GrassRest - Grassland restoration in Northern China from a whole plant perspective

Status
current
Project begin
01.05.2011
Project end
30.04.2013
Project-Homepage
www.grassnet.info
Keywords
China, degradation, Gras, Renaturierung
Description

Project dscription

Background: Inner Mongolia grasslands of Northern China are representative for large areas of the Eurasian steppe belt (Bai et al. 2004). These ecosystems, ranging from South-Eastern Europe to Mongolia and Northern China are the livelihood base for millions of livestock farmers. In Inner Mongolia, the replacement of nomadic and semi-nomadic pastoralists by stationary livestock farming systems during the last three decades and the simultaneous increase of livestock from 5 to more than 20 million ungulates resulted in extensive degradation affecting more than 80% of the natural grasslands (Zhang et al. 2004, Tong et al. 2004). Overgrazing can amplify effects of wind and water erosion, increase soil compaction and the encroachment of less palatable plant species, induce the loss of soil carbon and nitrogen stocks, and reduce soil fertility (Steffens et al. 2008, 2009, Gao et al. 2009). In addition to consequences of overgrazing, effects of climate change are threatening the natural grasslands through increased variability of rainfall and raising temperatures (IPCC 2007).

In the recent years distinct measures were undertaken to decrease grazing pressure and mitigate grassland degradation. In this context, restoration ecology became more and more important to cope with grassland degradation and to develop management options to improve grassland quality towards a sustainable livestock based land-use system (Jiang et al. 2006, Li et al. 2007, 2008). Overgrazing and climate change result in unpredictable effects on grassland productivity due to multiple feedbacks on resources availability. During the restoration process, the limited availability of resources often constrain plant establishment and growth, but most research approaches focus on aboveground plant productivity dynamics to assess restoration progress rather than following a whole plant perspective including the belowground part.

In temperate steppe ecosystems plant carbon is predominantly located belowground and it is evident that resource allocation between shoot and root plays an important role in ecosystem’s resilience in response to multiple stresses (Gao et al. 2008, Giese et al. 2009). Plant species of steppe ecosystems are usually well adapted to water stress and harsh winter conditions of the continental climate by storing nutrients and carbohydrates in perennial belowground organs. A depletion of these belowground resources increases vulnerability of plants to stress periods and endangers the restoration process. The belowground response of grassland plants to multiple stresses thus can be a key process in grassland restoration and ecosystem’s adaptation capacity to climate variability or change. Therefore, assessing different restoration techniques from a whole plant perspective will contribute to optimize grassland management towards a sustainable land-use practice to assure farmers income from livestock based systems. The intended new cooperation of the University of Hohenheim (UHOH), the North East Normal University (NENU) in Changchun and the International Livestock Research Institute (ILRI), will create synergy effects combining long-term experience in plant stress physiology, grassland ecology, and livestock management to strengthen the efforts to restore natural grassland ecosystem functions and services in a global perspective.

Goal: To optimize restoration strategies of degraded semi-arid grasslands by providing indicators of improved resource use efficiency

Purpose: To enable policy makers in agricultural research to develop strategies to improve grassland restoration and to help farmers to adapt their land-use practice towards a sustainable land-use system.

Expected outputs:

1.     Understanding the effects of different restoration techniques on below- and aboveground productivity, biomass partitioning, nutrient dynamics, diversity and carbon sequestration potential

2.    Understanding the response mechanisms of dominant Inner Mongolia grassland plant species to greenhouse-based multiple stress experiments

3.     Identification of indicators for optimized restoration management  

a) Total net primary production, incl. above- and belowground net primary production.

b) Carbon and nitrogen storage.

c) Fodder quality and root carbohydrates.

The expected outputs are of relevance for practical agriculture and animal husbandry:

1.     A further understanding of grassland restoration from a whole plant perspective will enable to select for most effective measurements to increase grassland performance after degradation.

2.     Understanding single plants stress response will help to select the best species mix for restoration purposes. Stress sensitive species should be avoided for heavily degraded and vulnerable grassland sites or early stages of restoration. Stress tolerant species should be promoted for grazing sites.

3.   a)  Grassland productivity is the basis of livestock farming and thus directly linked to animal production and farmer’s income.

b)    Restoration methods should increase grassland C and N sequestration. Degraded soil organic matter pools weaken ecosystems resilience to climate variability (drought) and grazing. Grasslands vulnerable to stresses increase the farmers risk for loss of production.

c)     Restoration methods should aim to increase crude protein of grasses and forbs and root carbohydrates. Increased fodder quality corresponds to higher animal production potential per unit dry matter. Perennial root carbohydrates function as energy source and increase plant re-growth ability after defoliation, winter, and dry spells and thus contribute to long-term sustainable grassland production.

Involved persons

Involved institutions

Further Information

Sponsors

  • GIZ/BMZ (Small Grant)