羊尿对典型草原不同生活型草地植物生长特性的影响

The effects of sheep urine on growing characteristics of different life form plants in a Chinese steppe grassland

连续2a研究了施尿量(4,2,1L/m2和0L/m2)和施尿期(营养期和生殖期)对典型草原多年生密丛型禾本科植物长芒草(Stipa bungeana)、多年生轴根型菊科植物茵陈蒿(Artemisia capillaries)和多年生半灌木豆科植物胡枝子(Lespedeza davurica)生长特性的影响。结果表明,不同植物对畜尿沉积的响应不同,并受施尿量和施尿时期的作用。畜尿对草地植物具短期(4周内)灼烧作用,灼烧主要发生于尿斑中心;畜尿对长芒草生长具长期正效应(4周后),对茵陈蒿和胡枝子生长具持续负效应,此效应持续至少2a且随施尿量降低而降低。一般尿斑中心(4L/m2)所有植物伤害,尿斑中心至边缘圈植物局部器官(嫩枝叶)伤害(2～4L/m2),尿斑外渗区域(1～2L/m2)所有植物无显著伤害。高施尿量(2～4L/m2)下,长芒草具较高的年均分蘖数和地上生物量,而胡枝子和茵陈蒿与之相反。尿斑处3种植物具较高的分蘖(枝)死亡率和死物质率。茵陈蒿对各时期施尿均反应敏感,胡枝子和长芒草对生殖期施尿更敏感。尿斑处禾草枯黄期延迟,返青期提前。

The effects of sheep urine deposition volume （0, 1,2 L/m^ or 4 L/m^2 ） and stage of plant growth at deposition （ vegetative or reproductive） on the growth characteristics of Stipa bungeana, Artemisia capillaries and Lespedeza davurica in Steppe grassland were determined. Measurements quantified treatment effects on the number and size of tillers or branches, and population biomass. The results indicate that the response of the three plant species to sheep urine deposition differs, and is influenced by both urine volume and stage of growth at deposition. Urine deposition had a short-term （ 1 - 4 weeks after application） scorch effect on grassland plant growth, which mainly occurred in the inner zone of urine patches. Application of urine had a long-term positive effect （ 〉 4 weeks after application） on S. bungeana growth and a long-term negative effect on A. capillaries and L. davurica growth, which lasted at least two years and decreased with decreasing urine volume. All species growing in the inner zone of urine patches （ equivalent to 4 L/m^2 ） were harmed by sheep urine deposition. While some species from the middle zone of patches （2 -4 L/m^2 ） were also harmed, no species were harmed in the outer zones （1 -2 L/m^2）. S. bungeana in higher sheep urine deposition plots （2 -4 L/m^2） had higher mean annual tiller numbers and aboveground biomass, whereas L. davurica and A. capillaries exhibited an inverse trend. All species growing in urine patches had a higher percentage of dead tillers or branches, and a higher percentage of dead biomass at first harvest. The reproductive and vegetative stages of A. capillaries and the reproductive stages of S. bungeana and L. davurica were sensitive to sheep urine deposition. In addition, S. bungeana growing in urine patches became active earlier in the spring and delayed senescence until later in the growing season than the control.