Theory and application of Agricultural Innovation Platforms for improved irrigation scheme management in Southern Africa

Abstract

Many small-scale irrigation systems are characterized by low yields and deteriorating infrastructure. Interventions often erroneously focus on increasing yields and rehabilitating infrastructure. Small-scale irrigation systems have many of the characteristics of complex socio-ecological systems, with many different actors and numerous interconnected subsystems. However, the limited interaction between the different subsystems and their agents prevents learning and the emergence of more beneficial outcomes. This article reports on using Agricultural Innovation Platforms to create an environment in which irrigation scheme actors can engage, experiment, learn and build adaptive capacity to increase market-related offtake and move out of poverty.     

Dynamics of transboundary governance and management of small scale fisheries on Lake Kariba: implications for sustainable use

Lake Kariba and its fisheries are international resources shared by Zambia and Zimbabwe. Despite efforts to harmonize the regulatory system, there are still conflicting approaches of managing the fisheries resources. The paper discusses the divergent approaches and their relation to the sustainable use of the small-scale gill net fishery. Zimbabwe appears to focus on sustainability of the fisheries, and Zambia on maximizing employment opportunities from the fishery. The paper shows that uncoordinated management of the fishery at international level leads to weak local level institutions for managing the fishery.     

Detection and mapping of long-term land degradation using local net production scaling: Application to Zimbabwe

Degradation of vegetation and soils in drylands, sometimes called desertification, is thought to be a serious threat to the sustainability of human habitation, but maps of the extent and severity of degradation at country and global scales do not exist. Degraded land, by definition, has suffered a change relative to its previous condition set by its climate, soil properties, topography and expectations of land managers. The local net production scaling (LNS) method, tested here in Zimbabwe, estimates potential production in homogeneous land capability classes and models the actual productivity using remotely-sensed observations. The difference between the potential and actual productivities provides a map of the location and severity of degradation. Six years of 250 m resolution MODIS data were used to estimate actual net production in Zimbabwe and calculate the LNS using three land capability classifications. The LNS maps agreed with known areas of degradation and with an independent degradation map. The principal source of error arose because of inhomogeneity of some land capability classes caused by, for example, the inclusion of local hot-spots of high production and differences in precipitation caused by local topography. Agriculture and other management can affect the degradation estimates and careful inspection of the LNS maps is essential to verify and identify the local causes of degradation. The Zimbabwe study found that approximately 16% of the country was at its potential production and the total loss in productivity due to degradation was estimated to be 17.6 Tg Cyr^− 1, that is 13% of the entire national potential. Since the locations of degraded land were unrelated to natural environmental factors such as rainfall and soils, it is clear that the degradation has been caused by human land use, concentrated in the heavily-utilized, communal areas.     

Do metal grain silos benefit women in Kenya,Malawi, Zambia and Zimbabwe?

Metal silos can reduce maize losses during storage in smallholder farm systems, contributing towards international goals of reducing food waste and moving towards Sustainable Development Goal 2, Zero Hunger. However, technologies are introduced into farming systems with complex sets of relationships. These may differentially affect the ability of women and men to secure the expected benefits of metal silos. This, in turn, may affect adoption rates and expected outcomes. To better understand these relationships, a mixed methods study was conducted in Kenya, Malawi, Zimbabwe and Zambia where metal silos were introduced through the Effective Grain Storage Project (EGSP). EGSP distributed 1717 metal silos across the four countries.Quantitative surveys using random sampling were conducted in Kenya (124 respondents) and Malawi (100 respondents) with metal silo owners. Qualitative surveys, using purposive sampling, were conducted in all four countries covering 14 ethnic groups using focus group discussions (360 respondents), key informant interviews (62 respondents), and household case studies (62 respondents). The aim was to understand gendered post-harvest management and storage strategies in traditional systems and to map changes when metal silos were introduced.The findings suggest roles and responsibilities regarding the ownership and management of storage structures are strongly gendered with some differences between ethnic groups and countries. Men benefit more than women from the introduction of metal silos. Ownership of the grain storage facility, and the benefits attached to ownership, can switch from women to men with women having less scope for bargaining over their rights to use the stored grain for their own needs and the benefit of all household members. Women and men fail to fully follow guidelines for effective use of metal silos. They differ in their preferred attributes for their ideal storage system. Whilst some attributes are shared, women’s preferences were sharply differentiated from men in others.     

