Department of Soil Science
http://41.89.164.27:8080/xmlui/handle/123456789/194
2024-03-28T22:20:36ZUltra‑Trace Analysis of Fallout Plutonium Isotopes in Soil: Emerging Trends and Future Perspectives
http://41.89.164.27:8080/xmlui/handle/123456789/1930
Ultra‑Trace Analysis of Fallout Plutonium Isotopes in Soil: Emerging Trends and Future Perspectives
Osano, Odipo; et. al...
The measurement of isotopic abundances and ratio variations of plutonium can provide important information about the
sources and behaviours of radiogenic isotopes in the environment. The detection of ultra-trace isotopes of plutonium is
increasing interest in the scientific literature for the determination of soil erosion rates due to their long retention times in
the environment. The characteristics of plutonium within the environment make it an ideal tracer for the determination of
soil redistribution rates and its robustness presents the opportunity to replace more commonly used radioisotopes such as
137 Cesium and 210 Lead. However, ultra-trace analysis of plutonium (fg g −1 ) presents analytical challenges which must be
overcome in a variety of soil types. Inductively Coupled Plasma Mass Spectrometry has proven valuable for detection of
plutonium in a range of environmental samples. However, severe polyatomic interferences from uranium isotopes significantly
limits its application. Due to the improvements in detection sensitivity and reaction cell technology, inductively coupled
plasma tandem mass spectrometry, which is also commonly referred to as triple quadrupole inductively coupled plasma
tandem mass spectrometry (ICP-MS/MS), has emerged as an exceptional tool for ultra-trace elemental analysis of plutonium
isotopes in environmental samples overcoming the limitations of standard quadrupole ICP-MS such as limited sensitivity
and cost of analysis. In this review, common methods reported in the literature for the separation and subsequent detection
of plutonium isotopes are compared to recent advances in analysis using ICP-MS/MS technology.
2023-01-01T00:00:00ZSpatial Prediction and Mapping of Gully Erosion Susceptibility Using Machine Learning Techniques in a Degraded Semi-Arid Region of Kenya
http://41.89.164.27:8080/xmlui/handle/123456789/1913
Spatial Prediction and Mapping of Gully Erosion Susceptibility Using Machine Learning Techniques in a Degraded Semi-Arid Region of Kenya
Were, Kennedy; et. al...
This study aimed at (i) developing, evaluating and comparing the performance of support
vector machines (SVM), boosted regression trees (BRT), random forest (RF) and logistic regression
(LR) models in mapping gully erosion susceptibility, and (ii) determining the important gully erosion
conditioning factors (GECFs) in a Kenyan semi-arid landscape. A total of 431 geo-referenced gully
erosion points were gathered through a field survey and visual interpretation of high-resolution
satellite imagery on Google Earth, while 24 raster-based GECFs were retrieved from the existing
geodatabases for spatial modeling and prediction. The resultant models exhibited excellent per-
formance, although the machine learners outperformed the benchmark LR technique. Specifically,
the RF and BRT models returned the highest area under the receiver operating characteristic curve
(AUC = 0.89 each) and overall accuracy (OA = 80.2%; 79.7%, respectively), followed by the SVM and
LR models (AUC = 0.86; 0.85 & OA = 79.1%; 79.6%, respectively). In addition, the importance of the
GECFs varied among the models. The best-performing RF model ranked the distance to a stream,
drainage density and valley depth as the three most important GECFs in the region. The output
gully erosion susceptibility maps can support the efficient allocation of resources for sustainable land
management in the area
2023-01-01T00:00:00ZEffect of land rehabilitation measures on soil organic carbon fractions in semi-arid environment
http://41.89.164.27:8080/xmlui/handle/123456789/1832
Effect of land rehabilitation measures on soil organic carbon fractions in semi-arid environment
Ng'etich, Wilson; et al.
