The effects of climate change are unparalleled in magnitude, ranging from changing weather patterns that endanger food production to increasing sea levels that increase the likelihood of catastrophic flooding. Therefore, determining the extent of such variations on regional and local scales is imperative. We used monthly precipitation data from 25 meteorological stations in northern Pakistan (NP) to document the observed changes in seasonal and annual precipitation. The station density in the NP is small and unevenly distributed; therefore, ERA-5 reanalysis data were used to supplement the observed dataset to assess the spatial trends in NP. The non-parametric Mann–Kendall (MK), Sen’s Slope estimator (SSE), and Sequential Mann–Kendall (SQMK) tests were performed to assess the trends. In addition, the wavelet analysis technique was used to determine the association of precipitation with various oceanic indices from 1960 to 2016. Results indicate that maximum precipitation was shown in the annual and summer seasons. In NP, annual, winter, spring, and summer precipitation declined, while an increase in autumn was observed at a rate of 0.43 mm/decade between 1989 and 2016. The spatial trends for observed and ERA-5 reanalysis datasets were almost similar in winter, spring, and autumn; however, some disagreement was observed in both datasets in the summer and annual precipitation trends in NP during 1960–2016. Between 1989 and 2016, summer and annual precipitation increased significantly in Region III. However, seasonal and annual precipitation decreased in NP between 1960 and 2016. Moreover, there were no prominent trends in annual precipitation until the mid-1980s, but an apparent increase from 1985 onwards. Annual precipitation increased in all elevations except at the 500–1000 m zone. The ENSO (El Niño–Southern Oscillation) shared notable interannual coherences among all indices above 16–64 months. Inter-decadal coherence with the ENSO, AO (Arctic Oscillation), and PDO (Pacific Decadal Oscillation) in NP for 128 months and above. Generally, AO, AMO (Atlantic Multidecadal Oscillation), and NAO (North Atlantic Oscillation) exhibited less coherence with precipitation in NP. The regression of seasonal and annual precipitation revealed that winter and spring precipitation levels had higher linear regression with the AO and ENSO, respectively, while both the AO and ENSO also dominated at the annual scale. Similarly, the IOD and PDO indices had a higher influence in summer precipitation. The findings may help water resource managers and climate researchers develop a contingency plan for better water resource management policies in the face of changing climate change in Pakistan, particularly in NP.

This study was conducted in a rice-based cropping scheme to investigate the impact of green manuring on soil health, considering soil physicochemical properties and sustainable crop production. A field experiment was started on 2 November 2015 and completed on 15 April 2018 under a rice–berseem (Trifolium alexandrinum) cropping system in calcareous soil. Two green manuring patterns, rice–berseem and rice–wheat–sesbania (rostrata), were compared with a commonly practiced rice–wheat (Oryza sativa-Triticumaestivum) cropping pattern. Green manuring of the berseem crop (last cutting) along with 50, 75, and 100% of the recommended fertilizer doses of nitrogen, phosphorus, and potassium (NPK) were compared with recommended NPK fertilization along with control (no fertilizer). The plant growth parameters of rice, including plant height, tillers per plant at maturity, and yield data, were recorded at harvest. The pre-sowing soil analysis revealed that the experimental soil was low in salts, and the nutrient (NPK) status was very low. The results indicated that green manuring substantially enhanced the grain and straw yield of rice crops. Green manuring combined with 75% of recommended NPK produced the highest grain yield (5.83 t ha⁻¹ in year III) compared to the other treatments. The soil analysis showed that the bulk density was reduced while soil porosity, organic carbon, and N, K, and P contents were significantly improved. From the results of this study, it is recommended that under calcareous soil conditions, the regular use of green manuring can significantly improve crop growth, yield, and physicochemical properties of soil and, therefore, should be adopted by farmers.

