kg-1 of Cu, Fe, Mn, and Zn, respectively. The more frequently defi cient nutrients were P, K, and N, with 42, 39, and 13% of the fi elds with concentrations in leaves below the critical concentrations. The results show that the actual soybean productivity could be partially affected by nutrient defi ciencies, suggesting that soil pH, and P or K corrections need to be considered in the nutritional management program for each crop production system.

Agronomic and Taxonomic Consequences of Agricultural Use of Marginal Soils in Argentina

Expansion of the agricultural frontier over marginal soils leaves a significant environmental imprint on the southern semiarid region of the Argentina pampas. A chronosequence of anthropogenic soils in a cultivated area was investigated to determine the role of human actions on the development of a highly compacted horizon below the plow layer observed during a detailed soil survey in Villarino County. A model area of 300 ha (6 × 0.5 km) representative of the county soilscapes was used to (i) characterize the main physical, chemical, and morphological features of the soils in the chronosequence, and (ii) discuss taxonomical issues that can be improved on to facilitate information transfer. Based on our observations, we propose a new diagnostic feature to classify these soils according to USDA Soil Taxonomy guidelines placed at a taxonomical level above series. Our investigation confirmed that soil morphology is modified within 27 yr of cultivation. Tillage leads to the development of a noncemented plowpan immediately below the Ap, here called ACd, with distinctive morphological features. The ACd is compact and massive with extremely hard rupture resistance when dried. Cultivation-induced alterations were considered important enough to classify the soils into unique soil series. Given the widespread environmental and financial costs and implications of soil compaction, and the genetic connotations of the plowpan, we propose the densipan as a diagnostic horizon and a new class densic to be use at the family level. Advantages of its use will lead to increased utility and precision in published soil maps and improved communication and understanding among stakeholders.

Numerical analysis of reinforced soil walls with granular and cohesive backfills under cyclic loads

Novel approaches to the dynamic analysis of the reinforced soil walls have been reported in the literature. Use of marginal soils reduces the cost of geosynthetic reinforced soil walls if proper drainage measures are taken. Therefore the affect of using cohesive marginal soils as backfill in geosynthetic reinforced retaining structures were investigated in this research. The dynamic response of reinforced soil walls was investigated in a similar focus, using finite element analysis. The results obtained from walls with cohesive backfill were compared to the results obtained from walls with granular backfill. The height of the wall was chosen as 6 m in the two-dimensional plane strain finite element model and the base acceleration was chosen to be a harmonic motion. The effects of various parameters like the backfill type, facing type, reinforcement stiffness, and peak ground acceleration on the cyclic response of reinforced soil retaining walls were investigated. After analyzing the wall response for end of construction and dynamic excitation phases, it was determined that the deformations and reinforcement tensile loads increased during the cyclic load application and that the amount of additional deformation that occurred during cyclic load application was strongly related to backfill soil type, facing type, reinforcement type and peak ground acceleration. It was determined that a cohesive backfill and geotextile reinforcement was a good combination to reduce the deformations of geosynthetic reinforced walls during cyclic loading for medium height walls.

The potential contribution of forage shrubs to economic returns and environmental management in Australian dryland agricultural systems

In face of climate change and other environmental challenges, one strategy for incremental improvement within existing farming systems is the inclusion of perennial forage shrubs. In Australian agricultural systems, this has the potential to deliver multiple benefits: increased whole-farm profitability and improved natural resource management. The profitability of shrubs was investigated using Model of an Integrated Dryland Agricultural System (MIDAS), a bio-economic model of a mixed crop/livestock farming system. The modelling indicated that including forage shrubs had the potential to increase farm profitability by an average of 24% for an optimal 10% of farm area used for shrubs under standard assumptions. The impact of shrubs on whole-farm profit accrues primarily through the provision of a predictable supply of ‘out-of-season’ feed, thereby reducing supplementary feed costs, and through deferment of use of other feed sources on the farm, allowing a higher stocking rate and improved animal production. The benefits for natural resource management and the environment include improved water use through summer-active, deep-rooted plants, and carbon storage. Forage shrubs also allow for the productive use of marginal soils. Finally, we discuss other, less obvious, benefits of shrubs such as potential benefits on livestock health. The principles revealed by the MIDAS modelling have wide application beyond the region, although these need to be adapted on farm and widely disseminated before potential contribution to Australian agriculture can be realized.

Comparison of Field and Laboratory Pullout Tests on Geosynthetics in Marginal Soils

The increasing use of geosynthetics to reinforce soils in many geo-technical engineering applications requires better evaluation of the soil-geosynthetic interface properties for use in the design and analysis of the different reinforced soil structures. The soil-geosynthetic interaction can be determined from direct shear tests or pullout tests. Until now, most research was focused on investigating the interface properties between geosynthetics and granular materials. Interest has increased in the use of marginal soils as backfill materials in mechanically stabilized earth (MSE) walls and embankments because of the cost-effectiveness of using the available cohesive soils. This strategy requires the evaluation of interaction parameters between geosynthetics and marginal soils. For this purpose, a series of laboratory and field pullout tests was carried out with different types of geosynthetic reinforcements in marginal silty clay soil of medium plasticity. Four types of geogrids and three types of geotext...

Comparison of Field and Laboratory Pullout Tests on Geosynthetics in Marginal Soils

The increasing use of geosynthetics to reinforce soils in many geotechnical engineering applications requires better evaluation of the soil–geosynthetic interface properties for use in the design and analysis of the different reinforced soil structures. The soil–geosynthetic interaction can be determined from direct shear tests or pullout tests. Until now, most research was focused on investigating the interface properties between geosynthetics and granular materials. Interest has increased in the use of marginal soils as backfill materials in mechanically stabilized earth (MSE) walls and embankments because of the cost-effectiveness of using the available cohesive soils. This strategy requires the evaluation of interaction parameters between geosynthetics and marginal soils. For this purpose, a series of laboratory and field pullout tests was carried out with different types of geosynthetic reinforcements in marginal silty clay soil of medium plasticity. Four types of geogrids and three types of geotextiles were used in this study. Laboratory and field pullout tests were compared. The coefficient of interaction ( Ci) between geosynthetics and cohesive backfill, the variation of pullout design parameters ( F*, α) with overburden depth, and the shear stress distribution along the reinforcement specimen also were evaluated.