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Much effort has been spent on promoting conservation agriculture (CA) in Northern Benin to sustain the transition of cotton (Gossypium hirsutum L.) cropping systems toward agroecology. However, its limited adoption by farmers is often ascribed to initial yield penalties during the transition to CA and to trade-offs around crop biomass use. Here, we assess the effect of different CA-based cropping systems promoted in the region on water productivity and cotton yield in a three-year cotton/maize (Zea mays L.) crop rotation during the initial transition phase to CA. Three CA options were assessed combining different levels of soil disturbance and cover, and introducing cover crops to alleviate the biomass trade-offs. Direct seeding (DS), strip tillage (ST), and direct seeding mulched-based cropping systems (DMC) were compared with conventional tillage (CT) from 2017 to 2019 under a dominant soil type in the region, Haplic Lixisols. Two legume species, Stylosanthes guianensis (Aubl.) Sw. and Crotalaria retusa L. were grown as cover crops with maize under ST and DMC. The experiment followed a randomized block design comprising six replicates. After 2–3 years of DMC, the cotton yield advantage with respect to CT increased from 5 % to 7 %. Cotton yield penalties of respectively 11 % in 2018 and 26 % in 2019 were found for DS. ST treatment went from a yield advantage of 8 % in 2017 to a yield penalty of 20 % in 2019. The DMC and CT treatments gave similar and highest boll weights compared to the ST and DS treatments. The treatments had no significant difference regarding the number of bolls per plant. Soil water storage in the upper 30 cm depth and water use efficiency (WUE) were the highest in the plots with the DMC treatment compared to CT, ST, and DS. At 28 days of active vegetative stage (between 34 and 62 days after sowing), the WUE of seed cotton was 0.11 kg ha−1 mm−1 under DMC, while it was 0.08, 0.07, and 0.04 kg ha−1 mm−1 under DS, CT, and ST, respectively. The performance of DMC at increasing water productivity could be an argument to improve adoptability by farmers in northern Benin who are facing increased weather variability, given that the yield penalties often associated with early transitions to CA were not observed here with full DMC. • After 3 years of DMC, the cotton yield increases of 5–7 % compared to CT. • DMC exhibited no yield penalties in a transition to conservation agriculture. • Soil water storage use efficiency were the highest in the DMC treatment. • For maize yields, no significant differences were observed between treatments. [ABSTRACT FROM AUTHOR]

Wildfires and other disturbances play a fundamental role in regenerating lodgepole pine forests. Though severe, stand-replacing fires are typical of this ecosystem, they can have dramatic impacts on soil properties and biogeochemical processes that influence the rate and composition of vegetation recovery. Organic soil amendments are often applied to manage post-fire erosion, but they can also improve soil moisture and nutrient retention and potentially alter the trajectory of post-fire revegetation. We compared change in soil nutrients, microbial communities, and understory plant cover and composition on six burned hillslopes treated with 1) biochar (20 t ha −1), 2) wood mulch (37 t ha−1), 2) biochar + mulch, and 4) an untreated control a decade after the 2010 Church's Park fire. Wood mulch increased soil moisture and N retention the first three years following treatment. Mulch and biochar were still visible when we resampled in 2023. Mulch continued to increase soil moisture compared to unamended controls, though it had few lasting effects on soil N or cations. Conversely, biochar added alone increased dissolved organic C in soil leachate, C:N in soil and leachate, and hosted microbial communities distinct from those in mulch and combined biochar and mulch treatments. Biochar also elevated various dissolved and extractable soil N forms but reduced net nitrification. The amendments had no general effect on total graminoid, forb, or shrub cover, but had plant species-specific impacts. For example, biochar doubled cover of the dominant shrub Vaccinium scoparium , and mulch reduced cover of the most common forb (Oreochrysum parryi) by more than 50 %. The combined biochar and mulch treatment had persistent, additive effects on both soil and plant responses that exceeded impacts of the individual treatments. As seen increasingly in western North America, conifer regeneration remains scarce in the Church's Park burn scar, and these findings suggest that mulch and biochar amendments may improve reforestation success following severe wildfires. • Biochar and woody mulch remained visible a decade after application. • Mulch had lasting effects on soil water, but little impact on soil nutrient cycling. • Biochar increased cover of the most common shrub species • Conversely, woody mulch decreased cover of the most common forb species. • There were distinct bacterial communities in biochar-amended soils. [ABSTRACT FROM AUTHOR]