ABSTRACT
In the face of agricultural challenges posed by both abiotic and biotic stressors, phytopathogens emerge as formidable threats to crop productivity. Conventional methods, involving the use of pesticides and microbes, often lead to unintended consequences. In addressing this issue, ICAR -Indian Institute of Oilseeds Research (ICAR-IIOR) has developed a chitosan-based double-layer seed coating. Emphasizing crop input compatibility, entrapment, and characterization, the study has yielded promising results. The double-layer coating on groundnut seeds enhanced germination and seedling vigor. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed the structural changes and entrapment of crop inputs. The persistence of T. harzianum (Th4d) and Bradyrhizobium sp. in chitosan blended film in studied soils revealed that viable propogules of Th4d were recorded in double layer treatment combination with 3.54 and 3.50 Log CFUs/g of soil (colony forming units) and Bradyrhizobium sp. with 5.34 and 5.27 Log CFUs/g of soil at 90 days after application (DAA). Root colonization efficacy studies of Th4d and Bradyrhizobium sp. in groundnut crop in studied soils revealed that, maximum viable colonies were observed at 45 days after sowing (DAS). This comprehensive study highlights the potential of chitosan-based double-layer seed coating providing a promising and sustainable strategy for stress management in agriculture.
ABSTRACT
Nanocitrates of iron (Fe) and zinc (Zn) in the form of plant nanonutrients were examined for their behavior in soil and the uptake of these by 20-day old groundnut (Arachis hypogaea) seedlings under greenhouse conditions. The Fe (0.04 to 0.008 mmol/kg of soil) and Zn (0.02 to 0.004 mmol/kg of soil) nanocitrates were applied to soil and compared with commercial counterparts (FeSO4, ZnSO4, nano-Fe, nano-Zn, Fe-EDTA, Zn-EDTA). The combined nanocitrate compositions were also formulated by physical means and characterized. The plant uptake of Fe and Zn was determined through atomic absorption spectrometry (AAS). All the treated plants showed good germination and higher vigor indexes compared to the control treatments. The highest available Fe and Zn soil contents after leaching were 150.5 and 18.9 mg/kg, respectively, in combined nanocitrate compositions, whereas in the control (untreated) soil, the Fe and Zn contents were 6.0 and 0.7 mg/kg, respectively. The plant's Fe content was 0.48 mg/pot for the combined nanocitrate composition, and that of the untreated plant sample was 0.02 mg/pot. The plant's Zn content was 82.3 µg/pot for pure zinc citrate, and the respective untreated-plant Zn content was 2.1 µg/pot. These values are better than those observed for commercial fertilizers. Additionally, no trend in promotional and antagonistic correlations between Fe and Zn in combined nanocitrates was observed in the studied period (20 days in duration). Among the 34 synthesized citrates, six nanocitrates show promising trends for evaluation under field conditions with higher stability.
ABSTRACT
A series of iron (Fe) and zinc (Zn) plant nanonutrients in citrate form were prepared by an eco-friendly solid-state grinding of the respective nitrates and citric acid. Ball-milling of the as-prepared Fe and Zn citrates resulted in nanosize particles. The as-prepared and ball-milled Fe and Zn citrates were characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis and differential thermal analysis (TGA/DTA), and powder X-ray diffraction (XRD). The particle size and morphology of the obtained samples were studied using a scanning electron microscope (SEM) and transmission electron microscope (TEM). The obtained nanosized Fe and Zn citrates were analyzed for their plant uptake in the test crop soybean (var. JS-335) using the white-sand technique. The concentration of nutrients was estimated by atomic absorption spectrometry (AAS). A significant increase in nutrient absorption was observed in 6 h ball-milled samples of both Fe (789.8 µg per g of dry weight) and Zn (443.8 µg per g of dry weight) citrates. Such an increased nutrient absorption is due to the high mobility of nanocitrates. Therefore, nanocitrates can serve as an excellent source of plant nutrients in agriculture.
ABSTRACT
Fungi under genus Trichoderma as ameliorates of biotic and abiotic stresses in cultivated crops is gaining popularity world-wide and their application in conjunction with seed coating polymers is an attractive proposition to reduce bioagent wastage and harnessing benefits of combined application. The synergistic action of Trichoderma with natural polymers like chitosan can enhance antimicrobial activity. A series of blended film solutions were synthesized by using chitosan, PEG and plasticizer in varying concentrations. The optimization of blended film composition and dose for coating of seeds was done w.r.t seed coating. Studies on compatibility of film forming ingredients with Trichoderma have not shown any inhibition and antimicrobial activity has shown different levels of inhibition of plant pathogens. Films were structurally characterized by XRD, SEM, FT-IR, TGA, DSC. The optimized film solution in combination with different Trichoderma strains improved seed quality parameters in test crop castor (Ricinus communis). Significant increase in vigour index (3110) was observed with Th4d treatment followed by chitosan and Th4d combination formulation (3023). In conclusion, the optimized chitosan-PEG-Th blend was effective in enhancing seed germination and plant growth of castor. The material can be further tested under large field evaluation as a seed coating agent against various plant diseases.
