Background. Soil acidity is a major soil health challenge that impacts agricultural productivity in Kenya while information on its national extent and severity remains limited. Objective. To determine national extent and spatial distribution of soil acidity, estimate the number of farming households affected and quantify lime requirements for acid soils within the Country. Methodology. This was achieved through application of data-driven approach, utilizing existing soil data collected at 0 -30 cm depth between 2012 and 2024, gridded environmental GIS layers, digital farmer registry data and geospatial analysis techniques. Soil pH and exchangeable acidity were then integrated to map acidity classes, estimate affected land area and households, and compute lime requirements for soils with pH≤5.5. Results. Soil pH (H2O) across the Agricultural soils ranged from 3.7 to 10. 8. Approximately 13.29% (7.7 million ha) of the national land area was affected by soil acidity (pH ≤ 5.99), comprising < 1% (< 100 ha) extremely acid (pH ≤ 4.5), 0.2% (0.12 million ha) very strongly acid (pH 4.51 – 4.99), 5.5% (3.16 million ha) strongly acid (pH 5.00 – 5.50) and 7.6% (4.4 million ha) moderately acid (pH 5.51 – 5.99). The soil acidity problem spanned across 29 counties, with higher severity in Western, Rift Valley and Central Kenya. The counties with largest proportion of acidic land were Kisii (100%), Nyamira (100%), Vihiga (93%), Nandi (91%) and Kakamega (91%). Out of the 6.4 million digitally-registered farming households nationwide, Kisii County had the highest number (184,103) and proportion (83.6%) affected. Additionally, lime requirements at pH <5.5 were observed to vary widely ranging from 269 metric tons (MT) in Kakamega to 8 MT in Kisumu, and 0.58 ± 0.08 t ha-1 in Nakuru to 1.51 ± 0.07 t ha-1 in Nyamira. Implications. Obtained spatially-explicit soil acidity maps and lime requirement estimates provides evidence for supporting government and stakeholders in operationalization of soil health interventions, lime use policies, subsidy programs and prioritization of acid soil remediation and research. Conclusion. This study provides a nationally representative, spatiall assessment of soil acidity and lime requirements, offering critical guidance for targeted remediation and integrated soil health management approaches.

Efficient nitrogen (N) management is critical for optimizing rice productivity, especially in nutrient-deficient soils of sub-Saharan Africa. A split-plot design with three replications was used, with rice variety as the main plot and nitrogen rate as the subplot. This study evaluated the response of five upland rice genotypes (Nerica 1, CSR36, Komboka, 17KH090014B, and AT058 to seven nitrogen application rates (0, 17, 34, 51, 67.5, 83.4 and 101 kg N ha-1) in two agro-ecological zones Bura and Taveta across two cropping seasons.The Nitrogen (N) treatments were applied as topdressing in 3 equal splits, at 15 Days after Transplanting (DAT), peak tillering (30 DAT) and panicle initiation stage (45 DAT). Data collected was subjected to ANOVA using Statistical Tool for Agricultural Research and means were separated using the Turkey's Test Honest Significant Difference HSD test. All statistical analysis was performed at alpha=0.05. Nitrogen significantly (P < 0.05) enhanced vegetative and yield traits up to an optimal rate of 67.5 kg N ha⁻¹, beyond which gains were minimal. At this level, plant height, tiller number, leaf length, panicle length, and fertile grains per panicle increased by 12%, 15%, 9%, 8%, and 47%, respectively, over unfertilized plots. Genotype 17KH090014B exhibited superior performance, producing the highest total (142.22) and fertile (99.28) grains per panicle, longest panicles (20.65 cm), and most leaves per plant, while Nerica 1 was tallest (60.63 cm) and Komboka had the most tillers (25.2). The variety–nitrogen interaction peaked with 17KH090014B at 83.4 kg N ha⁻¹, yielding 143.8 grains per panicle. Findings suggest that 67.5 kg N ha⁻¹ for 17KH090014B during the long rains could be a variety- and site-specific recommendation for upland rice in Taita Taveta County, provided further validation is conducted using broader sampling across the region.

