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.

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.

Based on a light-use efficiency model and MODIS data, the net primary productivity (NPP) of grassland during the growing seasons from 2000 to 2018 in native grassland in Inner Mongolia was continuously estimated, and the spatial-temporal change trend of NPP over the past 20 years was also analyzed using a least square method at pixel scale to determine the degree of grassland degradation. It was found that NPP increased from west to east across Inner Mongolia, with an annual average of 198.04 g C·m^-2·yr^-1. An area of potential grassland degradation of 162200 km² was identified. The areas of severely and heavily degraded grassland identified were 2000 and 11100 km², respectively. The latter were mainly distributed in areas with intensive human activities, such as mining areas, or construction land and its surrounding areas. In terms of grassland types, the potentially degraded areas of temperate steppe, temperate meadow, temperate desert and temperate desert-steppe were 52200, 14000, 40400 and 22100 km² respectively. Through analyzing the correlation between NPP and climate factors in the last two decades, it was found that NPP is significantly correlated with precipitation, but has no correlation with temperature. The response of NPP to precipitation was the most sensitive in temperate meadow, that of temperate desert steppe was the second, and that of temperate steppe was the lowest. Based on the above results, this paper puts forward some suggestions for grassland ecological protection.

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.

The objective of this study was to evaluate the effects drinking water temperature on production performance, apparent digestibility of nutrients and blood biochemical parameters in fattening sheep in winter, and rumen structure was also observed using a microscope. Information on the ideal temperature of drinking water for fattening sheep might well lead to improved production efficiencies through mechanisms such as alleviation of cold stress. A flock of 135 healthy fattening sheep with similar weight were randomly assigned into three groups, with drinking water supplied at 2, 8 and 20 ℃ for the respective groups. Each treatment contained three pens (15 sheep·pen^-1). The experiment duration was 28 days. It was found that: 1) Compared with the 2 ℃ group, the 8 and 20 ℃ groups had increased daily water consumption (P<0.05). Although there was no statistical difference (P>0.05) in daily feed intake and daily gain between any of the groups, the feed conversion efficiency in the 20 ℃ group was higher than that in 2 ℃ group (P<0.05). 2) There was a difference (P<0.01) between groups in the serum glucose (GLU) contents. The GLU content in 8 and 20 ℃ groups was 1.39 and 1.14 times higher, respectively, than that in the 2 ℃ group, and the 20 ℃ group had decreased the serum cholesterol (P<0.05). The serum urea nitrogen, total protein and serum hormone (triiodothyronine, thyroxine and growth hormone) contents did not differ between groups (P>0.05). 3) The length, width, and surface area of rumen papilla in the 20 ℃ group were increased (P<0.05) compared with the 2 and 8 ℃ groups. The group drinking water at 20 ℃ had reduced rumen muscle layer thickness (P<0.05) and increased submucosal thickness (P<0.05). However, there was no difference (P>0.05) in thickness of mucosal epithelium among groups. 4) With increase in drinking water temperature, the apparent digestibility of crude fat, neutral detergent fiber (NDF) and phosphorus (P) increased (P<0.05), especially P and NDF, while the digestibility of other nutrients did not differ between treatment groups (P>0.05). The results showed that drinking warm water improved the feed conversion efficiency of fattening sheep. In addition, drinking warm water may improve rumen function and promote the digestion and absorption of nutrients.

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.

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 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).