Available Si In Soil Research Articles

Effect of Silicon based Fertilizer and Biochar from Crop Residues on Dry Matter Accumulation and Si Uptake by Rice Crop in Central Vietnam

Background: Silicon (Si) has been considered a beneficial element for many plants. Si-rich biochar (Sichars) from rice husk or peanut shell have been suggested to be a potential source of bioavailable Si for Si-accumulator plants. Our study aimed to assess the Si-fertilization efficiency from chemical fertilizer and rice husk and peanut shell biochars on rice dry matter and shoot Si uptake. Methods: Pot trials were conducted in two crop seasons in 2023 (from February to April - spring season and from May to July- summer season) in the close net house. Treatments included 1 treatment with pure soil (control), 4 treatments with Si and N–P–K fertilizers and 6 treatments with biochar amendments and N-P–K fertilizers. These pot experiments were designed in the randomized complete block (RCBD) with 4 replications. Result: Shoot dry matter increased from 35.6 to 66.7% compared with control in different rates of Si fertilizer application and was also found the highest values in RHB and PSB at 15 g/kg soil application. Different Si and biochar application rates had a significant effect (P less than 0.05) on Si uptake by rice shoot. Therefore, Si-rich biochar considers as potential material for providing available Si to maintain the required level of available Si in soil and plant for healthy and high crop production.

Evaluating the comparative effects of acid modified rice husk and nano-silicon derived from rice husk on phosphorus use efficiency in wheat and lettuce plants with differing silicon contents

The use of nanotechnology in agriculture has become an area of great interest for soil scientists. Therefore, it is important and necessary to investigate the effects of nanoparticles on plant growth and its nutritional interactions. The aim of this study was to investigate the effects of acid modified rice husk (MRH) and nano-Silicon (Si) derived from rice husk on the growth and phosphorus uptake and phosphorus use efficiency in Si accumulator wheat and non-accumulator lettuce plants. MRH and nano-Si were applied at 200 mg kg−1 and P was applied 100 mg kg−1 for wheat and 200 mg kg−1 for lettuce plants. The highest dry weight was obtained with the application of nano Si + P treatment; while both MRH and nano-Si had no significant effect over the applied 100 mg P kg−1. Phosphorus fertilization significantly reduced Si concentrations in both plants of wheat and lettuce. However, the decrease in Si concentration was partly compensated by nano-Si treatment. When P was applied together with nano-Si, its uptake and phosphorus use efficiency (PUE) significantly increased in wheat plants as compared to other treatments. Nano-Si derived from rice husk is a sustainable waste biomass and is an important alternative Si fertilizer source, which can be a valid strategy for the effective use of P fertilizers. The depletion of available Si in soil can be recovered by applying nano-Si as a fertilizer. The overall results obtained from the current research were promising.

Effect of organosilicone and mineral silicon fertilizers on chemical forms of cadmium and lead in soil and their accumulation in rice

Cadmium (Cd) and lead (Pb) pollution in soil and their accumulation in edible parts possess a worldwide eco-environmental and health risk, especially in developing countries. Recently, organosilicone fertilizer (OSiF) has been reported to reduce uptake of heavy metals, but the effectiveness has not been verified and its associated mechanisms are not fully understood. This work investigated whether and how OSiF and mineral silicon fertilizer (MSiF) affect mitigation of Cd and Pb stress in rice (Oryza sativa). Both soil incubation and pot experiments were conducted to assess the effect of OSiF and MSiF on bioavailability of Cd and Pb in soil and their accumulation in rice. Additionally, a hydroponic experiment was conducted to study whether Si in rice can alleviate Cd stress. We found that both Si fertilizers could increase soil pH, induce the transformation of the acid soluble and reducible fractions of Cd and Pb to the oxidizable and residual fractions in soil, decreasing their bioavailability and the uptake of Cd and Pb in rice. However, Si in OSiF was not phyto-available, but Si in MSiF was available since available Si in soil and Si in plant increased in MSiF treatments but not in OSiF treatments. Meanwhile, rice grain yields significantly increased and the Cd and Pb content of brown rice reduced in MSiF treatments but not in OSiF treatments. In addition, Si was found to be able to alleviate Cd stress by improving the antioxidant capacity of rice. These results suggested that the decreased Cd and Pb accumulation in OSiF-treated rice was due to Cd and Pb immobilization in soil simply with pH increase, but in MSiF-treated rice Cd and Pb immobilization in soil (ex planta effect) and Si-conferred inhibitory effect of root-to-shoot Cd and Pb transport (in planta effect) contribute to the lower accumulation in rice.