The current study reports the results of a baseline survey conducted to establish current status of optimizing productivity of crop-livestock systems in Kenya. Results from the study showed that 74% and 18% of the household head and respondents were male and female respectively, indicating a male dominance of household headship. The household head (69%) and respondents (16%) reported to have completed classes for formal school. On average, farmers were walking 1.83 Km, 5.18 Km, 4.65 Km, and 12.79 Km to the nearest village market, town market, extension office and farmers’ training centers respectively. This shows that extension and communication services are still far apart from the farming communities, with a negative implication on technology adoption and household food and nutrition security. Majority of the farmers did not utilize organic nutrients for crop production (96%). Open heaping/piling, composting with other materials, use of solid and liquid manures was reported to be utilized on average 67 kg, 30 kg, 11 kg and 2 kg respectively. This implies a poor manure management, low adoption and utilization levels of organic manures, with subsequent impact on climate change, crop productivity and household food and nutrition security. The main constraint limiting the use of organic fertilizers were ranked as follows; ignorance of the technical aspects linked to the use of manure as an organic fertilizer (17.8%), low awareness of manure usefulness to improve soil fertility (16.4%), high affordability and timely accessibility of chemical fertilizers (16.3%). Results further show that majority of the respondent did not utilize Nitrogen fixing plants (66%), nutrient cycling (84%) and legume crops (75%). The main Nitrogen-fixing plants were faba bean (10%), Sesbania (9%), cowpea (5%), alfalfa (2%) and sunflower (1%) respectively. The survey recommends promotion of climate smart interventions and organic soil fertility management approaches, farmers capacity building and promotion of agribusiness.

Though mining promotes global industrialization and economy, it disrupts natural ecosystem that calls for sustainable reclamation. A field study was conducted at Base titanium limited - Kwale County to investigate the potential of mined soils to support growth and yield of green grams when subjected to organic and inorganic fertilizers. A two factor experiment was laid down in RCBD with split plot arrangement and three replications. Green gram varieties (KS20 and N26) and amendments (organic and inorganic fertilizers) were tested. Obtained data that included: soil properties, plant height, leaf development, pods and grains per plant, root nodules, biomass, and grain yield was subjected to ANOVA using the Genstat statistical package and means ranked using Fisher's protected least significant difference at (P≤0.05). Results showed that combined manure and fertilizer significantly improved plant plant height by 36% and 36.4% for KS20 and N26 varieties respectively in season one and, 23% and 23% for KS20 and N26 varieties respectively in season two compared to unfertilized soils. Similarly, leaf development was increased by 54.9% and 52.2% for KS20 and N26 varieties respectively in season one and, 46.1% and 37% for KS20 and N26 varieties respectively in season two compared to unfertilized soils. Sole manure and sole fertilizer did not have significant effect on plant height and leaf development. Combined application of manure and fertilizer did not have significant influence on green gram nodulation, shoot and root dry matter accumulation, number of seeds per pod and pods per plant. It however increased N26 variety grain yield in the second season alone. Additionally, grains harvested from the post mined soils had adequate levels of phosphorus, Iron, Zinc, magnesium, potassium, and low levels of calcium and copper. Although the findings show that this post mined soils have the capacity to support green gram growth, further research to ascertain long term effects of green gram establishment on profile development, biological nitrogen fixation, enterprise return to capital and crops response after application of all limiting nutrients is recommended.

Cabbage is an important vegetable containing considerable amount of water, protein, lipids, carbohydrates, fibre, vitamins, assorted minerals, phenols and glucosinolates. In Kenya, cabbage production is done mainly by smallholder farmers for food and sale. The crop is mainly grown between 800m and 2900m above sea level. It plays an important role towards achieving improved human nutrition and health conditions, reducing poverty through food security, and enhancing ecosystem resilience as a source of income, human food, and livestock feed. Statistics show that though the average area under production has been growing since 2017, average production has been fluctuating and consumption increasing steadily. Profitable production of the crop within the country is mainly constrained by myriad of factors such as climate change effects, pest and disease prevalence, poor agronomic practices, land degradation, soil health deterioration, lack of structured marketing systems and poor research-extension- farmer linkages. Possession of limiting climate-smart agriculture knowledge and skills, challenging access to credit facilities and agro-processing technologies, as well as narrow post-harvest loss management knowledge and skills, was identified as other key cabbage production constraints within the country. It was however noted that the country has the potential to achieve profitable cabbage farming if the adoption of climate smart technologies, farmer-extension linkage, government policies, credit facilities as well a structured market system were streamlined. The current work reviews the cabbage crop, with emphasis on its biology, economic importance, ecological requirements, current production status in Kenya and production constraints.

