Influence of the adverse condition of shading-nets on yield and quality of flue-cured tobacco

The influence of the adverse condition of shading-nets in flue-cured tobacco was studied．The res ults show that the field clim ate changes remarkably under the shading-net cover．The average daily temperature decreases by 3.2"C ．The penetrating rate among plants reduces by 17.2％ ．The evaporations among rows and plants respectively drop 1.7mm and 1.0mm ．The climate change makes flue-cured tobacco delay in bud emergence and blossoming，and decrease its growth of roots，stems and leaves．The yield decreases to 1126．5kg／hm²．The percentage of the superior and medium tobacco reduces by 36．1％．Therefore．a 1ong term of covering is not suitable for flue-cured planting．