Due to the influence of the Asian southwest monsoon, seasonal drought is serious and water resources are scarce in the Yunnan province of Southwest China. More effective water-saving irrigation methods should be developed to solve the problem of water scarcity in the dry season. In this study, a subsurface drip irrigation method was used to improve the water productivity of tomato cultivation. Deficit irrigation was conducted. We controlled the lower limit of soil moisture at three different levels (55~65%, 65~75%, and 75~85% of the field capacity). The results indicated that the subsurface drip irrigation treatment significantly increased tomato height in the later stage of tomato growth. Due to the buried pipes, the root/shoot ratio was 8~18% higher for subsurface drip irrigation than for surface drip irrigation methods. Though the yields using subsurface drip irrigation methods were slightly lower than those obtained using surface drip irrigation methods, the tomato quality and water productivity improved significantly. The subsurface drip irrigation methods improved the water productivity by 8.5~21.8% at different soil moisture levels and improved the chlorophyll content by 9.1~17.3%. The VC, soluble sugar, soluble solids, and the ratio of sugar to acid increased by 6.5~15.2%, 7.3~21.6%, 4.1~6.6%, and 3.2~20.8%. This study also indicated that by optimizing the irrigation methods and patterns, water productivity and fruit quality could be improved by more than 50%. This research will be helpful for guiding irrigation during the drought season in the southwest monsoon area in Asia.

Agroforestry systems can fully exploit the ecological benefits of an ecosystem’s component plants, and improve the ecological environment, soil quality, and land use efficiency, all of which have recently attracted the attention of many scholars. Southwest China’s karst graben basins have barren soil that needs immediate improvement. The karst graben basin in southwest China was used for this study to examine the impacts of several forest–grass composite systems of Bingtang orange–alfalfa–ryegrass on soil improvement, which is located in Jianshui County, Honghe Prefecture, Yunnan Province. The experiment had four treatments, Bingtang orange–alfalfa sowing (B2), Bingtang orange–ryegrass × alfalfa mixed sowing (A), Bingtang orange–ryegrass × alfalfa intercropping (R), and Bingtang orange monocropping (CK). The results showed that different forest–grass composite patterns had noticeable effects on improving the soil’s organic carbon (SOC), total nutrients, and available nutrients, especially in the rainy season when plants grew vigorously. Forage grass intercropping under forest exerted the best effect on soil improvement in the surface layer, and the effect decreased with the increase in soil depth. Alfalfa intercropping under Bingtang orange forest had the strongest effect on improving SOC, total N, ammonia nitrogen, and nitrate nitrogen, whose content increased by 30.7%, 27.3%, 35%, and 36.3%, respectively, in the dry season and 38%, 46.7%, 48.7%, and 55.3%, in the rainy season. However, the effect of alfalfa–ryegrass intercropping under the Bingtang orange forest on soil total P, total K, and available P was better than that of the Bingtang orange–alfalfa intercropping system. The C:N ratio is more suitable in the Bingtang orange–ryegrass-alfalfa composite system. Forage grass intercropping under the Bingtang orange forest effectively improved the soil NPK and C status, and the results of this study provided a basis for the selection of forest–grass composite patterns for soil improvement.

When species of different abundance coexist, their ecological strategies remain uncertain. Assessing the functional diversity and niche characteristics of species with different levels of abundance contributes to understanding vegetation properties and is essential for species conservation. Based on the species abundance of 380 plots in the Gutianshan subtropical evergreen broad-leaved forest in the Zhejiang Province of China, woody plants were categorized as common species (86 species), occasional species (87 species), and rare species (79 species). Plant functional traits, including maximum height, seed dispersal modes, first flowering stage, flowering duration, and fruit length, were used to assess the functional diversity of the community of common, occasional, and rare species, while 15 environmental factors were used to evaluate their Levins’ niche breadth and Pianka’s niche overlap. The results showed that rare species have the highest functional evenness, while functional dispersion and Rao’s quadratic entropy were higher for common species (2.05 and 5.07, respectively) compared to occasional species (1.57 and 3.10) and rare species (1.35 and 2.48). Furthermore, the 15-dimensional mean value of niche breadth of common species (ranging from 0.277 to 0.955) was also higher than that of occasional (ranging from 0.193 to 0.710) and rare species (ranging from 0.100 to 0.345), and the same trend was also observed in niche overlap. The results suggest that common species have diverse functional traits and a greater ability to adapt to the environment and use resources, whereas occasional species have a limited ability to use the environment. Rare species are evenly distributed within functional space to reduce direct competition with other species, but they thrive only under specific environmental conditions, mainly following a K reproductive strategy. Niche differentiation mechanisms are important determinants of species coexistence in subtropical evergreen broad-leaved forests. In summary, more attention and greater efforts should be paid to the conservation of rare species. Our findings could help forest managers in the restoration and conservation of subtropical forests.