Resilience of Organic versus Conventional Farming Systems in Tropical Africa: The Kenyan Experience

In Kenya, agriculture is largely carried out by smallholder farmers, in a mixed farming noncommercialised setting where application of synthetic fertilisers and pesticides is minimal. Agricultural production is low and constrained by declining soil fertility, pest and diseases and increasingly unpredictable weather due to global warming. This calls for more resilient farming systems

First season maize performance in a long-term farming systems comparison trial at KARI-Thika, Kenya

Kenya’s smallholder farmers contribute 65% to total agricultural output in a predominantly mixed farming system where application of inorganic fertilizers and pesticides is minimal. By contrast, agriculture in developed temperate countries is dominated by large-scale farming and heavy reliance on fertilizers and pesticides to sustain high yields. Research conducted in temperate developed countries has shown that organic farming is superior to conventional farming in resource use efficiency, ecosystem functioning, soil fertility conservation and economic performance but results cannot be transferred directly to the tropics because of disparities in climate, soils and socio-economic environments. A long-term farming systems comparisons experiment was initiated at KARI-Thika in 2006 to assess the contribution of organic agriculture to food security, poverty alleviation and environmental conservation. Four treatments (Conventional High, Conventional Low, Organic High and Organic Low) were imposed in 8m x 8m plots using a randomized complete block design and replicated five times. The ‘High’ treatments received 118 kgN/ha and 66+5kgP/ha while the ‘Low’ treatments received 65 kgN/ha and 27 kgP/ha. Conventional treatments received the nutrients from farmyard manure, diammonium phosphate and calcium ammonium phosphate while compost, Tithonia diversifolia, and phosphate rock were applied in the organic treatments. Maize variety Pannar was planted at the onset of rains in April 2007 and harvested in August from a net plot area of 6m x 6m. The plots were hand weeded while stock borer was controlled using a Neem extract and ash/soil mixture in organic treatments and Bulldock® in conventional treatments. Stover dry weights were significantly higher in Conventional High than Organic Low (P=0.034) and indistinguishable from those observed in Conventional Low and Organic High. It was reasoned that availability of applied nutrients and the low poorly distributed rainfall received during the flowering and grain filling stages impacted negatively on grain yield

Long-term performance of organic crop rotations in the tropics: First results from a high and a medium potential site in sub-humid Central Kenya

Organic Agriculture is perceived by many stakeholders as a promising approach to increase food security in developing countries. However, only few attempts have been made so far to assess agronomic and economic performance of Organic Agriculture in these regions in a systematic way. The Research Institute of Organic Agriculture (FiBL), together with its partners, is presently establishing long-term comparisons of farming systems in various agro-ecological and socio-economic contexts to study the different parameters that are essential for sustainable development. To date, three study areas have been selected: (a) a sub-humid area in Kenya where farming is subsistence-oriented; (b) a semi-arid area in India where cotton is produced for the export market; and (c) a humid area in Bolivia where cacao and other perennial products are produced for the export and domestic markets. The key elements are replicated long-term field trials. These are complemented by farm surveys and short-term trials under on-farm conditions. This network of comparison of farming systems in the tropics is expected to (1) put the discussion on the benefits and drawbacks of Organic Agriculture on a rational basis; (2) help to identify challenges for Organic Agriculture that can then be addressed systematically; (3) provide physical reference points for stakeholders in agricultural research and development and thus support agricultural policy dialogue at different levels. In Kenya, the two trials sites are located in a high potential zone in Meru South District (Chuka) and in a medium potential zone in Maragua District (Thika). They consist of four treatments: conventional and organic, each at a low and a high input level, representing subsistence oriented and commercial farming, respectively. Maize, brassicas and maize were planted during the first, second and third season respectively in both organic and conventional plots. In the first three seasons, we found the following results: in Chuka, organic yields of the low input treatments were on average 4% lower than conventional yields. On the high input level, organic yields were 6% lower. In Thika, organic yields were on average 57% (low input level) and 33% (high input level) lower than conventional yields. It is assumed that the organic crops in Chuka could benefit from N and P mobilisation from the soil. In Thika, where N and P were probably less available, the crop depended on the easily soluble nutrients applied in the conventional treatments. The effect of lower nutrient availability in the organic treatments in Thika was possibly aggravated by serious drought spells during the second and third season. The questions of interest are a) whether the organic treatments can keep the yield level of the conventional treatments in Chuka or if they will go through a depression typical for conversion from conventional to Organic Agriculture; and b) if the organic treatments can improve soil fertility and thus the organic yield levels in Thika in the coming years

The impact of conventional and organic farming on soil biodiversity conservation: a case study on termites in the long-term farming systems comparison trials in Kenya

