The extension agent of the future

The Community of Practice in Data-Driven Agronomy (Big Data Platform – CGIAR) and the Feed the Future Developing Local Extension Capacity (DLEC) have joined forces to explore and define the future of agricultural extension far beyond sustainable crop production. The findings highlight the main knowledge, skills and attitudes that the Extension Agent of the Future should have

Data from: Landscape-scale movement of terrestrial pyrogenic carbon following land-use change in headwaters of the White Nile watershed of East Africa

NSF BREAD; Fondation des Fondateur

Agronomic Potential Of Biochar In Contrasting Maize-Based Temperate And Tropical Agro-Ecological Zones

Managing soil fertility is important to sustain both a productive agricultural economy and to preserve our natural environment. However, soil management practices will vary depending on the agro-ecosystem; agricultural soils in the temperate world often experience excess applied nutrients, while soils in the humid tropics often have a net negative nitrogen economy. Co-applications of organic amendments with synthetic fertilizers have been proposed to increase the efficiency of nutrient cycling and reduce nutrient losses in diverse agroecosystems. Soil applications of biochar may be an effective nutrient management technique with applications in both temperate and tropical cropping systems. Biochar derived from maize stover was applied to a maize cropping system in central New York at rates of 0, 1, 3, 12, and 30 t ha-1 in 2007. Secondary nitrogen fertilizer applications were added in treatments consisting of 100, 90, 70, and 50% of the recommended rate. Nitrogen fertilizer enriched with 15N was applied in 2009 to the treatment combinations of 0 and 12 t ha-1 of biochar and 100 and 50% secondary N application. Maize yield and plant N uptake did not change with any biochar treatment (P>0.05; n=3). However, significantly less N (by 75%) was lost through leaching at 100% N fertilization, albeit at low total losses of applied 15N (0.42% of applied N). The reason for an observed 140% greater N retention in the topsoil may have been the incorporation of N into microbial biomass which increased 3-fold. The resulting total N recovery in the soil-plant system of 83% with the addition of biochar in comparison to 61% without biochar after one cropping season may also indicate lower gaseous losses with biochar. The residual effects of organic inputs of contrasting quality on maize productivity were investigated as a function of soil degradation in the highlands of western Kenya. Tithonia (Tithonia diversifolia (Hemsl.) A. Gray) green manure, cypress sawdust, and biochar made from eucalyptus wood were applied at a rate of 6 t C ha-1 for three cropping seasons, both with and without mineral fertilizer additions (120 kg N ha-1, 100 kg K ha-1, 100 kg P ha-1). Maize grain yield was monitored for four years beyond the initial organic matter additions. The greatest yield responses for all amendments were found on the most degraded soil. During those years when amendments were added, tithonia applications resulted in the greatest yield increases, between 153 and 183% more than the unamended control in comparison to 136% with biochar and 107% with sawdust additions. However, four years after tithonia applications to highly degraded soils stopped, yields rapidly declined to only 110% of the unamended control, whereas yields after biochar additions remained constant at 0.3-1.8 t yr-1 or 9-265% greater than yields without organic amendments. Four years after organic matter additions ended, maize yields were not significantly different irrespective of additions of the quality of organic amendments. Even four years after organic matter additions, yields in response to fertilizer additions to highly degraded soils were 113% greater when applied together with the organic inputs than alone. No significant differences were found with or without fertilizer or organic matter additions in the farms recently converted from forest. The data indicate that yield responds in the short-term to input quality and specifically the amount of applied N; while the residual effects of organic matter additions on yield dynamics may relate more to input C quality and increasing soil C. i

Antropogenic And Natural Pyrogenic Carbon In Tropical Environments: From The Rhizosphere To The Landscape

Despite an increasing body of literature, the interactions of pyrogenic carbon (PyC) in the environment are not as well understood as other forms of C. This dissertation focused on generating knowledge of the interactions of (PyC) in tropical terrestrial ecosystems. Main areas of concentration include 1. Investigations into the mechanisms driving increased biological nitrogen fixation (BNF) in common bean (Phaseolus vulgaris) following the additions of anthropogenic PyC to agricultural soil, 2. Evaluating the differing ability of pyrolyzed and non-pyrolyzed crop residues to protect introduced strains of rhizobium against soil water deficit, and 3. Tracing the movement of natural PyC through the landscape and waterways following land-use change from forested ecosystems to intensive agricultural lands. Biological N fixation and nodule biomass increased by up to twenty-fold and thirty six-fold, respectively, following additions of anthropogenic PyC. This change was linked to greater plant-P uptake (r2=0.22; P0.05). Improved P nutrition likely resulted from 360% greater mycorrhizal colonization with biochar additions. When microbial inoculants were introduced to soil using pyrolyzed and non-pyrolyzed biomass, DNA fingerprinting of the root nodules indicated that nodule occupancy was dominated by native rhizobium and not the introduced strain. However, measured nodule occupancy (1-38%) of the introduced CIAT899 rhizobial strain by beans was significantly greater than expected values based on application rates (2-7%), irrespective of carrier. When natural terrestrial PyC was traced in stream water catchments following land-use change, up to 60% losses of the initial PyC stocks occured in the first 10 years after conversion from forest from mineralization and/or erosion. However, PyC was not preferentially eroded relative to total C or non-PyC C. This was true even when scaled to the entire river watershed where PyC concentrations in the headwaters and outlet into Lake Victoria were 3.8 and 3.5% of total C, respectivley . Pyrogenic C enrichment was found with depth in the soil profile from 5% of OC in the topsoil (0-0.15 m) to 23% of OC at 1-2 m

