Impact of environmental changes and land management practices on wheat production in India

Abstract

Abstract. Spring wheat is a major food crop that is a staple for a large number of people in India and the world. To address the issue of food security, it is essential to understand how the productivity of spring wheat varies with changes in environmental conditions and agricultural management practices. The goal of this study is to quantify the role of different environmental factors and management practices on wheat production in India in recent years (1980 to 2016). Elevated atmospheric CO2 concentration ([CO2]) and climate change are identified as two major factors that represent changes in the environment. The addition of nitrogen fertilizers and irrigation practices are the two land management factors considered in this study. To study the effects of these factors on wheat growth and production, we developed crop growth processes for spring wheat in India and implemented them in the Integrated Science Assessment Model (ISAM), a state-of-the-art land model. The model is able to simulate the observed leaf area index (LAI) at the site scale and observed production at the country scale. Numerical experiments are conducted with the model to quantify the effect of each factor on wheat production on a country scale for India. Our results show that elevated [CO2] levels, water availability through irrigation, and nitrogen fertilizers have led to an increase in annual wheat production at 0.67, 0.25, and 0.26 Mt yr−1, respectively, averaged over the time period 1980–2016. However, elevated temperatures have reduced the total wheat production at a rate of 0.39 Mt yr−1 during the study period. Overall, the [CO2], irrigation, fertilizers, and temperature forcings have led to 22 Mt (30 %), 8.47 Mt (12 %), 10.63 Mt (15 %), and −13 Mt (−18 %) changes in countrywide production, respectively. The magnitudes of these factors spatially vary across the country thereby affecting production at regional scales. Results show that favourable growing season temperatures, moderate to high fertilizer application, high availability of irrigation facilities, and moderate water demand make the Indo-Gangetic Plain the most productive region, while the arid north-western region is the least productive due to high temperatures and lack of irrigation facilities to meet the high water demand.

Gender, caste, and heterogeneous farmer preferences for wheat varietal traits in rural India

“…More research is required to understand farmers’ relative indifference towards the heat-tolerant attribute because of two reasons. One, wheat production is severely affected by warming atmospheric temperatures, particularly in central and eastern India [ 83 ]. Two, there is increasing investment in research-and-development programs for breeding and popularizing heat-tolerant wheat varieties in the Indian subcontinent [ 84 ].…”

Carbon fluxes in spring wheat agroecosystems in India

“…Carbon fluxes were measured during the 2013-14 growing season, and phenology data was measured during the latter two seasons. The ISAM was calibrated and validated using phenology observations from the 2014-2015 and 2015-2016 growing seasons (Gahlot et al, 2020). Taking this work forward, we used the same model to estimate the carbon fluxes in the spring wheat croplands of India.…”

“…This study used the ISAM in the same configuration as Gahlot et al (2020). For brevity, here we only briefly describe the model and its configuration.…”

“…For brevity, here we only briefly describe the model and its configuration. More details are available in Gahlot et al (2020). ISAM has a module for simulating generic C3 crops (Song et al, 2013).…”

“…The specific goals of this paper are (i) to validate the and agricultural management practices. Gahlot et al (2020) implemented a spring wheat module in ISAM and used it to simulate the phenology and production of spring wheat at the site scale at the Indian Agriculture Research Institute (IARI), Delhi, and regional scale for the entire India.…”