315 Records out of 22207 Records

Agents based crop health advisory system for farmers

Author: Mwangi, Zachariah M

Awarding University: University of Nairobi, Kenya

Level : MSc

Year: 2012

Holding Libraries: University of Nairobi Jomo Kenyatta Memorial Library ;

Subject Terms: Agricultural extension work ; Agents ; Crops ; Farmers ;

Abstract:

Despite their substantial efforts, small scale farmers in Kenya usually experience a number of challenges which include variable weather conditions: unreliable agricultural extension services, use of archaic technology, problems of pest and diseases, lack of information on the right type of farm inputs to use and the appropriate time of application of the same as well as soil nutrient deterioration. The challenges can be reduced through carrying out effective extension and advisory services. Although the common method of using agricultural extension officers in assisting these farmers is quite effective, it is very expensive and not sustainable. Application of ICT can significantly boost the extension work by reducing cost of collecting data, transmission, processing and dissemination of vital agricultural information to farmers. Unfortunately many ICT applications currently in use suffer from low adoption, difficulty in modifying, weak integration, complexity as well as failure to adapt to a continually changing environment within the crop health field. This has been resolved through the development of agents based crop health advisory system for farmers. Agents are sophisticated computer programs that act autonomously on behalf of their users, across open and distributed environments, to solve a growing number of complex problems. This system is using agents-based technology to provide advisory services to farmers in different areas that affect crop health which are nutrition, weather, crop failure, seeds, diseases and pests. The farmer will access the system through crop health advisory agent which will interact with nutrition agent, weather agent, crop failure agent, diseases/pests agent as well as seeds agent. The agents will exhibit autonomy, social ability, reactivity and pro-activeness in providing advisory services to the farmers. In order to successfully interact, agents will have the ability to cooperate, coordinate, and negotiate with each other. To make the system accessible to rural farmers, mobile phone interface will be used. It will also be possible to access the system through the internet.

The effect of appraisal system on employee performance in Horticultural Crops Developement Authority

Author: Choge, Elphas K.

Awarding University: Kenyatta University, Kenya

Level : MBA

Year: 2010

Holding Libraries: Kenyatta University Moi LIbrary ;

Subject Terms: Employees ; Performance appraisal ; Horticultural Crops Development Authority ;

Abstract:

This research paper sought to conceptualize the effect of employee's appraisal on their performance at Horticultural Crops Development Authority. The paper also sought to determine whether employee relations and teamwork, motivation and competence (skill) development and training as affected by em-ployee appraisal, had lead the employees of Horticultural Crops Development Authority to improve their performance at work place. The paper explored the importance of employee appraisal on employee career progression and corporate performance, while addressing the problems and challenges experienced while carrying out employee performance appraisal, in order to provide suggestions on the corrective limprovement steps where necessary. Descriptive survey was used to carry out the research. A sample size of two hundred and eight (200) employees was used, comprising, the management staff, technical staff, marketing and systems analysts staff, human resource and administration staff and finance staff who were selected using stratified sampling techniques of ration 0.5(50%) across the staff categories of employees who participated in the study. Observation and oral interview of a third (1/3) of each sample category of staff was used as primary source of data. Books, journals, published and unpublished thesis and dissertations, magazines, abstracts, periodicals, computers search and the internet was used by the researcher as secondary data sources. Closed and a few open ended questionnaire was used to collect data. Descriptive statistics mainly frequency and cross tabulation was used to analyze the data. Statistical package for social sciences (SPSS) was also applied to enhance the data analytical process. Appropriate interpretation, findings and recommendations was later done accordingly. sssWhile carrying out the research, the following limitations were encountered; other respondents failed to respond to the questionnaire on time and the researcher had difficulties in obtaining adequate information from the empirical studies done on the researched area. The output from this research were; improved employee work performance, enhanced employee relations/teamwork, identification of relevant training and development and enhanced staff morale and motivation at HCDA. The outcomes of this study are widely supported by other empirical and secondary data discussed in the literature review. The study shows that despite of the varied thoughts and opinion by the respondents on the effects of appraisal systems on employee work performance at HCDA there was a general consensus that performance appraisal system though marred with myriad challenges, it remains an important management tool that greatly influence employee work performance. It is on this premise that the researcher recommends further research on performance appraisal systems and especially on the methodology and approaches.