A long-term experiment at two trial sites in Kenya has been on-going since 2007 to assess the effect of organic and conventional farming systems on productivity, profitability and sustainability. During these trials the presence of significant numbers of termites (Isoptera) was observed. Termites are major soil macrofauna and within literature they are either depict as ‘pests’ or as important indicator for environmental sustainability. The extent by which termites may be managed to avoid crop damage, but improve sustainability of farming systems is worthwhile to understand. Therefore, a study on termites was added to the long-term experiments in Kenya. The objectives of the study were to quantify the effect of organic (Org) and conventional (Conv) farming systems at two input levels (low and high) on the abundance, incidence, diversity and foraging activities of termites. The results showed higher termite abundance, incidence, activity and diversity in Org-High compared to Conv-High, Conv-Low and Org-Low. However, the termite presence in each system was also dependent on soil depth, trial site and cropping season. During the experiment, nine different termite genera were identified, that belong to three subfamilies: (i) Macrotermitinae (genera: Allodontotermes, Ancistrotermes, Macrotermes, Microtermes, Odontotermes and Pseudocanthotermes), (ii) Termitinae (Amitermes and Cubitermes) and (iii) Nasutitiermitinae (Trinervitermes). We hypothesize that the presence of termites within the different farming systems might be influenced by the types of input applied, the soil moisture content and the occurrence of natural enemies. Our findings further demonstrate that the organic high input system attracts termites, which are an important, and often beneficial, component of soil fauna. This further increases the potential of such systems in enhancing sustainable agricultural production in Kenya

Tillage system and integrated soil fertility inputs improve smallholder farmers’ soil fertility and maize productivity in the Central Highlands of Kenya

We designed and implemented an on-farm trial in Meru South and Gatanga sub-counties to understand the effects of integrated soil fertility management (ISFM) technologies on soil nitrogen (N), phosphorus (P), potassium (K), and maize productivity. The technologies included combinations of mineral fertiliser and maize stover (CrMf); crop residue, Tithonia diversifolia and rock phosphate (CrTiP); crop residue, Tithonia diversifolia and goat manure (CrTiMan); crop residue, inorganic fertiliser and goat manure (CrMfMan); crop residue, goat manure and Dolichos lablab (CrManLeg), and sole inorganic fertiliser (Mf) executed under conventional (ConC) and minimum (MinTill) tillage methods. We interviewed the farmers who participated in implementing the trials at the end of the study to understand the likelihood to uptake the technologies. We observed that the technologies increased soil N, P, K, and maize productivity compared to ConC (the control). There was a high likelihood of uptake of high-performing ISFM technologies. We recommend CrTiP for the two sub-counties for the short-term. However, a long-term experiment is needed to evaluate performances of CrTiMan, CrTiP, CrMfMan, and CrManLeg under the two tillage methods for site-specific recommendations taking into consideration rainfall variations

Corrigendum to “Data on the response of Zea Mays L. and soil moisture content to tillage and soil amendments in the sub-humid tropics” Data in Brief 43 (2022) 108381

The purpose of this corrigendum is to include the Grant ID in the acknowledgements that was missed in the published article. Grant ID We are grateful to the Swiss National Science Foundation for providing financial support (SNSF, 152224) The authors would like to apologise for any inconvenience caused

Data on the response of Zea Mays L. and soil moisture content to tillage and soil amendments in the sub-humid tropics

The datasets presented were collected from Chuka and Kandara on-station trials sites in Kenya, conducted for two consecutive years. The main aim of the data collection was to evaluate the soil amendments and tillage influence on Zea Mays L. (maize) crop performance and soil moisture content, as reported by Kiboi et al. [1]. Rainfall data were collected using a manual rain gauge installed within the trial site. A non-destructive sampling of four maize plants next to each other on the centre row in each plot was conducted at the 6th and 10th leaf phase to determine crop growth dynamics. Maize grain and stover were harvested at maturity from net plots of 21 m2 in Chuka and 15 m2 in Kandara. The net plot was derived by excluding the first, the last (guard) rows, and the first and last maize plants in each plot. The net plot approach aimed to minimize the edge effect. For soil moisture content determination, a Polyvinyl Chloride access tube was installed at the centre of each plot. Crop phenology was observed and recorded at 50 and 100% stages per treatment. The datasets presented are supplementary materials to the research article by Kiboi et al. [1]. For statistical analysis, the data were subjected to analysis of variance (ANOVA). The datasets under consideration include daily rainfall, relative chlorophyll content- SPAD values and plant heights, grain yields and stover yields, and periodic soil moisture content

The relationship between race and delinquency and the factors that influence disproportionate minority contact in Missouri [abstract]

