After China has halted grassland degradation, it will be very important to rapidly improve current grassland management policies, especially those related to determining the grassland-livestock balance and payments for ecosystem services, and to achieve sustainable development goals (SDGs) for ecological conservation and improvement of herders’ well-being. Over the past 90 years, the United States has created and adjusted its public rangeland management systems and the US experience provides much valuable information for the reform of grassland management policies in China. The lessons from American public management suggest that multiple use and ecosystem service of grassland are two key concepts for sustainable management of grassland. These concepts should be firmly confirmed by social consensus, through the legal system, and in administrative management. Furthermore, public ownership rights form the legal premise for establishing multiple ecosystem services of grassland. The other stakeholder industries beyond animal husbandry provide the economic foundation to realize multifunctional grassland systems. Precise and responsive management by administrative agencies will guarantee the balance between livestock production and ecological conservation. The public participation of multiple stakeholders is the engine to drive forward the reform of grassland management systems. Meanwhile, the twists and turns of public rangeland management evolution in the United States suggest that common elements in the historic development of grassland management policy include: failure and adjustment of ecological policies, the flexibility to reconsider grazing prohibition and supervision intensity, and conflict and compromise between interest groups. All these elements may appear in China’s journey to achieve sustainable grassland management. In the next stage, optimization of grassland property rights, refinement of administrative management, coordination between herders and ecological conservation are the core tasks in the drive to achieve sustainable grassland management in China.

The amounts of nitrogen, phosphorus and potassium applied and the ratio of legume to grass in mixed sowings are key factors affecting the yield and fertilizer use efficiency of mixed grassland. The forage yield and utilization efficiency of nitrogen, phosphorus and potassium under different application ratios of those nutrients were analyzed to provide a scientific basis to manage cultivation of mixed grass-legume grassland for high yield. Field experiments were conducted on mixed swards of alfalfa and smooth brome. The experiment comprised two row configurations (legume:grass inter-row pattern 2:2 and 1:2) and seven nitrogen, phosphorus and potassium combinations: N₂₈₀P₁₅₀K₀ (A₁), N₃₅₀P₁₀₀K₃₆₀ (A₂), N₁₄₀P₃₀₀K₃₀₀(A₃), N₄₂₀P₂₅₀K₁₂₀ (A₄), N₇₀P₅₀K₆₀ (A₅), N₂₁₀P₀K₂₄₀ (A₆) and N₀P₂₀₀K₁₈₀ (A₇), where subscripts after each element indicate the application rate as kg·ha^-1 N, P₂O₅, and K₂O, respectively. The highest value for annual total yield of mixed legume-grass forage (11.68 t DM·ha^-1) occurred in the A₂ treatment, and yield in this treatment was significantly higher than in other treatments (P<0.01). Alfalfa yield in the A₂ treatment was 8.60 t DM·ha^-1, and it was significantly higher than A₁, A₅, A₆ and A₇ treatments (P<0.01). Grass yield in the A₁ treatment was 3.80 t DM·ha^-1, and it was significantly higher than in other treatments (P<0.01). Yields of grass and grass-legume forage were lowest in the zero nitrogen treatment, A₇. The combined grass-legume yield was significantly related to the rate of N fertilizer. Both combined grass-legume yield and alfalfa yield displayed a N×K interaction (P<0.05). The NPK partial productivity, and uptake efficiency of grass, alfalfa and grass-legume forage all showed a downward trend with increase in NPK level, and the A₅ treatment was significantly superior to other treatments (P<0.01). The nitrogen utilization efficiency of alfalfa decreased significantly in the zero potassium (A₁) and low potassium (A₅) treatments, and the potassium utilization efficiency of grass, alfalfa and grass-legume forage decreased significantly in the zero phosphorus (A₆) and high phosphorus (A₃) treatments. The annual total yield of alfalfa and legume-grass forage in the 2:2 row configuration were significantly higher than in the 1:2 configuration, with extreme significance (P<0.01). Also, the partial productivity, uptake rate and uptake efficiency of alfalfa NPK, and partial productivity of NPK, N uptake rate and N uptake efficiency of grass-legume forage in the 2:2 row configuration mixture were significantly higher than in the 1:2 configuration with extreme significance (P<0.01), and the partial productivity, uptake amount and absorption efficiency of grass NPK were significantly lower in the 2:2 than in the 1:2 configuration with extreme significance (P<0.01). Considering forage yield and nutrient utilization efficiency, alfalfa-smooth brome mixed sowing in a 2:2 row configuration, and fertilizer application of 140 kg·ha^-1 N, 100 kg·ha^-1 P₂O₅, and 120 kg·ha^-1 K₂O can be recommended, based on these results.

