Quantifying the thermal heat requirement of Brassica in assessing biophysical parameters under semi-arid microenvironments

Abstract

Evaluation of the thermal heat requirement of Brassica spp. across agro-ecological regions is required in order to understand the further effects of climate change. Spatio-temporal changes in hydrothermal regimes are likely to affect the physiological growth pattern of the crop, which in turn will affect economic yields and crop quality. Such information is helpful in developing crop simulation models to describe the differential thermal regimes that prevail at different phenophases of the crop. Thus, the current lack of quantitative information on the thermal heat requirement of Brassica crops under debranched microenvironments prompted the present study, which set out to examine the response of biophysical parameters [leaf area index (LAI), dry biomass production, seed yield and oil content] to modified microenvironments. Following 2 years of field experiments on Typic Ustocrepts soils under semi-arid climatic conditions, it was concluded that the Brassica crop is significantly responsive to microenvironment modification. A highly significant and curvilinear relationship was observed between LAI and dry biomass production with accumulated heat units, with thermal accumulation explaining >or=80% of the variation in LAI and dry biomass production. It was further observed that the economic seed yield and oil content, which are a function of the prevailing weather conditions, were significantly responsive to the heat units accumulated from sowing to 50% physiological maturity. Linear regression analysis showed that growing degree days (GDD) could indicate 60-70% variation in seed yield and oil content, probably because of the significant response to differential thermal microenvironments. The present study illustrates the statistically strong and significant response of biophysical parameters of Brassica spp. to microenvironment modification in semi-arid regions of northern India.

Influence of Different Sowing Date on the Morphology, Phenology and Thermal Indices of Rapeseed: A Review

“…Adak and Chakravarty [28] found that fewer heat units were absorbed on October 30 than on October 15 sown brassica. Akhter et al [18] laid out a field experiment of rapeseed on four different dates on S1-18 Oct, S2-2 Nov, S3-17 Nov, S4-3 Dec and the results showed that the growing degree day (GDD), heliothermal unit (HTU) and heat use efficiency (HUE requirement decreased with delayed sowing to different phenological stages and S1 required the highest followed by S2, S3 and S4 at all phenological stages.…”

Implications Test of Temperature, Rainfall and Carbon Dioxide Combinations on Indian Mustard Using Multi Crop Simulation Models for Western Haryana, India

“…Fertilization effects on CO 2 on crop production will be necessary in future climate change scenarios to offset the anticipated negative impacts of high temperature and to feed ever increasing human population (Ainsworth et al, 2008). Indian mustard suffers from exposure of low temperature during vegetative and early pod filling stage and relatively higher temperature during vegetative and early pod filling stage and relatively higher temperature during grain filling and maturity (Kumar et al, 2007;Adak et al, 2010).…”

Forecasting phenology of mustard crop in North-western Himalayas

“…This duration for particular species could be predicted using the sum of daily air temperatures. Phenological development in mustard crop at Delhi conditions is also considered to be altered primarily by photoperiod, with a general shortening of phases as day length increases (Adak and Chakravarty, 2010). Heat use efficiency (HUE) i.e., efficiency of utilization of heat in terms of dry matter accumulation depend on crop type, genetic factors and sowing time and has great practical application (Rao et al, 1999).…”