Assessing soil system changes under climate-smart agriculture via farmers' observations and conventional soil testing

S Eze, AJ Dougill, SA Banwart, SM Sallu, RN Mgohele, CJ Senkoro

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Soil degradation remains a challenge in African highlands, where land management lacks a strong context-specific evidence base. We investigated the impacts of recently implemented soil and water conservation (SWC) practices ? farmyard manure addition, incorporation of crop residues in soil and Fanya juu terracing under agroforestry system on soil health indicators in the East Usambara Mountains of Tanzania. Farmers? observations of soil changes were combined with conventional soil testing to assess the initial impacts of SWC practices relative to conventional non-SWC practice. Majority of farmers (66-83 reported that combining Fanya juu terracing with organic amendments led to soil colour change from red to black and an increase in crop yield. Despite the observed darkening of the soil, there was no significant increase in soil organic carbon stock and the contents of N, P, K. There were important changes in soil physical properties, including greater aggregate stability (mean weight diameter of 1.51-1.71 mm) in the SWC plots, a greater volume of transmission pores (>60 mum) and coarse storage pores (10-60 mum) in the surface soil layer (0-15 cm) and greater volume of fine storage pores (0.2-10 mum) and residual pores (0.2 mum) in the sub-surface layer (15-30 cm) of the SWC plots compared to the conventional plots. These changes indicate that SWC rapidly enhances infiltration and retention of water within the root zone, which are important for increasing crop yields and improving the resilience of the agro-ecosystem to environmental stress. Combining SWC with effective soil fertility management is needed for sustainable highland agriculture.
Original languageEnglish
JournalLand Degradation & Development
Early online date13 May 2022
Publication statusPublished - 31 May 2022

Bibliographical note

This article is protected by copyright. All rights reserved. This is the peer reviewed version of the following article: Eze, S., Dougill, A.J., Banwart, S.A., Sallu, S.M., Mgohele, R.N. and Senkoro, C.J. (2022), Assessing soil system changes under climate-smart agriculture via farmers? observations and conventional soil testing. Land Degrad Dev. Accepted Author Manuscript., which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley?s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.


  • Soil health
  • Soil conservation
  • Local soil knowledge
  • Climate resilience
  • Usambara Mountains
  • African highlands

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