This research investigated the soil nutrient status and balance in Meitan tea plantations. Six indicators were selected (pH, organic matter, total nitrogen, alkaline nitrogen, available phosphorus and available potassium) and data on these collected for six categories of tea plantation. The data were evaluated by principal component analysis. It was found that: 1) The soil pH of Meitan tea plantations ranged from 3.73 to 7.26, with an average value of 5.01. In 61.11% of the surveyed tea plantations, the soil tests satisfied the standard set for high quality tea plantations. Hence, the soil pH of Meitan tea plantations was generally suitable, although soil in 16.67% of the tea plantations had an acidification trend. 2) The contents of organic matter, total nitrogen, alkaline nitrogen, available phosphorus and available potassium in Meitan tea plantations were in most cases rich, with average values of 22.84 g·kg^-1, 1.43 g·kg^-1, 124.50 mg·kg^-1, 44.16 mg·kg^-1 and 135.61 mg·kg^-1, respectively. For the same list of tests, soil in 61.11%, 70.37%, 61.11%, 55.56% and 59.26%, respectively, of the tea plantations met the standard for high quality tea plantations, but the status for individual nutrients differed between plantations. 3) The integrated fertility index (IFI) range for the surveyed Meitan tea plantations was 0.179-0.989, with an average value of 0.683. In 51.85% of the tea plantations soil was at level Ⅰ status, and in 31.48%, it was at level Ⅱ. Hence, the soil nutrient status is generally good. There were obvious differences in IFI between the different categories of tea plantations, with the ranking being: medium mountain yellow soil>hilly yellow soil>hilly calcareous soil>low mountain yellow soil>medium mountain calcareous soil>low mountain calcareous soil. 4) There was a very significant negative correlation between pH and organic matter, total nitrogen, and available phosphorus, and a significant negative correlation of pH with alkaline nitrogen. There was a significant (P<0.05) and a very significant (P<0.01) positive correlation between the nutrient indexes; i.e. the values for the various nutrients at any one test site were relatively close and homologous. Tea plantation values for soil pH were negatively correlated with IFI (P<0.01), and test values for other nutrients were positively correlated with IFI (P<0.01).