Soil erosion threatens the sustainable intensification of food systems among
smallholder farmers in arid and semi-arid lands (ASALs). Intensifying adoption of soil
mitigation and rehabilitation measures is thus needed urgently in these ASALs, but
scaling up thesemeasures depends on scientific evidence of their contributions to key
components of sustainable intensification such as soil organic carbon. However, there
is no information on how existing mitigation and rehabilitation measures influence
soil carbon fractions and carbon management indices in ASALs. This study evaluated
the influence of soil erosion mitigation and rehabilitation measures on soil carbon
fractions and management indices in Arenic Lixisols of semi-arid environments in
West Pokot County, Kenya. We evaluated dierent vegetation types (maize-beans
intercrop and pastures) with and without two locally developed terrace designs for soil
conservation (Fanya Juu and Fanya Chini). Combining terracing with annual cropping
significantly increased total organic carbon (TOC). The highest TOC (13 g C kg−1) was
recorded in pasturelands with terraces while degraded land with no intervention was
found to have the lowest TOC (6.0 g C kg−1). Terraced farms with longer residence
time (>4 years old) had significantly higher organic carbon than (<4 years old). Other
soil properties remained stable with terrace age (1–5 years). Labile SOC and non-
labile SOC diered significantly within and across vegetation types with or without
terraces (p < 0.05). Pasture and crop systems with terraces had high labile SOC
content of 5.9 g C kg−1 and 7.2 g C kg−1, respectively. Labile SOC followed the
TOC trend with terrace age, i.e., increasing from 1 year to 5 years old. Combined
pasture and terraces had a significantly higher carbon management index (CMI) of
161.7, or 14 times the CMI found in degraded systems with no interventions and 1.5
times the combined crop system with terraces. CMI was also directly correlated with
residence time terraces had stayed in the crop system, increasing from 1 year to 5
years old. Contrary to CMI and other indices, the weighted enrichment ratio was found
to inversely correlate with age of terrace. Improvement of carbon content and CMI
resulted from restorative measures and likely improved soil quality and ecosystem
functions. Although terraces play a significant role in the restoration of degraded soils
as indicated by the above-mentioned changes, they are most beneficial when used
in combination with croplands because of the high level of disturbance and flows of
both inputs and outputs of carbon for these croplands.
2023-02-01T00:00:00ZCombining measurements, modeling and machine learning to improve N2O accounting for sustainable agricultural development in sub-Saharan Africa
http://41.89.164.27:8080/xmlui/handle/123456789/1830
Combining measurements, modeling and machine learning to improve N2O accounting for sustainable agricultural development in sub-Saharan Africa
Otinga, A.; Njoroge, R.
Sub-Saharan Africa continues to grapple with food insecurity due to low crop yields. While an
increase in synthetic fertilisers could potentially increase agricultural productivity in the region, it
would lead to an increase in emissions of nitrous oxide (N2O). Moreover, in this region, the lack of
quantification of parameters and documentation of the processes relevant to N2O emissions have
hampered the adoption of climate-smart agricultural practices and advancement of N2O
inventories. This study aims to conduct the first online measurements of N2O fluxes and isotopic
composition from agricultural soils in Uasin Gishu County, Kenya, using the TREX-QCLAS system:
quantum cascade laser absorption spectrometer (QCLAS) coupled to a preconcentration unit-
TRace gas EXtractor (TREX). The isotopic measurements obtained will be useful in the inference of
N2O production and consumption rates for different pathways and will improve understanding of
the key drivers of variability in tropical cropland N2O fluxes. Further, a collation and analysis of
available N2O flux and isotope data along with campaign measurements and data science
approaches will enhance the potential to predict future emissions and promote the development
of targeted mitigation strategies.
