| Sludge is a solid substance deposited in the process of sewage treatment,which contains essential mineral nutrients,organic matter and humic acid and auxin.The experiment with sufficient water and drought under two kinds of water of Bluegrass(Poa pratensis L.)application of IBA,tryptophan and sludge,determination of chlorophyll and carotenoid content,photosynthetic rate,turfgrass quality and leaf relative water content,water use efficiency,soil water and root growth the relevant indicators,the sludge of Bluegrass photosynthesis and water use efficiency and drought resistance effect.The split-plot experiment design was used,and the main factors were divided into water content and drought treatment.Full water capacity was 90%field water capacity.The moisture gradient of drought treatment was 90%,50%,30%,25%and rewatering 90%of field capacity of water in the study area.The secondary factors were divided into 5 treatments:CK,the exogenous IBA,the exogenous tryptophan,the sludge and the exogenous tryptophan and the sludge.The nitrogen was supplied by ammonium nitrate,and the sludge was supplied with ammonium nitrate,and each treatment was done with 5 replicates.Results show:(1)In the two water conditions,compared with CK,the application of IBA,tryptophan,sludge,sludge and tryptophan,chlorophyll and carotenoids were increased by 30%,15%,52%and 40%(P<0.05),two applied sludge content significantly(P<0.05);under the drought condition,compared with CK,all the treatments of photosynthetic rate increased by 80%(P<0.05).After rewatering,chlorophyll a carotenoid content and photosynthetic rate of sludge sludge showed the greatest impact,improve bluegrass leaf growth,and protection of plants against drought stress damage,improve the drought resistance of Bluegrass.(2)Under sufficient water condition,turfgrass quality by sludge impact,sewage sludge and tryptophan were 12%and 10%higher than that of CK(P<0.05);especially in the drought condition,sludge and sludge and tryptophan on Bluegrass turfgrass quality were increased by 37%and 35%(P<0.05);in the two water conditions,leaf sludge and tryptophan and the relative water contents of 20%and 15%higher than that of CK(P<0.05).The results showed that the water use efficiency of Kentucky bluegrass leaves was increased,and less water loss was obtained.(3)Under the drought condition,compared with CK,application of sewage sludge and water use rate of tryptophan significantly(P<0.05);under sufficient water condition,compared with CK,tryptophan,tryptophan and sludge and sludge treatment for root activity and weight were increased by 37%70%,47%(P<0.05),under the drought condition,all root vigor and weight decreased by 50%.The results showed that both sludge and tryptophan could maintain high water use efficiency and root activity under two water conditions.To sum up,the sludge could improve the photosynthesis of Bluegrass,and the sludge and tiyptophan could increase the underground biomass,so as to improve the water use efficiency,enhance the root growth and vitality,and improve the drought tolerance of Bluegrass. |
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