Influence of common interest group strategy on implementation of crop production technologies in Nyando District-Kenya

Author: Owiro, Joash Otieno

Awarding University: University of Nairobi, Kenya

Level : MA

Year: 2010

Holding Libraries: University of Nairobi Jomo Kenyatta Memorial Library ;

Subject Terms: Nyando District ; Crops ; Agricultural production ; Farmers ; Interest groups ; Group technology ;

Abstract:

Government has toyed with a variety of interventions ,to promote the implementation of crop production technologies, One such intervention is Common Interest Group approach (CIG) .CIGs are congregations of farmers brought together for the purpose of implementation of agricultural technologies. This study is significant because there was no official documentation of the influence of CIG strategy on implementation of crop production technologies in Nyando district, data generated may be used to develop new policies and extension packages for improving food security. The purpose of this study was to determine the influence of CIGs strategy on the implementation on of data that could be used to improve food security in the district. Guided by the theory of diffusion of innovations, the study was conducted through ex post facto research design, on a sample of 139 respondents from 70 CIGs out of a target population of 85 in Nyando district, 71 farmers who are not in CIGs 15 opinion leaders through simple random, snowball and purposive sampling techniques for the opinion leaders. Data was collected using interview, questionnaire techniques and focus group discussions in April 2010. The data collected was collected and analyzed through t-test technique at 5 percent (.05) level of significance to determine whether there was a sufficient difference between the means of implementations of farmers who belong to CIGs and those who did not and presented in tables and figures. The study findings indicated that CIGs had a positive influence on the implementation of crop production technologies and concludes that the CIG strategy have a significant Influence on the implementation of crop production technology among farmers. Thus CIGs can cause farmers to maintain production records, use certified seeds, use fertilizers and use soil conservation study makes the following recommendations. the ministry of agriculture should modify the CIG methodology to encourage production of food crops to improve food security, the department of Social Services and Cooperatives department to facilitate the CIGs on group development for sustainability, records keeping among farmers be up scale, affordability of fertilizers can be mitigated by development of Cf Gs into viable cooperatives, facilitation of a wider network of certified seeds stockists by the Ministry of Agriculture and other stakeholders at subsidized costs and more awareness be carried out on soil conservation. Suggested area for further study is to determine the actual Influence of CfGs on crop production technologies. Since the strategy was introduced in 2004, its influence on the implementation of agricultural technologies had not been determined. There was therefore need to determine the influence of ClGs strategy on the implementation of CPT among farmer groups in Nyando District.

Effects of legume cover crops and sub-soiling on soil properties and maize growth in Machakos district, Kenya

Author: Karuma, Anne Nyambura

Awarding University: University of Nairobi, Kenya

Level : MSc

Year: 2009

Holding Libraries: University of Nairobi Upper Kabete Library ;

Subject Terms: Soils/Legumes/Cover crops/Maize/Zea mays/Dolichos/Kalama Division, Machakos District/Machakos District/Soil fertility/ ;

Abstract:

Incorporating legume cover crops into the cropping systems and sub soiling/ripping has been used as an alternative method of improving soil fertility, crop yields and minimizing soil erosion problems. The current study explored the use of legumes and subsoiling in Kalama division, Machakos District, Kenya. The area has an average annual rainfall of 600 mm which has 66% reliability. In order to achieve this objective, a survey and a field experiment were conducted to: identify the factors that influence the adoption of Conservation Agriculture (CA) technologies in Machakos District; determine the effect of legume cover crop, subsoiling/ripping on soil properties and maize growth. The survey was conducted in midseason of the long rains in the area (LR, 2008). This was in order to observe the land use trends, agronomic practices, farm resources and the soil fertility management practices practiced in the area. The target population consisted of the farmers who were instructed on or practiced conservation technologies introduced by the K.ARI/LRNP project in the district. The field experiments were carried out in a randomized complete block design in four farms during the 2008 long (LR) and short rain (SR) seasons. The first trial (LR, 2008) had three treatment groups (T l=maize +dolichos + subsoiling, T rmaize + dolichos + no subsoiling, T 3=maize alone + no subsoiling). The second trial (SR, 2008) had four treatment groups (T 1= maize + dolichos + susbsoiling; T 2 = maize + dolichos + no subsoiling; T 3 maize alone + no subsoiling; T 4 = maize with subsoiling). Socio-economic factors played a greater role in adoption of CA technologies with respect to gender, age, education and farmer's resources. Fifty seven percent of the respondents were female and more men were educated than female (65%). It was thus recommended that farmers be trained more on cover crops use as method of increasing soil fertility. Further there is a need to improve level of education with special focus on women in the area to enhance proper maximization of farms and improve food security. Results from the field experiments showed that rainfall amount and its distribution affected the growth of dolichos and maize. Early in the season, the dolichos had a higher ground cover than maize with a peak at 8 weeks after planting (W AP) and thereafter tended to decrease slowly due to moisture stress. A further increase in cover was noted at 14-16 W AP after some rainfall showers 12 W AP. The maize did not recover from the drought spell and was harvested at 17 WAP in SR 2008. In 2008, there was crop failure due to lack of adequate rainfall. There were significant differences in cover among the treatments at P ~ 0.05 in all the different W APs. In reference to legume biomass. there were no significant differences among the treatments at P ~ 0.05 but T I had greater biomass than T 2. Different treatments showed differences in maize heights and subsoiled plots gave a higher height of 2-10 cm more than in the non-subsoiled plots as the W APs progressed. Plots with dolichos (T 1 and T 2) gave higher maize dry matter yield than the maize alone plots (T 3 and T4) in LR 2008. In SR 2008, the maize dry matter yield was significantly different at P ~ 0.05 with higher yields in T 3 and T4 than in T 1 and T 2? This could also be due to lack of competition of nutrients, water and light with the legume cover crop. There was a significant increase in total soil nitrogen content in SR 2008 compared to the initial characterization of the soils and this could be attributed to the dolichos in the field. The penetration resistance in all the plots ranged from 3.83- 4.18 kgcm-1 with T4 reporting the highest and T 1 lowest penetration resistance.

Integrated management of groundnut rosette disease

Author: Karanja, Catherine Njambi

Awarding University: University of Nairobi, Kenya

Level : MSc

Year: 2009

Holding Libraries: University of Nairobi Upper Kabete Library ;

Subject Terms: Groundnuts/Groundnut Rosette Disease/Siaya District/Teso District/Aphis craccivora/Trap crops/Integrated Pest Management/ ;

Abstract:

Groundnut is an important food, feed and cash crop in sub-Saharan Africa. This crop suffers greatly from a viral disease; groundnut rosette (GRD) vectored by an aphid cause 100% yield loss if it occurs before flowering. Management strategies for the disease include reduction of vector populations using pesticides, cropping practices to delay onset and spread of both vector and the disease and growing groundnut varieties resistant to the virus and the vector. The objective of this study was to assess the effectiveness of selected cultural practices, chemical pesticide and host plant resistance in the management of groundnut rosette disease. Field experiments were conducted between March 2007 and February 2008 at Siaya Agricultural Training Centre (Siaya district) and Kenya Agricultural Research Institute, Alupe sub station (Teso district) in Western Kenya. The cultural disease management strategies included alteration of time of planting (early planting at the onset of rains and late planting one month later), host plant resistance, use of trap crops (cowpea and sesame), vector control using a chemical insecticide (dimethoate) and roguing. The experimental design used was randomized complete block laid out as a split-plot and replicated three times. The disease management practices and groundnut varieties were allocated to main plots and subplots respectively. The time of planting significantly influenced aphid population and groundnut rosette disease incidence. High aphid population and GRD incidence was observed in lateplanted than in early-planted groundnut. Late planting reduced groundnut yield by 48- 71 %. Application of dimethoate lowered vector population and reduced GRD incidence by 85-94%. Cowpea and sesame trap crops reduced the disease incidence by 56-76% while roguing reduced the disease incidence by 30-44%. Groundnut yield increased by 167-255% where insecticide and trap crops were applied. Planting of varieties resistant to the virus (ICGV-SM 90704) and the vector (ICGV 12991) reduced the disease incidence by 46-61 %. Aphis craccivora Koch was the most abundant of the aphid species. This study recommends early planting in addition to combination of host plant resistance with other protective measures such as cultural practices for effective management of groundnut rosette disease. There is however, a need to undertake further studies in order to establish economic injury levels and action thresholds to guide in integrated management of groundnut rosette disease and its vectors.

