Nan ZhiBiao

Redesigning Livestock Systems to Improve Household Income and Reduce Stocking Rates in China’s Western Grasslands

Synopsis Results and implications of a study of rangeland/livestock systems in four counties in western China are discussed. Two key questions were posed: (1) Can changing the current livestock production system to an alternative enterprise, or (2) can changing key management practices in current enterprises increase household profit at same stocking rate (SR) or maintain profit at lower SR? The answers to these questions and their implications in terms of structural adjustment and attitudinal change for the long term sustainability of NW China are helpful in planning new livestock systems.

Stress tolerance mechanisms of 6 native plant species growing in China's northern grassland and their utilization

It is a long term work to assemble the knowledge needed to utilize the rich native plant resources to assist social and economic development in China. The progress of the research results and their application of mechanisms underlying the stress-tolerance in native plants including Zygophyllum xanthoxylum, Artemisia sphaerocephala, Microula sikkimensis, Achnatherum inebrians, Cleistogenes songorica and Leymus chinensis were reviewed in this paper. The main results and findings are as follows: based on discovering the physiological mechanism of drought tolerance of Z. xanthoxylum, the key genes involved in drought tolerance were cloned and applied into the genetic improvement of important legume forage lucerne (Medicago sativa) and lotus (Lotus corniculatus); the desert shrub A. sphaerocephala and alpine species M. sikkimensis contain high contents of polyunsaturated fatty acids, the highest contents being found in the seeds; the diversity of drunken horse grass fungal endophyte symbiont was investigated on a national scale. The alkaloids produced by the symbiont are the main reason for both increased plant stress tolerance and the toxicity symptoms observed after intake by grazing animals; the biological, physiological and molecular genetic characteristics of C. songorica were studied. As a result, the species is expected to be domesticated successfully. Technical information on procedures for pasture establishment and seed production of this species has been developed; the seed dormancy mechanisms of L. chinensis were explored, and techniques to effectively break dormancy were developed.

Effects of Achnatherum inebrians infected with Neotyphodium endophyte on accompanying species of Stipa capillata and Poa sphondylodes.

Drunken horse grass(Achnatherum inebrians),an intoxicating grass in native grasslands of Northwest China,often grows in conjunction with Stipacapillataand Poa sphondylodes.Competitive interactions between endophyte infected(E+)A.inebrians and endophyte free(E-)A.inebrians with S.capillataand P.sphondylodes were investigated.E+A.inebrians had a significant inhibition effect on percentage seed germination and seedling growth(P0.05),which declined significantly by 17.1%,13.6%,respectively.Similarly,seedling length declined 23.2%and by 16.3%;E+ plants had significant inhibition effects on tiller heights of S.capillataand P.sphondylodes from the first week after germination(P0.05)and on tiller numbers and total biomass(P0.05).E-A.inebrians had no significant effects on seed germination,seedling growth,tiller height,tiller number or total biomass(P0.05).S.capillataand P.sphondylodes had no significant effects on A.inebrians.In summary,E+A.inebrians showed significant antagonism to S.capillataand P.sphondylodes,but E-A.inebrians had no significant effects on the other two grasses.

Effects of sheep urine on growth characteristics of different life form plants in a Chinese steppe grassland

Abstract The effects of sheep urine deposition volume (0, 1, 2 or 4 L/m2) and deposition stage of plant growth (vegetative or reproductive) on the number and size of tillers/branches and the biomass of Stipa bungeana, Artemisia capillaries and Lespedeza davurica in a Chinese steppe grassland were determined. The results indicate that the response of the three plant species to sheep urine deposition differs, and is influenced by both urine deposition volume and deposition stage of plant growth. Urine deposition had a short-term scorch effect on grassland plants, which mainly occurred in the inner zone of urine patches. Urine application had a long-term positive effect on S. bungeana and a long-term negative effect on A. capillaries and L. davurica, which lasted at least two years and decreased with decrease in urine deposition volume. All species growing in the inner zone of urine patches were scorched by sheep urine deposition, some species in the marginal zone of patches were also scorched, while no species were scorched in the outer zones. The reproductive and vegetative stages of A. capillaries and the reproductive stages of S. bungeana and L. davurica were sensitive to sheep urine deposition.