Sorghum (Sorghum bicolar (L) Moench) is an important cereal crop grown in arid and semi-arid areas. It is ranked as the fifth key cereal crop globally and acts as a source of grain, animal feed, pasturage, fodder, fiber, fuel, bioethanol, alcoholic beverages as well as building materials. In Kenya, sorghum production is done mainly by smallholder farmers as a key food and cash crop. Most of the country’s crop production is mainly in the arid and semi-arid regions with an altitude of between 800 and 2,000 m above sea level. The country’s average sorghum yield ranges between 0.7-1ton/ha compared to variety specific average yield of >2 tons/ha. The production is mainly constrained by myriad of factors such as climate change effects, poor agronomic practices, poor fertility management practices, poor pest and disease management, lack of ready markets, lack of organized market infrastructure, poor research- extension- farmer linkages and access to credit facilities as well as poor sorghum processing and value addition technologies. The current work reviews sorghum crop, with emphasis on its biology, economic importance, ecological requirements, current production status in Kenya and production constraints.

A survey was conducted on farmers' fields at Werugha and Wusi-Kishamba wards in Taita Taveta County, Kenya, to assess the factors influencing farmers' decisions on the use of bioslurry in the management of soil fertility. Knowledge gaps on bioslurry use provide contrasting claims about the value of bioslurry from source, storage and handling, crop types, soil, and climate conditions, and as a fertilizer. The majority of the farmers in the study sites double up as dairy farmers which has resulted in enormous production of under-utilized cow dung. Over-dependence on the use of inorganic fertilizers leads to the destruction of soil physical and biological properties; hence, the provision of essential nutrients required by plants for growth and development is not achieved at the maximum recommended rates. This results in a yield decrease with potato yield ranging from 8 to 15 t ha(-1), which is 2- to 3-times below the achievable yield of 40 t ha(-1). A survey questionnaire was developed and administered to 120 small-scale farmers within the two wards. Results showed that the use of bioslurry has not been well adopted by farmers from the two wards as only 18% responded to using bioslurry on their farms whereas 78% relied on chemical fertilizers and other forms of manures such as farmyard manure. However, even those using slurry had since been reported to have challenges with its use and application. The 36% of farmers who applied bioslurry alone did so due to its availability considering the high cost of inorganic fertilizers while those who combined it with inorganic fertilizers had faith in chemical fertilizers and that they aimed at achieving high crop yields. The major challenges farmers faced while using slurry on their farms were reported to be on lack of knowledge on the exact quantity to be applied per unit area and on the storage of excess slurry from biodigesters. This implied that even though slurry was available, it was still not useful to the farmers due to under/over application and poor storage. The study, therefore, recommends capacity-building programs and agricultural extension services to be developed, to ensure adequate knowledge on bioslurry use and adoption by smallholder farmers in the management of soil fertility in enhancing crop productivity.

Mining is an important economic activity globally that is associated with provision of raw materials, industrial growth, employment creation as well as degradation of natural ecosystems and agricultural land. A study was conducted at Base Titanium limited mining company to evaluate the response of maize-green intercrop to farmyard manure and mineral fertilizer in post mined soils. Treatments were sole manure, sole inorganic fertilizer, manure + inorganic fertilizer and unfertilized (control) laid down in randomised complete block design (RCBD) and replicated three times. Data collected included soil nutrients before and after cropping, maize and green grams growth and yield parameters. Obtained data was subjected to analysis of variance using genstat software and means separated using Fisher's LSD. The post mined soils were slightly acidic with optimal levels of Ca, Mg, Mn and Zn, Low levels of P,K, S, B,Cu, CEC, TN and organic matter. After two cropping seasons, S and TN was observed to increase in all treatments, while Ca, Mg, Mn, B and Zn decreased in all treatments. Combined manure and fertilizer application increased average maize plant height, stem circumference and LAI by 38%, 34%, 60% respectively and ears per plant, cob length, grains per cob, grain yield and dry matter weight by 57%, 13%, 47%, 31% and 35% respectively compared to unfertilized plants. Green grams growth and yield in the intercropping system was however not significant after either manure and/or fertilizer application. Although the findings showed that manures and fertilizers application improved nutrient availability in this post mined soils, further research is required to ascertain maize–green gram intercrop, optimal establishment time, spacing, fertilizer and manure rates that can provide optimal intercrop yield as well as soil regeneration.

