Browsing by Author "Harjot Kaur"
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ThesisItem Open Access Evaluation of some new chemical and organic amendments in rice-wheat system under sodic water irrigation(Punjab Agricultural University, Ludhiana, 2022) Harjot Kaur; O.P. ChoudharyPersistent and continuous use of sodic water for irrigation in south-western regions of Punjab has led to the development of sodicity in soils which severely impacts the physical, chemical and biological properties. The deteriorated soil health proves futile to plant growth causing yield losses and lower farm income. The problems caused by the irrigation-induced sodicity can be rectified by the amelioration of the soils using amendments. Gypsum has been popular among farmers as a source to ameliorate sodic water irrigated soils but the issue with its availability and quality has propelled the scientific community to explore the potential of some others resources such as yellow gypsum, a by-product of steel industry which can help sustain growth in sodic soil environment. Organic amendments such as farm yard manure (FYM) has been studied extensively while others like rice straw compost, rice straw (RS) and biochar (BC) are presently getting attention in terms of their utility in restoring sodic soils. A pot experiment was conducted to collate the effect of application of inorganic (yellow; YG and grey gypsum; GG) and organic amendments (FYM, rice straw compost, RS and BC) on properties of soils (loamy sand; ls and sandy clay loam; scl) irrigated with sodic water and biomass yield of crops. Soils were irrigated with different levels of RSC of irrigation water i.e. RSC 0, 5, 7.5 and 10 meq L-1 . Organic amendments, FYM @ 15 t ha-1 , Rice straw compost @ 6 t ha-1 , RS 6 t ha-1 and BC @ 4 t ha-1 were applied once before sowing of wheat whereas gypsum (both types) @ 50%GR was applied on soil basis and later with each irrigation to neutralize sodicity of water. Individual effect of these amendments was studied through 56 treatment combinations in completely randomized design replicated three times. Results revealed decrease in biomass yield, photosynthetic activity, stomatal conductance and uptake of Ca, Mg and K on irrigation with sodic water in wheat and rice crop whereas uptake of Na and proline content increased. With regard to soil properties, irrigation with sodic water increased pH, sodium adsorption ratio (SAR) (higher in scl), exchangeable sodium percentage (ESP) (higher in ls), and bulk density (BD) but decreased microbial biomass carbon (MBC) and mean weight diameter (MWD). Upon application of gypsum (both types), decrease in pH, SAR and ESP was observed along with significant improvement in biomass yield and other soil properties such as MBC and MWD. Among the organic amendments, BC reduced uptake of Na whereas rice straw compost and FYM gave promising results in restoration of soil properties and biomass yield in both the crops. Further, field studies need to be conducted to evaluate the restorative effect of yellow gypsum vis-à-vis grey (mined) gypsum and it combined application along with the organic amendments in soils receiving sodic water irrigation.