2023-06-01T00:00:00ZEFFECT OF SOIL AMENDMENTS ON THE PERFORMANCE OF SELECTED AFRICAN INDIGENOUS VEGETABLES IN UASIN GISHU AND TRANS NZOIA COUNTIES
http://41.89.164.27:8080/xmlui/handle/123456789/1545
EFFECT OF SOIL AMENDMENTS ON THE PERFORMANCE OF SELECTED AFRICAN INDIGENOUS VEGETABLES IN UASIN GISHU AND TRANS NZOIA COUNTIES
KIBIRU, BENSON
African Indigenous Vegetables (AIVs) have high nutritive value, require less inputs and can be a reliable source of income to resource challenged families. However, their production in western Kenya is hampered by limited information on their soil nutrition requirements. To meet these needs two studies (Agronomic trial and soil pH study) were conducted during the rainy season and dry season, which was between July 2013 and March 2014 under drip irrigation. The studies aimed at determining the best fertilizer-variety combination and ideal soil pH level in the two regions for growing AIVs. The experiments were laid out in a Randomized Complete Block Design in a split-split plot arrangement for the agronomic trial and a split-plot for pH study. Both experiments were replicated three times. In the agronomic study, three vegetable types formed the main plot treatments which included Spider plant (Cleome gynandra), African Nightshade (Solanum scabrum) and Amaranthus spp. Varieties formed the sub plot treatments which were Local variety, UG-SF-15 and ML-SF-29 for spider plant; Local variety, UG-AM-40 and Ex-Zim for Amaranthus spp and Local variety, BG-16 and SS-49 for African nightshade. Fertilizer treatments formed the sub-sub plots and include Mavuno fertilizer, poultry manure and the control. In the soil pH study, species (African nightshade, Amaranths & Spiderplant) formed the main plot treatment while the lime rates formed the sub plot treatment. Data were collected on cumulative fresh yield, soil pH trend and characterization, biomass and nutrient concentration, root biomass and root length density and chlorophyll content at flowering. Data were subjected to ANOVA using SAS version 9.3. In the agronomic study, the results exhibited that fertilizer application significantly (p=0.05) increased cumulative fresh yield of all selected varieties of the three AIVs. In African nightshade, developed variety BG-16 with mavuno fertilizer had the highest mean cumulative yields in Eldoret (9,980 kg/ha) and Kitale (13,880 kg/ha). In Amaranths, developed variety UG-AM-40 with poultry manure recorded the highest yields in Eldoret (4,490 kg/ha) and Kitale (6,060 kg/ha). In spiderplant, local variety (LV-SP) and developed variety (UG-SF-15) recorded highest yields with mavuno fertilizer while developed variety ML-SF-29 had highest yields in Eldoret (2600 kg/ha) and Kitale (3830 kg/ha) with poultry manure. In the soil pH study, acid soils responded to liming, whereby all the liming rates were significantly different at P=0.05. A mean pH of 6.33 for liming rate 4.1625 t/ha , 5.78 for liming rate 2 t/ha and 5.18 for the control were achieved. Generally, in all the species, fresh biomass at floweing was highest at lime rate 2 t/ha with a target pH of 5.5. For dry biomass mixed response was exhibited with Amaranth recording highest biomass at lime rate 2 t/ha (2370 kg/ha), spiderplant at zero liming(1350 kg/ha) and African nightshade at lime rate 4.16 t/ha with a target pH 6.5 (1340 kg/ha). In all the vegetable species, %N and % P in the plant tissue increased tremendously in the rainy season though no significant differences (p=0.05) were exhibited. Root biomass increased with increase in lime applied. In all the species zero lime treatment had the lowest dry root biomass. There were significant differences in spider plant and amaranthus (P=0.05) whereby, treatments with zero lime (NL0 and AL0) were significantly different from the other lime rates. However, in spiderplant there were no significant differences (p=0.05) between the lime rates. Overall, the studies concluded that yields of AIVs will greatly increase with utilization of improved germplasm, use of appropriate fertilizer and maintaining ideal soil pH through liming of acid soils.
2016-01-01T00:00:00ZEFFECTIVENESS OF PROMISING COMMERCIAL BIOFERTILIZERS ON SOYBEAN PRODUCTION IN BUNGOMA COUNTY, WESTERN KENYA.
http://41.89.164.27:8080/xmlui/handle/123456789/1535
EFFECTIVENESS OF PROMISING COMMERCIAL BIOFERTILIZERS ON SOYBEAN PRODUCTION IN BUNGOMA COUNTY, WESTERN KENYA.
