Dynamic Changes of Farmland Water and Heat Flux under Straw Mulching and Its Response to Meteorological Factors in North China Plain
Revealing the dynamic changes of water and heat fluxes in straw-covered farmland ecosystems can provide a theoretical basis for the quantitative regulation of efficient water use by crops under agronomic mulching.Two treatments of straw mulching(S)and none mulching(N)were set up in the experiment.The dynamic changes of net radiation flux(Rn),latent heat flux(λET),sensible heat flux(H)and soil heat flux(G)of farmland energy flux elements under straw mulching in North China Plain and their responses to meteorological factors were studied by using Bowen ratio energy balance method and measured data.The results showed that the diurnal variation of Rn,λET and H in each growth period showed an obvious single-peak pattern.Compared with N treatment,S treatment mainly reduced the daily peak of Rn,λET and H in each growth period in both wheat and maize growing seasons.However,from the perspective of daily mean value,S treatment increased the proportion of λET in Rn in wheat growing season,and the proportion of λET in Rn in the total growth period of S treatment(68.8%)was slightly higher than that of N treatment(68.4%).The proportion of λET to Rn in the total growth period of S treatment(65.0%)was lower than that of N treatment(65.9%).The meteorological factor that had the greatest influence on instantaneous λET in wheat growing season and maize growing season was Rn,and the other factors had little influence.Each meteorological factor affects instantaneous λET through direct and indirect effects.The influence of Rn on instantaneous λET is mainly reflected in the direct effect,and the other factors are mainly reflected in the indirect effect.
Straw mulchingBowen ratioWater and heat fluxMeteorological factors
万方数据
维普
