Accessibility and Reliability of Information Sources in Dissemination of Soil Fertility Management in Eastern Kenya

Increased recognition of soil fertility depletion as the main factor limiting crop production in many small holder farms in sub-Saharan African has renewed interest in the dissemination of soil fertility management technologies. Despite soil technology development and research outputs, few of the recommendations from various soil fertility management research activities have been adopted by the small-scale farmers on a large-scale level. Only a small proportion of allocated research resources is invested in dissemination among research institutions. The objective of the study was to investigate communication channels used in dissemination of soil fertility management practices in Mbeere and Meru South Districts. Two hundred and forty randomly selected farmers were interviewed. Data collected was analyzed using SPSS. The study revealed that 32.5% of the farmers who used combined organic and inorganic fertilizers received information from government extension officers while 41.3% of the farmers who use animal manure utilized their own farming experience. In disseminating soil erosion control measures, 51.2% of the farmers indicated that, farmer to farmer extension was the most commonly used. Also, 33.8% mentioned demonstration as the main method used in training soil fertility management practices. In general, the most common source of information was other farmers while there was least participation of researchers and agro input dealers in dissemination of soil fertility technologies. Thus, the study recommended more participation of stakeholders other than government extension officers as well as use of combined extension methods with farmer involvement in dissemination of soil fertility management practices.  Keywords: manure, extension agents, farmer to farmer extension method, demonstration DOI: 10.7176/DCS/10-11-03 Publication date: November 30th 202

Site-specific organic and conventional crop yields in a long-term farming systems comparison in sub-humid central Kenya

Organic farming is increasingly being taken up by farmers and agricultural development agencies in tropics. This is in a bid to improve world food security and rural livelihoods in a sustainable way. Long-term field trial that compares organic and conventional systems was set up in sub-humid central Kenya since 2006 to provide a scientific basis for organic agriculture in the region. The project seeks to gather data on how organic farming affects: yield and yield stability; stability of the agro-ecological system; and natural and economic resource efficiency. The experiments were set up at two sites namely Chuka and Thika. Both sites are at an altitude of 1500m asl. While Chuka lies in a high potential area with 2000 mm of rainfall and good soil phosphorus availability, Thika has fair yield potential, 1000 mm rainfall and low phosphorus availability. Crop rotations include maize, beans and vegetables.” The trials compares organic and conventional systems at two input levels, namely subsistence and commercial levels, resulting in four treatments: Conventional high input, organic high input, conventional low input and organic low input. In Chuka, organic yields were on average the same as conventional yields. On the low potential site of Thika, organic yields reached an average 55% of the conventional yields. Organic yields on the low input level were on average 13% lower than conventional yields on the low input level. On the high input level, organic yields were on average 26% lower than conventional yields. Organic maize yields achieved on average 77% of conventional maize yields, whereas organic brassica yields were 66% lower than conventional brassica yields. No significant difference was observed between mean organic and conventional legume crop yields. Our results suggest that: on high potential site of Chuka, organic crops can be grown without yield reduction; on low potential site of Thika, especially if low nutrient availability coincide with low rainfall, considerable yield reductions must be expected in organic systems in the transition phase; low input systems are less sensitive to conversion to organic agriculture than high input systems and relative yield levels in organic systems vary between crops

Effect of plant biomass, manure and inorganic fertilizer on maize yield in the central Highlands of Kenya

Soil fertility degradation remains the major biophysical cause of declining per capita crop production on smallholder farms in sub-Saharan Africa. Appropriate soil fertility regimes, are therefore, critical for improved crop productivity. This study investigated the feasibility of using sole organics or their combinations with inorganicfertilisers to improve maize (Zea mays) production in the highlands central Kenya. Sole application of Calliandra calotyrsus, Leucaena trichandra trichandra, Mucuna pruriens, Crotalaria ochroleuca, Tithonia diversifolia and cattle manure at 60 kg N ha-1 or combined application of the organic materials (30 kg N ha-1) plus inorganic fertiliser (30 kg N ha-1) gave significantly (P < 0.05) higher maize grain yields than the recommended rate of inorganic fertiliser (60 kg N ha-1). These treatments maintained maize yields at 4 to 6 t ha-1. Farmers had theirown innovations where they combined organic resources and generally appreciable yields (3.0 to 5.6 t ha-1) were obtained from these innovations. However, there was a maize yield gap between on station and on farm trials with on station yields having on average 65% more yields than the on-farm yields. This was mainly attributedto differences in management practices arising from partial adoption of recommended rates. There is need therefore to develop and implement mechanisms tailored to ensure that farmers’ modications recommended soil amendment regimes and other agronomic practices are appropriate for enhanced crop productivity. Further studies are needed to establish the optimum mixture of different organic materials

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

Adoption and utilisation of Zai pits for improved farm productivity in drier upper Eastern Kenya

