Prakash Nagabovanalli

• PhD., JSPS Post Doc. FISSS
• Professor and Dean (Agri) at University of Agricultural Sciences, Bangalore

Although silicon (Si) is ubiquitous in the earth’s crust, its essentiality for growth of higher plants is still under discussion. By recognising the overwhelming potential of Si in alleviating a wide range of biotic and abiotic stresses, the Association of American Plant Food Control Officials and the International Plant Nutrition Institute, Georgi...

Biochar is known to decrease the soil acidity and in turn enhance the plant growth by increasing soil fertility. Major objective of the present work was to understand the effect of biochar treatment on alleviation of soil aluminium (Al) toxicity and its role in enhancing plant growth parameters. Soil incubation study was conducted to understand the...

Silicon (Si), a beneficial element, plays an overwhelming role in not only improving the crop productivity but also provides resistance against various biotic (insects and pathogens) and abiotic (salt stress, heavy metal toxicity, nutrient toxicity, ultraviolet radiation, drought condition) stresses. It may be considered as the only element which h...

Practice of silicon (Si) fertilization has been neglected in agriculture under the common notion that Si is abundant in soil. However, it is true that extensive and continuous cultivation can lead to depletion of available Si in soils, especially in tropical countries like India where there is extensive cultivation of Si accumulator crops like rice...

Plants’ ability to take up silicon from the soil, accumulate it within their tissues and then reincorporate it into the soil through litter creates an intricate network of feedback mechanisms in ecosystems. Here, we provide a concise review of silicon’s roles in soil chemistry and physics and in plant physiology and ecology, focusing on the process...

Approximately 500 million people around the globe is affected by arsenic (As) contamination of ground water. The regions of India, Bangladesh, Nepal, Vietnam, and China that make up the South and Southeast Asian Belt are the most arsenic-polluted areas. Although the amounts are often lower in contrast to Asian countries, developed countries such as...

Applying fertilizers correctly is crucial for enhancing soil fertility and crop productivity. Nonetheless, the long-term effects of slag-based gypsum (SBG) and commercial gypsum (CG) on soil fertility and crop yield remain poorly understood. Field experiments were conducted over six seasons with rice crops to investigate the impact of long-term app...

A field experiment was conducted at the research farm of the College of Agriculture (CAU), Kyrdemkulai, Ri-Bhoi, Meghalaya, during the Kharif season of 2023 to study the “Comparison of Application Methods of Phosphorus and Silicon in Finger Millet ( Eleusine coracana ).” The experiment was designed in a factorial randomized block design with three...

Silicic acid (SA) is an important source of silicon (Si) that induces resistance in plants against insect pests. The present study aimed to investigate the impact of foliar spray of SA on the biological parameters of aphid, Lipaphis erysimi and the activity of defensive enzymes in rapeseed (Brassica napus L.). The first experiment evaluated the bio...

Background Gypsum is a valuable resource for farmers, supplying essential calcium and sulfur for plant growth. It serves as a crucial soil amendment, particularly in reclaiming alkali and sodic soils. While not a liming material, gypsum is widely recognized as a nutrient source for calcium and sulfur in acidic soils. The presence of calcium in vari...

Silicon (Si) enhances plant resistance against herbivores and improves crop yield. This study investigated the effect of foliar application of silicic acid (SA), an important available form of Si, on the population growth of aphids (Lipaphis erysimi), gas exchange parameters and yield of rapeseed. The first experiment with treatments of foliar spra...

Silicon, a quasi-essential nutrient element, is well known for imparting tolerance to various biotic and abiotic stresses in crops. The experiments were carried out to evaluate the effect of orthosilicic acid (a silicon source) with two methods of application viz., soil drenching and foliar application against phloem feeders under field conditions...

Silicic acid (SA) is an important source of silicon (Si) that induces resistance in plants against insect pests. The present investigation aimed to investigate the impact of foliar spray of SA on the biological parameters of aphid, Lipaphis erysimi and the activity of defensive enzymes in rapeseed. The results demonstrated applying 0.4% SA signific...

