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

Influence of soil fertility management technologies on phosphorus fractions, sorption characteristics, and use efficiency in humic Nitisols of Upper Eastern Kenya

Fractions of phosphorus (P) and its sorption characteristics are affected by different soil fertility (FM) technologies which ultimately affect crop growth and productivity. However, the response of P fractions and sorption characteristics to soil fertility technologies that integrate diverse amendments is still poorly understood in acidic Nitisols. A randomized complete block design was layout in an acidic Nitisol to determine fractions of P, its sorption characteristics and use efficiencies in acidic Nitisols under various FM technologies in field conditions. The use of minimum tillage + maize residue + inorganic fertilizer + goat manure (MTCrGF) had the highest impact on and significantly increased resin-Pi, NaHCO3-Pi, and maximum P sorption (Smax) by 182, 76, and 52 mg P kg−1. Moreover, NaOH-Pi and Smax concentrations were higher under conventional tillage + maize residue + inorganic fertilizer + goat manure (CTCrGF) by 216 mg P kg−1 and 49 mg P kg−1 than the control. MTCrGF and CTCrGF also had the lowest P bonding energy (0.04 L mg−1). CTCrGF had the highest P partial productivity factor (0.093 and 0.140 kg biomass kg−1 P) and P agronomic efficiency (0.080 and 0.073 kg biomass kg−1 P) during the two cropping seasons. The results demonstrate the positive influence of combining multiple P sources on soil P fractions, sorption characteristics, and use efficiencies. Notably, combining either conventional or minimum tillage with maize straw and applying integrated manure and inorganic fertilizer (MTCrGF or CTCrGF) can increase the labile P concentrations and reduce the potential depletion of the non-renewable rock phosphate and the use of inorganic phosphatic fertilizers for agricultural production

Determinants of Farmers’ Knowledge on Soil and Water Conservation Technologies in Dry Zones of Central Highlands, Kenya

Agricultural productivity has been on the decline globally and in sub-Saharan Africa. This is as a result of soil nutrient depletion and low soil water availability. To curb this problem various soil and water conservations have been recommended, but there is still low uptake among farmers. The farmer’s knowledge level influences uptake and eventual adoption of these technologies. Therefore, we carried a cross-sectional survey from 400 farming households to assess farmer’s knowledge levels on the selected ISFM and SWC technologies and to determine the household’s socio-economic determinants influencing farmers’ level of knowledge on soil and water conservation technologies in the dry ones of the Central Highlands of Kenya. Knowledge levels were assessed by asking farmers questions that demanded a true or false answer. Knowledge index was then calculated and data analyzed using multinomial logistic regression model. Results showed that majority of the farmers had inadequate and insufficient knowledge on the use and benefits of soil and water conservation technologies. The socio-economic factors that influence knowledge levels of the knowledge-intensive technologies were education level, gender, perceptions on soil fertility, farmer group membership, access to training, farm size, access to credit, livestock keeping, and access to farm equipment. This implies the need to come up with an all-inclusive policy that can be employed in improving farmer’s level of knowledge through the use of more innovative methods of information dissemination. This can be done by strengthening the existing farmer groups, enhancing extension services, and also formulating gender-friendly policies

Determinants of Farmers’ Knowledge on Soil and Water Conservation Technologies in Dry Zones of Central Highlands, Kenya