MAJENGO, COLLINS OTIENO
The study was conducted to compare the performance of promising commercial bio-fertilizers that have been evaluated under the green-house conditions at TSBF-CIAT, in farmers’ conditions through the use of promiscuous soybean variety (SB19). The trials were laid out on small scale farms in Bungoma County, situated in Western Kenya. The experiment was established in March 2010 during the long rains (LR) and repeated during the short rains (SR) of 2010; laid out in multi-locational one farmer field one replicate design. Treatments were not replicated within each field. During LR 2010, 50 farms were researched on and 100 farms in the second season (SR 2010). A promiscuous medium-maturity soybean variety TGx1740-2E (SB 19) was inoculated with Legumefix (Rhizobia) or/and Rhizatech (mycorrhizae) inoculants. The mycorrhizae inoculum was applied to the soil in the seed furrows at the recommended rate of 30 kg ha-1. Nodulation was examined at mid-podding (50% podding) by carefully uprooting all plants with their entire root system from a 1 m2 section in each plot. Nodules were counted and weighed; the root and shoot parts separated, and fresh and dry weights assessed. Analysis of variance was conducted to determine the effects of (and interactions between) the two inoculants on plant parameters using a mixed linear model (MIXED procedure, SAS). Rhizobial inoculation resulted in significantly (p<0.01) higher nodule biomass (0.93 g plant-1) compared to the control (0.27 g plant-1) across many farms. Mycorrhizal inoculation had no significant effect on nodulation when applied solely (0.38 g plant-1), but co-inoculation of Rhizobia and mycorrhizae increased nodule biomass further by 0.09 g plant-1. There was a significant difference (p<0.01) in terms of biomass yield between treatments. Rhizobial inoculated plants had the highest biomass production of 2086 kg/ha. Rhizobial inoculation resulted in higher grain yields of 1116 kg/ha above the control. Soybean inoculation increased both nitrogen and phosphorus uptake in the biomass. Rhizobial inoculant had the highest soybean N uptake of 48.6 N kg/ha which was significantly different (p<0.05) from control and sole application of mycorrhizae. Statistical analysis showed that soil factors (pH, P, C, N) significantly (p<0.001) affected soybean grain yields during both seasons. It is concluded from this study that rhizobial inoculants have a high potential as commercial bio-fertilizers and can substitute the need for mineral N fertilizer in the legume farming systems. However, there is need to target these inputs to the most responsive fields. Further studies are needed to elucidate the conditions under which synergism between both inoculants may occur, with specific focus towards soil P availability and management of P inputs.
2013-01-01T00:00:00ZEVALUATION OF NITROGEN FERTILIZER, LIME AND SOIL-WATER EFFECTS ON THE YIELD AND MALTING QUALITIES OF BARLEY (Hordeum vulgare L.)
http://41.89.164.27:8080/xmlui/handle/123456789/1517
EVALUATION OF NITROGEN FERTILIZER, LIME AND SOIL-WATER EFFECTS ON THE YIELD AND MALTING QUALITIES OF BARLEY (Hordeum vulgare L.)
