Zhang Wenhao

Scientific basis and practical ways forsustainable development of China’s pasture regions

Great changes have taken place in the dietary structure of urban and rural residents in China since the country’s reform and opening starting from the end of 1970s. During the past three decades, grain consumption has reduced and animal food consumption has increased significantly, causing a sharply increased demand of forage. However, the country’s cropping structure has not been adjusted timely, resulting in a large number of grain to be used as forage. Although China has a grassland area of 4×10 8 hectares, which should play an important role in the country’s ecological security and food security, its forage grass and livestock production are considerably low, with different levels of degradation across the grasslands, so that it is far not satisfied with a need of animal husbandry development, because of its extensive management and less input of prataculture. Our analysis showed that developing artificial pasture, which grass yield can be more than 10 times higher than natural grassland, is an effective way to promote the production of forage grass in China. We thus developed the “animal-husbandry development” model, which uses a small area (less than 10% of the grassland) with high quality site to develop intensive artificial pasture to enhance forage grass production, and prevents a large area of the natural grassland (more than 90% of the grassland) from degradation and over-grazing. In order to implement “animal husbandry development” model, we proposed to construct an “eco-animal husbandry experimental zone” in the grassland areas. The “experimental zone” is planned and designed as a coupled system of nature-economy-society complex in a considerably large area, to promote production of artificial pasture and animal husbandry and improve ecological functioning of natural grassland. This paper also discusses the bottleneck issues about socio-economic development in pasturing areas, and proposed seven principles for the development of pasturing areas, including grass breeding, artificial grassland planting, efficient harvesting, efficient use of water, protection and better use of natural grassland, trade-off between grass production and ecological functioning, and system development.

Optimal formula feed is a key for efficient transformation of forage to animal products in grass-based livestock husbandry

The animal husbandry in China can be categorized broadly into pastoral and farming animal husbandry. Grazing has long been a main form of animal husbandry in the pastoral areas. The lack of sufficient supply of high quality forage is a key factor that limits the development of animal husbandry in both the pastoral and farming animal husbandry. Natural grasslands in China have degraded seriously since 1970s due to overgrazing and global climate changes, exhibiting low productivity and poor ecological functions. Import of forages (mainly alfalfa and oat hay) from overseas (mainly USA and Australia) has increased markedly in recent years. The insufficiency for supply of high quality of forage and poor ecological function of natural grasslands are major issues limiting the social and economical development in large pastoral areas in China. How to develop a high-efficiency and environmentally-friendly animal husbandry has been a big challenge in these areas. The development of concept of “Grass-based Livestock Husbandry (GLH)” is novel in solving these problems by integrating the processes associated with grassland management, forage planting, forage processing and livestock feeding. More specifically, the GAH theory emphasizes that grasslands are of ecological importance with less function for forage production, while the production of high quality of forage will rely on the development of artificial pasture to sustain the livestock husbandry. Extensive efforts have been made to manage and restore the degraded grasslands, and develop artificial pasture with great yield, high quality and use efficiency of resources. In contrast, less attention has been paid to harvest, process, and store as well as utilize the forages for livestock husbandry in both pastoral and farming areas. In this paper, we discussed the effective ways to supply forage to livestock in both pastoral and farming areas. We further explored the technical solutions to improve the insufficient supply of forage in the two areas. We specifically highlighted the important roles of artificial pasture in provision of sufficient forage with high quality for livestock, thus protecting the natural grasslands and maximizing their ecological functions. Finally, we proposed that development of formulated forage systems with high efficiency is a crucial step for success in the grass-based livestock husbandry, and that green animal product is a main driver for development of ecological grass-based livestock husbandry in China. These theories and methodologies have great implications in development and practice of the grass-based livestock husbandry in both pastoral and farming areas.

