Sulphur (S) is an essential plant nutrient. S deficiency slows down the formation of all amino acids which are required for optimal plant growth and final maximum crop yield. Recent research has shown that many agricultural soils worldwide are increasingly suffering (S) nutrient deficiency for crop production. Various types of granular fertilisers containing elemental sulphur (ES) with or without ammonium sulphate (AS) have been commercialised. Since plants cannot absorb ES directly, ES oxidation to SO4-S by soil microbes must occur to enable ES to provide plants available S. In this paper, the results of several literature reports from laboratory soil incubation studies with granular.
(ES±AS) products were extracted and reviewed critically. Granulation of micronised ES particles result in a locality effect on dispersion of ES particles after granule disintegration, limiting contact between ES surface and ES oxidising microbes in the soil. It is concluded that ES oxidation of these granular S fertilisers often is too slow or inadequate to provide initial available SO4-S. Therefore, granular ES products are generally inferior to SO4-S fertilisers for agronomic effectiveness.
Keywords: Granular elemental Sulphur, oxidation of elemental Sulphur, available Sulphur, Sulphur response
Low soil fertility due to monoculture cereal production systems and inadequate fertiliser application are some of the major causes for declining crop production in developing countries. Integrated use of organic and inorganic fertilisers is an option to alleviate soil fertility problem as it utilises available organic and inorganic nutrients for sustainable agricultural production and productivity. A field experiment was conducted in 2014 at Universiti Putra Malaysia to evaluate the effect of the integrated application of poultry manure and inorganic fertiliser on soil chemical properties and nutrient uptake of maize and soybean in maize-soybean intercropping. Treatments comprised combinations of three cropping systems (sole maize, sole soybean, and maize + soybean) and four fertilisation regimes (control, 100% NPK, 100% poultry manure (PM) and 50% NPK + 50% PM). The experiment was laid out in a randomised complete block design (RCBD) with three replications. Results showed that either growing soybean alone or as an intercrop with maize resulted in increased soil organic matter (OM) (P<0.05), total N (P<0.0001), soil available P (P<0.0001) and soil cation exchange capacity (CEC)(P<0.05). Intercropping maize with soybean significantly reduced N, P and K uptake of soybean (P<0.0001), but uptake of N, P and K by maize was not significantly (P>0.05) affected by intercropping. Application of 100% PM and integrated application of 50% NPK+50% PM gave significantly higher soil pH (P<0.001), soil OM (P<0.0001), soil total N(P<0.0001), soil available P (P<0.0001), soil exchangeable K (P<0.001) and soil CEC(P<0.0001) compared to control and 100% NPK. For both maize and soybeans, the highest uptake of N, P and K was observed from the integrated application of 50% NPK+50% PM (P<0.0001). It can be concluded that integrated application of organic and inorganic fertiliser is the best option to improve soil chemical properties and nutrient uptake of maize and soybean.
Keywords: Intercropping, chemical fertiliser, NPK, poultry manure, soil chemical properties
There exist opportunities to increase rice production in Nigeria as currently rice production is low and consumption level is high. The floodplains of river Benue offer great potential for sustainable large scale rice production. Twenty-five thousand hectares of land bordering river Benue were selected to assess the fertility, texture and drainage status of the soil for rice production, and to suggest possible soil management practices for optimising rice production. Standard field sampling methodologies and soil laboratory procedures were employed. The soils of the area were found suitable for rice production but with certain identified constraints. Apart from the low soil nutrient status of the floodplain, which could be easily mediated with fertiliser application, the most critical limitation related to poor drainage and flooding. To avert this problem, it is recommended that a proper drainage network be designed and executed along with the construction of strategic embankments to prevent flooding of the river Benue.
Keywords: Food security, land evaluation, Nigeria, rice
Soil compaction alters the soil pore system, and may adversely affect the availability of water and air to plants and microorganisms. This study was conducted on a loamy soil to investigate water flow path using dye patterns. Five treatments were compared: control (no traffic), single, two, four and eight passages in three replications in the field. A dye tracer of Brilliant Blue FCF solution was uniformly added to each treatment for eight hours at a rate of 5 mm/h using a rain simulator. Flow paths were photographed with a digital camera. The images were processed by digital image analysis in order to analyse the spatial distribution of the stained area. Results indicated that induced compaction significantly altered the hydraulic properties of the soil. Highest impact was observed at 0-20 cm soil depth; no visible changes were observed in soil physical properties for subsoil. Results also showed that stained area as index of water infiltration was reduced by 77.5% in eight times passages treatment compared to control. Dye infiltration was uniform in control treatment while in the four and eight times tractor traffic treatments, dye infiltration was low on the surface and preferential flow of dye was observed in deeper parts of the profile.
Keywords: Dye tracer, image processing, rainfall simulator
We studied two groups of samples called “La Calera” and “Amotape,” in situ from the Peruvian districts of Alto Laran and Amotape, respectively. Different techniques were needed to characterise them. By using X-ray diffractometry, we determined their phases as well as corroborated the cation exchange process in some samples; however, in other samples there was a large interplanar spacing. Through transmission Mössbauer spectroscopy, we obtained the valence state of iron. Consequently, we determined that the samples contained calcium and sodium clays. Additionally, we proceeded to optimise the calcium clays by cation exchange to obtain sodium clays, which can be used in wastewater treatment and other applications.