Inadequate and poorly distributed rainfall and declining soil fertility have led to low crop productivity in most smallholder farms in sub-Saharan Africa. As a result, there has been a renewed quest for sustainable and resource-use efficient agricultural production practices. Zai pit technology is a practice that has the potential to alleviate water stress and enhance soil fertility. We assessed the factors that influence farmers' adoption and utilisation of Zai pits in Tharaka-Nithi County in upper Eastern Kenya. We interviewed 291 farm household heads. Descriptive statistical analysis and a logistic regression model were applied to evaluate socio-economic factors that affect the adoption of Zai pits by farmers. Binary logistic regression estimation revealed that the number of non-formal training, beneficiaries of nongovernmental organisations, wealth status and membership of a social group play an essential role in the adoption of Zai pits. Based on the findings, we recommend that farm characteristics and socio-economic characteristics of farmers should be considered in the promotion of Zai pits as a water harvesting technology. The results of the study will be useful to extension service providers in planning, designing and evaluating effective and efficient agricultural policies, programs and projects at local, regional and national scales in the dissemination of Zai pit technology among smallholder farmers in the semi-arid tropics

Optimizing interaction between crop residues and inorganic N under zero tillage systems in sub-humid region of Kenya

Conservation agriculture practices involving zero tillage and residue retention are promising nutrient management strategies for soil health restoration. Despite their potential positive impact on soil fertility, improved crop yields and increased revenues for smallholder farmers; their effect on nitrogen inputs and crop growth is not clearly understood. This may limit their potential as a nutrient management strategy that may remedy soil degradation and boost crop yields for farmers. This study investigated how different tillage practices, crop residues and inorganic nitrogen (N) options affect maize production, soil fertility and economics of smallholder farming systems. The study was conducted in a short-term (2 years) on-station trial, under randomized complete block design with three replications in a maize monocrop system. Six treatments, involving three different rates of maize stover residue (0, 3 and 5 t ha−1) and inorganic N (0, 3 and 5 t ha−1) inputs, respectively, were assessed under conventional and zero tillage systems. Mineral N and organic C were assessed at four depths (0–10 cm, 10–30 cm, 30–60 cm and 60–90 cm) whereas soil aggregate distribution was assessed at 0–5 cm, 5–10 cm, 10–15 cm and 15–20 cm depths. Application of inorganic N as the only input increased (p ≤ 0.05) grain yield (with the yields doubling in the short rains (SR) of 2015 and increasing by 1.4 times in long rains (LR) of 2016) compared to unfertilized control treatment. Treatment, soil depth and the time of sampling significantly affected soil mineral N concentration (p ≤ 0.05). Soil organic C reduced significantly (p ≤ 0.05) with sampling depths, but no differences were observed across treatments. At 0–5 cm depth, the proportion of large macroaggregates in zero tillage increased (48%; p ≤ 0.05) after application of crop residues at 5 t ha−1 relative to 3 t ha−1. Zero tillage treatment with application of 5 t ha−1 of residue and 80 kg N ha−1 was the most dominant and most profitable compared to the other treatments. This treatment had a benefit cost ratio (BCR) of 2.9 (in the short rains season of 2015) and 3.0 (long rains of 2016 seasons). Its marginal rate of return (MRR) was 368% (in the 2015 short rains season) and 416% (in the 2016 long rains season). This makes it a good nutrient management strategy with potential of optimizing maize yields.

Soil water use efficiency under integrated soil management practices in the drylands of Kenya

Soil moisture scarcity and soil fertility decline in the drylands contribute to declining crop productivity. The possible synergistic effects of integrating soil & water conservation, and soil fertility management practices on soil moisture, and hence water use efficiency (WUE) in the drylands of Tharaka-Nithi County in Kenya was assessed. The experiment was laid in a three by three split plot arrangement, with four replications, for four cropping seasons. Minimum tillagewith mulch, tied ridges, and conventional tillage formed the main plot factors. The sub-plot factors included animal manure plus fertilizer at 120, 60, and 30 N kg ha−1. There was significant improvement in soil moisture by 35 and 28% by minimum tillage with mulch and tied ridges, respectively, compared to conventional tillage. Manure plus fertilizer rates of 120 and 60 N kg ha−1 had significantly lower soil moisture by 12 and 10%, respectively than the 30 N kg ha−1across the seasons. The WUE was significantly enhanced by 150 and 65% under minimum tillage with mulch and tied ridges, respectively, compared to conventional tillage. Compared with 30 N kg ha−1, the 120 N kg ha−1 and 60 kg ha−1significantly enhanced the WUE by 66 and 25%, respectively. Across the seasons, the best treatment combination for improving WUE was minimum tillage with mulch at 120 N kg ha−1 rate of manure plus fertilizer

Nutrient and organic carbon losses by erosion, and their economic and environmental implications in the drylands of Kenya