Abstract only availableFaculty Mentor: Dr. Anne Dannerbeck, Social WorkDisproportionate Minority Contact has been an issue in Missouri since the 1980s, when reports were released claiming that there was a greater amount of minority youth coming in contact with the juvenile justice system than Caucasian youth (OJJDP, 2004). DMC studies prior to this project include initiatives supported by Jackson and St. Louis County to address disproportionate minority contact. This study focuses on the risk factors that drive children to delinquent behavior, and eventually their interactions with law enforcement. This study looked at a data set of 1633 delinquents in 13 counties in Missouri. Hirschi theorized along with Gottfredson that a child's criminal propensity is fairly fixed by age 10. Once established, these propensities do not change (Winfree, Taylor, He, & Esbensen, 2006). Approximately one-third of the children in the data sets analyzed for this research first came in contact with the justice system at the age of 12, with the rest of the ages dispersed between 13 and 16 years old. A chi-square analysis revealed that family issues, including parental incarceration and a poor social support structure, may put an African American child at greater risk for delinquency than a Caucasian youth (OSCA, 2001). This study is part of the assessment and diagnosis process, which is also being carried out by other researchers. Following this process, an intervention phase will begin to address disproportionality within the state, which will include a presentation of this information at a conference. After evaluating the results yielded by this study, a monitoring process will be established so as to help reduce future occurrences of DMC in the Missouri juvenile justice system. However, more research is needed to further address DMC within the state of Missouri, and as members of law enforcement and the justice system come together with a better understanding of the data that has been presented, these efforts will have a greater impact on their future actions in the juvenile justice and court system.Disproportionate Minority Contact has been an issue in Missouri since the 1980s, when reports were released claiming that there was a greater amount of minority youth coming in contact with the juvenile justice system than Caucasian youth (OJJDP, 2004). DMC studies prior to this project include initiatives supported by Jackson and St. Louis County to address disproportionate minority contact. This study focuses on the risk factors that drive children to delinquent behavior, and eventually their interactions with law enforcement. This study looked at a data set of 1633 delinquents in 13 counties in Missouri. Hirschi theorized along with Gottfredson that a child's criminal propensity is fairly fixed by age 10. Once established, these propensities do not change (Winfree, Taylor, He, & Esbensen, 2006). Approximately one-third of the children in the data sets analyzed for this research first came in contact with the justice system at the age of 12, with the rest of the ages dispersed between 13 and 16 years old. A chi-square analysis revealed that family issues, including parental incarceration and a poor social support structure, may put an African American child at greater risk for delinquency than a Caucasian youth (OSCA, 2001). This study is part of the assessment and diagnosis process, which is also being carried out by other researchers. Following this process, an intervention phase will begin to address disproportionality within the state, which will include a presentation of this information at a conference. After evaluating the results yielded by this study, a monitoring process will be established so as to help reduce future occurrences of DMC in the Missouri juvenile justice system. However, more research is needed to further address DMC within the state of Missouri, and as members of law enforcement and the justice system come together with a better understanding of the data that has been presented, these efforts will have a greater impact on their future actions in the juvenile justice and court system

Greenhouse Gas fluxes from Selected Soil Fertility Management Practices in Humic Nitisols of Upper Eastern Kenya

We quantified soil Carbon dioxide (CO2), Methane (CH4), and Nitrous oxide (N2O) fluxes five soil fertility management practices (Inorganic fertilizer (Mf), maize residue + Inorganic fertilizer (RMf), Maize residue + Inorganic fertilizer + goat manure (RMfM), maize residue + Tithonia diversifolia + goat manure (RTiM), and a Control (CtC)) in Kenya's central highlands using a static chamber method from March 2019 to March 2020. The cumulative annual soil CH4 uptake ranged from -1.07 to -0.64 kg CH4-C ha-1 yr-1, CO2 emissions from 4.59 to 9.01 Mg CO2-C ha-1 yr-1, and N2O fluxes from 104 to 279 g N2O-N ha-1 yr-1. The RTiM produced the highest CO2 emissions (9.01 Mg CO2-C ha-1 yr-1), carbon sequestration (3.99 Mg CO2- eq ha-1), yield scaled N2O emissions (YSE) (0.043 g N2O-N kg-1 grain yield), the lowest net global warming potential (net GWP) (-14.7 Mg CO2-eq ha-1) and greenhouse gas intensities (GHGI) (-2.81 Kg CO2-eq kg-1 grain yield). We observed average maize grain yields of 7.98 Mg ha-1 yr-1 under RMfM treatment. Integrating inorganic fertilizer and maize residue retention resulted in low emissions, increased soil organic carbon sequestration and high maize yields