In this research two experiments were conducted to investigate the effects of slope and cultivation system on soil erosion control. In Experiment 1, a completely random design was used to study the runoff efficiency and the rainfall threshold to produce runoff for ridges along different slopes (0°, 5° and 10°). In Experiment 2, a split-plot design with slope (5° and 10°) as the main plot factor and tillage method (traditional planting, open ridging and tied-ridging) as the split-plot treatment was adopted to study the effect of tied-ridging rainwater harvesting on soil moisture, runoff, sediment yield, nutrient loss, alfalfa fodder yield and water use efficiency (WUE). The mean runoff efficiencies for ridges along slopes of 0°, 5° and 10° were 88.2%, 91.1% and 92.7%, respectively. The threshold precipitation to produce runoff for the respective treatments was 1.55, 1.33 and 1.00 mm, respectively. Compared with traditional planting, the decreases in runoff, runoff efficiency, sediment yield, total nitrogen loss, total phosphorus loss and organic matter loss for open ridging were 62.3%-67.9%, 51.0%-54.5%, 95.6%-96.4%, 95.3%-96.2%, 95.3%-96.1% and 94.1%-95.6%, respectively, whereas the corresponding decreases for tied-ridging were 76.4%-79.9%, 67.8%-68.2%, 98.4%, 98.1%-98.2%, 98.2% and 97.8%-97.9%, respectively. The open ridging and tied-ridging increased shallow-layer (0-60 cm) soil moisture. The increase in alfalfa forage yield and WUE for open ridging were 40.3%-50.4% and 4.4-11.5 kg·ha^-1·mm^-1, respectively. The corresponding increases for tied-ridging were 16.0%-18.7% and 2.0-5.3 kg·ha^-1·mm^-1. The runoff, runoff efficiency, sediment yield, total nitrogen loss, total phosphorus loss and organic matter loss for the 10° slope were 1.44, 1.40, 2.34, 2.24, 2.39 and 1.97 times greater than those for the 5° slope. Lastly, average soil water storage, alfalfa fodder yield and WUE for the 5° slope were 1.05, 1.28, and 1.41 times greater than those for the 10° slope. Tied-ridging rainwater harvesting was particularly beneficial for reducing runoff, sediment yield and nutrient loss. Open-ridging was offered particular effects on increase of alfalfa fodder yield and WUE.

This research studied the distribution of plant communities in response to soil environmental factors in desert steppe. We selected a soil habitat transition gradient from sierozem to sandy soil in Yanchi, Ningxia, China. Within, at the edge of, and outside of the sierozem habitat, vegetation characteristics and soil sampling were conducted using a line transect method. Based on the soil environmental factors and community species composition data, we quantitatively classified the plant communities using multivariate regression trees and redundancy analysis. Then we analyzed the differences between the different plant communities using principal component analysis. It was found that dominant species of the plant communities changed from Stipa breviflora+Cleistogenes squarrosa+Thermopsis lanceolate to Sophora alopecuroides+Pennisetum centrasiaticum and to Artemisia scoparia+Salsola collina across the soil gradient. Key soil factors associated with the shift of plant community species dominance included soil coarse sand, soil organic carbon and soil total phosphorus contents. Across the habitat gradient from sierozem to sandy soil, height, cover and biomass of the plant communities showed a statistically significant increase, community species abundance showed a significant decrease, and plant community diversity showed an increase and then a decrease. As soil texture became coarser and soil nutrient content decreased along the gradient, perennial plant communities were replaced by annual plant communities. Compared with the plant communities in the sierozem habitat, the proportion of perennial plant species, plant species diversity and biomass were low in sandy habitats.

To explore the effects of drought and salt stress on germination characteristics of halophytes, this study simulated drought stress with different concentrations of PEG-6000 and four sodium salts (NaCl, Na₂SO₄, NaHCO₃, Na₂CO₃) to evaluate the effects of those treatments on the seed germination characteristics of Halogeton glomeratus. It was found the germination percentage and germination energy decreased with increasing PEG-6000 concentration, while the seedling fresh weight, dry weight, plant height and root activity initially increased and then decreased at higher PEG-6000 concentration. Cluster analysis and principal component analysis showed that the different PEG-6000 concentrations could be divided into two groups with 6% PEG-6000 as the point of separation. Fresh weight appeared to be an important parameter. In addition, germination percentage germination energy, seedling fresh weight, dry weight, plant height and root activity declined with increase in concentration of the four sodium salts. This indicated that salt stress inhibited seed germination and seedling growth, with the effects of the four tested sodium salts ranked: Na₂CO₃>NaHCO₃>NaCl>Na₂SO₄. Cluster analysis and principal component analysis showed that the sodium salt concentrations were divided into two groups with the separation points falling at 50.00 mmol·L^-1 NaHCO₃, 62.50 mmol·L^-1 Na₂SO₄, 25.00 mmol·L^-1 Na₂CO₃ and 100.00 mmol·L^-1 NaCl. Among the plant traits evaluated as indicators of H. glomeratus stress tolerance in the germination stage, the germination index was the key indicator of NaHCO₃ and Na₂SO₄ stress, root activity emerged as the primary indicator of Na₂CO₃ stress and dry weight was the major indicator of NaCl stress in H. glomeratus.