NADIR, STANLEY WALUCHIO
Barley (Hordeum vulgare L.) is a cereal crop that grows over a wide range of environments
and in Kenya it is grown primarily for malting. Barley requires adequate nitrogen (N) for
good grain yields and quality malting, but the balance between adequate and excessive N is
important therefore an experiment was set up between July 2011 and July 2012 to address
the problems of N fertilizer use and soil moisture effects on grain yield and malting
qualities. The experiment was conducted at medium altitude at University of Eldoret
(Chepkoilel) (2185m asl) and at high altitude in Mau-Narok (2740m asl). The objective was
to evaluate effects of nitrogen fertilizer rates, liming and varying soil water on the grain
yield and malting qualities of barley. The experiments were done in the field and in the
greenhouse. For the field experiment, nitrogen as C.A.N fertilizer was applied at 5 levels 0,
30, 40, 50 and 60Kg N/ha, all at planting. Phosphorus inform of TSP at 45 Kg/ha as P205,
and potassium in form of muriate of potash at 35 Kg/ha as K20, were applied both as blanket
in plots with nitrogen treatments, and as a treatment. Lime was applied at 2 levels (0 & 1.5
t/ha). Split plot arrangement in RCBD design was used in the field. Two different
experiments were conducted in the greenhouse; the first one being a simulation of the field
experiment which had similar treatments as those in the field. The second greenhouse
experiment was a split-split arrangement in CRD design, with 3 soil water contents (field
capacity, 80% field capacity and 50% field capacity) applied in 4 nutrient types (nitrogen,
phosphorus, lime and control having all combined) tested on the two site soils. The results
indicated the soils of the two sites were acidic and deficient in phosphorus. Mau-Narok site
had more soil N than University of Eldoret. The effect of Nitrogen on grain yield was highly
significant (P 0.001). Increasing N rates beyond 40Kg N/ha increased the grain protein
content beyond the malting range. Effect of lime on grain yield in the field was significant at
(P 0.01) while (P 0.05) in the greenhouse for both site soils. Lime treatments had higher
grain protein contents than non-limed ones but not significantly different. Lime-nitrogen
interaction on kernel weight was highly significant (P 0.001) but not significant for grain
yield. The differences in grain yield, kernel weight and biomass due to soil type were highly
significant (P 0.001).There was a significant relationship (P 0.001) between soil moisture
content and lime on barley growth. Limed treatments of both site soils utilized less water to
produce mature grains compared to the un-limed ones. The effect of soil moisture levels on
biomass and tillering was highly significant (P 0.001). Application of lime in combination
with N rates at 30 and 40 N Kg/ha produced best results for grain yield (>7 t/ha for both
field and green house), biomass, kernel weight and grain crude protein (10-13.5 %) with soil
moisture contents of between field capacity and 80% field capacity being ideal for barley
growth on both soils. Nitrogen rates at 30N and 40 N Kg/ha produced highest grain yield,
highest kernel weight and ideal maltable grain protein content for both site soils and
therefore was recommended as optimum agronomic rates for both sites. In addition, liming
was recommended for Chepkoilel while increase in phosphorus use for Mau-Narok.
2013-01-01T00:00:00ZEFFECT OF HARVESTING METHODS AND NPK FERTILIZER ON SOIL pH, SOIL AND LEAF MAJOR NUTRIENTS CONTENTS AND YIELD OF TEA IN TANZANIA
http://41.89.164.27:8080/xmlui/handle/123456789/1486
EFFECT OF HARVESTING METHODS AND NPK FERTILIZER ON SOIL pH, SOIL AND LEAF MAJOR NUTRIENTS CONTENTS AND YIELD OF TEA IN TANZANIA
MAKWETA, AMOS JOEL
Tea (Camellia sinensis, (L), O. Kuntze crop in Tanzania has been traditionally harvested
by hand. In recent years, high cost and shortage of labour have compelled tea growers to
opt for mechanical harvesting. Mechanical harvesting is becoming very important and is
considered vital for survival of the tea industry. However tea growers have reported
decline in yield after some years of mechanical harvesting and there is a notion that
nutrients lost through the harvested crop differ from hand harvested tea. Thus there is need