Silicon, a quasi-essential nutrient element, is well known for imparting tolerance to various biotic and abiotic stresses in crops. The present studies were carried out to evaluate the effect of silicon with two methods of application viz., soil drenching and foliar application against phloem feeders under field conditions for two seasons on two di...

Quantitative information on carbon (C) mineralization of soil under different long term nutrient management is essential for better assessment of easily hydrolyzable C and loss of C from soil. With an aim to evaluate the differences in C mineralization due to long term fertilization and manuring treatments, a laboratory incubation study was conduct...

Soil organic carbon which is transient in nature, undergoes decomposition process but its rate of loss or retention in soil, depends on the management practices, weather conditions and it is not responsive to changes of soil quality in short-term with various soil or crop management practices due background levels and natural variability. Hence, a...

Silicic acid (SA) is an important source of silicon (Si), a quasi-essential element inducing growth, yield and abiotic and biotic stress tolerance in crops. SA was obtained from ReXil Agro BV, Chennai, India and a field experiment with factorial randomized block design (FRBD) was carried out in Jorhat, Assam to find out the influence of foliar appl...

Phytoliths are composed of 66 to 91% SiO2 and 1 to 6% organic carbon (C) known as phytolith occluded carbon (PhytOC). PhytOC is critical for long-term C storage in the agroecosystem. A field experiment was carried out to investigate the effect of three different sources of exogenous Si, i.e., diatomaceous earth (DE), silicic acid (SA) and rice husk...

An experiment was conducted for 90 days in outdoor, circular, 1000 L, cement cisterns with soil base for evaluating the effect of nutrient supplemen-tation on planktonic quality and quantity. All the cisterns were manured with cow dung (400 g), Urea (1 g) and single super phosphate (1.5 g) at fortnightly intervals. Water-soluble forms of Magnesium...

Kalleshwaraswamy, C.M.; Dhananjaya, B.C.; Prakash, N.B.; Deshmukh, S.S.; Sunil, C.; Hossain, M.A.; Mallikarjuna, H.B. Silicon Accumulation in Leaves Reduces the Herbivory by Invasive Fall Armyworm Spodoptera frugiperda and Enhances the Yield of Maize. Int. J. Plant Biol. 2023, 14, 701-713. https:// Abstract: Fall armyworm (FAW) Spodoptera frugiperd...

An experiment was conducted for 90 days in outdoor, circular, 1000 L, cement cisterns with soil base for evaluating the effect of nutrient supplemen-tation on planktonic quality and quantity. All the cisterns were manured with cow dung (400 g), Urea (1 g) and single super phosphate (1.5 g) at fortnightly intervals. Water-soluble forms of Magnesium...

The invasive fall armyworm (FAW), Spodoptera frugiperda has become one of the major pests of maize In India and various strategies need to be developed for its management. Currently, silicon (Si) is known to reduce damage caused by pests by inducing resistance and promote plant growth and development. There are many sources of Si and few of them ar...

Background: Slag based gypsum (SBG) is a value-added product of iron and steel industry. Application of gypsum as source of calcium and sulphur for groundnut cultivation is common practice and mainly applied during peg initiation stage of groundnut. However, its effect is mainly influenced by the type of soil and dissolution of gypsum, which facili...

The spatial distribution of soil properties and plant available Si was studied in three important rice producing command areas of Karnataka by collecting random georeferenced surface (0-15cm) soil samples using GPS and GIS techniques. The soil samples were analysed for different soil properties and plant available Si and the data along with GPS rea...

Gypsum as a nutrient source has been used in agriculture for many years. Slag-based gypsum (SBG) is a synthetic gypsum prepared from by-product of steel industry. A pot culture experiment was conducted to know the effect of SBG on growth, yield and nutrient availability of rice in three different soils (acidic, neutral and alkaline soil) under cont...