Continuous land degradation and soil acidity are some of the major causes of below optimal crop yields in Kenya. Sustainable crop production therefore calls for efficient soil health management strategies. Field experiments were carried out at Waruhiu Farmers Training Centre, Kiambu for two seasons to evaluate the effects of tillage methods, phosphorus and lime application on selected properties of acid soils. Ploughing, strip tillage and hand hoe tillage methods and, DAP + lime (DAPL), TSP + lime (LP), TSP (P) were evaluated. Burnt lime at 3.2 tones ha-1 rate was used as lime source while 52kg P ha-1 was used as Phosphorus source. Obtained data indicated that the soils were strongly acidic with high exchangeable Al3+ and Al saturation, low cation Exchange capacity (CEC) and available P. Combination of Ploughing, lime and phosphorus in form of TSP significantly (P ≤ 0.05) led to > 38% increase of soil pH, >75% extractable P, 51% exchangeable Ca, >60% CEC, 54% Exchangeable Mg and reduced Al concentrations by >83% compared to the control. Similarly, combination of ploughing, DAP and lime significantly (P ≤ 0.05) increased CEC by 42% and available P by 81% compared to control. DAPL was observed to significantly (P ≤ 0.05) promote higher levels of exchangeable Al Compared to control and LP in both seasons. Plough DAPL also increased available P by 49% compared to strip DAPL. Strip LP significantly increased Exchangeable Ca by 46% compared to control. Sole tillage methods did not significantly affect soil properties. It can, be concluded that integrating ploughing with either DAPL or LP improves the selected acid soil properties. There is however need for long term studies to understand long term effects of the fertilizer- lime -tillage methods interaction on soil acidity management.

Biogas bioslurry, which is normally a bio-digestion product from livestock refuse, can be utilized as an inorganic fertilizer, thus boosting not only soil fertility but also crop growth and yield. Its use can mitigate climate change by reducing methane gas emissions, which are associated with the direct application of fresh animal manure. The current study was carried out on farmer’s fields based at Wusi-Kishamba and Werugha wards in Taita Taveta County, Kenya, and it aimed at investigating the effect of bioslurry coupled with synthetic fertilizer on potato (Solanum tuberosum L.) growth and yield. There were four treatments: sole bioslurry, sole fertilizer (DAP), bioslurry + DAP, and control, which were replicated five times in a randomized, complete block-designed layout. Data were collected on plant growth (plant height and leaf length) and yield (marketable and unmarketable tubers and the number of tubers plant−1). The results indicated a general increase in plant height from week one to week seven, where peak values were noted with sole slurry, sole fertilizer, and bioslurry + DAP treatments, which recorded 9, 18, and 43% taller plants, respectively, relative to control. Further, the combined application of bioslurry and DAP fertilizer significantly (p ≤ 0.05) improved potato growth and yield. For instance, there was a higher (23.3 t ha−1) yield in bioslurry + DAP treatment compared to the respective least record of 14.2 t ha−1 in control. Therefore, the study recommends a synergistic application of synthetic fertilizer (DAP) and bioslurry to potato crops for optimal crop growth and production.

