Department of Agricultural Resources Economics and Economics
https://karuspace.karu.ac.ke/handle/20.500.12092/1808
2024-03-28T14:43:28ZFarm Household Typology Based on Soil Quality and Influenced by Socio-Economic Characteristics and Fertility Management Practices in Eastern Kenya
https://karuspace.karu.ac.ke/handle/20.500.12092/2864
Farm Household Typology Based on Soil Quality and Influenced by Socio-Economic Characteristics and Fertility Management Practices in Eastern Kenya
Wawire, Amos; Csorba, Ádám; Zein, Mohammed; Rotich, Brian; Phenson, Justine; Szegi, Tamás; Kovács, Eszter Tormáné; Michéli, Erika
The smallholder farming systems in Sub-Saharan Africa (SSA) are highly diverse and heterogeneous in terms of biophysical and socio-economic characteristics. This study was conducted in upper Eastern Kenya (UEK) to categorize farm households and determine the influence of socio-economic characteristics (SeC) and soil fertility management practices (SFMP) on soil fertility across farms. Conditioned Latin hypercube sampling (cLHS) was performed to determine 69 soil sampling sites within Meru and Tharaka Nithi counties. From each household (whose field soil sample was obtained), data relating to resource endowment and soil fertility management were collected through a household questionnaire survey. Standard laboratory procedures were used to analyse soil samples. Data reduction was performed using categorical principal component analysis (CATPCA) (for SeC and SFMP) and standard principal component analysis (PCA) (for soil properties). Two-step cluster analysis identified three distinct farm categories or farm types (FT), namely, low fertility farms (FT1), moderately fertile farms (FT2), and fertile farms (FT3). The correlation of clusters against soil properties was significant across pH, soil organic carbon (SOC), cation exchange capacity (CEC), available P, plant available K, and exchangeable bases. FT1 had low SOC, pH, CEC and available P (soil characteristics), low usage of fertilizer and manure (soil fertility management), and smaller household size, lower income, and smaller farm size (socio-economic). FT2 had lower SOC (compared to FT3) and available P. In terms of soil fertility management, FT2 had higher cases of fallowing and composting with moderate fertilizer usage. Households in this category had moderate income, family size, and land size (socio-economic). FT3 had relatively high SOC, pH, CEC, and mineral nutrients. This farm type was characterized by high fertilizer use (soil fertility management) as well as larger household size, higher income, and larger farm size (socio-economic). The results indicate the importance of nutrient management in enhancing soil quality. Delineation and characterization of farms based on the various parameters including resource endowment reveal imbalanced farm resource flows, suggesting a need for locally tailored interventions suited for location-specific conditions to facilitate improved targeting of soil fertility-enhancing technologies and sustainable crop production regimes. While fertilizer is one of the most critical inputs for enhancing agricultural production, it is a major contributor to nitrous oxide emissions from agriculture and can have negative environmental effects on soil biota and water sources. Farmers’ knowledge on the use of fertilizer is thus necessary in developing strategies (such as integrated approach) to promote its efficient use and minimize its detrimental impacts.
Farm Household Typology Based on Soil Quality
2023-04-12T00:00:00ZEnhancing Tripartite Symbiosis between Soybean, Bradyrhizobia and Arbuscular Mycorrhizal Fungiunder Contrasting Farm Management Practices in Tharaka-Nithi County-Kenya
https://karuspace.karu.ac.ke/handle/20.500.12092/2802
Enhancing Tripartite Symbiosis between Soybean, Bradyrhizobia and Arbuscular Mycorrhizal Fungiunder Contrasting Farm Management Practices in Tharaka-Nithi County-Kenya
Gitonga, Nicholas Mawira
Organic farming is gaining popularity as agronomically and environmentally sound
soil management strategy with the potential to enhance soil microbial diversity and
fertility, environmental quality and sustainable crop production. However, the role
of bradyrhizobia and arbuscular mycorrhizal fungi (AMF) in organic farming
systems is poorly understood. Field experiments were carried out to evaluate the
effects of organic farming and bradyrhizobia inoculation on soybean nodulation,
AMF root colonization, growth, production and yield quality. Greenhouse and
laboratory experiments sought to determine the effects of bradyrhizobia and/or AMF
inoculation and dual inoculation in promoting root colonization and nodulation,
determine soil mycorrhizal inoculum potential (MIP), evaluate the abundance and
effectiveness of native bradyrhizobia and determine the morphological and genetic
diversity of native bradyrhizobia isolates under different farm management
practices. Field experimental treatments included native bradyrhizobia, commercial
Bradyrhizobiun japonicum, a mixture of native and commercial Bradyrhizobium
japonicum and control. Promiscuous soybeans varieties SB 19 and SC squire as well
as non-promiscuous Gazelle were used as test plants. All field experiments were
carried out in split-split plot design. In the greenhouse, AMF and bradyrhizobia were
inoculated and dual inoculated on SC squire soybeans. The AMF inoculants used
were Funneliformis mosseae and Rhizophagus irregularis while bacteria involved
commercial bradyrhizobia and native bradyrhizobia. Greenhouse experiments were
set out using completely randomized design. The native bradyrhizobia were isolated
and characterized. Deoxyribonucleic acid (DNA) from nodule isolates was extracted
using Gene Jet DNA extraction kit. Polymerase chain reaction (PCR) targeting 16S
rDNA gene was carried out using universal primers P5-R and P3-F. Polymerase
chain reaction product purification and sequencing was carried out in MacrogenNetherlands. Sequencing was done using the same primers. Non molecular data
obtained was analyzed using analysis of variance (ANOVA). Means that were
significantly different at p< 0.05 were separated using Tukey’s HSD test. Field
experiment results demonstrated significant improvement of soybean nodule dry
weight (NDW), shoot dry weight (SDW) and seed dry weight (SEDW) due to
inoculation. Bradyrhizobia inoculation increased soybean seed yields by between
29-59% of its potential yield. Remarkably, organic farming significantly (p=0.001)
out-performed conventional systems in SDW, NDW, SEDW and AMF root
colonization. Moreover, seed nutrient significantly differed in organic and
conventional farming where, seed nitrogen, phosphorus, potassium and organic
carbon were higher in organic farming. Soybean varieties differed significantly on
SDW, NDW and SEDW, where SC squire performed better compared to SB 19 and
Gazelle. Greenhouse results showed bradyrhizobia and AMF dual inoculation
significantly enhanced AMF root colonization, NDW and SDW compared with
individual bradyrhizobia, AMF or control. Moreover, organic farming significantly
(p=0.001) increased SDW, NDW and AMF root colonization compared to
conventional farming. Organic farming had a significant effect (p = 0.001) on soil
MIP. Based on molecular analysis, isolates were bradyrhizobia and matched with
Bradyrhizobium japonicum among other species. There was little or no genetic
differentiation of isolates with the highest molecular variation (91.12%) within the
populations and 8.88 % among populations. The results demonstrate the importance
of organic farming and dual inoculation in sustainable crop production. The highly
potential native bradyrhizobia isolates (GRPc and GRPk) and exotic AMF should be
xix
popularized and commercially ultilized by farmers to alleviate declining soil fertility
and increase food production with minimum expenses.