Soil erosion is an inexorable process of land degradation affecting economy and environment of the region. Assessment of soil erosion is important for planning and implementing conservational practice in the affected region. In the present study, Revised Universal Soil Loss Equation (RUSLE) integrated with remote sensing (RS) and Geographical Infor...

Understanding on the bioavailability of silicon (Si) in intensively cultivated agricultural ecosystem still remains a challenging topic which requires attention by the scientific community. Monosilicic acid (soluble Si) and polysilicic acid (insoluble Si) affect various physicochemical properties of the soil. Thus, quantification of plant available...

Slag-based gypsum (SBG) produced from steel industry have better plant nutritional value in terms of calcium (Ca), sulphur (S), phosphorus (P), iron (Fe), silicon (Si) and other trace metals (Ashrith et al. 2020). Prakash et al. (2020) reported that the application of varied levels of SBG increased the yield and soil chemical properties especially...

Indiscriminate burning of crop residues in the open fields in India has a tremendous negative consequence on human-animal-soil-plant continuum. Particulate matter released during the in-situ crop residue contributes to the environmental pollution. Management of the residues of rice, wheat and sugarcane crops, which account for more than 80% of the...

A field experiment was conducted to study the different sources of silicon (Si) on plant growth and yield. The experiment was laid in randomized complete design (RCBD) with four treatments and four replications. The experiment results revealed that There was an increase in plant height and the number of tillers plant-1 with the application of diffe...

Yellow gypsum (YG), a synthetic product from Linz-Donawitz slag containing high iron (Fe) (5.41%), zinc (Zn) (0.37%) and silicon (Si) (3.41%) can be used as a source of these nutrients along with calcium (Ca) and sulphur (S) for groundnut production. Three field experiments were conducted to know the effect of different rates (500 and 625 kg YG ha...

Silicon (Si) is known for mitigating biotic stresses in various crops through diverse array of mechanisms. The present study was undertaken to decipher the mechanisms of Si in suppressing the impact of pink stem borer incidence and damage to wheat plants under field conditions. For this study, we have applied different Si sources like diatomaceous...

Silicon (Si) and Plant growth regulators (PGR’s) are known to induce resistance against various insect pests. A study was conducted to determine the effect of Si and PGR’s on biology and induced resistance in maize against recently invaded fall armyworm (FAW), Spodoptera frugiperda. Different foliar silicic acid (FSA), gibberellic acid (GA3) and ja...

Slag-based gypsum (SBG) is produced from LD slag (Linz-Donawitz slag) which is a byproduct of the steel industry. As the constituents of SBG are almost similar to the commercial gypsum (CG), two field experiments on acidic and alkaline soil under aerobic and wetland conditions were conducted to know their performance on rice. The treatments include...

Agricultural pest management involves a thorough understanding of biology and ecology of insects and their interaction with plant constituents. Exogenous silicon (Si) application has been shown to boost plant tolerance to herbivory while also increasing output. The silicon application contributes to reduced oviposition, feeding, digestibility, fitn...

Field experiments were conducted in two different soil conditions viz., location 1 and 2 during the rainy season (kharif) of 2017 and 2018, respectively, at V.C. Farm, Mandya, Karnataka, South India to evaluate the response of maize (Zea mays L.) to different levels of customised NPK fertilizers (CF). Results showed that the application of grades o...

Carbon (C) occluded in phytoliths is stable and an important source of long-term C storage into the agroecosystems. As a silicon (Si) accumulator crop, rice produces a large amount of phytolith occluded carbon (PhytOC) and which plays a crucial role in the coupled biogeochemical cycle of C and Si. In this study, we sampled above ground biomass from...

In rice-producing countries, the abundance of rice residue must be sustainably managed to avoid environmental problems. Moreover, repeated usage of inorganic fertilizers has caused rapid soil deterioration in these arable lands. Converting rice husk residue into rice husk biochar 2(RHB) and reapplying it back to paddy fields as a soil amendment can...