This research aimed to clarify the effects of fungicides applied in Medicago sativa production on the safety of an important pollinating insect, the honeybee (Apis mellifera), One-day-old adult honeybees were fed a diet containing dimetachlone, prochloraz, iprodione, at a range of concentrations (diluted with water 1:500, 1:1000, 1:1500, 1:2000 and 1:2500) or no fungicide (Control). Subsequently, the activities of three protective enzymes, superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and three detoxifying enzymes, carboxylesterase (CarE), glutathione S-transferase (GST), cytochrome P450 (P450) in the honeybees were measured. It was found that different concentrations of all the three fungicides could induce increased activities of SOD and POD in the honeybees. In particular, treatment with prochloraz solution at the 1:1500 dilution (0.17 mg·L^-1) induced a 1.82-fold SOD activity and a 5.40-fold POD activity compared to the Control treatment. All three fungicides showed low concentration induction and high concentration inhibition of CAT, CarE and GST activities, and showed inhibition (prochloraz) or induction (dimetachlone and iprodione) of P450 activity. With extended treatment time, the 1:1000 dilution of all three fungicides (0.40, 0.25 and 0.50 mg·L^-1 of dimetachlone, prochloraz, and iprodione, respectively) showed an overall induction effect on the activities of the three protective enzymes in Italian bees, but a variable effect on the activities of detoxifying enzymes. Specifically, dimetachlone initially increased the activities of the three protective enzymes and then inhibited activity after 6 h; iprodione induced P450 activity at all times, but inhibited the activities of CarE and GST in the first 12 h, then induced their activity thereafter; prochloraz elicited a gradual decrease in P450 activity with time, but initially induced then later inhibited the activities of CarE and GST. The results indicate that Italian bees can reduce the negative effects of fungicides by regulating the activities of protective and detoxifying enzymes in their bodies, but the fungicides have an impact on the normal physiology and metabolism of bees, even so. Therefore, care should be taken when applying fungicides to protect bees and ensure their safety while pollinating agricultural crops.

Grassland is an important natural resource and plays a key role in maintaining the stability of ecosystems on a regional scale. Confirmation of grassland contracts and property rights provides an institutional guarantee for grassland ecological protection and development, and is a specific measure to implement the relevant central government requirements. Previous research showed that the speed of determining grassland ownership varies from region to region due to unique local factors in the various grassland areas in China, and in some regions the progress towards determining the ownership of grasslands is relatively slow. Based on analysis of the historical background and current situations relating to contract and property confirmation for grasslands, we here summarize the basic work in grassland contract and property confirmation, including data collection, contract content, contract optimization, issuing of certificates of ownership, landholder training, information management and improvement of grassland dispute resolution mechanisms, et al. The thinking of the planning sector in grassland management including the main building blocks, basic function, workflow, key technologies, is put forward. Finally, consideration of and suggestions for the next stage of the work involving ‘three property rights separation’ are put forward. This research is of great significance to furthering the development of the contract and information management of grasslands in China.