Geochemical methods for mapping available-Si distribution in soils in West Sumatra, Indonesia

Silicon (Si) is an important element for rice plant, and its availability in soil is an important factor affecting sustainable rice production. Herein, the distribution of available Si and its correlation with land-use type and soil-erosion status were investigated and discussed using the universal soil loss equation (USLE) in the Sumani watershed (SW). This watershed is the main rice-production area in Sumatra, Indonesia. Results showed that the available Si levels in sawah soil were less than 300 mg SiO2 kg−1 on average. Sawah means a leveled and bounded rice field with an inlet and an outlet for irrigation and drainage, respectively. Available Si content in river sediments was also studied and determined to be higher than those in sawah or other land-use types. This finding may indicate that available Si or soil rich in Si was redistributed through soil erosion. Soil-erosion rate was negatively correlated with the concentration of available Si in soils. Land-use types with smaller values of crop factor in USLE calculation and soil with lower pH showed relatively lower available Si in the soils. Overall, our findings indicated that soil erosion and land-use types affected the distribution of available Si in the watershed.

Identifying critical limit in soil and plant for determining response of rice (Oryza Sativa L.) to silicon application in periyar vaigai command area of Tamil Nadu, India

A survey was undertaken during 2018 to assess silicon (Si) status of soils and to determine its critical limits in soils and plants. A total of 100 surface soil samples (0–15 cm) were collected from 7 major rice growing soil series of Periyar Vaigai Command (PVC) area of Tamil Nadu, India based on their percent coverage. Plant available Si in soils was extracted by 1 M sodium acetate (pH 4.0) and varied from 4 to 250 mg kg−1. Based on the results of pot culture experiment, the critical limit of Si for grain and straw of rice (Oryza sataiva L.) variety ADT-45) determined was 0.49 and 2.53 percent respectively. Similarly the critical limit of soil Si established was 122 mg kg−1. Based on this critical limit, soils were classified into low (< 122 mg kg−1), medium (122 to 181 mg kg−1) and high (> 181 mg kg−1). Rice plants were highly responded to Si application in soils below the critical limit of 122 mg kg−1 whereas soils with Si above 181 mg kg−1 did not respond. Among the levels of Si, 225 mg kg−1 of Si was found to be the optimal dose in Si deficient soils to get higher rice grain yield.

Silicon (Si) use efficiency in sandy soil amended by Si-loaded hydrogel

ABSTRACTSilicon (Si) plays an essential role in the mineral nutrition of plants. This creates a need to improve tools can provide plant-available Si (PAS) and increase its use efficiency (UE), especially under sandy soil conditions. This study was conducted to estimate Si use efficiency (Si-UE) in sandy soil treated by a hydrogel (water-absorbing polymer) loaded by Si. A field experiment was carried out using a hydrogel (H, 0.7 g kg−1 soil) that was mixed with quartz silica (S, 98.4% SiO2) to give HS homogenous mixtures with three mixing ratios 1:0.5 (HS1), 1:1 (HS2) and 1:1.5 (HS3). The HS mixture was sprayed by potassium humate solution (K-humate, 0.5 mL g−1 hydrogel) to obtain HS1K, HS2K, and HS3K treatments. All treatments were mixed with soil subsurface before wheat (Triticum aestivumL.) cultivation. Results showed that wheat yield and seed yield (t ha−1) increased significantly by applied treatments compared to the control C in the range 9.52–23.80% and 2.59–30.60%, respectively. The HS3 treatment significantly increased the total nitrogen N (mg kg−1) in seeds by 34.99%, phosphorus P by 17.46%, and potassium K by 4.84%. Available Si in soil (mg kg−1) increased in the order HS1 < HS2 < HS3, and with K-humate in the order HS1K < HS2K < HS3K. Total Si (g kg−1) in wheat seeds increased significantly in the order HS1 < HS2 < HS3, and HS1K < HS2K < HS3K with K-humate. Silicon use efficiency may decrease as the rate of applied Si increases.

Combined Silicon-Phosphorus Fertilization Affects the Biomass and Phytolith Stock of Rice Plants.

