Journal of Environmental Biology

Development of non-stress baseline of crop water stress index for wheat in humid sub-tropical climate in India

M. Pramanik¹, R. Ranjan¹*, N.K. Garg², S.K. Tripathi³ and R. Singh³ 

¹Division of Hydrology and Engineering, ICAR-Indian Institute of Soil and Water Conservation, Research Centre, Datia-475 661, India

²Department of Civil Engineering, Indian Institute of Technology, New Delhi-110 016, India

³Department of Hydrology, Indian Institute of Technology, Roorkee-247 667, India

*Corresponding Author Email : rajeev4571@gmail.com

Paper received: 06.06.2019??????? ?????????????????????????????????????? Revised received: 26.10.2019????????????? ????????????????????????? Accepted: 27.11.2019

Abstract

Aim: A study was conducted to develop a new approach of non-stress baseline and evaluate different approach of determining non stress baseline for Crop Water Stress Index (CWSI).

Methodology: To observe maximum and minimum canopy temperature, two plots with three replications were maintained at fully stress (no irrigation) and no stress (fully irrigated) conditions, respectively. Portable weather station with data logger was installed at the middle of field to record continuous data at half an hour interval. Gypsum block soil moisture sensor were buried at 20 cm interval up to 100 cm and connected with data logger. Infrared radiometer was used to measure canopy temperature. ???

Results: The evaluation was based on five statistical indicators; correlation coefficient (R2), root mean square error (RMSE), mean absolute error (MAE), mean bias error (MBE) and Wilmot index of agreement (d). It was found that new regression base line performed better than other existing approaches. The calculated value of RMSE, MAE, MBE, d and R2 were 0.65, 0.51, 0.02, 0.79 and 0.83, respectively, for new baseline approach. ??

Interpretation: The newly developed multiple regression equation (incorporating three weather parameters (R_n, VPD and u) and two crop growth parameters (h and CC)) helped to reduce error in the calculation of non-stress baseline for wheat crop in humid subtropical climate. ?????

Key words: Canopy temperature, Crop water stress index, Non-stress baseline, Wheat

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