Current Science

K. S. Reddy ¹, M. Kumar ¹, V. Maruthi ¹, B. Umesha ¹, Vijayalaxmi ¹, C. V. K. Nageswar Rao ¹

Affiliations
1 Central Research Institute for Dryland Agriculture, Santoshnagar, Hyderabad 500 059, IN

Abstract

Weather-generating models are widely used for studying the climate change over longer periods. LARS-WG model was evaluated for southern Telangana region (Hayathnagar, Yacharam and Rajendranagar). A 30- year base weather data (1980-2010) was used to generate the long-term weather series from 2011 to 2060. The results of t and F tests at probability of 5% for comparing means and standard deviations of monthly rainfall and air temperatures indicated that the observed and predicted series for the base period are within acceptable limits. The statistics of model efficiency indicates that mean monthly rainfall and daily air temperature are close to the predicted series over the base period. The model efficiency was highest in the case of Rajendranagar (98.75%). The ischolar_main mean square error and sum of square error varied from 0.4 to 1.3 mm and 615 to 1745 mm respectively. The model predicted the maximum increase in average annual rainfall of 5.16% in 2030 and 9.5% in 2060 for Yacharam compared to Hayathnagar and Rajendranagar over the normal annual rainfall of the base period (1980-2010). However, the model predicted increase in average seasonal rainfall for Hayathnagar (6.2% in 2030 and 8.8% in 2060). In case of air temperature, the model predicted increase in maximum temperature in the range 1-1.53% and 2.5% for 2030 and 2060 respectively, for these locations whereas minimum temperature decreased in the range 3.7-10.2% and 6.3- 11.7% respectively, for 2030 and 2060. The performance of LARS-WG model was ranked high with maximum model efficiency in all selected mandals of Ranga Reddy district in southern Telangana. This model can be replicated in other mandals of southern Telangana as climate characteristics of the present mandals are similar to other districts in the region.

Keywords

Climate Change, Rainfall, Temperature, Weather-Generating Models.

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K. S. Reddy ¹, M. Kumar ¹, V. Maruthi ², B. Umesha ¹, Vijayalaxmi ¹, C. V. K. Nageswar Rao ¹

Affiliations
1 Division of Resource Management, Central Research Institute for Dryland Agriculture, Santhoshnagar, Saidabad, Hyderabad 500 059, IN
2 Division of Crop Science, Central Research Institute for Dryland Agriculture, Santhoshnagar, Saidabad, Hyderabad 500 059, IN

Abstract

Water application systems under wells extracting groundwater are one of the major factors influencing climate change in the agricultural sector. In the context of growing demand for adaption of pressurized irrigation with electric pumps in South Central India, the present study was undertaken to assess the carbon dioxide emission (CO₂ e) for different irrigation systems. The crop water requirements and pumpsets prevailing in the area were considered for estimation of CO₂ e. The estimation includes operational energy consumption, well digging, installation and manufacturing of the irrigation system as well as the pumpsets. The irrigation systems used in major crops under wells include surface (rice, maize, groundnut, vegetables and sugarcane), raingun (maize, groundnut, vegetables and sugarcane), sprinkler (maize, groundnut and vegetables) and drip (vegetable and sugarcane). The analysis indicated that the energy used in pumping irrigation water made the highest contribution to total CO₂ e footprint, which ranged from 2.52 to 15.72 t/ha depending on the irrigation system. Sugarcane crop showed maximum energy requirement (17.27 MWh/ha) under surface irrigation system, contributing 15.72 t/ha CO₂ e. Maximum reduction in energy requirement and CO₂ e was recorded in the case of drip (11.52 MWh/ha; 10.48 t/ha) system followed by sprinkler (12.58 MWh/ha; 11.52 t/ha) and raingun (14.81 MWh/ha; 13.47 t/ha) under tube wells. It was observed that among all the irrigation systems, the drip system gave the lowest CO₂ e indicating the maximum climate change mitigation potential in the irrigation sector of selected region under wells.

Keywords

Carbon Dioxide Emission, Climate Change, Groundwater, Pressurized Irrigation, Tube and Dug Wells.

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K. S. Reddy ¹, M. Kumar ¹, V. Maruthi ², P. Lakshminarayana ¹, Vijayalakshmi ¹, B. Umesha ¹, Y. V. K. Reddy ¹

Affiliations
1 Division of Resource Management, ICAR-Central Research Institute for Dryland Agriculture, Hyderabad 500 059, IN
2 Division of Crop Sciences, ICAR-Central Research Institute for Dryland Agriculture, Hyderabad 500 059, IN

Abstract

Maize (Zea mays L.) is predominantly grown as a commercial crop in river basins of lower Krishna, Telangana, South India. A long-term crop water balance analysis for maize in two sowing windows (normal sowing: 20 June; late sowing: 25 July) was done for A1b climate change scenario using the downscaled climate data from the GCM model ECHAM5. The crop water balance parameters such as rainfall, effective rainfall, crop evapotranspiration (ET) and irrigation requirements of maize during the two sowing windows were estimated using the CROPWAT model for the base period (1961-90) and long-term period (2011-50; mid-century). In the normal sowing window of maize, there was significant variation in the decadal crop ET (24% to 28%) and irrigation requirements (-7% to 26%) having increasing trend during 2011-2050 over base period. The amount of average decadal rainfall and effective rainfall decreased during 2011-2050 in the range 6% to -23% and 10% to -7% respectively, over the base period. The decadal average rainfall and effective rainfall showed increasing trends of 147-151% and 96-110% respectively, over base period in late sowing window. Also, the crop ET and irrigation requirements exhibited a decreasing trend. The study indicates a shift in the seasonal rainfall in normal sowing window during June to July and it extends up to October and November after the season, indicating more rainfall in late sowing window of maize and scope for rainwater harvesting in the lower Krishna river basin for sustaining maize production.

Keywords

Climate Change, Crop Evapotranspiration, Effective Rainfall, Irrigation Water Requirement, Maize.

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