Coastal Kenya is arid and semi-arid. Farmers in coastal Kenya use saline borehole irrigation water for crop production. There is limited information regarding the perception of farmers on effect and management of salinity on crop production. This study assessed farmers’ perception on effects and management of saline water on soil and crops in coastal Kenya. The study was carried out in Kilifi County (Kaloleni, Magarini and Kilifi sub-Counties) and Kwale County (Msambweni and Matuga sub-Counties). A purposive sampling procedure was used to select farmers from the two study sites. Farmers owning boreholes and practicing irrigated agriculture for at least three calendar years were selected per site resulting in a sample size of 30 farmers from each county. Data were obtained from sampled farmers through interviews and structured questionnaires. The farmers’ survey was undertaken using a single - visit survey approach. Data collected were divided into four subsections, which include, socio-demographic profiles, farmers’ sources of information on crop production, history of borehole water, crops grown and soil and water management. Survey data were coded and analyzed using SPSS software, version 14. Data were analyzed using descriptive statistics. Results revealed that all (100 %) household size in Kilifi County and 92.2 % of Kwale County consisted of four or less members, showing that the smaller household sizes depended on irrigated crop production either for food or income generation. Radio was the most common means of communication (Kilifi 90 % and Kwale 87.5 %) through national and vernacular languages. Farmers in Kilifi County (93.3 %) and Kwale County (86.7 %) did not belong to any agricultural society. This meant that some farmers lacked information on the advantages and how agricultural societies are formed. Farmers growing crops under irrigation in Kwale County obtained water from boreholes. Farmers in both counties never tested the quality of borehole water used to irrigate their crops. All farmers (100 %) in Kwale County and 86.7 % in Kilifi County reported gradual decline in yield, 13.3 % of famers in Kilifi County reported stunted growth, 84.6 % of farmers from Kilifi County and 78.6 % from Kwale County reported that salts in irrigation water (indicated by white residues on soil after irrigation) accumulate in soil over time that degraded the soil and harmed plants. Farmers in both counties (Kilifi 84.6 % and Kwale 64.3 %) use manure during planting to manage their soils. Key words: Salinity, Farmers’ perception, Soil and water management, Irrigation water quality

Green gram (Vigna radiata L. Wilczek), also known as mung bean, is an important grain legume containing a high amount of digestible protein, amino acids, sugar, minerals, soluble dietary fibers, and vitamins. In Kenya, green gram production is done mainly by smallholder farmers for food and sale. The crop is mainly grown in arid and semi-arid regions and plays important role towards achieving improved human nutrition and health conditions, reducing poverty through food security and enhancing ecosystem resilience as a source of human food, animal feed, soil nitrogen and soil health. Statistics show that though average area under production has been growing since 1978, average production has been fluctuating and consumption increasing steadily upholding constant deficit which is catered for through imports. The country’s average green gram yield ranges between 0.5-0.6 ton/ha compared to crop potential of 1.5 ton/ha and global average yield of 0.73 tons/ha. The production is mainly constrained by myriad of factors such as climate change effects, pest and disease prevalence, poor agronomic practices, land degradation and soil health decline. Other challenges included: lack of structured marketing systems and poor research- extension- farmer linkages, Possession of limiting climate smart agriculture knowledge and skills. Access to credit facilities and agro processing technologies as well as narrow post-harvest loss management knowledge and skills was also identified as other key green gram production constraints more so for small scale farmers. It was however noted that the country has potential to achieve optimal greengram production and optimal production require adoption of climate smart technologies, improved flow of information, streamlined government policies, credit facilities as well as structured market system. The current work reviews green gram crop, with emphasis on its biology, economic importance, ecological requirements, current production status in Kenya, production constraints and their management.

