| To compare the effects of species, organic manure, NPK and sophora alopecuroides straw on leaf photosynthetic characteristics, an artificial pasture planting in Ningxia in arid sandy area using L18 (61×36) orthogonal test was implemented. The results showed that the optimal combination to enhance net photosynthetic rate (Pn), stomatal conductance (Gs), water use efficiency (WUE), chlorophyll content and intercellular CO2 concentration(Ci) was to use Melilotus offcinalia + organic manure 36 t·hm-2+NPK (N 165 kg·hm-2, P 135 kg·hm-2 and K 135 kg·hm-2) + straw 15 t·hm-2. The combination was consistent with the Treatment 15 that had the highest Pn, Gs, WUE, chlorophyll content and lowest Ci. The influencing effects on transpiration rate (Tr), Pn, Gs, Ci were in the order of species>organic manure>NPK>straw and WUE, and for chlorophyll content, the order was species>NPK>organic manure>straw. The effects of species and organic manure on Pn, transpiration rate, Gs, WUE and chlorophyll content were highly significant (P<0.01), and those of NPK on Pn, Gs, WUE and chlorophyll content were highly significant (P<0.01) but significant (P<0.05) on transpiration and rate Ci. Effects of straw on Pn and WUE were highly significant (P<0.01). Legume was significantly (P<0.05) higher in Pn, Tr, Gs, WUE and chlorophyll content than gramineae. Melilotus suaveolens had stronger productive performance than Medicago sativa and Astragalus adsurgens, and Elymus cylindricus had higher Pn, WUE and chlorophyll content than Agropyron cristatum and Agropyron mongolicum Keng. Pn had highly significant positive correlations with Tr, Gs, WUE and chlorophyll content and significant negative correlation with Ci (P<0.01). |