Appropriated protection time and region for Qinghai-Tibet Plateau grassland

Grassland accounts for 67% of the land area in Qinghai-Tibet Plateau (QTP) to sensitive to climate. This article carried out extensive temporal-spatial variations of grassland water deficit/surplus (GWDS) and net primary productivity (NPP) of QTP grassland using meteorological data of 1981-2018. The results indicate that precipitation's temporal variations are not related to potential evapotranspiration (PET). The maximum monthly precipitation occurs in July, while the maximum monthly PET appears in June. Precipitation is the second highest in spring when PET is the highest. The water deficit (PET-precipitation) from March to June takes up 51.4% of the total year. Therefore, droughts are more likely to happen in spring and June. This is the most important period for grassland protection. Water deficit is higher in the central and west and the highest in the northwest of QTP grasslands. This indicates the place where the droughts are more likely to occur. The grassland's annual NPP is high in the southeastern part of QTP and low in the west. This shows the central and western parts of QTP grassland should receive more attention. The specific time and region obtained in this study are important for environmental protection policy-making and reducing grassland degradation in QTP.