Global climate change stress has greatly influenced agricultural crop production which leads to the global problems such as food security. To cope with global climate change, nature based solutions (NBS) are desirable because these lead to improve our environment. Environmental stresses such as drought and salinity are big soil problems and can be eradicated by increasing soil organic matter which is directly related to soil organic carbon (SOC). SOC is one of the key components of the worldwide carbon (C) cycle. Different types of land use patterns have shown significant impacts on SOC stocks. However, their effects on the various SOC fractions are not well-understood at the global level which make it difficult to predict how SOC changes over time. We aim to investigate changes in various SOC fractions, including mineral associated organic carbon (MAOC), mineral associated organic matter (MAOM), soil organic carbon (SOC), easily oxidized organic carbon (EOC), microbial biomass carbon (MBC) and particulate organic carbon (POC) under various types of land use patterns (NBS), including cropping pattern, residue management, conservation tillages such as no tillage (NT) and reduced tillage (RT) using data from 97 studies on a global scale. The results showed that NT overall increased MAOC, MAOM, SOC, MBC, EOC and POC by 16.2%, 26.8%, 24.1%, 16.2%, 27.9% and 33.2% (P < 0.05) compared to CT. No tillage with residue retention (NTR) increased MAOC, MAOM, SOC, MBC, EOC and POC by 38.0%, 29.9%, 47.5%, 33.1%, 35.7% and 49.0%, respectively, compared to CT (P < 0.05). RT overall increased MAOC, MAOM, SOC, MBC, EOC and POC by 36.8%, 14.1%, 25.8%, 25.9, 18.7% and 16.6% (P < 0.05) compared to CT. Reduced tillage with residue retention (RTR) increased MAOM, SOC and POC by 14.2%, 36.2% and 30.7%, respectively, compared to CT (P < 0.05). Multiple cropping increased MAOC, MBC and EOC by 14.1%, 39.8% and 21.5%, respectively, compared to mono cropping (P < 0.05). The response ratios of SOC fractions (MAOC, MAOM, SOC, MBC, EOC and POC) under NT and RT were mostly influenced by NBS such as residue management, cropping pattern along with soil depth, mean annual precipitation, mean annual temperature and soil texture. Our findings imply that when assessing the effects of conservation tillage methods on SOC sequestration, SOC fractions especially those taking part in driving soil biological activities, should be taken into account rather than total SOC. We conclude that conservation tillages under multiple cropping systems and with retention of crop residues enhance soil carbon sequestration as compared to CT in varying edaphic and climatic conditions of the world.

Climate change is a major threat to food security. The global population is increasing at a stimulated rate. Wheat and maize are the globally important crops. There is a need to focus on the methods that help to improve crop production. Since, conventional tillage (CT) is the major tillage practice in rain-fed areas. Conservation tillage methods are practiced to conserve soil moisture in order to increase crop productivity. However, the effects of conservation tillage methods under varying soil textures, precipitation and temperature patterns are still unknown. We took data from 119 peer-reviewed published articles and carried a meta-analysis to assess the effects of 3 conservation tillage practices including no tillage (NT), reduced tillage (RT) and subsoil tillage (ST) on precipitation storage efficiency (PSE), soil water storage at crop planting (SWSp), grain yield, evapotranspiration (ET) and water use efficiency (WUE) under varying precipitation and temperature patterns and soil textures in dry land wheat and maize cropping systems. We took conventional tillage as a control treatment and compared it with different types of fallow conservation tillage systems. Compared to conventional tillage (CT), conservation tillage methods overall increased PSE, SWSp, grain yield, ET and WUE by 22.6%, 17.8%, 24.1%, 6.5% and 12.1%, respectively in winter wheat. Among conservation tillage methods, NT had a better performance on SWSp, grain yield and WUE compared to RT and ST. Fine-textured soils showed better response of tillage methods on PSE, SWSp and ET than medium and coarse-textured soils, while medium-textured soils showed greater positive response ratio (RR) of conservation tillage methods on grain yield and WUE. The enhancement of conservation tillage on PSE and grain yield was greater in the regions having mean annual precipitation (MAP) of >600 mm, while crop yield, ET and WUE were greater when MAP was <400 mm. Conservation tillage methods also increased PSE, grain yield and WUE in the regions where mean annual temperature (MAT) was 8-15 ℃, while SWSp was greater when MAT was <8 ℃. In dryland spring maize, conservation tillage overall increased PSE, SWSp, grain yield, ET and WUE by 38.1%, 20.6%, 29.6%, 16.9% and 11.0%, respectively. The regions having medium-textured soils showed better response of tillage methods on PSE, SWSp, ET and WUE, while coarse-textured soils showed greater positive response ratio (RR) of tillage methods on grain yield. Compared to CT, the RR of conservation tillage on PSE, grain yield, ET and WUE was greater when MAP was <400 mm, while SWSp was greater when MAP was 400-600 mm. Conservation tillage also increased PSE, SWSp and ET in the regions where MAT was <8 ℃, while grain yield and WUE were greater when MAT was >15 ℃. We conclude that NT is a global promising practice among all conservation tillage methods to increase soil water storage and crop production under varying precipitation and temperature patterns and soil textures in both winter wheat and spring maize cropping systems.