Release of silicon (Si) from different Si sources and Si budgeting in varied types of soils are required for the exploration of sustainable rice production. Si products are shown to be effective in improving crop growth and yield; however, its reactivity differs based on the soil type. A pot experiment was conducted by using three Si sources (calci...

The foliar nutrition of silicic acid is considered to be a novel approach in enhancing the performance of many crops worldwide. The present study aimed to assess if the foliar application of silicon (Si) could influence the performance of soybean varieties with distinct crop duration, MAUS-2 (long duration) and KBS-23 (short duration). Field experi...

Slag-based gypsum (SBG) is a synthesized product of steel industry. SBG has better plant nutritional value in terms of sulphur (S), calcium (Ca), phosphorus (P), iron (Fe), silicon (Si) and traces of other micro-nutrients. Field experiments were conducted with randomized complete block design (RCBD) to evaluate the effect of SBG over commercial gyp...

Balanced nutrient application is an important concern to minimize fertilizer use in crop culture. Field experiments were conducted during kharif 2017 and 2018 to find out the best level of NPK fertilizer for rice with two varieties of rice of same duration (130-135 days). Three grades of customized fertilizers (250, 350 and 450 kg ha⁻¹) along with...

Silicate slags are one of the most widely used silicon (Si) source in agriculture. Even though the agronomic significance of slags has been demonstrated in several crops, only a few attempts were made to evaluate these Si sources based on their chemical composition. The main objective of this study was to characterize different silicate slags based...

Silicon (Si) and potassium are known to impart tolerance against numerous biotic stresses in crop plants. A study was conducted to determine the effect of diatomaceous earth (DE), a soil-applied Si source and soluble silicic acid, a foliar applied Si source at two levels of potassium for their efficacy against pink stem borer (PSB) incidence and da...

Although the role of silicon (Si) in enhancing crop performance has been proven in many field crops including rice, wheat, sugarcane and soybean, its influence on Si non-accumulator crops like tomato is very much limited. In order to evaluate the effect of silicic acid on tomato, a field experiment was conducted during summer 2018. The experiment c...

Soils and vegetable crops being irrigated with water from six lakes in Bengaluru, India were analysed using ICP-OES for heavy metals and characterized based on the permissible limits of the European Union (EU) and the Indian Standards (IS). Chromium, nickel and lead content in the soils ranged from 89.36 to 145.21, 0.90 to 19.17 and below detection...

The 1% Na2CO3 method used for measuring amorphous silicon (ASi) in soils was initially developed by DeMaster (1981) for measuring biogenic silica in marine sediments. Although this method is widely used for quantifying ASi content in soil, it has a few limitations which requires specific attention in case of the digestion period. In this study, we...

Rice husk biochar (RHB) • RHB has a non-crystalline mineral content of 88.32% of SiO 2 , 0.46% Al 2 O 3 , 0.67% Fe 2 O 3 , 0.67% CaO, 0.44% MgO, 0.12% Na 2 O 3 , and 2.91% K 2 O. • The physical properties of RHB is grey in colour, has irregular texture, <45 mm in size, odourless, 2.3 specific gravity and a very fine appearance.

Toxicity of aluminum (Al) is a serious problem for agricultural plants, especially due to excessive soil acidification caused by continuous intensive agriculture and modified environmental conditions related with global climate change. Decreased root elongation and shoot growth, reduced biomass production, nutrient imbalance and altered physiologic...

Slag-based gypsum (SBG) is a unique synthetic gypsum which is alkaline in nature, besides calcium (Ca) and sulphur (S); it contains appreciable amounts of iron (Fe), silicon (Si), phosphorus (P) and zinc (Zn). In this study, we evaluated the efficacy of SBG as a source of S, Ca and Si for groundnut in comparison with natural gypsum (NG). The effect...

