Editorial: Mixed Farming Technologies for Increased Resilience, Mitigation and Adaptation to a Changing Climate for Smallholder Farmers in Southern Africa

Hupenyu A. Mupambwa^1*, Adornis D. Nciizah² and Ndakalimwe N. Gabriel³

• ¹University of Namibia, Sam Nujoma Marine and Coastal Resources Research Center (SANUMARC), Namibia
• ²Agricultural Research Council of South Africa (ARC-SA), South Africa
• ³Faculty of Agriculture and Natural Resources, University of Namibia, Namibia

Smallholder farmers account for up to 70% of the farmers in most Southern African countries. Their productivity is therefore critical to national food security. However, most of the farming techniques still being practiced by smallholder farmers involve unimproved mixed farming methods, where yields are low. This Research Topic focuses on research that improves the efficiency of these traditional mixed farming techniques whilst incorporating newer technologies within an integrated climate-smart framework. This is critical in driving the resilience and adaptation of these vulnerable smallholder farmers.

One of the main mixed farming technologies presented by this topic focuses on intercropping of legumes and cereals and their effects on the land equivalent ratio. Nkhata et al. (2021) evaluated 2 newly released common bean varieties available in Malawi and their performance in a sole of intercropped maize system. The results of this research pointed out that the common bean varieties did not significantly influence the yield of maize with no significant difference when maize was grown alone. However, their results indicated a significant difference in land equivalent ratio (LER) between the 2 varieties NUA45 and SER83, with the SER83 having the highest LER. Overly, this study indicated a 159% yield advantage for NUA45 grown in association with maize and 177% if SER83 grown in association with maize. Similarly, Parwada and Chinyama (2021) evaluated the LER of intercropping cowpeas, a legume, with sorghum under different cattle manure amendment rates in a 3-year study. The sorghum, cowpeas were planted as sole crops and as intercrops, and fertilized using manure applied at 100% rate (17.7t/h); 75%, 50% and 0%. Intercropping with the application of more than 75% manure was observed to result in 75% increase in sorghum yield whilst it increased harvest index by 125% relative to where there was no manure. It was also noted in this study that application of 75% of manure rate in the intercrop enhanced sorghum grain yield whilst it increased the biomass production and not grain yield of cowpeas. These research manuscripts indicated the agronomic importance of intercropping as it resulted in higher land equivalent ratios as well as increased yield for the legumes, though not for the cereal crop.

As part of the mixed farming technologies, the other research papers focused on issues of climate change and the various scientific aspects of intercropping as well as social aspects of farming such as gender issues. Crop diversification has been indicated as a proxy indication of climate risk mitigation strategy, and Awiti et al. (2022) evaluated the effects of diversification under a changing climate on variable production cost structure among smallholder farmers. In this study, it was indicated using both the Allen and Morishima elasticities that the variable costs (land, capital, labor, fertilizer, and seeds) substitute each other in crop production. This study indicated that though crop diversification has potential climate mitigation effects, the total cost of production is positively influenced by the substituted variable cost. This study clearly shows that the benefits of crop diversification should seriously consider the trade-offs created by the variable costs.

With climate change becoming a major factor affecting crop productivity, there is a call for climate smart cropping systems. However, few studies have evaluated the gender differences that surround the issue of access and use of climate smart agriculture (CSA). Using a bean cropping system in Malawi, Nchanji et al. (2022) acknowledged that more women than men and youths, tend to use fertilizer, better seed varieties and plant earlier, as a climate mitigation strategy. Men were shown to prefer the adoption of physically involving activities like irrigation, whilst youths prefer technologically advanced systems like pesticides and conservation agriculture. Unlike recommending climate smart agriculture systems without understanding the gender roles in adoption, the study recommends the implementation of policies that promote gender responsive CSA systems.

Also focusing on climate change, the paper by Ajibade et al. (2022) concentrated on a climate smart technology called vermicomposting and its potential in organic agriculture. This study evaluated the effects of different vermicomposts (cow and pig manure based) used as a soil amendment and observed best growth in pig manure based vermicompost relative to the inorganic P source alone. Furthermore, the vermicompost was shown not to result in elevated levels of potentially toxic metals, indicating its potential as an effective soil amendment in organic soil fertility management. This technology can therefore be effective in reducing the use of industrially produced and environment polluting chemical fertilizers. Moreover, the use of carbon-based fertilizers can also sequester soil carbon thus mitigating climate change.

The last study by Sokombela et al. (2022) focused on healthy food production by evaluating the various agronomic performance of Moringa oleifera under different nitrogen and phosphorus levels. This is critical in the domestic growth of Moringa, which is mainly found and harvested for medicinal purposes in the wild. In this study, it was concluded that a combination of 100kg N per ha and 80 kg P per ha is recommended for the highest agronomic performance of Moringa.

We hope that these articles will give the reader a perspective on the various farming technologies for increased resilience, mitigation, and adaptation to a changing climate for adoption by smallholder farmers in Southern Africa.