Delaying application time of slow-release fertilizer increases soil rhizosphere nitrogen content,root activity,and grain yield of spring maize

Application of slow-release fertilizer(SF)is a nutrient-management measure aimed at improving maize nutrient use and yield and saving labor cost.One-time application of SF at sowing usually results in nutrient deficiency during the post-silking stage,owing to the long growth period of spring maize.This study was conducted to investigate the effects on spring maize of SF application stage(zero,three-,and six-leaf stages,designated as SF0,SF3,and SF6,respectively)on grain yield,total soil rhizosphere nitrogen(N)content,and root activity,in comparison with the conventional fertilization mode(CF,application of compound fertilizer at sowing time,and topdressing urea at six-leaf and tasseling stages)at the same fertilization level as the control.Compared with no fertilization(F0)and CF,SF increased grain number and weight.The maize cultivars Suyu 30(SY30)and Jiangyu 877(JY877)produced the highest grain yield and net return under SF6 treatment over the three years.SF6 increased enzymatic activities including oxidoreductase,hydrolase,transferase,and lyase in rhizosphere soil at silking(R1)and milking stages(R3).SF6 increased the total N contents of rhizosphere soil by 7.1%at R1 and 9.2%R3 stages compared with SF0.The activities of antioxidant enzymes in roots were increased under SF6 treatments at R1and R3.The mean root activities of SF0,SF3,and SF6 increased by 7.1%,12.8%,and 20.5%compared with CF at R1 and by 8.8%,13.0%,and 23.5%at R3.Delaying the application time of SF could increase grain yield by increasing total N content of rhizosphere soil,delaying root senescence,and increasing root activity at the late reproductive stage.Applying SF at the six-leaf stage is recommended as an effective fertilization strategy for the sustainable production of spring maize in southern China.

Analysis of the Predictive Factors for the Recurrence of Deep Infiltrating Endometriosis:A 2-Year Prospective Study

Objective:To investigate factors that may be associated with the recurrence of deep infiltrating endometriosis(DIE)and DIE-related symptoms.Methods:Starting in September 2014,women with a confirmed diagnosis of DIE based on surgical and histological findings were included in the prospective study with a 2-year follow-up in our hospital.A total of 84 consecutive patients were included,all of whom underwent laparoscopic surgery.The data were obtained from the medical records of the patients.Follow-up data,including presence of pain as assessed using the visual analog scale(VAS)score and ultrasonography/magnetic resonance imaging findings,were obtained at 3,6,9,12,and 24 months postoperatively.Variables,such as age,body mass index,severity and duration of symptoms,size and location of the lesion,and pre-and postoperative medical treatment,were evaluated using univariate and multivariate analyses to identify factors correlated to recurrence.Results:A total of 11(13.1%)patients presented with recurrence,with a mean time to recurrence of 14.2 months.The univariate analysis showed that the longer duration of menstruation(7.4 vs.6.0,P=0.010),the more advanced revised American Fertility Society(rAFS)stage(Stages I and II vs.III and IV,χ^(2)=9.964,P=0.001),the higher VAS score for dysmenorrhea(9.4 vs.5.2,P=0.001),and the more severe pain during defecation(7.8 vs.4.8,P=0.016)were positively correlated to DIE recurrence.However,the multivariate analysis also revealed that a more severe dysmenorrhea and advanced rAFS stage were the independent factors associated with the recurrence of DIE,with an odds ratio of 1.895(confidence interval[CI]:1.061-3.385,P=0.031)and 4.310(CI:1.091-17.028,P=0.037),respectively.Conclusions:More than 10%of patients presented with recurrence of DIE 2 years after surgery.Recurrence of DIE was more common in patients who complained of more severe dysmenorrhea and had an advanced rAFS stage.