Agricultural productivity has been on the decline globally and in sub-Saharan Africa. This is as a result of soil nutrient depletion and low soil water availability. To curb this problem various soil and water conservations have been recommended, but there is still low uptake among farmers. The farmer’s knowledge level influences uptake and eventual adoption of these technologies. Therefore, we carried a cross-sectional survey from 400 farming households to assess farmer’s knowledge levels on the selected ISFM and SWC technologies and to determine the household’s socio-economic determinants influencing farmers’ level of knowledge on soil and water conservation technologies in the dry ones of the Central Highlands of Kenya. Knowledge levels were assessed by asking farmers questions that demanded a true or false answer. Knowledge index was then calculated and data analyzed using multinomial logistic regression model. Results showed that majority of the farmers had inadequate and insufficient knowledge on the use and benefits of soil and water conservation technologies. The socio-economic factors that influence knowledge levels of the knowledge-intensive technologies were education level, gender, perceptions on soil fertility, farmer group membership, access to training, farm size, access to credit, livestock keeping, and access to farm equipment. This implies the need to come up with an all-inclusive policy that can be employed in improving farmer’s level of knowledge through the use of more innovative methods of information dissemination. This can be done by strengthening the existing farmer groups, enhancing extension services, and also formulating gender-friendly policies

Determinants of Farmers’ Knowledge on Soil and Water Conservation Technologies in Dry Zones of Central Highlands, Kenya

Agricultural productivity has been on the decline globally and in sub-Saharan Africa. This is as a result of soil nutrient depletion and low soil water availability. To curb this problem various soil and water conservations have been recommended, but there is still low uptake among farmers. The farmer’s knowledge level influences uptake and eventual adoption of these technologies. Therefore, we carried a cross-sectional survey from 400 farming households to assess farmer’s knowledge levels on the selected ISFM and SWC technologies and to determine the household’s socio-economic determinants influencing farmers’ level of knowledge on soil and water conservation technologies in the dry ones of the Central Highlands of Kenya. Knowledge levels were assessed by asking farmers questions that demanded a true or false answer. Knowledge index was then calculated and data analyzed using multinomial logistic regression model. Results showed that majority of the farmers had inadequate and insufficient knowledge on the use and benefits of soil and water conservation technologies. The socio-economic factors that influence knowledge levels of the knowledge-intensive technologies were education level, gender, perceptions on soil fertility, farmer group membership, access to training, farm size, access to credit, livestock keeping, and access to farm equipment. This implies the need to come up with an all-inclusive policy that can be employed in improving farmer’s level of knowledge through the use of more innovative methods of information dissemination. This can be done by strengthening the existing farmer groups, enhancing extension services, and also formulating gender-friendly policies

Smallholders' coping strategies in response to climate variability in semi-arid agro-ecozones of Upper Eastern Kenya

Rainfed agriculture dominates food production systems in arid and semi-arid agro-ecozones. Water is a key limiting factor to crop growth in the small-scale farming systems of the Sub-Saharan Africa (SSA) region. Climate adaptation is a fundamental and necessary response to the threat posed by the current and future climatic changes in semi-arid farming systems of the SSA region. This study was implemented to identify the socioeconomic drivers and determinants of adaptation to rainfall variability at the farm level in contrasting agro-ecological zones of Kenya. Two hundred and seventy (270) farmers were selected. The survey was implemented in Mbeere South, Meru South, and Maara Sub-Counties in Kenya to determine farmers' perceptions of climate variation during the decade that preceded the survey and climate adaptation strategies that farmers implemented. The most common climate adaptation strategies included the use of terraces (89%), early maturity crop varieties (82%), and intercropping (79%). In comparison, the least common strategies included water-harvesting strategies (29%), trenches (35%), and staggering planting dates (46%). Farmers in low potential agro-ecological zones recorded lower education levels, less secure land tenure systems, and poor access to training, extension, and credit facilities necessary for successful climatic adaptation strategies. The study findings indicated that farmers in low potential zones, including Mbeere South Sub-County, faced more risks due to the nature of climatic variation in this agro-ecozone. Farm socioeconomic characteristics were important factors that influenced farmer adaptation, including gender and age differentials, education attainments and agricultural training, farm labor availability, household food security status, and preceding annual occurrences of crop failure. There is a need to develop holistic approaches that incorporate scientific findings from the researchers and the local household-based strategies that can enhance risk assessment and management, coping and adaption strategies, and decision-making by multiple stakeholders

Influence of soil fertility management technologies on phosphorus fractions, sorption characteristics, and use efficiency in humic Nitisols of Upper Eastern Kenya

