Effects of Different Water Treatments on Water Use Feature for Monoculture and Mixed Cropping of Gramineous and Leguminous Forages

SU Ying; GAO Xue; ZHANG Huili; ZHU Lin

doi:10.15933/j.cnki.1004-3268.2018.02.008

Abstract：In order to understand water use feature of monculture and mixed cropping of leguminous and graminaceous forages under different water treatment conditions,the pot controlled experiment with three water treatments,i.e.severe water stress[T1,45% field capacity(FC)],moderate water stress[T2,55% FC],well watered[T3,75% FC]was used to study the yield,water use efficiency(WUE),carbon isotope resolution(Δ13C), and the relationship among yield,WUE and Δ13C was analyzed.The results showed that the WUEs of monocultures and mixed cropping under T1,T2 treatments were higher than those under T3 treatment.The WUE of Astragalus adsurgens was higher than that of Medicago sativa under three water conditions.Under T1 and T3 treatments,WUE of the combinations between Medicago sativa and Elymus dahuricus was higher than that of monoculture of Medicago sativa and lower than that of monoculture of Elymus dahuricus.Under T3 treatments,WUE of the mixtures between Astragalus adsurgens and Elymus dahuricus was higher than that of monoculture of Astragalus adsurgens and lower than that of monoculture of Elymus dahuricus.The Δ13C values of monocultures and mixtures increased in line with the increase in irrigation.The Δ13C values of Medicago sativa were lower than that of Elymus dahuricus under all the treatments in the sowing combinations with the ratio of leguminous and graminaceous being 3:7 and 7:3. However,the Δ13C values of Medicago sativa were higher than that of Elymus dahuricus under the T1,T3 treatments and same with Elymus dahuricu in combination with the ratio of leguminous and graminaceous being 5:5 under T2 treatment.The relationship between WUE and Δ13C was negative under T1 and T2 treatments,and positive under T3 treatment.In summary,moderate water deficit and mixed sowing were helpful to enhance WUE.