Erosion causes soil nutrients and financial losses, and negatively impacts the environment. We sought to assess the effects of integrated soil fertility and soil & water management practices on nutrient losses, their equivalent economic losses, and environmental disturbance in the drylands of Tharaka-Nithi County. An experiment was set in a randomized complete block design with four replications. Six treatments implemented included manure + fertilizer + tied ridging under 120 kg ha−1 and 30 kg ha−1 nitrogen (N) application rate, manure + fertilizer + minimum tillage with crop residue mulch under 120 N kg ha−1 and 30 N kg ha−1, Managing Beneficial Interactions in Legume Intercrops with 60 N kg ha−1, and conventional control. A two (120 N kg ha−1 and 30 N kg ha−1) by two (Minimum tillage with mulch and tied ridges) split-plot arrangement was used to evaluate the interaction effect of soil fertility, and soil & water conservation practices. Soil & water conservation and soil fertility management practices reduced soil nutrients and organic carbon losses, ecosystem disturbance, and monetary nutrient losses when isolated or integrated. Minimum tillage with mulch had a higher reduction in the nutrient loss by 20–165% compared to tied ridges. The 120 N kg ha−1 reduced nutrient loss by 16–19% more than 30 N kg ha−1. The enrichment ratio (ER) under all the treatments was above unity, which indicated ecosystem disturbance. Minimum tillage with mulch reduced ER more than the tied ridges, whereas 30 N kg ha−1 had lower ER than 120 N kg ha−1. The equivalent monetary losses of nutrients were as high as 30 US$ha−1for soil organic carbon, 28 US$ ha−1 for nitrogen, 73 US$ha−1 for phosphorus, and 140 US$ ha−1 for potassium per season. The combined treatment with the least economic losses was manure + fertilizer (120 N kg ha−1) + minimum tillage with mulch. Hence, the technology should be promoted for sustainable agricultural productivity. Erosion causes soil nutrients and financial losses, and negatively impacts the environment. We sought to assess the effects of integrated soil fertility and soil & water management practices on nutrient losses, their equivalent economic losses, and environmental disturbance in the drylands of Tharaka-Nithi County. An experiment was set in a randomized complete block design with four replications. Six treatments implemented included manure + fertilizer + tied ridging under 120 kg ha−1 and 30 kg ha−1 nitrogen (N) application rate, manure + fertilizer + minimum tillage with crop residue mulch under 120 N kg ha−1 and 30 N kg ha−1, Managing Beneficial Interactions in Legume Intercrops with 60 N kg ha−1, and conventional control. A two (120 N kg ha−1 and 30 N kg ha−1) by two (Minimum tillage with mulch and tied ridges) split-plot arrangement was used to evaluate the interaction effect of soil fertility, and soil & water conservation practices. Soil & water conservation and soil fertility management practices reduced soil nutrients and organic carbon losses, ecosystem disturbance, and monetary nutrient losses when isolated or integrated. Minimum tillage with mulch had a higher reduction in the nutrient loss by 20–165% compared to tied ridges. The 120 N kg ha−1 reduced nutrient loss by 16–19% more than 30 N kg ha−1. The enrichment ratio (ER) under all the treatments was above unity, which indicated ecosystem disturbance. Minimum tillage with mulch reduced ER more than the tied ridges, whereas 30 N kg ha−1 had lower ER than 120 N kg ha−1. The equivalent monetary losses of nutrients were as high as 30 US$ha−1for soil organic carbon, 28 US$ ha−1 for nitrogen, 73 US$ha−1 for phosphorus, and 140 US$ ha−1 for potassium per season. The combined treatment with the least economic losses was manure + fertilizer (120 N kg ha−1) + minimum tillage with mulch. Hence, the technology should be promoted for sustainable agricultural productivity

Influence of education levels on dissemination of soil fertility management information in the central highlands of Kenya

Inadequate links between researchers and farmers has resulted in low uptake of research advances recommended to improve food security in the central highlands of Kenya. Access to timely and accurate information by extension agents and farmers is paramount in dissemination of soil fertility management practices. Hence, the study sought to investigate the effect of education levels on communication channels used to disseminate soil fertility technologies in the Central highlands of Kenya. Questionnaires were used to elicit information from 105 extension agents and 240 farmers. About 50.5% of the extension officers were certificate holders while 29.5% were diploma holders from agricultural institutes. Majority of the farmers had attained primary education (59.6%) while 25.8% and 9.2% had attained secondary and post secondary education, respectively. Research institutions were the most accessible sources of information on soil fertility management practices by extension agents while internet and scientific conferences were the least scored as accessible sources of soil fertility management information by extension agents. Education levels significantly influenced preference of individual approach methods by farmers. There was a significant positive relationship between education and accessibility of internet as a source of information on green manure. The implication of the study was that education levels influenced the mode of communication used in the transfer of soil fertility research outputs to the end users. Consequently, it is extremely important to consider education levels in selection of dissemination pathways used in agriculture