to replenish nutrients lost through harvested crop which is different from hand harvested
tea, however to replenish soil nutrients in mechanical harvested tea, growers are applying
the same fertilizer rates as in hand harvesting method. The objective was to determine the
effect of tea harvesting methods (hand and mechanical) and NPK fertilizer on soil pH,
major nutrients (NPK) uptake, tea yield components (shoot weight, shoot type
composition) and yield. The study had two parts. First a survey was conducted on tea
estates (Ngwazi, Itona and Itambo) where both hand and mechanical harvesting had been
practiced for more than three years. Soil and leaf samples were collected for soil pH, soil
and leaf major nutrients (NPK) analysis. Yield data were used to compare yield trend in
hand and mechanical harvesting. In the second part, two experiments were set at the Tea
Research Institute of Tanzania stations (Marikitanda and Ngwazi) using randomized
complete block design (RCBD) with split-plot arrangement. Experiments were conducted
for 10 and 8 months at Marikitanda and Ngwazi respectively. Hand and mechanical (shear)
harvesting formed the main plots and the six fertilizer rates (0, 50, 100, 150, 200, 250 kg
N/ha) the sub-plots. NPK 25:5:5 fertilizer was applied once. Soil and leaf samples were
analyzed for soil pH, soil and leaf major nutrients (NPK) contents. Yield, shoot count and
shoot weight data were recorded. Results showed that, tea in mechanical method had
higher soil pH and K uptake by tea plants. Tea plants in hand method had higher uptake of
N and P. Mechanical method had significantly (p<0.05) lower shoot weight and had higher
proportions of mature leaf and broken leaf (low quality greenleaf). Yield was significantly
(p<0.05) higher in mechanical than hand method. The interaction between harvesting
methods and fertilizer rates on shoot weight was not significant. Effects of fertilizer rates
showed that, soil pH decreased with fertilizer rates, soil nutrients uptake increased with
fertilizer rates but declined at high rates: At Marikitanda Tea Research Station, nitrogen
declined at 250 kg N/ha, phosphorus at 250 kg N/ha and potassium at 150 kg N/ha. At
Ngwazi Tea Research Station, nitrogen declined at 250 kg N/ha, phosphorus at 200 kg
N/ha and potassium at 200 kg N/ha. Shoot weight increased with fertilizer rates but not
significantly. At both experimental sites, shoot weight declined at 250 kg N/ha. Yield
increased with fertilizer rates but declined at high rates: At Marikitanda Research Station,
the yield declined at 200 kg N/ha, at Ngwazi Tea Research Station it declined at 250 kg
N/ha. Only at Marikitanda did fertilizer rates showed significant (p<0.05) difference. There
was no significant difference in fertilizer rates between hand and mechanical harvesting.
The interaction between harvesting methods and fertilizer rates on yield was not
significant. It is recommended that during the first few years (≤ 3) same rate of fertilizer
should be applied in both hand and mechanical harvesting, this study should be continued
in order to further assess the effects of harvesting methods on soil pH, nutrients uptake and
yield
2015-01-01T00:00:00ZWHEAT RESPONSE TO PHOSPHORUS FERTILIZERS AND AGRICULTURAL LIME IN UASIN GISHU COUNTY, KENYA.
http://41.89.164.27:8080/xmlui/handle/123456789/1478
WHEAT RESPONSE TO PHOSPHORUS FERTILIZERS AND AGRICULTURAL LIME IN UASIN GISHU COUNTY, KENYA.
SIMATWO, PERES RACHAEL
When water is not limiting, soil acidity, deficiencies of phosphorus (P) and nitrogen (N) amongst others are considered to be the major causes of low wheat yields in Uasin-Gishu County, Kenya. In this County, average annual wheat grain yields have always been low with an average of 2.34 t ha-1 but small scale farmers get much lower yields of as low as 0.7 t ha-1. The study aimed at investigating response of wheat growth pattern, grain and straw yields, and soil chemical properties as influenced by liming at 2 t ha-1 (main plots), P sources 23:23:0 (NPK), (DAP) 18:46:0, and 0:20:0 (SSP) - (sub-plots) and, P rates (sub sub-plots) P0; 0 kg P ha-1, P1; 8.8 kg P ha-1, P2; 17.6 kg P ha-1 and P3; 26.4 kg P ha-1. A split-split plot arrangement laid out in a RCBD experiment was set up in two sites; Chepkoilel and Kipsangui in 4 m2 plots, replicated 3 times. Data collected on soil (pH, available P, SOC, and exchangeable K, Ca, Mg, Na), plant height, grain, straw yields and plant total P and N were subjected to ANOVA using SAS 9.1 for Windows 2012 statistical package. Lime application increased the soil pH thus likely making P more available in the acidic soils in the two sites and generally increased exchangeable cations K, Mg, Na and Ca thus improving soil fertility. Phosphorus rich fertilizer application resulted in a significant (p≤0.05) increase in P and soil nutrients content during plant growth, heading and maturity stages. ANOVA showed lime application had a significant (p≤0.05) rise in the wheat grain yield in both sites. Fertilizer application and liming significantly (p≤0.001) improved grain yield in both sites. Rates of applied P also significantly (p≤0.001) influenced wheat grain yields in the two sites. Use of compound fertilizers with balanced ratios of nutrients resulted into increased wheat grain yields. Phosphorus application plus lime at 2 t ha-1 had a significant (p≤0.001) influence on the straw yield in Chepkoilel and Kipsangui. Lime at 2 t ha-1 significantly (p≤0.05) influenced straw yields in Kipsangui and Chepkoilel sites. NPK (23:23:0) fertilizer recorded higher wheat straw means in Kipsangui and Chepkoilel, with DAP giving the lowest yields. Grains’ total N in Kipsangui was higher under SSP (1.80 %). There was no significant difference (p≤0.05) in the level of total N in grain using DAP and 23:23:0 in Kipsangui and Chepkoilel respectively. P uptake was high under P3 application rate plus liming. P uptake was high in both sites. The study recommends 23:23:0 fertilizers at a rate of 26.4 kg P ha-1 for Chepkoilel and Kipsangui plus lime at 2 t ha-1 as most productive and economical. The study also recommends further research on fertilizer use to further increase wheat grain yields from 5.39 t ha-1 to the optimum of 7.2 t ha-1, as the study only managed a 43.0 % wheat grain increase.
2016-01-01T00:00:00ZEffect of soil amendments on availability of soil phosphorus and uptake by maize in Vihiga County, western Kenya
http://41.89.164.27:8080/xmlui/handle/123456789/1410
Effect of soil amendments on availability of soil phosphorus and uptake by maize in Vihiga County, western Kenya
NJOGO, S. M.; et. al...
The combined use of organic inputs and fertilizers as promoted via Integrated Soil
Fertility Management (ISFM) approach may have a significant effect on bioavailability
of phosphorus (P) and enhance its uptake by crops. To assess this, a field study was
conducted to determine the effects of combined use of lime, NPK fertilizer, farmyard
manure (FYM) and Zinc (Zn) on short-term changes in available soil P. This was
followed by determination of P uptake in the stover and the maize grain. Thus, four
field experiments were established in four sites in Vihiga County, western Kenya; two
sites (Gurugwa 1 and 2) in Sabatia sub-county and two (Bumuyange and Jivogoli) in
Hamisi sub-county during the long rain (LR) and short rain (SR) seasons of 2015. The
treatments comprised of (i) an absolute control, (ii) NPK (100 kg N ha-1, 30 kg P ha-1
, 42 kg K ha-1 ), (iii) NPK + FYM (2 t ha-1), (iv) NPK + FYM (2 t ha-1) + Lime (2 t
ha-1) + Zn (3 kg ha-1), (v) NPK + FYM (3 t ha-1), (vi) NPK + FYM (4 t ha-1) and (vii)
NPK + Lime (2 t ha-1) + Zn (3 kg ha-1). Each of these treatments were replicated three
times and randomly allocated within each replicate. Soils were sampled at 0, 42, 86
and at 120 days after planting and analyzed for available P content. Results showed that
combined use of NPK fertilizer, FYM, lime and Zn (treatment iv) gave significantly
larger (P<0.05) available P levels after 42, 86 and 120 DAP (Days after planting)
relative to the control. In the maize ear leaf, the largest total P content were observed
in all treatments containing FYM. In the maize grain, again, the treatment (iv) resulted
in the largest P content. Further, use of NPK fertilizer with FYM at 3 t ha-1 and 4 t ha-1
resulted in significantly larger (P<0.05) P content in the maize stover. By embracing
ISFM strategies, low P uptake at farm level may be alleviated. Locally adapted fertilizer
packages and amendment blends aimed at addressing specific limiting soil conditions
such as Zinc deficiencies can further enhance P uptake in maize.
2018-01-01T00:00:00Z