Agricultural productivity and soil carbon dynamics: a bio-economic model

The strong link between poverty, natural resources and the environment is apparent in smallholder agriculture: farmers are making repeated land use and management decisions while facing diverse resource endowments and significant environmental constraints on production. To investigate the likely effects of changes in agricultural practices on the natural resource base and on farmer welfare, we develop a bio-economic dynamic model of agricultural households in the western Kenya highlands. Our modeling framework extends economic farm household models to incorporate the dynamic nature of natural resource management and its implications for household welfare, and to permit a meaningful interface with biophysical processes through soil carbon management. Using an eight-year panel data set, the model combines econometrically estimated production and soil carbon flow equations in a dynamic programming framework. We use the model to determine the optimal management of the farming system over time in terms of the quantity of mineral fertilizer and crop residues to apply, taking into consideration initial resource endowments and prices. Understanding how soil resources respond to the combined applications of mineral and organic resources is important for improved resource allocation at the farm level and for national agricultural policy decisions

Getting the message out: Information and communication technologies and agricultural extension

There has been much optimism about the potential of information and communication technologies (ICTs) to provide agricultural extension services to remote households. Yet, little is known about how different communication methods fare, and, moreover, whether different segments of the population adopt information communicated via different means equally. We conduct a randomized controlled trial comparing the effectiveness of three ICTs—radio, voice response messages, and a smartphone app—with traditional extension training in communicating fertilizer management practices across four districts in rural Nepal. We find that farmers in the smartphone app and the extension training programs are on average 8.4 and 13 percentage points more likely to adopt topdressing fertilizer practices compared to control farmers, statistically significant at the 1% and 5% levels, respectively. Farmers in the smartphone app treatment achieve the highest agronomic literacy test scores, 7.8 percentage points higher than the control, statistically significant at the 1% level. In contrast, farmers receiving radio or voice response messages were not more likely to adopt the same fertilizer recommendations nor show improved specific or general agronomic knowledge relative to control farmers. Our results suggest that smartphone apps are more cost effective at inducing farmer knowledge and technology adoption than extension trainings. Heterogeneous treatment effects, however, reveal that a targeted ICT approach may be more effective in disseminating extension advice

Perceived, measured, and estimated soil fertility in east Africa: Implications for farmers and researchers

Bringing together emerging lessons from biophysical and social sciences as well as newly available data, we take stock of what can be learned about the relationship among perceived soil fertility, measured soil fertility, and farmer management practices in east Africa. We identify the correlates of Kenyan and Tanzanian maize farmers’ reported perceptions of soil fertility and assess the extent to which these subjective assessments reflect measured soil chemistry. Our results offer evidence that farmers base their perceptions of soil quality and soil type on crop yields. We also find that, in Kenya, farmers’ reported soil type is a reasonable predictor of several objective soil fertility indicators while farmer-reported soil quality is not. In addition, in exploring the extent to which publicly available soil data are adequate to capture local soil chemistry realities, we find that there is still immense value to the time-consuming collection of soil samples where highly accurate soil measures are important to research objectives. However, in the estimation of agricultural production or profit functions, where the focus is on averages and where there is low variability in the soil properties, there may be limited value to including any soil information in the analysis

Performance and Adaptability of Common Bean-Released Cultivars at Three Agro-Ecological Zones in Tanzania

This study focused on examining the genetic performance and stability of common bean genotypes across multiple environments in Tanzania using an alpha-lattice experimental design. The aim was to minimize environmental variability and maximize genetic expression. Three experimental sites were selected to represent the ecologies of the main bean growing areas of Tanzania, which are Tropical Savannah represented by TARI-Seliani, Tropical highlands represented by TARI-Uyole and semi-arid regions represented by Babati region. The sites were planted with are diverse of common bean genotypes, all of which were released for use in Tanzania. Agronomic practices, such as hand-hoe weeding and fertilizer application, were consistently applied. Key data collected included days to 50 percent flowering, growth habit, plant height, pod and seed count, yield per plot, and 100 seed weight. Advanced statistical analyses, including ANOVA, AMMI, and stability tests, were conducted using R software to evaluate yield and yield components. This paper findings discuss about the yield performance, stability, and the discriminating verses representative power across locations. In terms of yield, Babati was the leading site with mean yield of 1413.07 kilogram per hectare (kg/h) with Uyole 96 being the lead genotype (2845.567kg/h). Genotypes that were found to be stable and high-yielding in multiple locations include, Rojo, SUA Kalima, SAKILA, Fibea, and Nyeupe Uyole with the mean yields of 1045.83kg/h, 1023.73kg/h, 1003.33kg/h, 670.4kg/h and 544.77kg/h respectively. In discriminativeness and representativeness, Babati was the most discriminating site among the three locations while Seliani was the most representative among the three. These findings revealed significant variations and allowed the assessment of genotype performance and environmental interactions