Variation and attribution of energy distribution for salinized sunflower farmland in arid area

Abstract

Agricultural water resources consumption and soil salinity interact with the distribution of radiation energy in arid salinized farmland. Understanding the temporal changes in energy distribution is necessary to enhance water resource use efficiency. Based on two years of monitoring the energy fluxes in a salinized sunflower field, it was found that field energy fluxes were dependent on available energy, and the temporal dynamics of energy distribution was strongly influenced by crop growth. As expected, soil moisture and meteorological conditions were the main factors limiting latent heat (LE) fluxes in the relatively dry year, with leaf area index showing a more significant positive correlation with LE under abundant soil moisture. Furthermore, path analysis revealed that soil moisture affected energy distribution at budding and flowering stages through the negative regulation of soil surface heat fluxes and the positive regulation of LE. The accumulation of soil salt decreased LE (with Pearson correlation coefficient of −0.59 and a total effect of −0.55), and positive regulated sensible heat (with Pearson correlation coefficient of 0.27 and a total effect of 0.31). Additionally, approximately 40% of actual evapotranspiration was contributed by groundwater, potentially influencing energy fluxes. Moreover, a negative correlation was observed between surface albedo and salinity, which might be another pathway influencing energy distribution. Our findings are important to understand energy distribution and water consumption during the crop growth period in salinized field in arid area.