Fractions of phosphorus (P) and its sorption characteristics are affected by different soil fertility (FM) technologies which ultimately affect crop growth and productivity. However, the response of P fractions and sorption characteristics to soil fertility technologies that integrate diverse amendments is still poorly understood in acidic Nitisols. A randomized complete block design was layout in an acidic Nitisol to determine fractions of P, its sorption characteristics and use efficiencies in acidic Nitisols under various FM technologies in field conditions. The use of minimum tillage + maize residue + inorganic fertilizer + goat manure (MTCrGF) had the highest impact on and significantly increased resin-Pi, NaHCO3-Pi, and maximum P sorption (Smax) by 182, 76, and 52 mg P kg−1. Moreover, NaOH-Pi and Smax concentrations were higher under conventional tillage + maize residue + inorganic fertilizer + goat manure (CTCrGF) by 216 mg P kg−1 and 49 mg P kg−1 than the control. MTCrGF and CTCrGF also had the lowest P bonding energy (0.04 L mg−1). CTCrGF had the highest P partial productivity factor (0.093 and 0.140 kg biomass kg−1 P) and P agronomic efficiency (0.080 and 0.073 kg biomass kg−1 P) during the two cropping seasons. The results demonstrate the positive influence of combining multiple P sources on soil P fractions, sorption characteristics, and use efficiencies. Notably, combining either conventional or minimum tillage with maize straw and applying integrated manure and inorganic fertilizer (MTCrGF or CTCrGF) can increase the labile P concentrations and reduce the potential depletion of the non-renewable rock phosphate and the use of inorganic phosphatic fertilizers for agricultural production

Effects of different soil management strategies on fertility and crop productivity in acidic nitisols of Central Highlands of Kenya

Managing soil fertility, especially nitrogen (N) and phosphorus (P), to sustain increased crop productivity is a complex challenge, especially in cultivated Nitisols. Experiments were conducted over eleven (11) cropping seasons in the acidic Nitisols to assess the impact of soil management strategies on soil N, P, and crop productivity. Fourteen treatments were laid out in a Randomized Complete Block Design. The treatments include; control (C), conventional tillage + inorganic fertilizer (CTF), conventional tillage + maize residues + inorganic fertilizer (CTCrF), conventional tillage + maize residues + inorganic fertilizer + goat manure (CTCrGF), conventional tillage + maize residues + Tithonia diversifolia + rock phosphate (CTCrTiR), conventional tillage + maize residues+ goat manure + Dolichos lablab (CTCrGL), conventional tillage + maize residues + Tithonia diversifolia + goat manure (CTCrTiG), minimum tillage (MT; no amendments), minimum tillage + inorganic fertilizer (MTF), minimum tillage + maize residues + inorganic fertilizer (MTCrF), minimum tillage + maize residues + inorganic fertilizer + goat manure (MTCrGF), minimum tillage + maize residues + Tithonia diversifolia + rock phosphate (MTCrTiR), minimum tillage + maize residues+ goat manure + Dolichos lablab (MTCrGL), and minimum tillage + maize residues + Tithonia diversifolia + goat manure (MTCrTiG). Available P was significantly higher by 51, 48, 43, 38, 37, 36 and 27% under MTCrGF, CTCrGF, MTCrF, CTF, CTCrF, MTCrGL, and CTCrTiG than the control. Available soil N was significantly higher (59, 59, 59, 57, 57, 57, 55, 55, 55, 50, and 50%) under MTCrGL, CTCrGL, CTCrTiR, MTCrTiR, MTCrF, CTCrTiG, MTF, CTCrGF, CTF, MTCrTiG and MTCrGF compared to the control. Grain radiation use efficiency was significantly higher under CTCrGF, MTCrF, CTCrTiR, CTF, MTCrTiG, CTCrF, MTCrGF, CTCrTiG, and MTCrTiR than the control by 95, 93, 93, 93, 92, 92, 92, 91 and 88% during the SR2020 cropping season. In the LR2021 season, it was significantly higher under CTCrGL, MTCrGL, CTCrGF, CTF, MTCrGF, CTCrF, MTF, MTCrF, MTCrTiG, MTCrTiR, CTCrTiG and CTCrTiR than the control by 80, 79, 78, 77, 77, 74, 73, 72, 70, 67, 66 and 62%. Grain yield was significantly higher under CTCrGF, MTCrF, CTCrF, MTCrGF, MTCrTiG, CTCrTiR, CTF, CTCrTiG, and CTCrTiR than the control in the SR2020 season by 95, 93, 93, 93, 92, 92, 92, 92 and 88%. During LR2021, CTCrGF recorded the highest grain yield, which was 74% higher than the control, while CTCrGL, MTCrGF, MTCrGL, CTF, MTCrF, CTCrF, MTF, MTCrTiG, CTCrTiG, MTCrTiR, and CTCrTiR, had higher yields than the control by 73, 71, 70, 69, 69, 66, 65, 64, 58, 55 and 49%. Overall, CTCrGF, CTCrGL, MTCrGF, and MTCrGL had a comparative advantage regarding soil fertility and crop productivity in acidic Nitisols, strongly illustrating the concept of 'complementarity' in integrated soil fertility management