Effect of slag-based gypsum (SBG) and commercial gypsum (CG) on maize was investigated in acidic and neutral soils. A randomized complete block design (RCBD) with seven treatments consisting of three levels (150, 450, and 750 kg ha −1) of SBG and CG with recommended dose of fertilizer (RDF) and one control was maintained. Application of SBG @750 kg...

Soil-borne Salmonella is associated with a large number of food-related disease outbreaks linked to pre-harvest contamination of plants (like tomato) in agricultural fields. Controlling the spread of Salmonella at field is very important in order to prevent various food-borne illnesses. One such approach involves the utilization of antimicrobial se...

Si is one of the most abundant element on earth and an abundant literature shows its beneficial effects on plant growth and resistance. We here question the influence of termites, as key soil bioturbators, on the distribution of Si in a tropical soil. The abundance and forms of Si in termite mounds build by Odontotermes obesus (TM) or in the soil e...

Application of 4 ml L-1 foliar Si as silicic acid increased Si uptake to an extent of 54.6 % over control. There was a significant increase in Ca and P content in straw and glumes with the application of foliar Si. In grains the concentration of all these mineral nutrients remained unaffected but the grain weight showed significant increase with th...

Effect of silicon on incidence and severity of purple blotch disease in onion was assessed by conducting field experiments at College of Horticulture Bengaluru. Silicon treatments significantly reduced the disease incidence and severity in two varieties (Bellary Red -Highly susceptible and Arka Kalyan - moderately resistant) of onion taken for the...

The 7th International Conference on Silicon in Agriculture (www.silicon2017.com) was organized at University of Agricultural Sciences (UAS), Bangalore, India during 24th to 28th October, 2017. This was a unique event, being hosted for the first time in India, despite being the 7th in a triennial International series. More than 150 participants, nat...

Five major pools of silicon (Si) such as mobile Si, adsorbed Si, Si bound to organic matter, Si occluded in pedogenic oxides/hydroxides and amorphous Si were extracted from three soils namely one each from low, medium and high categories of plant available Si using a sequential extraction method. Different pools of Si extracted from soils were in t...

Application of fermentation technique is known to significantly enhance nutrient contents in foods and hence, this study was conducted to develop and evaluate fermented dhokla from maize. Different levels of maize semolina (600 μm) were mixed with bengal gram dhal (2:1, 3:1 and 4:1 ratios) and evaluated for acceptability using subjective and object...

Diatomite or Diatomaceous earth (DE) is a sedimentary rock that results from the deposition of Si rich unicellular life forms (diatoms) found in both salt and fresh water. The cell walls of these dead diatoms consist of amorphous silica. Amorphous silica is more easily solubilised than crystalline silica and is expected to release more PAS (Plant a...

Five major pools of silicon (Si) such as mobile Si, adsorbed Si, Si bound to organic matter, Si occluded in pedogenic oxides/hydroxides and amorphous Si were extracted from three soils namely one each from low, medium and high categories of plant available Si using a sequential extraction method. Different pools of Si extracted from soils were in t...

Biochar has been proposed as a technology to mitigate climate change as well as improving soil fertility, energy production, and organic waste treatment. However, the implementation of such techniques in existing cropping systems requires knowledge about potential adaptation barriers. These adaptation barriers are only partly dependent on expected...

Salmonella is an established pathogen of the members of the kingdom Animalia. Reports indicate that the association of Salmonella with fresh, edible plant products occurs at the pre-harvest state i.e. in the field. In this study, we follow the interaction of Salmonella Typhimurium with the model plant Arabidopsis thaliana to understand the process...

Several silicon (Si) sources have been reported to be effective in terms of their effectiveness on rice growth and yield. Apart from that, it is crucial to understand the bioavailability of silicon from different silicon sources for adequate plant uptake and its performances in varying types of soils. In this point of view, a pot experiment was con...