Phytoliths are silica bodies formed in living plant tissues. Once deposited in soils through plant debris, they can readily dissolve and then increase the fluxes of silicon (Si) toward plants and/or watersheds. These fluxes enhance Si ecological services in agricultural and marine ecosystems through their impact on plant health and carbon fixation by diatoms, respectively. Fertilization increases crop biomass through the supply of plant nutrients, and thus may enhance Si accumulation in plant biomass. Si and phosphorus (P) fertilization enhance rice crop biomass, but their combined impact on Si accumulation in plants is poorly known. Here, we study the impact of combined Si-P fertilization on the production of phytoliths in rice plants. The combination of the respective supplies of 0.52 g Si kg–1 and 0.20 g P kg−1 generated the largest increase in plant shoot biomass (leaf, flag leaf, stem, and sheath), resulting in a 1.3-fold increase compared the control group. Applying combined Si-P fertilizer did not affect the content of organic carbon (OC) in phytoliths. However, it increased plant available Si in soil, plant phytolith content and its total stock (mg phytolith pot−1) in dry plant matter, leading to the increase of the total amount of OC within plants. In addition, P supply increased rice biomass and grain yield. Through these positive effects, combined Si-P fertilization may thus address agronomic (e.g., sustainable ecosystem development) and environmental (e.g., climate change) issues through the increase in crop yield and phytolith production as well as the promotion of Si ecological services and OC accumulation within phytoliths.

Effects of Silicon and Phosphatic Fertilization on Rice Yield and Soil Fertility

A pot experiment was conducted to investigate the effects of silicon and phosphatic fertilization on rice yield and soil fertility. Three levels of silicon (Si) fertilization i.e., SiO2: 45, 135, and 225 kg hm−2 and the two phosphatic fertilizer i.e., P2O5: 15 and 45 kg hm−2 for each of calcium superphosphate (CS) and combined calcium-magnesium phosphate (FCMP) (used as phosphatic fertilizer source) were applied to a rice cultivar “II you 128”. The treatment applied with P2O5 45 kg hm−2 CS and without Si fertilization was taken as control (CK). The grain yield was improved with increasing Si fertilizer application, whereas phosphatic fertilization also affected the grain yield significantly. The FCMP showed better grain yield than CS whereas the interactive effect of Si and CS fertilizer showed higher Si contents in stem sheath, available Si in soil, water-soluble Si contents in soil and soil active Si contents but lower available phosphorus in soil and soil phosphatase activity than the Si and FCMP fertilizer interaction. Moreover, the grain yield showed significant positive correlation with aboveground dry weight (r = 0.9951) and harvest index (r = 0.8364). Overall, Si fertilization improved rice yield, whereas FCMP was found better than CS regarding grain yield improvement. The grain yield increased with increasing Si fertilizer application whereas the FCMP was found better than CS regarding grain yield improvement of rice. The supplementation of Si and phosphatic fertilizers substantially improved available Si and P contents of soil.

Silicon as a Beneficial Element and as an Essential Plant Nutrient: An Outlook (Review)

Silicon application has been known to enhance the plant tolerance against several biotic and abiotic stresses. The mechanisms of alleviation of UV-radiation, drought, salt, and heavy metal stresses have been investigated but still definitely unknown. As a consequence, the needs for understanding the role of Si in the physiological and biochemical processes in plants are of a major importance. In most cases, the published data supported the role of Si in regulation and alleviation the adverse effects of several environmental stresses under specific conditions and for specific plant species. The physiological functions of Si in plants have been studied and showed that Si influx and efflux is regulated by specific genes in plasma membrane of plant cells. The role of these genes in Si transport and alleviation several stress conditions is still poorly understood. The occurrence of high Si content in tissues of graminaceous plants (rice, barley and maize) has positively activated physiological, physical and biochemical defense mechanisms for increasing stress balance, such as decreased lipid peroxidation, reduced membrane permeability, and stimulation of defense enzymes activities. The activities of stress defense enzymes, also called antioxidative enzymes (ascorbate peroxidase, catalase, peroxidase, and superoxide dismutase), have been found to be linked to Si nutrition especially under abiotic stress conditions. There are genotypic differences controls the accumulation of Si within a specific plant species, such as rice. These differences are originated from variations in abundance of certain transporters of Si in roots or/and shoot of plant. These genotypic differences allow the plant to facilitate high growth under abiotic stress conditions. However, the responsible genes for Si accumulation in plant varieties have not yet been well characterized. Harvesting cultivated high Si – accumulator plant species results in removal of large quantity of available Si from soil. In order to replenish the needed amount of available Si from such soil, application of Si – fertilizer would improve its status in soil and maintain appreciable amount of available Si in this soil. Fertilization of soil by the required and safe rate of Si has been found to improve the chemical, physical and biological properties of plant and soil. Tests for available Si in soil and for Si content in specific plant tissue in combination with evaluation of the quantitative relationship between both would be reliable guides for Si–fertilization. In this concern, whether Si is known as a beneficial element or as an essential plant nutrient, the use of Si compounds as a fertilizer or as an amendment has been proved to be of a major importance in the present and near future.

