| Autor: |
Pfeiffer, Mirjam, Hoffmann, Munir P., Scheiter, Simon, Nelson, William, Isselstein, Johannes, Ayisi, Kingsley, Odhiambo, Jude J., Rötter, Reimund |
| Předmět: |
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| Zdroj: |
Biogeosciences Discussions; 4/8/2022, p1-33, 33p |
| Abstrakt: |
Smallholder farming systems in southern Africa are characterized by low-input management and integrated livestock and crop production. Low yields and dry-season feed shortages are common. To meet growing food demands, sustainable intensification (SI) of these systems is an important policy goal. While mixed crop-livestock farming may offer greater productivity, it implies trade-offs between feed supply, soil nutrient replenishment, soil carbon accumulation and other ecosystem functions and services. Such settings require a detailed systems understanding to assess the performance of prevalent management practices and identify potential SI strategies. Models can evaluate different management scenarios on extensive spatio-temporal scales and help identify suitable management strategies. Here, we linked the process-based models APSIM for cropland and aDGVM2 for rangeland to investigate the effects of (i) current management practices, (ii) a SI scenario for crop production, and (iii) a scenario with separated rangeland and cropland management in two representative villages of the Limpopo province, South Africa, for the period 2000-2010. Village surveys informed the models of farming practices, livelihood conditions, and environmental circumstances.We found that modest SI measures (manure application, small fertilizer quantities, weeding, crop rotation) led to moderate yield increases but could cause increased water limitation effects in dry years. SI effects therefore strongly varied between years. Dry-season crop residue grazing substantially reduced feed deficits, but could not compensate severe feed deficits during the transition period from dry to wet season. Targeted irrigation or measures to improve water retention and soil water holding capacity may enhance SI efforts. Off-field residue feeding during the dry-to-wet season transition could further reduce feed deficits and reduce grazing pressure on rangeland during the early growing season. We argue that integrative modeling frameworks are needed to evaluate landscape-level interactions between ecosystem components, evaluate the climate resilience of landscape-level ecosystem services, and identify effective mitigation and adaptation strategies. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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