This research explored the physiological leaf response mechanisms of sugar beet to re-watering after drought with a focus on photosynthetic physiological traits and photo-responsive parameters. Two cultivars with different drought resistance, ‘XJT9907’ (a drought sensitive type) and ‘XJT9916’ (a drought tolerant type) were studied. A controlled water deficit was imposed on plants in the leafy growth stage, whereby soil moisture content was allowed to fall to 45%-50% of field water holding capacity for 7 days, then irrigation water was added to raise soil moisture to 70%-75% of the field water holding capacity for 48 hours. At this point, the photosynthetic physiological parameters of leaves were determined, and nonlinear regression used to fit sigmoid curves for the relationship between net photosynthetic rate of leaves and light intensity. It was found that drought stress during the leafy growth stage of sugar beet development significantly reduced the SPAD value, net photosynthetic rate (P_n), stomatal conductance (G_s), intercellular CO₂ concentration (C_i), and transpiration rate (T_r) of both sugar beet varieties. After re-watering, the SPAD value, net photosynthetic rate (P_n), stomatal conductance (G_s), intercellular CO₂ concentration (C_i) and transpiration rate (T_r) of sugar beet leaves under drought stress treatments all improved. The values of physiological parameters for drought tolerant XJT9916 were significantly higher than those of drought sensitive XJT9907, although none of the values exceeded those of plants with a normal level of water supply, indicating a degree of compensation effect. After the re-watering treatment, the maximum net photosynthetic rates (P_nmax) of XJT9916 and XJT9907 varieties were, respectively, 6.2% and 17.1% lower than the control, and the apparent quantum efficiency (AQY) was, respectively, 6.5% and 12.2% lower than the control. Similarly, comparing drought tolerant and drought sensitive varieties to control plants. respiration rates (Rd) were, respectively, 19.1% and 14.9% lower than the control, light saturation points (LSP) were 19.6% and 14.1% lower than the control, while the light compensation points (LCP) were, respectively, 15.4% and 17.6% (P<0.05) higher than the control. For the drought sensitive variety, the light energy utilization interval was comparatively narrow, and the light energy utilization efficiency was reduced. Taken together, the results show that when the soil moisture content is 45%-50% of the field water holding capacity during the sugar beet leafy growth period, the photosynthetic potential of sugar beet leaves is not realized, the photosynthetic capacity of the leaves is weakened and cannot be restored to normal levels after re-watering. The drought-tolerant sugar beet variety XJT9916 has strong photosynthetic recovery ability in the context of re-watering after drought.

The effect of nitrogen fertilizer application rate on chlorophyll fluorescence characteristics and dry matter accumulation of switchgrass (Panicum virgatum) is of great significance for the improvement of light use efficiency and biomass yield of switchgrass in saline-alkali land. In this research, the patterns of variation in chlorophyll fluorescence parameters and dry matter accumulation in switchgrass were studied in field conditions with a range of nitrogen application treatments: no nitrogen (0 kg·ha^-1, N₀), low nitrogen application (60 kg·ha^-1, N₆₀), medium nitrogen application (120 kg·ha^-1, N₁₂₀) and high nitrogen application (240 kg·ha^-1, N₂₄₀), and the comprehensive effect of nitrogen application on chlorophyll fluorescence and dry matter accumulation in switchgrass was evaluated using a multivariate Grey relational analysis procedure. It was found that: under N₆₀, N₁₂₀ and N₂₄₀ treatments, the PSⅡ maximum photochemical efficiency (F_v/F_m), PSⅡ actual photochemical quantum efficiency (Φ_PSⅡ), potential activity (F_v/F_o), photochemical quenching (qP), non photochemical quenching (NPQ) and biomass yield were significantly higher, and the heat dissipation of quantum ratio (F_o/F_m) was significantly lower than for the N₀ treatment during the flowering and seed maturation stages of switchgrass development. During the flowering period of switchgrass, the PSⅡ potential activity (F_v/F_o) was initially increased and subsequently decreased across the range of nitrogen application rates, with a maximum observed value of 3.13 at N₁₂₀ (increased 16.26% compared with N₀). The effect of nitrogen application rate on dry matter accumulation differed between the crop growth stages. Dry matter accumulation was high during jointing and booting periods, reached its maximum at the seed filling stage, and decreased slightly thereafter. The maximum observed dry matter accumulation (378.13 g·hole^-1) occurred under the N₂₄₀ treatment during the post-flowering stage and was, respectively, 24.33%, 20.09% and 7.24% higher than that of the N₀, N₆₀ and N₁₂₀ treatments. Grey relational analysis showed that the association between the weighted correlation index and the ideal fertilization level was the highest under the N₂₄₀ treatment. In summary, the N₂₄₀ treatment in this study in the Yinbei saline-alkali area of Ningxia optimized the photochemical activity of PSⅡ and dry matter accumulation of switchgrass.