This review paper describes the livestock production systems in China, their status and trends, driving factors, and major issues with profound impact. Three distinct livestock production systems are discussed; grazing, mixed farming, and industrial systems. The ‘grazing system’ is generally characterised by harsh climate, rangeland, and low livestock output. Market forces, biophysical constraints and environmental concerns are putting a ceiling on the potential for intensification of the grazing system except in some areas where the agro-ecological potential permits. This system needs to be re-oriented towards adding ecosystem service provision, rather than mere production or subsistence. The ‘mixed farming system’, with the highest share of most kinds of livestock commodities, forms the backbone of China’s agriculture and is undertaking a notable intensification and specialisation process. The ‘industrial system’ is geographically concentrated in areas close to densely populated demand centers. Although growing fast, the share of national livestock output remains relatively small. The past two decades have seen a rapid growth in both consumption and production of livestock food products in China. This new food revolution has been driven to a great extent by the rapid growing economy, personal income and urbanisation. Among the most important issues related to livestock production systems in China are severe rangeland degradation, caused mainly by overexploitation of these lands, increasing demand and competition for feed grain, and environmental and public health risks associated with industrialised livestock production. China will have to cope with such challenges through proper policy and technological interventions to sustain the livestock development and simultaneously secure the natural resources and environmental health.

Alfalfa, an important forage legume, is an ideal crop for sustainable agriculture and a potential crop for bioenergy resources. Drought, one of the most common environmental stresses, substantially affects plant growth, development, and productivity. MicroRNAs (miRNAs) are newly discovered gene expression regulators that have been linked to several plant stress responses. To elucidate the role of miRNAs in drought stress regulation of alfalfa, a high-throughput sequencing approach was used to analyze 12 small RNA libraries comprising of four samples, each with three biological replicates. From the 12 libraries, we identified 348 known miRNAs belonging to 80 miRNA families, and 281 novel miRNAs, using Mireap software. Eighteen known miRNAs in roots and 12 known miRNAs in leaves were screened as drought-responsive miRNAs. With the exception of miR319d and miR157a which were upregulated under drought stress, the expression pattern of drought-responsive miRNAs was different between roots and leaves in alfalfa. This is the first study that has identified miR3512, miR3630, miR5213, miR5294, miR5368 and miR6173 as drought-responsive miRNAs. Target transcripts of drought-responsive miRNAs were computationally predicted. All 447 target genes for the known miRNAs were predicted using an online tool. This study provides a significant insight on understanding drought-responsive mechanisms of alfalfa.

Semi-arid grassland in northern China faces degradation and desertification problems, with fertilizer application appearing to be a potential solution by improving soil fertility and plant fields or biodiversity. In this study, mineral and organic fertilizers were used in a semi-arid natural grassland in Hebei Province for three years. The plant characteristics, biomass and species diversity index were assessed and analyzed. In the years 2016 and 2017, mineral fertilizers (RC) significantly increased the total aboveground biomass and the aboveground biomass, natural height, density and coverage of Leymus chinensis compared with organic fertilizers (RO), especially at a moderate application rate (RC₂). Leymus chinensis was first divided into its own group and then separated into four groups via cluster tree analysis. The importance values of Leymus chinensis showed continuous increases in mineral fertilizer treatments, but not for organic fertilizers. Margalef’s species richness indexes increased significantly (to 2.09) in the organic treatment (RO₁) when compared with RC₂. Thus, it was concluded that mineral fertilizers could enhance the position of Leymus chinensis in the natural grassland, while organic fertilizers could promote species biodiversity. This study also provides recommendations regarding the use of fertilizers for the purposes of increasing plant biomass and biodiversity in semi-arid grasslands of northern China.

Leymus chinensis (Trin.) is the dominant vegetation type in eastern Eurasian temperate grasslands but is decreasing due to the combined pressure of reduced precipitation and overgrazing. This study evaluated the separate and combined effects of precipitation and defoliation on net primary productivity (NPP) and composition of a L. chinensis steppe to promote the sustainable development of temperate grasslands through improved management practices. The effects of three precipitation gradients (precipitation unchanged, reduced by 50%, and increased by 50%) and two clipping intensities (clipping once or twice per year) were examined on NPP and composition of the L. chinensis community using a 7-year in situ controlled trial at the Guyuan State Key Monitoring and Research Station of Grassland Ecosystem in China. The results showed that: (1) a 50% reduction in natural precipitation significantly decreased NPP; a 50% increase in precipitation did not significantly increase NPP, but it decreased the importance value of L. chinensis because more water promoted the growth of competing species. (2) Clipping twice per year increased NPP, but the increase was from the dry matter of other species (DMO) component, and not from the dry matter of L. chinensis. (3) The standardized coefficients of a regression model (β) for DMO, NPP, and the importance value of L. chinensis were 0.685, 0.532, and −0.608 for precipitation, and 0.369, 0.419, and −0.276 for clipping mode, respectively. This study demonstrated that variation in precipitationis the key driver of NPP and composition of a L. chinensis steppe under the precipitation range and clipping intensities evaluated. This improved understanding of the effects of precipitation and clipping on NPP and composition will allow for improved, sustainable management of L. chinensis temperate grassland steppes.

Abrupt-chilling events threaten the survival of alfalfa plants, the ability to cope with such condition should be considered during cultivar selection in the production. To assess biochemical and molecular responses of alfalfa to abrupt chilling, the cultivars “WL440HQ” (WL) and “ZhaoDong” (ZD) were subjected to a five-phase experimental regime that included two abrupt-chilling events. The freezing tolerance of the crown was determined as the semi-lethal temperature (LT₅₀) calculated from electrolyte leakage. Soluble sugar concentrations were quantified by ion chromatography. The mRNA transcript levels of four genes encoding enzymes (β-amylase, sucrose phosphate synthase, galactinol synthase, and stachyose synthase) involved in sugar metabolism and two cold-regulated genes (Cas15A and K3-dehydrin) were quantified using quantitative real-time PCR analysis. During the abrupt-chilling events, the LT₅₀ decreased significantly in ZD but not in WL. The rapid response of ZD to abrupt chilling may have been due to the large increases in raffinose and stachyose concentrations, which were consistent with increased transcript levels of the galactinol synthase and stachyose synthase genes. Transcript levels of the cold-regulated genes Cas15A and K3-dehydrin were correlated with increased freezing tolerance under abrupt chilling. The results provide a reference for selection of appropriate cultivars to reduce the risk of crop damage in production areas where early autumn or late spring frosts are likely.

Alfalfa (Medicago sativa L.) is an important perennial legume forage that is cultivated in saline soil worldwide. This study aimed to clarify the effects of organic base fertilizer and inorganic topdressing on the productivity of alfalfa growing in saline soil. A three-year field study was conducted in which alfalfa was grown in the saline soil of the Huanghe River Delta with a control (no fertilizer) and three treatments: organic base fertilizer (Base), topdressing with urea fertilizer (Top), and combined base and topdressing fertilizers (BT). The productivity in the BT and Base treatments was 13.21 and 13.82 t·hm⁻² in 3 years, significantly higher than that in the Top treatment and the control. The increased productivity in the BT and Base treatments were because organic matter promoted root growth of alfalfa seedlings in saline soil. The diversity of the soil bacterial community was not affected by the BT treatment, but the Base treatment increased the abundance of Acidobacteria, and the Top treatment increased the abundance of Gemmatimonadetes. Soil bacteria play an important role in improving the productivity of alfalfa growing in saline soil, and the mechanism by which soil microbes increase yield needs to be further studied.