Screening of Rice Genotypes against Sodicity in Relation to Physiological and Biological Traits

The study aimed to screen the rice genotypes against sodicity in relation to physiological and biological traits to identify the tolerant and susceptible genotypes. The field experiment was carried out at the Research Farm of Dr. Rajendra prasad central agricultural university, Pusa, Samastipur, Bihar during Kharif season of 2019-2020. The experiment was based on randomized block design with 30 plots in each of 3 replications where each replication consists of 30 rice genotypes. A total of 30 rice genotypes were screened of which 25 are exotic and 5 are indigenous. The exotic genotypes are GPV 1, GPV 2, GPV 3, RMS 1, RMS 2, RMS 3, RMS 4, RMS 5, RMS 6, RMS 7, RMS 8, SRL 1, SRL 2, SRL 3, CNN 1, CNN 2, KRH 4, PVP 221, MTU 1010, VR 181, PS 344, MTP 1, Vardhan, Rasi, CSR 23 (Check) while Prabhat, R. Sweta, R. Bhagwati, R. Mahsuri and Rajshree are the indigenous ones. The physiological and biological traits were evaluated at tillering and pre-flowering stages and their inter-relationship among various physiological parameters are established. The genotypes such as SRL 1, GPV 1, GPV 2, GPV 3, and Rajendra Mahsuri show the highest chlorophyll content, SPAD value, peroxidase and catalase activity, proline content, RLWC content, and MSI percentage, and the lowest was found in Prabhat, Rasi, and Rajendra Bhagwati. Based on response with regard to SPAD value, RLWC, and MSI the genotypes such as SRL 1, GPV 1, GPV 2, GPV 3, and Rajendra Mahsuri show positive increase compared to CSR 23 (Check). The inter-relationship concerning to various physiological parameters shows a strong significant and positive correlation among each other at tillering and pre-flowering stages. However, Total chlorophyll at the tillering stage was found to bear a highly significant correlation with all the physiological parameters except relative water content and membrane stability index. The genotypes such as SRL 1, GPV 1, GPV 2, and GPV 3, Rajendra Mahsuri possess better potential in sodic soil than the rest of the genotypes taken in the experiment with regard to various physiological parameters (taken as salt indices) by counteracting or minimizing the sodicity effect of sodium ion. The greater synthesis of antioxidant enzymes like catalase and peroxidase plays an important role in plant adaptation which effectively support to withstand and perform well in sodicity conditions hence SRL 1, GPV 1, GPV 2, GPV 3, and Rajendra Mahsuri categorized as salt tolerant genotypes which have great potential to boost up the rice production in sodic soil condition while Prabhat, Rasi and Rajendra Bhagwati categorized as salt susceptible genotypes. Thus, this study will be helpful for the identification of tolerant and susceptible genotypes through screening and pave way for the development of stable and high-yielding genotypes for the improvement of rice production under sodic soil

Effect of Long-Term Application of Inorganic Fertilizers, Organic Manure, and Lime on Different Forms of Potassium in Soil under Maize-Wheat Cropping System

The field study was undertaken with the major emphasis on potassium fractionation and its contribution in acid alfisol soils as affected by adoption of continuous cropping, fertilization, and manuring under maize-wheat cropping system in same field over 62 years of crop cycles. The experiment consisted of fourteen treatments, replicated thrice times in a randomized block design, out of which nine treatments were selected for the present study. The selected treatments were as follows - control, T2-100% N, T3- FYM, T4-100% NP, T5-100% NPK, T6- 1/2(N+FYM) + P(A-X/2) + K(B-Y/2) (INM), T7-100% NPK + Lime where the lime application in LR once in 4 years, T8-Lime+ FYM+ P(A-X) + K(B-Y), T9-Lime+N. Surface soil (0-15cm) and subsurface soil (16-30 cm) samples were collected after the harvest of wheat in 2017-18 to observe the initial Physico-chemical properties. Different fractions of potassium, viz., water-soluble K, exchangeable K, available K, 1NHNO3K, non-exchangeable K, Lattice K, and Total K were analyzed for the study. There was a significant difference among the different treatments with respect to potassium fractions in 0-15 cm, and 16-30 cm layers. Moreover, K fractions were significantly decreased with increasing depth of soil. Results showed that the percentage contribution of different forms of K with regard to the total K in surface soil and subsurface soil followed as: Lattice K (68.75-78.11%) > Non – Exchangeable K (19.15-25.49%) > Exchangeable K (1.65-2.45%) >Water soluble K (0.18-0.62%). Application of N and P without K caused depletion of soil, water-soluble K, available K, exchangeable K, non-exchangeable K, and lattice K because of continuous omission of potassium content during the all crop growing stages or the simultaneous leaching nature of residual potassium under same field of the experiment. Therefore, the present investigation stresses the vital importance of the inclusion of organic manure and lime in the fertilizer schedule to maintain soil K dynamics over the long run under the maize-wheat cropping system