Sains Tanah - Journal of Soil Science and Agroclimatology
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Mycorrhizae and a soil ameliorant on improving the characteristics of sandy soil
Get PDFAgricultural constraints on sandy soil are poor chemical characteristics and low biological activity resulting in the soil becoming less productive to be planted. One of the efforts to improve the quality of sandy soil are application of mycorrhizae and a soil ameliorant. The purpose of this study was to determine the effect of mycorrhizae and a soil ameliorant on soil chemical characteristics and soil biological activity. The experiment was arranged using a Complete Randomized Design that had two factors. The first factor (1) was mycorrhizae dose, without mycorrhizae (M0) and six spores of mycorrhizae/plant (M1), and the second factor (2) was types of soil ameliorant, without ameliorant (S0), cow dung (S1), rock phosphate (S2), biochar (S3), cow dung–rock phosphate (S4), cow dung–biochar (S5), and rock phosphate–biochar (S6). The results indicated that combination of six spores mycorrhizae/plant–cow dung 60 tons ha−1–biochar 25 tons ha−1 (M1S5) increased soil organic carbon (SOC) (235%), available P (675%), cation exchange capacity (CEC) (216%), total glomalin (101%), and easily extracted glomalin (69%), decreased exchangeable sodium percentage (66%), and increased absolutely for root infection and spore density than without mycorrhizae and a soil ameliorant (control). The lowest of SOC in non-mycorrhizae and rock phosphate, available P, CEC, root infection, spore density were found on the control, but the lowest of total glomalin and easily extracted glomalin were found on non-mycorrhizae–rock phosphate. The application of mycorrhizae, cow dung, and biochar improved the sandy soil characteristics
Intercalation and calcination as methods to reduce expansive soil properties
Get PDFThe expansive ability of soil causes a series of problems in various sectors. The dominance of smectite clay minerals significantly affects expansive ability because they have an unstable interlayer structure. Cation intercalation and calcination is a treatment method that can increase the stability of the clay interlayer structure. This research investigated the effects of intercalation cations and calcination treatment on the swelling ability and cracking properties in the clay from vertisols; the cations used for intercalation were aluminum and iron. The intercalation tested doses were based on the equivalent weight of 0x, 0.5x, and 1x cation exchange capacity (CEC) clay value. The calcination treatments used were 200°C, 300°C, and no calcination. Each treatment interaction was repeated three times. Parameters observed were the total area, average crack width, average lump area, total number of lumps, moisture content, swelling volume, and pH after treatment. The results showed that each treatment had a significant effect. Clay with an Al intercalation dose of 1x CEC without calcination treatment had the highest total area after drying, which was 41.035 cm2; the lowest average crack width was 0.153 cm, and the smallest swelling volume was 3.6 cm3. In contrast, the clay without intercalation and calcination treatments had a swelling volume up to 10 cm3 on the 7th day. The clay with an Al intercalation dose of 1x CEC with 200°C calcination exhibited the best results in reducing the expansive clay ability and can be used as a guideline for further testing to reduce the soil’s expansive ability
Sustainability performance of organic farming at vegetable fields in Tabanan, Bali, Indonesia
Get PDFSustainable agriculture aims to maintain high productivity while maintaining soil quality. The purpose of this study is to determine the sustainability performance of organic vegetable farming systems with soil quality indicators as a soil quality assessment tool. Soil physical, chemical, and biological properties in Chinese cabbage in Baturiti Subdistrict, Tabanan Regency, Bali, Indonesia, were evaluated as indicators for predicting organic cabbage production and yield. Soil samples were obtained from organic farming systems that have been going on for 1, 3, and 5 years after certification, compared with conventional farming systems. The results showed that the soil quality of the organic farming system after 5 years (OF5) was significantly higher than the conventional farming system. Physically, soil moisture at the field capacity in OF5 was significantly higher than that in the other systems. Chemically, the organic C and cation exchange capacity in organic systems were significantly higher than in conventional systems. The same results were shown by soil respiration, which means that there was high soil microbial activity. Based on the cumulative soil quality rating, it is concluded that the OF5 system met the sustainability criteria, with no high input required
Carbon dioxide emission and peat hydrophobicity in tidal peatlands
