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Bio-stimulants are gaining importance for elevating the stagnated yield level resulting from continuous use of chemical fertilizers (CF) in many crops, however, their use in pomegranate have not been fully explored. Two years of field experiments were conducted on a 5-years old pomegranate cv. Bhagwa orchard to investigate the effects of different combinations of commercial bio-stimulant products namely, microbial-based product A containing consortium of Rhizophagus spp. (5 kg ha−1), seaweed extract-based granular formulation D (30 kg ha−1) and liquid formulation B (625 and 1250 ml ha−1) through soil application as well as wettable granular formulation, C (1 and 2 g l−1) and liquid formulation, E (1 ml l−1) through foliar sprays along with chemical fertilizers on soil fertility, trees' nutrition, fruit yield and quality of pomegranate. Results showed that integrated use of CF and bio-stimulants significantly increased the number of bisexual flowers. However, the combination of microbial-based product A (5 kg ha−1), seaweed extract based liquid formulation B (625 ml ha−1) in soil and foliar spary of seaweed extract based wettable granular formulation C (1–2 g l−1) with CF resulted in production of the highest fruit yield (increased by 41.97–51.61%) with 23.08–33.38% increase in the exportable grade fruit and improved quality attributes viz. ascorbic acid, anthocyanin, non-reducing sugar, protein, and mineral content of fruits through enhancement in soil fertility and trees' micronutrient status compared to only CF. These doses combinations of bio-stimulants along with CF gave rise to the highest benefit–cost ratio of 2.10–2.34:1 and hence can be recommended for sustainable pomegranate cultivation. [ABSTRACT FROM AUTHOR]

In this investigation, cultivation of an economically important medicinal plant (Senna, Cassia angustifolia Vahl.) was explored in saline soil for improving productivity and quality through effective nutrient management practices. Field experiments were conducted in two consecutive growing seasons in saline soils of semi-arid region, where recommended dose fertilizer (RDF) supplied through organic (vermicompost) and inorganic (chemical) source alone or in combination with local microbial consortia (MC). Plant growth and nutrition significantly improved due to integration of organic and inorganic fertilizer alone or in combination with MC. The results also reflected in economic yield (leaf + pod) of senna where 29–37% increase in leaf and 57–76% increase in pod yield was recorded over control. The results revealed that integration of organic and chemical fertilizer along with MC recorded significant higher leaf (1682 kg ha−1) and pod (488 kg ha−1) yield as compared to the other treatment. Sennocide content in leaf and pod was significantly improved by organic as well as integrated application of organic and inorganic fertilizer. However, the highest sennocide content in leaf (2.81%) and pod (3.11%) was recorded in integrated application of organic fertilizer and MC. Additionally, integrated application of organic and chemical fertilizer was found effective in restoring organic carbon, increasing the amount of available nutrients (N, P, and K), and enhancing the biological activity of the saline soil. Therefore, integration of organic and chemical fertilizer as well as MC has potential to improve yield and quality of senna through enhanced soil fertility and biological function. [ABSTRACT FROM AUTHOR]

The chemical reactivity of Indian rock phosphates (RPs) was measured by five chemical extraction methods (i.e. water, neutral ammonium citrate (NCA), 2% citric acid (CA), 2% formic acid (FA) and absolute citrate solubility (ACS)). These measurements were assessed by agronomic response data obtained by growing ryegrass and palmarosa in two highly weathered acidic soils under pot culture experiment. The phosphorus (P) solubility value of RP measured by different methods followed the order: ACS > 2% CA > 2% FA > NAC > water. Considering triple superphosphate (TSP) as a standard reference P fertilizer, the agronomic response of RPs followed the order Udaipur RP > Jhabua RP ≥ Purulia RP > Mussorie RP. Methods based on citrate solubility (i.e. NAC, 2% CA and ACS) were significantly and positively correlated with agronomic response irrespective of the plant species and soil types. The best correlation value obtained with NCA indicated that P solubility in NAC solution may offer better prediction of agronomic effectiveness of RP in terms of biomass yield, relative agronomic efficiency (RAE) and P recovery efficiency. So, the present investigation will help to predict the agronomic effectiveness of low-grade RP based on chemical methods. [ABSTRACT FROM AUTHOR]

Clay minerals are natural materials well known for their role in retention and persistence of organic and inorganic compounds in soil. Clay minerals are being modified through different processes to alter their charge and surface properties tailored for specific purposes. Modified clays in general include pillared layered clays, organoclays, nanocomposites, acid and salt-induced and thermally and mechanically induced modified clays. Pillared organoclays and nanocomposites constitute a novel class of materials, mainly one kind of modification of expanding 2 : 1 clay minerals. Acid and salt treatments lead to modification of the catalytic properties of clays. Clay mineral-polymer nanocomposites are the hybrids which exhibit a change in composition and structure on a scale of nanometres. Modified clay imparts slow-release property to fertilizers and enhances the water-holding capacity of soil. Therefore, understanding the methods of clay modification and properties of modified clays may facilitate development of agricultural management systems that ensure long-term sustainability of soil resources. [ABSTRACT FROM AUTHOR]

An experiment was carried out to study the changes in nutrient contents during preparation of enriched organomineral fertilizers using rice straw, low-grade rock phosphate (RP), waste mica, and phosphate-solubilizing microorganism (Aspergillus awamori). Composting reduced the total carbon (C) but increased total nitrogen (N) content with the progress of composting. This was reflected in the decrease of the C/N ratio. Significant increases in total phosphorus (P) and potassium (K) were also observed where both RP and waste mica was added along with Aspergillus awamori. Ammonium N (NH4 +-N) decreased while nitrate N (NO3 --N) increased at the end of composting. Olsen P content increased up to 90 days, thereafter decreased up to day 150, whereas ammonium acetate K (NH4OAc-K) increased gradually with the progress of composting. The study thus revealed that crop residue could be converted into a value-added product through composting technology using low-grade rock phosphate and waste mica along with phosphate-solubilizing microorganisms. [ABSTRACT FROM AUTHOR]

The main aim of this research was to study the dynamics of K release from waste mica inoculated with potassium solubilizing microorganism ( Bacillus mucilaginosus) and to investigate its effectiveness as potassic-fertilizer using sudan grass ( Sorghum vulgare Pers.) var Sudanensis as test crop grown under two Alfisols. Results revealed that application of mica significantly enhanced biomass yield, uptake and per cent K recoveries by sudan grass than control (no-K). Biomass yield, uptake and per cent K recoveries increased further when mica was inoculated with bacterial strain in both the soils than uninoculated mica. Alfisol from Hazaribag recorded higher yield, uptake and K recoveries than Alfisol from Bhubaneswar. The dynamics of K in soils indicated that K was released from mica to water-soluble and exchangeable pools of K due to inoculation of mica with Bacillus mucilaginosus in both the soils. Significantly greater amounts of water-soluble, exchangeable and non-exchangeable K were maintained in Alfisol from Hazaribag than Bhubaneswar. Release kinetics of K showed significant release of K from mica treated with bacterial strain. Significant correlation between biomass yield, K uptake by sudan grass and different pools of K in soils were observed. X-ray diffraction analysis indicates greater dissolution of mica due to inoculation of Bacillus mucilaginosus strain in both the soils. Thus, bio-intervention of waste mica could be an alternative and viable technology to solubilize insoluble K into plant available pool and used efficiently as a source of K-fertilizer for sustaining crop production and maintaining soil potassium. [ABSTRACT FROM AUTHOR]