Preliminary results on nitric oxide emission from a southern African savanna ecosystem

During October to December 1994, we measured diel and seasonal variability in nitric oxide (NO) exchange by a southern African savanna ecosystem (Grasslands Research Station, Marondera, Zimbabwe). A set of automated dynamic chambers was installed in three sub-sites: Miombo forest, natural grassland, and cropped soils (maize, sorghum, groundnut). The latter received a single application of commercialy available in-organic or cowdung fertilizer. The dynamic chamber system is described in detail, including correction of the resulting data for wall losses and gas-phase reactions of the NO-NO₂-O₃ triad. During the dry season, net vertical NO fluxes were close to the detection limit (0.44 ngN m^-2s^-1) regardless of vegetation type. During the transition from dry to wet season strong "pulsing" effects of the NO flux were observed: NO emissions increased by a factor of up to 60 within hours. During the wet season, NO emissions varied between the different sub-sites of the ecosystem; corresponding means are in ranking order of fertilized agricultural plots (27.2 ngN m^-2 s^-1), unfertilized agricultural plots (8.5 ngN m^-2 s^-1 ), grassland (4.4 ngN m^-2 s^-1 ), and Miombo forest (1.5 ngN m^-2 s^-1). Soil moisture was found to be the dominant factor controlling the NO fluxes. Whenever it was not limiting, the diel behaviour of NO emission followed the daily variation of soil temperature measured 1 cm below the surface.     

津巴布韦卢比(Ruby)矿床——南部非洲一典型的BIF型金矿床

卢比金矿床位于津巴布韦克拉通中南部的马斯温戈绿岩带中,金矿体主要赋存在条带状含铁建造中的硫化物相、碳酸盐相中,成矿作用与火山喷发—沉积作用密切相关,为南部非洲一典型的BIF型金矿床。     

津巴布韦德特地区卡玛提维锡多金属矿地质特征及找矿方向

津巴布韦德特地区广泛出露电气石伟晶岩和含锡石伟晶岩,自1920年在该地区发现锡伟晶岩以来,总计持续了74年的矿山经营,直到1994年因资源枯竭关闭,因此寻找深边部隐伏矿体显得尤为重要。本文在现场考察以及收集该地区以往锡矿山开采资料的基础上,总结了含锡石伟晶岩的空间分布、地质特征和找矿标志,结合矿山钻孔资料和认为该区含锡伟晶岩中锂、铌、钽均具有较好的成矿潜力。本文在分析和讨论该矿床的产出地质环境和矿规律基础上,提出了该区下一步的找矿方向,供下一步勘查部署参考。     

津巴布韦烟草丛顶病调查

对津巴布韦烟草丛顶病进行了调查 ,并与云南烟草丛枝症病害进行了比较 ,认为津巴布韦烟草丛顶病与云南烟草丛枝症病害在危害、症状、传播、侵染途径及防治方法等方面基本相同 ,两者很可能属同一种病害。     

津巴布韦Zvishavane铬铁矿床地质特征及矿床成因

津巴布韦夏瓦尼(Zvishavane)铬铁矿床位于津巴布韦大岩墙南端,拥有丰富的铬铁矿资源。文章通过对夏瓦尼铬铁矿床区域地质背景、矿区矿床地质特征及找矿标志的分析,总结了矿床成因,认为矿体一般位于每个岩浆活动旋回顶部的辉石岩中或者辉石岩与方辉橄榄岩接触部位,且平行于岩层产状分布。方辉橄榄岩、辉石岩及铬铁矿在垂向上构成多个岩相韵律,与岩浆多期次脉动式的侵入及岩浆结晶分异作用的不断进行密切相关,属典型的晚期岩浆结晶分异矿床。     

津巴布韦Hashu水泥原料矿床地质特征

津巴布韦是一个水泥用灰岩较贫乏的国家。Hashu水泥原料矿是一集石灰岩、页岩和砂岩为一体的综合性矿床。该矿床的详细地质调查为华津（合资）水泥有限公司建厂提供了资源依据。