Consequential rice crop response to resultant soil properties in a toposequence in eastern coastal plain of Odisha, India

Abstract

Rice cultivation widely distributed in Southeast Asia on gently sloping coastal plains with different toposequences and elevation. These toposequences, slope differences primarily due to differentiation in soil development and water movement are key to rice production. Understanding soil variables under rice cultivation along the different toposequence models in coastal systems is rarely an attempt toward sustainable crop productivity. With the objectives of investigating variation in soil properties under rice cultivation along the toposequences in the eastern coastal part of Odisha, five soil series representing alluvial (old and young), colluvium, and coastal plain (plain and shore) toposequences were studied that are classified into two soil orders viz. Inceptisols (P1, P2, P4, and P5) and Vertisols (P3). The soils are deep to very deep, poor to moderately well-drained, color varied from brown to dark gray. The clay content varied from 12.6 to 81.4%. High clay content (>\u200960%) was observed in subsoils of colluvium (P3) and young alluvial plain (P2). Soil reaction varied from slightly acidic to moderately alkaline (pH 6.2–9.4) and electrical conductivity (EC) was ranging from 0.23 to 5.60 dS m−1. OC content was low to high (0.12–1.13%) and CEC and base saturation (BS) ranged from 4.9 to 37.1 cmol (p+) kg−1 and 73–95%, respectively. Rice soils suffer from different nutrient deficiencies (N, P, and Zn) and toxicities (Fe, Mn, and Cu) in different root zone depths in slope position. Variation in rice yield was highly significant with clay content, CEC, and negatively correlated with EC, Exchangeable sodium, and ESP. Linear regression of rice yield with soil properties R2 values varied from 0.29 (ESP) to 0.40 (CEC). Water movement and alternate wet and dry rice cultivation systems impact clay deposition, anion, and cation movement along the toposequence. Moreover, OC and K were increased down the slope on the coastal plain than alluvial soils. Conceptual toposequence model exhibition of the landscape is key to find major soils at the family level and crop response in the coastal systems. Thus, adopting site-specific or soil-based suitable management practices can improve the productivity of rice crops.