Mining plays an important role in Kenyan Economic development through provision of employment, raw materials as well as foreign income. Despite the important role played by this sector, it is associated with land degradation, impacting food security. Closure of mines calls for rehabilitation process through establishment of native trees, grass or crops. In order to promote crop production as a reclamation measure, performance of sorghum in post mined soils was evaluated in the south dune site of base titanium limited Kwale Company. The experiments were laid down in Randomized Complete Block Design (RCBD) with split plot arrangement and replicated thrice. Fertilizer, Manure, Manure + Fertilizer, Control (unfertilized) and Gadam and Silla sorghum varieties were tested. Data collected included: Initial soil properties, plant height, number of leaves, leaf length, leaf width, stem circumference, panicle length, panicle circumference and grain yield per hectare. Data collected was subjected to analysis of variance using Genstat software and means separated using the Fisher’s protected least significant difference at (P≤0.05). The soils were slightly acidic with low levels of exchangeable P, K, S, Cu and Bn. Manure + fertilizer significantly (P≤0.05) increased plant height by 14% (gadam), and 28% (silla), number of leaves per plant by 28% (gadam) and 29% (silla), panicle length by 18% (gadam), 8% (silla), dry matter by 30% (gadam) 40% (silla) and grain yield by 50% for both gadam and silla varieties compared to control plots in both varieties. Average yields in both seasons for manure + fertilizer treated plants were significantly high (5.3 tones/ha) for Silla variety and (5.7 tones/ha) for Gadam variety. Where gadam produced slightly high grain yield than silla variety by 7%. Combined application of farmyard manure and inorganic fertilizer were most effective in enhancing sorghum growth, dry matter and yield. Growth and yield data collected showed that combined farmyard manure + fertilizer can support optimal sorghum production in the post mined soils. Owing to the fact that the soils have compromised profile, soil structure and fertility, long term trials and simulation models are required to ascertain optimal sorghum production while ensuring sustainable soil health in such soils.

Cabbage is a popular vegetable grown in Kenya for food and income generation. Despite the important role played by the crop within the country, current climate change effects and population pressure pose a need for increasing production through utilization of available resources. A study was therefore conducted to evaluate the effects of black shade net on soil properties and cabbage water use efficiency in humid coastal environment. Black shade nets of 0%, 50% and 70% shading intensity and two cabbage types (Brassica rapa and Brassica oleracea) were evaluated in Randomized complete block design with three replications. 0% represented open field. Data collected included: soil chemical characteristics, soil moisture content, air temperature, fresh head weight, dry matter weight, and water use efficiency. Data obtained were subjected to analysis of variance using general linear model SAS Computer package version 9.1 and means separated using Tukey’s test at 5%. From the findings obtained, the use of black shade net of 70% and 50% shading significantly increased soil moisture content by 5.1% and 2.6% than open field. Maximum air temperature in 70% and 50% shade nets was lower than open field by 4.6⁰C and 1.8⁰C respectively while minimum air temperature under 70% and 50% shade nets was higher than open field by 2.7⁰C and 1.6⁰C respectively. Brassica rapa from 70% shading had 35% more fresh weight per plant than open field while those from 50% had 30%. Brassica oleracea from both 70% and 50% shading had 44% and 29% more fresh weight per plant respectively than those from open field. Although shade nets did not have significant effect on availability of nutrients within soil solution, Brassica rapa under 70% shading recorded 49% higher water use efficiency than open field while, 50% shading recorded 50% more WUE than open field. Brassica oleracea under 70% shading recorded 41% higher water use efficiency than open field, while 50% shading recorded 25% increase than open field. Owing to the fact that shade nets did not have significant effect on available nutrients within the soils but significantly influenced WUE, there is need for further studies to understand the effects of shade nets on cabbage nutrient use efficiency under the same environment.

Cabbage is an important vegetable to humans since it provides crucial nutrients such as fiber, minerals, and vitamins. They also help manage cancer, cardiovascular diseases, prevent type 2 diabetes, and inflammation of the digestive systems. However, its production in the tropics is constrained by climatic and edaphic factors that include soil moisture stress, high soil and air temperatures, high evapotranspiration, and unbalanced nutrition. Due to the above challenges, sustainable cabbage production requires adoption of technologies that can modify the growth environment with minimal environmental effects. A field study was conducted at Pwani University Crop Science farm, Kilifi County, to evaluate the effects of black shade net on yield of Brassica rapa and Brassica oleracea. A randomized complete block design experiment with three replications was set. The treatments included: 50%, 70% black shade net intensity and open field as control. Data collected included, leaf chlorophyll content, fresh head weight, and dry matter weight. The data obtained was subjected to analysis of variance using General Linear Model (GLM) SAS Computer package version 9.1. The results indicated that, shading resulted in decreased chlorophyll content, and that use of 50% and 70% black net shading intensity significantly resulted in 55% and 47.5%, more number of cabbage heads for Brassica rapa than open field respectively, while in Brassica oleracea, 70% shading and 50% resulted in 60% and 52% more cabbage heads than open field respectively.