Establishment and management of alfalfa pasture in cold regions of China

Grasslands occur naturally in cold regions in China, and are the traditional animal husbandry base. Natural grasslands have degraded severely due mainly to heavy use and global climate change, distinguished with low productivity and poor ecological function. The small scales and low-industrialization levels of alfalfa ( Medicago sativa L.) pasture are bottlenecks for development of modern animal husbandry in China. Therefore, forage production from natural grasslands cannot fully meet the demands for animal husbandry. Development of high-yield alfalfa pasture is an effective way to solve these problems. In this review, we systematically analyzed both domestic and international markets for alfalfa. Currently, alfalfa hay production in China can only supply less than 50% of total alfalfa demands, and more than 50% of alfalfa hay has to be imported from overseas countries, mainly from USA. On the one hand, the lack of forage supply greatly restricts development of animal husbandry in the alpine regions of China, which is a traditional base of animal husbandry in China. On the other hand, there are large areas of lands that can be used to develop alfalfa pasture in these regions. As a key component of “Grass-based Animal Husbandry”, establishment of alfalfa pasture with high yield and quality as well as high resource efficiency is of importance for the successful development of “Grass-based Animal Husbandry” in China. The development of large scale of alfalfa pasture in the alpine regions is hindered by the lack of alfalfa varieties adapted to the alpine regions and poor alfalfa establishment and management technologies. In practice, the management regimes of crops are often copied to manage alfalfa pasture. However, the crop and pasture systems differ markedly. For example, crops and alfalfa are used for harvesting grains and above-ground biomass, respectively. Moreover, crops are often annual, while alfalfa is perennial. To solve these problems, we developed comprehensive technologies in alfalfa pasture in the alpine regions. More specifically, we selected several elite alfalfa varieties that exhibited high yield and were capable of surviving the cold winters. We further developed planting methodologies that allowed for the rapid establishment of seedlings, facilitation of leaf growth, and minimizing weeds and water evaporation. Our results showed that production of alfalfa hay in the alpine region of Hulunbeir, Inner Monogolia Autonomous Region, China, was 5000 kg ha −1 in the first year of planting, and it reached 9000 kg ha −1 in the second year of planting. The crude protein contents of the alfalfa were as high as 20%. These achievements highlight that the development of high yield alfalfa pasture is feasible, and that it provides technical support and theoretical guidance in development and management of high quality alfalfa pasture in these regions.

Current status of grassland degradation and measures for grassland restoration in northern China

Grasslands in northern China are traditionally important bases for livestock production and ecological barriers for China. However, these grasslands degraded extensively due to global climatic change and poor management during the past half century. Such grassland degradation leads to dramatic declines in multiple ecosystem functions. Here we first analyzed the current status of these grasslands, with emphasizing on production and ecological functions. In general, the capability of annual aboveground biomass production in these grasslands has been greatly impaired in comparison with that in 1980s and not recovered to normal level despite application of some restoration measures. As indicated by large inter-annual variation in grasses production, the capability of feedback regulation to buffer the negative impacts of climatic change was greatly eroded. Carrying capability for animals of grasslands at the national level displayed an increasing trend in recent years, while the actual stocking capacity remained higher than its potential. Total water resources in these grasslands have declined greatly as evidenced by rapid losses of lakes and drying up of rivers. We next reviewed the major measures for restoration and management of grasslands in northern China during the past decades and analyzed their advantages and constrains, respectively. Fencing (prohibition of grazing) has been used in some area, but was difficult to extend to a larger area mainly due to economic reasons. Seasonal grazing and rotational grazing have been recommended by local governments. However, the outcomes of these measures are limited. Tillage and harrowing have also been suggested for restoration of the degraded grasslands, but it has rarely been largely used due to higher costs and inconsistent results. Reseeding grasses and/or legumes in natural grasslands are potentially useful for grassland restoration, but frequent droughts limit its application. Rotational mowing is a good measure for hey production system. Moreover, the yearly shift between grazing and mowing is much better than successive grazing or mowing. Fertilization has often been used in grassland management in most developed countries. However, this measure has not been widely applied in China due mainly to the lack of information on the types, rates and applied methods. Finally, based on our long-term studies on grassland ecology and practices in grassland restoration, especially the demonstration work in Hulunbuir grasslands, we propose some proposition on policy making and development of technical measures related to sustainable management of the grasslands in northern China. Ecological monitoring and evaluation of native grasslands should be done, and local farmers should be compensated for based on the evaluation results. Establishing cultivated pastures with high productivity and quality of forage grasses are key measures for protection and restoration of the degraded natural grasslands. As above-mentioned measures on grassland restoration usually take long time (from several years to decades) to restore the natural grasslands, new technical measures to restore the degraded natural grasslands are urgently needed. This review has important implications for improving the production and ecological functions of natural grasslands in general and for the sustainability of grass-based animal husbandry in particular.