Effects Of Seeding Rate And Row Spacing On The Yield,Quality Of Alfalfa, And Soil Enzyme Activity Of Alfalfa Field In Arid Desert Oasis Of Gansu Province

In order to investigate the effect of seeding rate and row spacing on alfalfa,to explore for sophisticated field management theories that could improve yielding and quality of alfalfas,(Medicago sativa L.cv.Gannong No.3)an experiment was carried out in arid hungriness oasis area of northwest China since 2015 to 2017.This research was conducted in the form of a split plot design in a randomized complete block,with four replications.Main plot was four seeding rates(12,16,20,and 24 kg seed/ha)and sub plots were three equal row spacings(10,15,20 cm)and two wide-narrow row spacings(60+40 cm and 60+30 cm).Results showed that.1.This research indicates that plant height,yielding,crude protein,NDF,and ADF are significantly influenced by seeding rate and row spacing configuration,yet no significant influence is observed in stem-leaf ratio,fresh-dry ratio,crude fat,calcium,and phosphorus by seeding rate and row spacing.The plant height and hay yielding increases as seeding rate and row spacing rise,and plant height peaks(105.47 cm)at seeding rate of 16 kg/hm2 and row spacing of 20 cm,while hay yielding peaks(25386.6 kg/hm~2)at seeding rate of 20 kg/hm2 and row spacing of20 cm,after the peaks a decline noted.The amount of Crude protein,ADF,NDF decreases as seeding rate rises,and decrease after a noticeable increase as row spacing widens.The highest amount of crude protein(200.56 g/kg)and lowest ADF and NDF(292.58 g/kg and 294.96g/kg)is observed at the seeding rate of 16 kg/hm2 and row spacing of 10 cm.2.This research explores also the influence on ureases,alkaline phosphatases,dehydrogenases,and the seasonal change of soil respiration in alfalfa fields by differentiated seeding rate and row spacing.The activities of ureases,alkaline phosphatases,and dehydrogenases shows a parabola shaped increase and decrease,with a summit at the seeding rate of 16 kg/hm2 and row spacing of 20 cm;all three enzyme activities are higher in shallower soil stratum of 0–20 cm than that of 20-40cm.Significant seasonal soil respiration and enzyme activity varieties are noted that in summers alkaline phosphatases and dehydrogenases activities are maximized and in springs minimalized,while ureases activity is maximized in falls and minimalized in springs.Significant positive correlations are observed between enzyme activity and soil respiration.3.In this research,attributes as plant height,hay yielding,stem-leaf ratio,crude protein,crude fat,NDF,ADF,fresh-dry ratio,calcium,and phosphorus among different groups are compared in 2005–2007,and concludes that,for alfalfa cultivation in arid desert oases,the ideal seeding rate that leads to the highest yield(23927.83 kg/hm~2)is 20 kg/hm2,and row spacing 20 cm.This research could be used as a guidance for alfalfa cultivation.