Field experiments were carried out during summer and kharif of 2015 and kharif of 2016 with and without application of silicon (Si) under rice cropped and non-cropped condition. Diatomite and rice husk biochar was used as Si source and applied @ 300 kg ha ⁻¹ and 2 t ha ⁻¹ , respectively. The continual application of Si increased the straw and grain...

Background and aims Although Si is recognized as a beneficial element for crops, the determination of plant-available silicon (PAS) in soils has become challenging. A correlation between pH and PAS indicators has been reported in the literature due to the higher degree of weathering of acidic soil. We tested this hypothesis in the cultivated rice f...

In many countries, blanket fertilizer recommendations for different crops have caused poor nutrient supply, low nutrient use efficiency and limited crop response. In contrast, soil and area specific, customized fertilizers may help to sustain soil health by ensuring appropriate fertilization. Hence, specific customized fertilizers should be promote...

Application of diatomaceous earth (DE) could improve the quality of soil, but its application in agriculture as a Si fertilizer requires additional research. Pot experiments were conducted with graded levels (0, 150, 300, 600 kg ha-1) of DE with recommended dose of N, P, K, in three types of soil (acidic, neutral and alkaline) from Southern India u...

Background and aims The benefits of Si for crops is well evidenced but the biogeochemical cycle of Si in agriculture remains poorly documented. This study aims at identifying and quantifying the Si sources (primary and secondary soil minerals, amorphous silica, irrigation, Si-fertilizer) to rice plants. Method Field experiments were carried out wi...

Green house experiment was conducted conducted to evaluate the effect of silicon in mitigating the heavy metals in soil and its uptake by spinach. Different silicon sources viz., rice hull biochar (RHB), diatomaceous earth (DE) and calcium silicate were used at different levels. Chromium concentration in spinach shoot after the crop harvest was fou...

Field trials were conducted to evaluate locally available calcium silicate, rice hull and rice hull ash as silicon (Si) source in acidic and alkaline rice fields and their effect on growth, yield and nutrient uptake of wetland rice. Application of calcium silicate and rice hull significantly improved growth parameters like number of tillers, LAI an...

The present study was undertaken to quantify and identify the phytoliths distribution in rice and sugarcane soils of Karnataka, South India. The quantity of phytoliths was higher in sugarcane than in rice soils at the surface. In the sub-surface soil, higher amounts of phytoliths were detected in rice soils, whereas, it decreased in sugarcane soils...

Leaf color chart (LCC) guides fertilizer nitrogen (N) application to rice as per requirement of the crop on the basis of a critical leaf color. Two field experiments were conducted to evaluate the effect of Silicon (Si) and LCC based N management in aerobic rice. Following LCC-based N management, from 60–90 kg N ha⁻¹ and 75–100 kg N ha⁻¹ with 10–40...

The antifungal activity of different concentration of silicon sources viz., OSAB, Silixol plus, Greensil plus, Greensil, Silicon power and Pro-sil in inhibiting the mycelial growth of P. infestans was investigated by using poison food technique. The results from in vitro study revealed that, all the silicon sources tested at different concentration...

Greenhouse experiments were conducted to study the effects of silicon on soil-cadmium availability and uptake in rice grown in an acid soil maintained under two different moisture regimes (field capacity or submergence). The silicon treatment decreased the cadmium concentration and uptake in grain and straw while it increased the cadmium uptake in...

The present investigation was conducted in green house to assess the effect of different sources of silicon on soil solution Si and its bioavailability for rice in three types of soil. Rate of dissolution and release of Si from Si fertilizers varied among different sources and types of soil. Bioavailability of Si increased significantly with applic...

An experiment was conducted in Division of Horticulture to evaluate the effect of foliar application Silicic acid on growth and yield attributes of Rose cut flowers under naturally ventilated poly house with seven treatments, three replications and four varieties. Among the treatments application of foliar Silicic acid @ 4ml L-1 at 10 days interval...