Abstract
Agroforestry systems are important, globally affecting 1.2 billion people and covering 0.6 billion hectares. They are often cited for providing ecosystem services, such as augmenting soil fertility via N accumulation and increasing soil C stocks. Improved-fallow slash-and-mulch systems have the potential to do both, while reducing nutrient losses associated with burning. In the absence of burning, these systems also have the potential to grow trees through multiple rotations. This project collected soil, mulch, and biomass data over the course of one 9-year crop-fallow rotation and the first two years of the second rotation. A split-plot design was used to assess the effects of P + K fertilization and inclusion of an N-fixing tree species, Inga edulis, on crop and tree biomass production. Fertilization increased growth and nutrient accumulation during Rotation 1 by an average of 36%, ranging from 11% in Parkia multijuga to 52% in Ceiba pentandra. Residual P + K fertilization improved tree and crop growth 20 months into Rotation 2 by an average of 50%, ranging from 15% in Cedrela odorata to 73% in Schizolobium amazonicum. The improved-fallow slash-and-mulch system increased the rates of secondary succession biomass accumulation (11−15 Mg ha−1 yr−1) by 41–64% compared to natural succession (7–8 Mg ha−1 yr−1). Furthermore, P + K fertilization increased secondary-succession biomass accumulation by 9–24%. Nutrient accumulation through biomass production was adequate to replace nutrients exported via crop root and timber stem harvests.
Highlights
Agroforestry systems (AFS), agricultural land with >20% tree cover, account for 0.6 billion hectares and support approximately 1.2 billion people often with limited landholdings that depend on some form of these practices for their livelihoods [1,2]
PK+I+ to 76% for P. multijuga in PK−I+ (Table 1). Both Fert and NFix treatments affected the survival of the planted trees, P+K fertilization more consistently decreased the survival than did the presence of I. edulis (Table 1)
Results from this research indicate that the simultaneous planting of the staple crop manioc with native tree species, in conjunction with slash-and-mulch site preparation, can yield two crop harvests and a merchantable timber harvest through the course of one crop–fallow rotation with P + K
Summary
Agroforestry systems (AFS), agricultural land with >20% tree cover, account for 0.6 billion hectares and support approximately 1.2 billion people often with limited landholdings that depend on some form of these practices for their livelihoods [1,2]. AFS are commonly employed in Brazilian Amazonia by smallholding farmers (
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
