Quantifying changes in the vulnerability of vegetation to various drought stresses in different seasons is important for rational and effective ecological conservation and restoration. However, the vulnerability of vegetation and its dynamics in a changing environment are still unknown, and quantitative attribution analysis of vulnerability changes has been rarely studied. To this end, this study explored the changes of vegetation vulnerability characteristics under various drought stresses in Xinjiang and conducted quantitative attribution analysis using the random forest method. In addition, the effects of ecological water transport and increased irrigation areas on vegetation vulnerability dynamics were examined. The standardized precipitation index (SPI), standardized precipitation-evapotranspiration index (SPEI), and standardized soil moisture index (SSMI) represent atmospheric water supply stress, water and heat supply stress, and soil water supply stress, respectively. The results showed that: (1) different vegetation types responded differently to water stress, with grasslands being more sensitive than forests and croplands in summer; (2) increased vegetation vulnerability under drought stresses dominated in Xinjiang after 2003, with vegetation growth and near-surface temperature being the main drivers, while increased soil moisture in the root zone was the main driver of decreased vegetation vulnerability; (3) vulnerability of cropland to SPI/SPEI/SSMI-related water stress increased due to the rapid expansion of irrigation areas, which led to increasing water demand in autumn that was difficult to meet; and (4) after ecological water transport of the Tarim River Basin, the vulnerability of its downstream vegetation to drought was reduced.

Improvements in nitrogen (N) use efficiency reduce stress on the environment and improve tomato production. A two-year trial was conducted in greenhouse tomatoes with a split-plot design, in which one factor was the N application rate (150 kg·ha⁻¹, N1; 200 kg·ha⁻¹, N2; and 250 kg·ha⁻¹, N3) and two other factors were the type of urea applied (urea, T1; slow-release (polymer-coated) urea, T2, and nitrification inhibitors (3,4-dimethylpyrazole phosphate, DMPP) + urea, T3); no N fertilizer was applied in the control. The effects of the nitrogen (N) application rate and type of urea applied on the root morphology indexes, growth indexes, photosynthetic parameters, yield (Y), water use efficiency (WUE), and nitrogen agronomic efficiency (NAE) of greenhouse tomatoes were investigated. The results show that an appropriate N application rate (200 kg·ha⁻¹) can improve tomato growth and net photosynthetic rate (P_n). With T3, the Y and WUE of greenhouse tomatoes first increased and then decreased as the N application rate increased, but with T1 and T2, the Y and WUE increased as the N application rate increased. The NAE of greenhouse tomatoes was significantly lower with N3 than with N2. The root growth, plant growth, P_n, Y, WUE, and NAE of the tomatoes were improved with T2 and T3 compared to T1. These findings can be used to promote N conservation and increase the Y of facility agriculture crops.

The aim of this study is to exam the effect of microsprinkler irrigation technology under plastic film (MSPF) and to evaluate the reasonable micropore group spacing and capillary arrangement density in the greenhouse. Compared with drip irrigation under plastic film (DIPF) and microsprinkling irrigation (MSI) conditions, the effects of different micropore group spacing (L1: 30 cm micropore group spacing, L2: 50 cm micropore group spacing) and capillary arrangement density (C1: one pipe for one row, C2: one pipe for two rows, and C3: one pipe for three rows) with the MSPF on photosynthetic characteristics and fruit yield of tomatoes were studied using completely randomized trial design. The results showed that under the same irrigation amount, compared with DIPF and MSI, the photosynthetic rate of tomatoes treated with L1C2 increased by 8.24% and 13.55%, respectively. The total dry matter accumulation, yield, and water use efficiency at condition of L1C2 increased by 12.16%, 19.39%, and 10.03% compared with DIPF and 26.38%, 20.46%, and 31.02% compared with MSI, respectively. The results provide evidence that the MSPF can be applied to greenhouse tomatoes. The photosynthetic rate, total dry matter accumulation, yield, and water use efficiency of tomato leaves cultivated at a micropore group spacing of 30 cm were 1.07, 1.13, 1.14, and 1.13 times higher than those of 50 cm, respectively. With the decrease in capillary arrangement density, the photosynthetic characteristics of the tomato leaves, the total dry matter accumulation, and yield of tomatoes all experienced a decline. It is recommended to use a combination of one pipe for two rows of capillaries at a 30 cm micropore group spacing as the technical parameter of greenhouse tomato with MSPF in arid and semiarid sandy loam soils.

Comprehensive management of the ecological environment and sustainable ecological development, such as the gully control and land consolidation (GCLC) project, may affect surface vegetation. The normalized difference vegetation index (NDVI) is a sensitive indicator of vegetation dynamics; however, an in-depth study that continually monitors the spatial and temporal variation of regional vegetation before and after the implementation of the GCLC project is still scarce. To address this issue, we analyzed the spatial and temporal variations of Landsat surface reflectance-derived NDVI data in the Jiulongquan watershed in Yan’an City, China, from 2010 to 2019, and examined the main driving factors for these variations. Results showed high overall vegetation coverage in the evaluated watershed. The NDVI was spatially varied and tended to be low in the gully area and high on the slope. From 2010 to 2019, the NDVI values exhibited an increasing trend, and the most evident changes were concentrated in the gully areas. The changes in NDVI were mainly driven by human activities rather than the evaluated climatic factors. This work indicates that the GCLC project had positive effects on the ecological and agricultural environment at a regional scale.

Microsprinkler irrigation under a plastic film in the greenhouse (MSPF) is a water‐saving way which adopts the porous discharge form of a pipe under the plastic film. The effects of different micropore group spacings (L1:30 cm, L2: 50 cm) and irrigation amounts [I1: 0.7 Epan; I2: 1.0 Epan; and I3: 1.2 Epan (Epan is the diameter of 20 cm standard pan evaporation, mm)] of the MSPF on the soil respiration and yield of tomato were studied. A completely randomized trial design was used, and drip irrigation under plastic film (CK1) and microsprinkler irrigation (CK2) were also used as controls. The results showed that under the same irrigation amount, the soil respiration rate, tomato yield, and water use efficiency (WUE) of MSPF in spring and autumn are 8.09% and 6.74%, 19.39% and 4.54%, and 10.03% and 2.32% higher than those of CK1, respectively; they are significantly increased by 31.02% and 20.46%, 49.22% and 38.38%, and 58.05% and 34.66% compared with those of CK2, respectively, indicating that MSPF increased the amount of CO₂ emission, but tomato yield and WUE were effectively improved, and a dynamic balance was reached among them. Compared with the 50 cm micropore group spacing, the spring and autumn tomato yields and WUE under the 30 cm micropore group spacing were significantly increased by 16.00% and 13.01% and 20.85% and 14.25%, respectively, and the micropore group spacing had no significant effect on the soil respiration rate in both root and nonroot zones. When the I increased from 0.7 Epan to 1.2 Epan, the soil respiration rate and yield in the root and nonroot zones of the spring and autumn tomatoes increased at first and then decreased, and the WUE showed a decreasing trend. The relationship of soil respiration rate between the nonroot and root zones obeys a logarithmic function, and the soil respiration rate in the nonroot zone has a quadratic curve relationship with the yield of tomato. This study can provide data support for the development of water‐saving irrigation and yield increase of facility agricultural tomato and the analysis of the soil carbon cycling mechanism.