Determinants of farmers’ knowledge on soil and water conservation technologies in dry zones of Central Highlands, Kenya

This study ascertained the socioeconomic determinants of farmers’ knowledge on soil and water conservation technologies in Dry zones of Central Highlands of Kenya involving 400 farming households. Results showed that the majority of the farmers had inadequate knowledge on the use and benefits of soil and water conservation technologies. The socio-economic factors that influence knowledge levels of the knowledge-intensive technologies were education level, gender, perceptions on soil fertility, farmer group membership, access to training, farm size, access to credit, number of livestock kept and access to farm equipment. This implies that there is the need to come up with an all-inclusive policy that can be employed in improving farmer’s level of knowledge through the use of more innovative methods of information dissemination. This can be done by strengthening the existing farmer groups, enhancing extension services, and also formulating gender-friendly policies

Smallholder cropping systems contribute limited greenhouse gas fluxes in upper Eastern Kenya

The contribution of smallholder farming systems to the National greenhouse gas (GHG) budget is missing in most developing countries, including Kenya. Data on the contribution of smallholder cropping systems to the GHG balance is essential for realising Sustainable Development Goal 13 on climate action, i.e., on nationally determined contributions (NDCs) and in compliance with the Paris Agreement. Do smallholder farming systems act as nature-based solutions for greenhouse gas emissions reduction? This study evaluated GHG emissions from cropping systems under on-farm smallholder farming conditions. We had five cropping systems on two smallholder farms: sole maize, maize-bean intercrop, coffee, banana, and agroforestry. Gas samples were collected using three static chambers per cropping system. The gas samples were analysed using gas chromatography (GC) fitted with a 63Ni-electron capture detector (ECD) for N2O and flame ionisation detector (FID) for CH4 and CO2 using N as carrier gas. Cumulative annual fluxes of (CH4, N2O, and CO2) varied significantly in farms one and two across the cropping systems. The cumulative soil GHG fluxes ranged from -1.34kg CH4C ha−1 yr−1 under agroforestry to -0.77kg CH4C ha−1 yr−1 under banana for CH4, 0.30kg N2ON ha−1 yr−1 to 1.23kg N2ON ha−1 yr−1 for N2O and 5949kg CO2C ha−1 yr−1 to 12,954kg CO2C ha−1 yr−1 for CO2. The maize grain yields ranged from 0 to 3.38 Mg ha−1. The N2O yields scaled emissions ranged from 0.10 to 0.26g kg−1 maize and 0.68 to 1.30g kg−1 beans. Smallholder farmers in Upper Eastern Kenya contribute a limited amount of soil GHG emissions and thus could act as a nature-based solution for lowering agricultural emissions