ENHANCING TRIPARTITE SYMBIOSIS BETWEEN SOYBEAN, BRADYRHIZOBIA AND ARBUSCULAR MYCORRHIZAL FUNGI
2021-05-01T00:00:00ZEffects of Blended Fertilizers on Leaf Nutrients Content of Mature Clonal Tea in Kenya. Journal of Experimental Research. Volume 6 (2).
https://karuspace.karu.ac.ke/handle/20.500.12092/2792
Effects of Blended Fertilizers on Leaf Nutrients Content of Mature Clonal Tea in Kenya. Journal of Experimental Research. Volume 6 (2).
itienei, Kibet S; Kamiri, Hellen W.; Kamau, David M.; Nyabundi, Wilson K.; Morogo, Maureen
Fertilizer studies in Kenya tea industry have focused predominantly on compound NPK. These fertilizers cannot be easily manipulated for specific soils and tea clones. In this respect, Athi River Mining limited has produced Mavuno blended NPK fertilizers with calcium (Ca) and magnesium (Mg). However, their application rates that would result in optimal nutrients uptake are lacking. This is the knowledge gap that this study sought to address. Therefore, the fertilizer blends were assessed for their effects on nutrients uptake at different rate in two sites. The sites were selected purposefully, one in the eastern and the other in the western tea growing areas. Randomized complete block design (RCBD) were used to select 36 trial plots in the two areas which were treated with three fertilizer types where one type was control, and four fertilizer application rates with one rate being a control. The trial was replicated three times Leaf samples were collected and analyzed for nutrients content. The data were then subjected to the analysis of variance (ANOVA) using Mstat C computer software package. Two leaves and a bud had higher nitrogen content (Timbilil 4.84%; Kagochi 4.53%) compared to deficient levels in mature leaf (Timbilil 2.26%; Kagochi 2.95%). This study has shown that supplementing the soil applied NPK fertilizers with calcium, magnesium and micronutrients resulted in better nutrients uptake.
Effects of Blended Fertilizers on Leaf Nutrients
Content of mature clonal tea
2018-06-01T00:00:00ZEFFECTS OF WEATHER ON THRIPS POPULATION DYNAMICS AND ITS IMPLICATIONS ON THE THRIPS PEST MANAGEMENT
https://karuspace.karu.ac.ke/handle/20.500.12092/2679
EFFECTS OF WEATHER ON THRIPS POPULATION DYNAMICS AND ITS IMPLICATIONS ON THE THRIPS PEST MANAGEMENT
Waiganjo, M.M.; Gitonga, L.M.; Mueke, J.M.
Onion thrips, Thrips tabaci Lindeman, is the most destructive insect pest of the onion crop,
Allium cepa L. worldwide. Both larvae and adults attack the onion crop at all stages of its
growth, resulting in reduction of yield and quality. Despite the heavy losses incurred as a result
of damage by the onion thrips, very little efforts have been made to develop an integrated pest
management strategy for the control of the pest in many African countries. Field trials were
conducted in four seasons at the Kenya Agricultural Research Institute (KARI) Mwea-Tebere
farm in Kirinyaga District. Onion plants were planted periodically and thrips populations
monitored weekly from onion plant samples and blue sticky traps for a full year under natural
field conditions. The purpose of the trials was to assess the effect of weather on thrips population
in onions with the aim of predicting thrips control requirements for a given climatic trend.
Weather variables monitored included: rainfall, temperature, relative humidity and wind. Thrips
occurred in the onion field and infested onions in all the crop seasons. However, there was
significant (P=0.05) variation in thrips numbers between the crop seasons. Dry weather (30.3
mm rainfall) with moderately high temperatures (15.6-28.2oC) increased seasonal thrips
numbers, while wet season (391mm rainfall) with moderately high relative humidity was
negatively correlated with thrips numbers. Regression analysis (step-wise selection model)
showed that minimum relative humidity was the only significant weather factor for predicting
thrips infestation in the onion crop (R2
=0.15; y = 60.342-0.1022x). The results suggest that
climatic trends can be used to determine the potential thrips control needs in onion production.
EFFECTS OF WEATHER ON THRIPS POPULATION DYNAMICS
2008-06-30T00:00:00Z