Mining is an important economic activity that promotes income generation, job creation, and industrialization globally. In spite its economic importance, it is classified as land degradation form that disrupts natural ecosystem through loss of biota and soil health. Paucity of information regarding the performance of reclaimed mined soils in supporting crop production abound in Kenya. To contribute to this knowledge gap, a study was conducted at Base titanium limited -Kwale to investigate the response of performance of bulb onions (red creole onion variety) to farmyard manure and inorganic fertilizer application on post mined soils. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replicates Treatments included: inorganic fertilizer, farmyard manure, inorganic fertilizer +farmyard manure and control. Obtained data that included: soil characterization, onion growth and yield parameters was subjected to analysis of variance (ANOVA) using R packages and means separated using the Fisher’s protected least significant difference (LSD) at (P≤0.05). Results showed that the soils had low TN, exchangeable P, K, S, Bo and Cu levels. Manure+ fertilizer significantly (P≤0.05) increased plant height by 38%, bulb diameter by 44%, neck thickness by 19.5% total bulb yield by 89% and marketable yield by 88% compared to control. A significant positive relationship between manure, fertilizer, fertilizer+ manure with plant height, number of leaves, bulb diameter, neck thickness and total yield was observed indicating that manure + fertilizer can support optimal onion production in these post mined soils. Further research is however, required to ascertain production approaches that promote sustainable soil development and onion yield.

Cabbages are important for income generation, human nutrition, and health promotion. Its production in the tropics is constrained by soil moisture stress and high temperatures. Sustainable production requires the adoption of technologies that modify growth environment. A study was conducted to evaluate the performance of Brassica rapa and Brassica oleracea under shade nets within coastal environments. Randomized complete block design, with three replications, was used. Treatments were: 0%, 50% and 70% shading, using black shade net. Data collected include plant height, stem diameter, crown diameter, leaf chlorophyll, number of open leaves and quality heads, and fresh head weight. Data obtained were subjected to ANOVA and means separated using Tukey’s test at 5%. 70%, and 50% shading significantly increased plant height than open field by 7.1cm and 5.3cm respectively. Number of open leaves and leaf chlorophyll content in both cabbages decreased with increase in shading intensity. Brassica rapa under 70% and 50% shading had 55% and 47.5% more yield than open field respectively, while Brassica oleracea under 70% and 50% shading had 62.5% and 53% more yield than open field respectively. Brassica rapa under 70% shading had 0.8 kg more fresh weight per plant than open field while 50% had 1 kg. Brassica oleracea had 1 kg more fresh weight per plant than open field in both 70% and 50% shading. Therefore, black shade net of 50% and 70% shading favoured cabbage production in a coastal environment and they can be used in areas with similar ecological conditions.

Agricultural utilization of bioslurry plays a critical role in soil conditioning and hence crop production. It also reduces greenhouse gas emissions thus mitigating climate change. Although the effect of bioslurry on growth and yields is well researched, that of different biodigester types is under-researched. Therefore, a study was carried out in Waruhiu Agricultural Training Centre, Githunguri sub-county, Kiambu county in Kenya, to investigate the effect of bioslurry from flexi and dome biodigesters on soil chemical properties, maize growth, yield and grain quality. Treatments were laid out in a Randomized Complete Block Design (RCBD) and replicated three times. The treatments were bioslurry from both Fixed Dome and Flexi biodigesters, applied separately at a rate of 400mls per hill as basal and top dress fertilizer. Planting was done during the 2019 short and 2020 long rains, using Duma 43 maize variety. The agronomic (germination percentage, number of leaves, leaf width, leaf length, plant height) and productivity data (stalk, stovers, grain yields and grain quality) were subjected to analysis of variance (ANOVA) through Proc general linear model (GLM) procedures. Mean separation was done using least square means (LS-Means). Results showed an increase in soil pH, total N and OC, exchangeable P, K, Mn and Na in both biodigester types. Total N and OC were higher in Dome treated soils by 38.89% and 37.00%, while in Flexi, it was 16.67% and 16.00% respectively. Exchangeable P and K was higher in Flexi treated soils with a 38.57% and 50.00% increase while in Dome it 37.86% and 47.22% respectively. Magnesium and Zn decreased after treatment by 34.30% and 22.59% in Dome while Flexi had 33.23% and 31.79% increase. Exchangeable Fe and acidity decreased in Dome but increased in Flexi treated soils. No statistical differences were observed on growth and yield parameters but Dome registered higher grain yields by 9.4% and 6.3% for short and long rains respectively. Flexi treated soils registered higher values in most grain nutrient content such as K, Fe, Cu, Mn and Zn in short rains and P, Ca, Fe, Cu, Mn and Zn in the long rains. Bioslurry from both biodigester types variably increased the evaluated soil chemical properties but decreased Mg and Zn. Despite the numerical differences noted between bioslurry from both biodigester types on maize growth and yield, there was no significant difference (p≤.05). However, Dome bioslurry increased N, OC and maize grain yield more while exchangeable P and K and most of the grain nutrient content were higher in Flexi treated soils. Therefore, bioslurry from either biodigester type can be used in enhancing soil conditions, growth, yield and quality of maize. However, a long-term experiment is required validate the findings.

