摘要
施肥是苜蓿生产的重要管理措施之一,但苜蓿刈割后的追肥效应以及最佳追肥管理方案尚不明确。本研究旨在探讨追肥时间和不同氮、磷追施配比对苜蓿刈割后再生长的影响。以建植当年陇东苜蓿为试验材料,设置两个追肥时间(刈割当日和刈割后7 d,分别表示为T_(0)和T_(1))、3个氮肥水平(0、25和50 kg·hm^(-2) N,分别表示为N_(0)、N_(25)和N_(50))和3个磷肥水平(0、30、60 kg·hm^(-2) P_(2)O_(5),分别表示为P_(0)、P_(30)和P_(60)),并设3个重复,共54个小区。研究发现:1)建植当年苜蓿刈割后追肥促进了后茬苜蓿的生长,其中刈割后立即施用少量磷肥(T_(0)N_(0)P_(30))处理下株高最高,比对照(T_(0)N_(0)P_(0))增加了20.53%。刈割后追肥提高了苜蓿的叶茎比,在T1时进行高氮低磷配施(N_(50)P_(0)和N_(50)P_(30))中最为明显。2)第2茬苜蓿产量在不同处理间差异显著(P<0.05),其中刈割后立即高磷高氮追施(T_(0)N_(50)P_(60))下干物质和粗蛋白产量最高,分别为3.58和0.94 t·hm^(-2),与T_(1)处理下的结果有显著差异。刈割后追肥对苜蓿酸性洗涤纤维、中性洗涤纤维含量和相对饲用价值均无显著影响(P>0.05)。3)氮磷肥配比追施对单位体积土壤中后茬苜蓿的根长、根表面积、根体积和根生物量影响显著(P<0.05)。最大根长密度(2.66 mm·cm^(-3))和根表面积密度(7.75 mm^(2)·cm^(-3))出现在无肥(N_(0)P_(0))、T_(0)N_(25)P_(30)处理中,根体积密度在T_(1)N_(25)P_(30)条件下最大。不同处理的根系生物量差异较大,但均高于不施肥处理(N_(0)P_(0))。综上所述,在陇东黄土高原雨养农区,刈割后追施氮、磷肥促进了建植当年苜蓿的再生。在当地的生产实践中,建议在苜蓿刈割后立即追施少量磷肥(30 kg·hm^(-2) P_(2)O_(5))或每公顷配合追施50 kg N和60 kg P_(2)O_(5)。
Fertilization is one of the important management measures in alfalfa(Medicago sativa)production,but the comparative effect of different topdressing regimes after cutting alfalfa and the optimal fertilization management plan are not clear.Hence,the aim of this research was to investigate the effects on the growth and production of alfalfa,of topdressing time and different combinations of N and P fertilizer applied to stimulate regrowth after cutting.The treatments comprised a complete factorial combination of two application times[on the day the cut was made(T_(0))and 7 d after cutting(T_(1))],three levels of N fertilizer(0,25 and 50 kg·ha^(-1) N,designated N_(0),N_(25) and N_(50),respectively)and three levels of P fertilizer(0,30,60 kg·ha^(-1) P_(2)O_(5),designated P0,P30 and P60,respectively),with three replicates(54 plots in total).The alfalfa variety was“Longdong”and the experiment was conducted in the establishment year.It was found that:1)Topdressing after the first cut promoted the growth of the second crop of alfalfa.The highest alfalfa growth was achieved by applying a small amount of P fertilizer immediately after cutting(T_(0)N_(0)P_(30)),and it was 20.53%higher than the control treatment(T_(0)N_(0)P_(0)).In addition,topdressing after cutting could increase the alfalfa leaf∶stem.This effect was most evident in the high N-low P treatment combinations(N_(50)P_(0) and N_(50)P_(30))with topdressing at T1.2)The yield of the second crop of alfalfa differed significantly(P<0.05)between the various treatments.The highest hay and crude protein yields were 3.58 and 0.94 t·ha^(-1),respectively,and these occurred with application of a large amount of N and P fertilizer immediately after cutting(T_(0)N_(50)P_(60)),which were significantly different from that of the treatment after 7 days.Topdressing after cutting had no significant effects on alfalfa second cut acid detergent fiber,neutral detergent fiber or relative feeding values(P>0.05).3)Root length,root surface area,root volume and root biomass per cm3
作者
徐睿智
吴晓娟
杨惠敏
XU Rui-zhi;WU Xiao-juan;YANG Hui-min(State Key Laboratory of Grassland Agro-Ecosystems,College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730020,China)
出处
《草业学报》
CSCD
北大核心
2022年第1期195-204,共10页
Acta Prataculturae Sinica
基金
国家自然科学基金(31572460)资助。
关键词
紫花苜蓿
刈割后追肥
建植当年
饲草生产
Medicago sativa
topdressing after cutting
establishment year
crop production