Get PDFPeatland describes the typology of tidal and freshwater swamplands. Peatlands are affected by tidal activity; the water level fluctuation causes the peat to dry out and then get wet, which affects the soil’s water content and carbon emissions. Additionally, mineral enrichment from river overflows affects soil fertility and peat stability. Peat stability is importantly related to the peatland management for agriculture. Functional groups in the peat, such as carboxyl and hydroxyl, are volatile and easily transform, decomposing from CHO bonds into CO2 under aerobic conditions. The characteristics of functional groups can be changed from polar to non-polar at the organic colloid surface, leading to hydrophobicity. This study evaluated carbon dioxide emissions and peat hydrophobicity. The research was conducted by survey and field sampling on two differently managed plots of peatlands: a rubber-and-pineapple intercrop plot and a traditionally-managed rubber plot. Parameters measured were CO2 flux, groundwater levels, water content, and peat hydrophobicity. Peat hydrophobicity was assessed by analyzing certain functional groups using a Fourier-Transform Infrared (FTIR) spectrophotometer. The results showed that CO2 emissions were 21.78 ± 5.44 (mg ha-1yr-1) for the rubber-and-pineapple intercrop and 19.15 ± 5.18 (mg ha-1 yr-1) for the traditionally-managed rubber plot. Peat hydrophobicity for both plots decreased with increasing soil depth, indicating that peat on the surface layer (0–50 cm) is more vulnerable to drought and fires, especially if there is no water management
The kinetics curve of nitrogen mineralization from perennial leaves litter decomposed by earthworm (Phretima californica)
Get PDFThe kinetics of N release during the process of decomposition of organic matter is influenced by organic matter quality, temperature, humidity, and decomposer. Acacia, coffee, salacca, and bamboo leaf litter are native plants and be the pioneer plants on the slopes of Mount Merapi after the eruption in 2010. However, there is a lack of information on the N mineralization process from the leaves litter of acacia, coffee, salacca, and bamboo. The study aimed to determine the kinetics of N release from the litter leaves of acacia (Acacia decurrens), coffee, salacca, and bamboo, which were tested with three approaches, namely zero order, first order, and second order. The experiment was carried out using 10 Phretima californica earthworms that were incubated with 35g of annual plant leaves at 25°C. The levels of NH4+ and NO3- were measured at 0, 7, 15, 30, 45, 75, and 105 days after incubation by using the indophenol blue and derivative spectrophotometric method, respectively. Throughout the decomposition 105 days, the release of NO3- was higher than that of NH4+ due to the nature of NH4+ that was more easily immobilized than NO3-. The highest NO3- release in acacia litter (1.56 mg kg-1) occurred 30 days after incubation, while in coffee, salacca, and bamboo occurred 105 days after incubation, reaching 1.92 mg kg-1, 2.47 mg kg-1, and 1.88 mg kg-1, respectively. High N compound on the leaves litter unaffected to increasing total biomass earthworms in the end of incubation however promotes N mineralization rapidly. The kinetics of the second-order equation showed higher compatibility than the other equations to the N release with coefficient determination was higher. The kinetics of mineralization can be a strategy to use the leaves litter of perennial plants as sources of N nutrient input into soil
Controls on the net dissolved organic carbon production in tropical peat
Get PDFSoil factors such as pH and the presence of polyvalent cations can influence the net production of dissolved organic carbon (DOC). This study aimed to determine the main factors that control net DOC production. The study was conducted at Buatan Village, Siak Indrapura Regency, Riau Province, Indonesia. Soil and water sampling were done every month for a year observation, from July 2018 to June 2019. Soil sampling was carried out to determine the concentration of C-organic acids, pH, N, P, K, Cu, and soil water content (SWC). Peat water sampling was carried out using modified pore water sampling to measure DOC concentration. Groundwater level (GWL) and soil temperature were also observed. Multiple regression analysis was performed to find out the soil and environmental factors controlling the net DOC production. The results showed that the net DOC production fluctuated with seasonal changes and soil pH was a significant controlling factor (P = 0.035) and positively correlated (P = 0.040) to the net DOC production. In addition, N-mineral, PO4, and Cu were positively correlated with net DOC production (P-value: 0.026; 0.033; and 0.028; respectively) while C-organic acids and SWC were negatively correlated (P-value: 0.033; and 0.020; respectively). There was no correlation between net DOC production with GWL, soil temperature, and K concentration. This finding confirmed that pH was the main factor controlling the net DOC production and reflects DOC contribution to the solution acidity
Methane flux from high-yielding Inpari rice varieties in Central Java, Indonesia