Keywords: Cation exchange, montmorillonite, Mössbauer spectroscopy, transmission X-ray diffraction
Enzyme activity in oil palm rhizosphere could be used as a quality indicator of peatland. Roots play an important role in producing exudates of organic acids that are deposited in the rhizosphere. This research aims to study root exudates and enzyme activities in oil palm rhizosphere based on the distance from the tree trunk. The research was done in an oil palm plantation at Koto Gasib, Siak District, Riau Province, Indonesia (0.74°–0.77° N and 101.77°–101.74° E) using the explorative method. The observation of oil palm rhizospheres was done by dismantling the root zone of the selected oil palm tree trunk. Oil palm root was collected at distances of 0–1, 1–2, and 3–4 m from the tree trunk while the adhered peat samples were taken at the surface layer of 0–25 cm depth within a quarter circle area of the canopy. The results showed that enzyme activities in oil palm rhizosphere decreased with increasing distance from the tree trunk. This decrease is attributed to the increase in organic acid root exudates and water content and a decrease in soil pH. Thickness of peat did not influence enzyme activity and organic acid content. Enzyme activities in the rhizosphere of severely degraded forest and shrubs were lower than those in oil palm rhizosphere. The organic acid exudates in the rhizosphere of oil palm, forest and shrubs consisted mainly of aliphatic compounds. Fertiliser application at 1–2 m from oil palm trees decreased organic acid content in the exudates. Results from this study also showed that the large N uptake by plants mainly originated from fertiliser application. Thus, nutrient supply for oil palm growth originated from fertiliser application rather than from peat decomposition.
Keywords: Root exudates, rhizosphere, enzyme activities, oil palm, peatland
Land conversion of forest to non-forest has led to a reduction in soil fertility, exhibited by a lower soil quality index value (SQI) in the Sub-Watershed of Krueng Jreue. This research aimed to determine soil quality associated with various land uses using the SQI value approach. SQI calculated based on the criteria proposed by Mausbach & Seybold (1998), which is suitable for field conditions using analysis of Minimum Data Set (MDS). The parameters analyzed include rooting depth, soil texture, bulk density, total porosity, pH of the soil, C-organic, N-total, P-available, K-exchangeable and soil respiration. The result showed that the quality criteria of the soil consist of three classes: low, medium and high, which have soil quality index values of 0.27, 0.52, and 0.64 respectively. The area of research was mapped accordingly by class: (1) high, covering an area of 14016.98 ha (60.38%); (2) medium, covering an area of 8542,90 ha (36.79%); and (3) low, covering an area of 658,18 ha (2.83%). Types of land use categorized as having high quality are primary forest, secondary forest and residential area with respective values of 0.66; 0.64, and 0.63. Open land, grassland, moor, rice field and shrubs were of medium quality, with respective values of 0.47; 0.48; 0.52; 0.51 and 0.55.
Keywords: Soil quality, Soil quality index, Land use, Hydrological disaster mitigation, Sub-Watershed of Krueng Jreue
Natural zeolite has been widely used as an ion exchanger since the 1950s. The purpose of this study was to quantify the cation exchange capacity (CEC) of natural zeolite from different locations (Bayah and Cikembar in West Java, Indonesia) based on particle sizes of 0.15 and 0.079 mm, using different displacement solutions of 0.5M cesium chloride (CsCl) and 0.5 M potassium chloride (KCl). Higher CEC was observed in Cikembar100 compared to Bayah100 due to its higher surface area (31%) and total pore volume (11%) compared to Bayah100. Cikembar100 had 11% higher clinoptilolite mineral content compared to Bayah 100. The low CEC measured for Bayah100 and Bayah200 may be due to the lower percentage purity of the clinoptilolite mineral content in those samples. The natural zeolite samples displaced with 0.5M CsCl had 6% higher CEC compared to 0.5M KCl, which means that Cs+ had more strength compared to K+ in displacing NH4+ into the solution from the nanocavity site of the zeolitic framework into the solution. In both displacement solutions (0.5M CsCl and KCl), Cikembar100 had 10% more net negative charge compared to Bayah100 due to its isomorphous substitution properties in natural zeolite. Isomorphous substitution in natural zeolite affects its negative charge and the capacity to retain NH4+ in the zeolitic framework, thus increasing its CEC and making natural zeolite with the particle size of 0.079 mm (Cikembar100) a promising material for cation removal, particularly Cs from aqueous solution.
Keywords: Natural zeolite, Clinoptilolite, cesium chloride, potassium chloride, isomorphous substitution
This study was conducted to understand the effects of fertiliser type (straights, compounds and controlled-release fertilisers) on N, P, K and Mg losses by surface runoff. The study was conducted in a mature oil palm field using three 20 m by 6 m erosion plots containing two palms per plot with the soil type being Typic Kandiudults and slopes ranging from 5.5° to 7.5°. Nutrient losses were measured in the eroded sediment and runoff water for every rainfall event over a period of 24 months. Nutrient losses were higher in the runoff water than in the eroded sediments. Broadcast application of controlled-release fertilisers and its slow dissolving nature made it prone to washing down the slope. Hence, higher nutrient losses were observed in the controlled-release fertilisers compared to other treatments. Compound fertilisers showed lower total losses for N (4.96%), K (3.95%) and Mg (0.65%) compared to straight fertilisers. Lower P losses were observed in the straights compared to the compound fertilisers due to higher percentage of soluble P in the compound fertilisers. Controlled- release fertilisers recorded high nutrient losses in the sediments caused by the washout Except for nitrogen, controlled-release fertilisers recorded higher losses for P (56.56%), K (19.83%) and Mg (10.36%) compared to straight fertilisers. Nitrogen losses were 18.15% lower in the controlled-release fertilisers compared to straights. Compound fertilisers showed lowest losses for N and K compared to straight fertilisers. Based on the data, it is postulated that compound fertilisers can lead to better nutrient uptake compared to straight fertilisers. However, this hypothesis needs to be tested through field experiments measuring nutrient uptake and its effect on oil palm productivity.
Keywords: Nutrient loss, surface runoff, oil palm, fertilisers, erosion