Distribution of Silicon in Rice Growing Soils of West Bengal in Relation to Some Important Soil Chemical Properties

Silicon (Si) is an essential mineral element for silicophilic plant species viz., rice and sugarcane. Rice takes more Si compared to any other primary nutrients from soil but few reports are available on the available Si status of major rice growing soils in India. With this view, about two hundred twenty five (225) georeferenced surface soil samples from intensively rice growing areas covering nine different districts of West Bengal were collected to study the distribution of available Si and their relationship with other soil chemical properties. Results showed that available Si in soils varied from 12.8 to 455.8 mg kg−1 with an overall mean of 103.0 mg kg−1. Among the districts, the soils of Nadia (185.2 mg kg−1) showed highest available Si content followed by Hooghly (120.5 mg kg−1) whereas, soils of the Jalpaiguri (30.4 mg kg−1) showed lowest in its content followed by Cooch Behar (30.4 mg kg−1). It was further indicated that the content of available Si in soil was positively correlated with pH (r = 0.38**), phosphorus (r = 0.43**) and available Cu (r = 0.15*) and negatively correlated with organic carbon (r =-0.21**), available zinc (r =-0.20**) and Fe (r =-0.09). The results of this study would immensely help the future researchers, as inventory information to optimise the application rate of Si in intensively rice growing soils of West Bengal.

Increase of available soil silicon by Si-rich manure for sustainable rice production

Depletion of bioavailable silicon, Si, in paddy soils can decrease the yields of rice. A potential solution is to amend soil with Si-rich organic wastes such as manure from animals fed with rice crop residues. Here, we studied Si in soils from 2000 to 2010 field experiments without manure, with 5 and 10 years of manure, in Eastern China. Results showed that available Si in soils increased from 130 to 270 mg kg−1 after 10 years of manure amendment. This finding is explained either by direct input of available Si or by Si produced by mineralization of Si minerals. To conclude, our results show that amending soil with Si-rich manure in the long term is a solution for sustainable rice production.

Relationship between mineral composition or soil texture and available silicon in alluvial paddy soils on the Shounai Plain, Japan

To evaluate the relationship between the amount of available Silicon (Si) in paddy soils and their mineral properties on the Shounai Plain in Japan, which is formed from several parent materials, we evaluated the amount of available Si, the particle size distribution, the oxide composition of crystalline minerals and the amount of oxalate-extractable Si (Sio), iron (Feo) and aluminum (Alo) in the soil. The amount of available Si in the soil and the oxide content of the crystalline minerals differed among four soil groups that were distinguished by their clay mineral composition. There was no difference in the particle size distribution among the soil groups. The amount of available Si was positively related to the SiO2/Al2O3 ratio of clay, the CaO concentration of silt and fine sand, and the amounts of Sio, Feo and Alo in the soil. The amount of available Si in the soils was negative correlated with the Na2O and K2O concentrations of silt, the K2O concentration of fine sand, and the coarse sand content. These results suggest that the amount of available Si in soils is affected by the weathering resistivity of their minerals and that the particle size distribution and mineral composition are related to the available Si of the soils. Mineralogical properties, including the particle size distribution and mineral composition such as the SiO2/Al2O3 ratio × clay fraction content and the amounts of CaO and MgO in silt-sized particles, were positively correlated with the amount of available Si in the soil, but these correlations were not found for fine sand-sized particles. The Sio, Feo and SiO2/Al2O3 ratio × clay fraction contents contributed approximately 50% to the amount of available Si in the soils. The amount of available Si in the soil was divided into two groups according to the location of the paddy field. The amount of soil-available Si in the alluvial plain was affected by the geology upstream through the mineral composition.

AVAILABILITY OF SILICON, YIELD AND UPTAKE BY RICE AS IN- FLUENCED BY SILICATE MATERIALS WITH FYM IN MADUKKUR SOIL SERIES

Field experiment conducted to study the effect of various silicate materials with or without FYM on availability of Si, yield, Si content and uptake by rice in Madukkur soil series revealed that addition of FYM at 25 t/ha and silicate materials at 1.0 t/ha increased available Si in soil and crop yield. The Si content was higher in straw than in rice grain.