Salinity is a major biotic factor that negatively affects growth and yield of crops. Over 90% of the coastal region of Kenya is arid and semi-arid, most farmers in the region use borehole irrigation water which is saline. Amaranthus spp. is one of the main vegetables grown in coastal region. There is limited information regarding the effect of salinity on amaranthus production. The study sought to determine the effect of saline irrigation water on amaranthus growth in coastal Kenya. Two experiments were set up, one at Mivumoni Secondary School farm in Kwale County and another at Pwani University farm in Kilifi County from beginning of September 2019 to the end of January, 2020. The experiments were laid out in a randomized complete block design and replicated three times. The six treatments tested were: fresh water alone, 75% saline water alone, 100% saline water alone, fresh water + DAP, 75% saline water + DAP, 100% saline water + DAP. Crop growth data collected were: emergence rate, plant height, leaf number, leaf area, chlorophyll content, stem thickness, root density, root weight, root volume and total plant biomass. Data obtained were subjected to analysis of variance using SAS statistical package (SAS, Version 10) and treatment effects were tested for significance using F-test. Significant means at F-test was ranked using Tukey’s test at 5% level of significance. Amaranthus seeds sown in fresh water had higher emergence rate compared to seeds sown in saline water. Salinity regardless of concentration used and application of DAP, resulted in decrease in height, leaf number, leaf area, stem tickness, chlorophyll content, root length, root weight, root volume and total biomass. The study demonstrates that saline irrigation water in coastal Kenya has a negative effect on Amaranthus growth.

Rice (Oryza sativa L.), is an important cereal crop grown within central, western and coast region of Kenya. Despite annual rice consumption being higher than maize (Kenya’s staple food), the country is unable to meet an annual demand of 0.55 million tons and depends on imports to fill a 73% deficit. In order to contribute to reducing the deficit gap, a field experiment was conducted at Dembwa and Kipusi, Taita Taveta County in Kenya during the 2019 long rain season to find out the effect of spacing and seeding rate on performance of New Rice for Africa (Nerica) 10 rice variety. Three spacings 30 cm x 15 cm (control), 20 cm x 15 cm and 20 cm x 10 cm and four seedrates drill (random seed placement in small groove/line), 1, 2, or 3 seedling(qs) per hill were used. The experiment was laid out in a randomized complete block design, factorial arrangement with three replications. Results showed that the interaction between 20 cm x 10 cm spacing at single seedling per hill significantly (p ≤ 0.05) increased grain yield by 58%, dry biomass by 33% and harvest index by 45% compared to 20 cm x 15 cm and 30 cm x 15cm (control). These results suggest that interaction between 20 cm x 10 cm spacing at 1(one) seedling per hill is the best for Nerica 10 grain yield maximization in Taita Taveta County. The current investigation is among preliminary studies on Nerica 10 rice variety in the county. Therefore, there is need for long term trials in various agro environments in the County.