Get PDFRice cultivation is a source of greenhouse gas emissions, particularly methane (CH4). One of the factors that affect CH4 emissions from rice fields is rice cultivar. In this study, a field experiment was conducted to determine CH4 emissions from various high-yielding inbred varieties and the relationship between CH4 emissions and rice growth parameters. The field experiment was conducted in Jaken, Pati Regency, Central Java province, during the wet season of 2014/2015. The experiment was arranged using a randomized block design with three replications and several cultivar treatments (Inpari 13, 18, 19, 20, 23, 24, 29, 30, 31, 32, and 33, with Ciherang as the comparison cultivar). The data collected includes CH4 flux, plant height, tiller number, biomass, grain yield, and root aerenchyma area. The CH4 flux was measured at several critical growth stages. The Inpari 24, Inpari 13, and Inpari 19 demonstrated CH4 emissions reduced by as much as 36.1%, 32.8%, and 21.3%, respectively, compared to Ciherang. The Inpari 13 and Inpari 24 varieties had significantly lower emission indices than Ciherang and the other Inpari varieties, with 17 and 20 g CH4 per 1 kg grain yield, respectively. CH4 flux was found to correlate significantly with tiller number per hill, total biomass, and root aerenchyma area at the panicle initiation growth stage
Phosphorus availability as affected by the application of organic amendments in Ultisols
Get PDFThe adequacy and availability of phosphorous (P) in the soil during the organic matter decomposition are important for plant growth, especially in the early stages since most organic matter slowly release plant nutrients. Therefore, this study was conducted to determine the availability of P during organic amendments in Ultisols. The incubation experiment used a completely Randomized Design (CRD) for 7 treatments which consisted of vermicompost, chicken, and cattle manure at the rate of 15 and 30 Mg ha-1. Soil and organic amendments were incorporated into a 5 kg polybag and the mixture was incubated for 7 weeks. The soil was sampled at the 2, 3, 4, 5, 6, and 7 weeks, and analyzed for P availability and pH. Also, the Total Soil Organic Carbon (TSOC), Total Soil Nitrogen (TSN), exchangeable Al, and Cation Exchange Capacity (CEC) were analyzed from the soil sampled either at week 4 or 7. The result showed that P increased slowly in the first 3 weeks of incubation, followed by a drastic continuous increase in week 4. The experiment also confirmed that chicken manure released the highest and fastest amount of P to the soil as compared to vermicompost, and cattle manure. On average, the increment of P was 2.28, 1.71, and 1.97 mg kg-1 week-1 for chicken manure, vermicompost, and cattle manure respectively. Furthermore, the improvement of soil chemical properties was achieved using amendment as indicated by the increase in TSN, soil pH, and a decrease in exchangeable Al. The result was significant for P organic fertilization to ensure its availability for plant growth, leading to improved productivity, especially in organic farming systems
Characteristics of Ultisols derived from basaltic andesite materials and their association with old volcanic landforms in Indonesia
Get PDFThe common problem with Ultisols is their low pH and soil fertility, with liming and fertilization being common solutions to overcome this problem; however, studies on Ultisol soil parent materials are still rare. This study aimed to examine the characteristics of Ultisols derived from andesite and basaltic andesite parent materials. In 2016–2017, five Ultisol pedons (P8, P9, P10, P11, and P15) were sampled from basaltic andesites and other associations. The five pedons consisted of 19 soil samples. The chemical and mineralogical properties of the soils were analyzed. It was found that the color of the basaltic andesite Ultisols varied from hue of 2.5 YR to 10 YR, with value of 3–5 and chroma of 2–8. The Ultisols derived from andesite/diorite (P8) were dominated by rock fragments (52–77%), while those derived from andesitic breccia (P9) were dominated by opaques (62–67%), those from basaltic andesite tuff/lava by weathering minerals (44–52%) and hydragilite (28–34%), those from basaltic andesite (P11) by quartz (48%) and (P15) by opaques (79–89%). The mineral reserves varied from very low (0–4%) in pedons P8, P9, P11, and P15 to very high (> 40%) in pedon P10. The results of this study are expected to be used as a guide for future agricultural development on Ultisols
Agriculture versus climate change – A narrow staple-based rural livelihood of Papua New Guinea is a threat to survival under climate change
Get PDFThis paper presents a synthesis related to the assessment of climate change and its impacts on productivity of staple crops in Papua New Guinea (PNG), paying close attention to the change in population in the next 80 years. As much as the changes in the climatic and environmental factors will affect agriculture, evidence available in the literature show increase in global and local population will put additional pressure on agriculture by competing with available land and other resources that support agricultural productivity. The developing and underdeveloped countries are considered to be largely vulnerable as more than 85% of the people depend on subsistence agriculture for rural livelihood. This synthesis showed more than 60–85% of the rural people in PNG depend on sweet potato, banana, Colocasia taro, and greater yam. Projection of the population showed there will be 22–31 million people by 2100 and will depend on narrow staple-based subsistence agriculture. The population projected means the density will be 42 people per km2, putting more pressure on limited land available. When that happens, PNG will not be prepared to mitigate, be resilient and adapt because of poor infrastructure, no development plans and lack of post-harvest technologies for loss management of the staples, most of which are root and tuber crops