Joyce Njoloma

Infection and colonization of aseptically micropropagated sugarcane seedlings by nitrogen-fixing endophytic bacterium, Herbaspirillum sp. B501gfp1

In this study, we used Herbaspirillum sp. B501gfp1 (B501gfp1), an isolate from wild rice, to investigate the interaction between a non-host nitrogen-fixing endophytic bacterium and micropropagated sugarcane plants under aseptic condition. Two Japanese sugarcane plants (Saccharum sp.) cultivars (cvs) NiF8 and Ni15 were inoculated using B501gfp1 in two inoculum doses of 108 and 102 bacterial-cells-per-milliliter suspension. The results showed that bacterial cells colonized both the root and stem tissues, and colonization was apparent in the intercellular spaces. Higher bacterial numbers were detected in plant tissues inoculated with the higher inoculum concentration treatment. Bacterial numbers also varied between the two cultivars, with the higher values determined in cv Ni15. This study provides evidence that Herbaspirillum sp. B501gfp1, a rice isolate, could colonize sugarcane tissues, suggesting non-specificity of host plant among endophytes.

Potential of aeroponics system in the production of quality potato (Solanum tuberosum l.) seed in developing countries

The production of potato seed under conventional system has not been effective in avoiding or reducing the build up of pathogens and has consequently led to reduced quality potato seed and low crop yields. Plants once cleaned through meristem culture and induction of tuberization under aeroponics system, produce high quality potato seed tubers rapidly that are free from contamination of pathogens. Further multiplication of potato seed tubers under aeroponics also compliments tissue culture (micropropagation), as it clones minitubers in a short time and reduces numerous labour steps associated with direct use of plantlets from tissue culture into the field in the post flask stage. Minitubers from air-rooted plants are planted directly in the field without a need for acclimatization to such environments. This system, as is the case with micropropagation, has potential to increase income and reduce cost of production of quality seed, thereby, making it more accessible to growers in developing countries where potato production is heavily constrained by the use of poor quality seed tubers. This review gives an insight on the potential of aeroponics in compliment to plant tissue culture in revolutionalizing the potato seed production in the agricultural systems of developing countries. Key words: Aeroponics, tissue culture, potato seed.

Agroforestry: Fertilizer Trees

Fertilizer trees are defined as nitrogen-fixing woody perennials used for soil fertility improvement in arable lands and pastures. Although such trees have played a significant role in traditional and improved crop and livestock production systems, their contributions have not received adequate attention in the debate on food security. This article suggests that diversification of agro-ecosystems with fertilizer trees can increase soil N supply, soil organic matter content, and initiate the restoration of agroecological function thereby increasing the productivity of degraded land. They are also an important component of multifunctional agriculture that provides timber, fodder, shade, watershed management, and resilience to climate change. The contributions they can make toward greater food production and the provision of ecosystem services are described in this article.

LOADING THE DICE IN FAVOUR OF THE FARMER: REDUCING THE RISK OF ADOPTING AGRONOMIC INNOVATIONS

Agricultural development projects frequently promote new crop production technologies for adoption at scale on the basis of research and pilot studies in a limited number of contexts. The performance of these production technologies is often variable and dependent on context. Using an example from the Agroforestry for Food Security Project in Malawi, that promoted agroforestry technologies for soil fertility enhancement, we explore the nature and implications of variation in performance across farmers. Mean effects of these technologies, measured by differences in maize yield between agroforestry and sole maize plots, were modest but positive. However, there was large variation in those differences, some explained by altitude, plot management and fertilizer use but with much unexplained. This represents risk to farmers. Those communicating with farmers need to be honest and clear about this risk. It can be reduced by explanation in terms of contextual factors. This should be an aim of research that can often be embedded in scaling up the promotion of agronomic innovations.

Farmers' evaluation of integrated soil fertility management methods in Northern Kasungu Central Malawi

There has been extensive recognition of the necessity to rejuvenate the fertility of soils for sustainable agricultural productivity, food security, household income and poverty alleviation in sub-Saharan Africa. In 2007, laboratory analytical results of the soils from Mkanakhoti extension area of Kasungu District, Central Malawi, indicated low levels of N, P and organic carbon (OC) and sandy texture. Socioeconomic data was collected and 40 on-farm experiments were also conducted. Integrated soil fertility management (ISFM) technologies tested on-farm included: pigeon pea biomass transfer in a maize field, pigeon pea/groundnut, maize/groundnut, maize/pigeon pea intercrops and maize treated with inorganic fertilizer. Initial assessments indicate wide-scale testing in the pilot areas and farmer adaptation and innovation of the options promoted. Farmers’ rated: pigeon pea/groundnut intercrop as very good by 85% or good by 8%; maize/pigeon pea intercrop as very good 60% and good 18%; sole cropped maize with urea very good by 55% and good by 35% of farmers; and maize intercropped with groundnuts as the least preferred technology with 40% of the farmers ranking it as very good and 15% as good. Efforts are underway to scale out and up the efforts through farmer to farmer extension, field days, extending the legume best bets project to other districts in Malawi and sensitizing policy makers at a higher level on the outcomes of the project.

TO CONTROL OR NOT TO CONTROL: HOW DO WE LEARN MORE ABOUT HOW AGRONOMIC INNOVATIONS PERFORM ON FARMS?

Our paper ‘Loading the dice in favour of the farmer: reducing the risk of adopting agronomic innovations’ revealed mean increases but also large variation in the impact of four agroforestry practises on maize yield, as experienced by farmers in Malawi. This prompted a response from Sileshi and Akinnifesi that was critical of the data and methods used. Their main concern was that farmers did not necessarily manage crops identically in plots with and those without trees, so the yield differences that we measured may be partly caused by these differences in crop management. We argue here that it is valid and useful to look at the actual effect on crop yield of farmers having trees intercropped with maize, rather than controlling for how the crop is managed, because this is what happens in the real world. Farmers respond to having trees in their field by treating their crop differently, so this is part of the system response to having trees in fields. Attempts to eliminate this will result in measuring an artefact rather than the real impact of trees on crop yield. By doing this, we revealed important variation in the impact of trees on crop yield amongst farmers, and we argue that it is important to explore, assess and communicate to farmers and development actors the extent and implications of this variation. Understanding the contextual factors that determine who is likely to benefit most from an innovation and for whom it is less suitable can then be incorporated in scaling up, so that targeting of innovations and the appropriateness of messages given to farmers are continuously refined.