Collection, morphological characterization and in vitro propagation of the Kenyan yam (dioscorea spp)

Author: Mwirigi, Peter

Awarding University: Jomo Kenyatta University of Agriculture and Technology, Kenya

Level : MSc

Year: 2009

Holding Libraries: Jomo Kenyatta University of Agriculture and Technology Library ;

Subject Terms: Food crops ; Tuber crops ; Kenyan yam ; Dioscorea ; Plant reproduction ;

Abstract:

Yam tuber is used as food where it provides cheap starch-rich staple food of the hot, humid tropics. In Kenya the yam is mainly boiled, fried or roasted although a minority of consumers also processes it into flour for use in some baked products. A majority of the farmers grow yams both for commercial and subsistence purposes. A set of three investigations were carried out in the period of August 2007 to August 2008 with the overall objective of collecting and documenting, morphologically characterizing and eventually optimizing an in vitro protocol for mass propagation of the Kenyan yam (Dioscorea spp). The first objective was achieved by carrying out a survey on 84 farm households in 6 selected administrative districts (Meru, Nyeri North, Nyeri South, Teso, Hamisi and Bungoma West) in the yam growing regions of Kenya. Data collection was carried out through individual interviews using structured and semi-structured questionnaires. 43 named landraces were recorded on farm where it was established that 38 landraces had limited distribution and abundance and only 5 dominant landraces were widely grown within the respective regions. However further studies are required to determine the actual extent of distribution and diversity of these named landraces. The second objective was to characterize the yam cultivars based on their morphological characters as recorded on farm. This involved subjecting data of seventeen morphological variables that were measured from the accessions to multivariate analysis using principal components and cluster analyses. A Dendogram generated through agglomerative hierarchical clustering based on a similarity matrix revealed that the 43 landraces belonged to four main groups of the Dioscorea genus. However, further confirmatory research through genetic analysis is required. The final objective was to optimize an efficient in vitro mass propagation protocol of this particular species. This experiment involved establishment of the best sterilization procedure for the explants that were initially grown in pots in a screen house at Jomo Kenyatta University of Agriculture and Technology then culturing the nodal cuttings in MS media supplemented with different levels of growth regulators. The two step-wise sterilization procedure using commercial bleach was found to be the best and hence recommended for future work. There were also significant differences among the treatments with the combination of BAP and IAA at levels of O.5mgll of BAP + O.02mgll of IAA giving the best results for plantlet regeneration. In vitro rooting was achieved without the use of hormones and the most vigorously growing plantlets acclimatized in the green house. In conclusion, the study found out that there is morphological diversity among the 43 cultivars grown in Kenya and that a new yam cultivar, 'nkone' was documented. Nevertheless, further confirmatory work based on molecular characterization is required. In addition with the development of an efficient in vitro protocol for micro-shoots growth, increased rates of multiplication can be achieved. This technique can then be exploited to generate clean, disease free material both for mass propagation and experimental work.

Influence of inorganic fertilizers on yield and quality of tissue culture banana Musa Sp. ratoon crop

Author: Miriti, Justin Kirimi

Awarding University: Jomo Kenyatta University of Agriculture and Technology, Kenya

Level : MSc

Year: 2009

Holding Libraries: Jomo Kenyatta University of Agriculture and Technology Library ;

Subject Terms: Fertilizers ; Crops ; Bananas ; Musa spp. ;

Abstract:

This study investigated the influence of in-organic fertilizers on the post harvest fruit quality characteristics of tissue culture banana (Musa sp.) cultivar giant Cavendish ratoon crop. The fertilizer rates under investigation in this trial were; Nitrogen (N) at 400kg/ha, half rate applied in the form of urea and a control with no Nitrogen applied. Phosphorous (P) at 50kg/ha applied in form of TSP and potassium (K) at 600kg/ha, half rate applied in the form of MOP and a control with no K applied. Micro-nutrients were supplied as follows; Magnesium (Mg) at 60kg/ha, Zinc (Zn) at 6kg/ha, Molybdenum at 0.5kg/ha and Boron at lkg/ha. Post harvest assessment was done on all the treatments. Day 0 was designated the day when ripening was commenced. Three hands from each treatment were ripened at 20?C at 90% ? 5% relative humidity until fully ripe stage six. Passion fruits were used to provide ethylene for ripening purposes. The bananas were harvested at three-quarter stage of maturity were harvested from an already existing fertilizer trial; undertaken at an established banana farm in Maragua Ridge, Maragua district. Three equatorial region hands were obtained from which three fingers per hand were analysed separately in the laboratory. On harvesting, the hands were weighed, washed to remove latex, then packed in crates and transported to JKUAT food science laboratory. Three hands from each treatment were ripened at 20?C at 90% relative humidity until fully ripe stage six. The fruits from the different treatments were analyzed for total soluble solids content, total titrable acidity, ascorbic acid content, individual sugars (sucrose, fructose and glucose) and their levels, ripening, peel colour, peel and pulp ratio, chlorophyll content, mineral content, moisture content, flavour and flesh firmness. Observations on the Shelf life were made. The fruit were assessed every second day during ripening period. Sensory analysis on the ripened fruit was done using 20 panelists for 15 out of the 20 harvests. Fresh weight decreased consistently and slowly between day 0 and day 6. Pulp moisture content was significantly different for fruits from different treatments (p=0.002). Fruits from 400kg/ha N, 50kg/ha P, Micro-nutrients treatment had the lowest pulp moisture content while those from 400kg/ha N, 50kg/ha P, 600kglha K, micro-nutrients treatment had the highest pulp moisture content. Total soluble solids were not significantly affected by the treatments (p=0.3). There were significant differences (p<0.05) in the measured bunch quality characteristics between the treatments. The yield was affected by macronutrients and micronutrients application rates. Inorganic fertilizers showed promise of increasing and stabilizing yields of tissue culture bananas ratoon crops.

Response of local sweet potato varieties to virus infection

Author: Njeru, Grace Mumbi

Awarding University: Jomo Kenyatta University of Agriculture and Technology, Kenya

Level : MSc

Year: 2008

Holding Libraries: Jomo Kenyatta University of Agriculture and Technology Library ;

Subject Terms: Crops ; Ipomoea batatases ; Ipomoea batatas ; Viruses ;

Abstract:

Sweet potato is an important crop in Kenya not only as a staple food in many communities, but also as a food security crop. The full production potential of sweet potato has however not been realized due to numerous production constraints with pests and diseases being rated most important. Lack of quantitative information regarding relationships between disease severity and the corresponding yield losses has been a major impediment in the evaluation of control programs for many disease problems. Therefore, the aim of this study was to analyze the effect of virus infection on root yield, vine production and source-sink interaction of six local sweet potato varieties (Bungoma, Nyathi Odiewo, Kemb 10, KSP 36, SPK 004 and CPT 560). The specific objectives of this study were (i) to determine the effect of single virus infections with sweet potato feathery mottle virus (SPFMV) and sweet potato chlorotic stunt virus (SPCSV) on growth, vigour and root yield of sweet potato (ii) to determine the effect of dual infection with SPFMV and SPCSV i.e. SPVD on growth, vigour and root yield of sweet potato and (iii) to determine the effect of single viruses (SPFMV and SPCSV) and the combination (SPVD) on, relative chlorophyll content, specific leaf area (SLA) and leaf area index (LAI) of sweet potato. The study was conducted at Jomo Kenyatta University of Agriculture and Technology. The experiment was set up in randomized complete block laid out as a two factor split plot replicated three times. The data collected during growth included vine number, vine length and leaf number. The experiment was terminated five months after planting by carefully harvesting the roots and vines. Data collected at harvest included, specific leaf area, leaf area index, fresh root weight, number of marketable and unmarketable roots, dry weight of shoots and roots, biomass and harvest index. Data collected were subjected to ANOV A using Proc GLM and means separated using SKN in the SAS statistical package. Findings from this study show . that single virus infection with SPFMV had the least severe effect on growth, vigour (number of vines, vine length and leaf number) and yield (fresh weight of roots, the number of marketable roots and harvest index) in all the six sweet potato varieties. Single virus infection with SPCSV reduced growth and vigour notably in all the six sweet potato varieties. Varieties were not significantly (P= 0.05) different from each other in the way they responded to virus infection in most of the parameters analyzed. Nyathi Odiewo however, revealed considerable virus tolerance as it was associated with the least reduction on growth (13%) and yield (37%) as compared to other varieties. Dual virus infection with both SPFMV and SPCSV i.e. (SPVD) consistently caused the most severe reduction on growth, vigour (56-74%) and yield (89-93%) in all the sweet potato varieties. Single virus infection with SPFMV did not drastically reduce relative chlorophyll content. SPCSV on the other hand, significantly reduced chlorophyll content and increased specific leaf area by (9- 38%).SPVD caused the most severe reduction on relative chlorophyll content (20- 30%) and had the highest disease severity scores. The range of symptoms caused by sweet potato viruses therefore, indicate the extent to which they interfere with assimilate production and partitioning. Furthermore, viruses compete and divert host resources for their own growth and replication, disrupting the source-sink relationships in the infected plant. This study underscored the fact that dual virus infection with the SPFMV and SPCSV has devastating effects on growth, vigour and yield of sweet potato as opposed to the single virus effects which were less severe. It is therefore recommended that field trials be done in many regions with a wider range of varieties to elucidate yield stability in the respective regions. Variety Nyathi Odiewo should be given special focus to assess the reason behind its hi

Genetic diversity analysis among cowpea [vigna unguiculata (L.) walp] accessions from sub-saharan Africa using simple sequence repeats (SSR's)

Author: Magembe, Eric Maina

Awarding University: University of Nairobi, Kenya

Level : MSc

Year: 2008

Holding Libraries: University of Nairobi Medical Library ;

Subject Terms: Cowpeas ; Genetics ; Crops ;

Abstract:

Cowpea is one of the most important legumes in the world. It is the second most important pulse crop in tropical Africa after common beans (Phaseolus vulgaris). Cowpea is valued for the high protein content of its grains which is about 25%. In Africa, where animal protein is not always freely available/ affordable, cowpea provides a valuable source of proteins. Cowpea diversity and relatedness in Africa is poorly understood. This lack of knowledge and information inhibits the use of novel germplasm and novel alleles in breeding programs and results in potential crop improvement bottlenecks. A core set of 1430 accessions of cowpea landraces from Sub-Saharan Africa were identified from the International Institute of Tropical Agriculture's (lIT A) global cowpea collection (15003 accessions). In this study sixteen SSR markers were used to evaluate the genetic diversity cowpea landraces in Sub-Saharan Africa. Within the core set a total of 125 alleles were detected with the mean number of alleles per marker being 7.8. The number of alleles per SSR ranged from 2 to 18. The mean polymorphism information content (PIC) was 0.453 J with the most informative marker being VM70 ~ith a PIC of 0.8636 while the least informative marker was VM54 with a PIC of 0.0376. The overall level of genetic diversity, measured as heterozygosities was medium to low, with an average gene diversity of 0.4988. The gene diversity (H) ranged from 0.0383 for VM54 to 0.8760 for VM70. The genetic diversity in West Africa was higher than North Africa indicated by H of 0.4987 and 0.4129 respectively. The mean observed heterozygosity was low (0.0953) as expected from a predominantly inbreeding species. Gene differentiation (FST) among populations was low (0.095) suggesting free gene flow between populations, a result confirmed by genetic distance (D A), and phylogenetic analysis. In, contrast, FIS which can be taken variously as a measure of heterozygote deficiency and departure from the Hardy-Weinberg equilibrium, but also as a measure of inbreeding, was found to be extremely high at 0.797.

Impact of long term application of organic and inorganic nutrient sources in a maize bean rotation to soil nitrogen dynamics and soil microbial populations and activity

Author: Kibunja, Catherine Njeri

Awarding University: University of Nairobi, Kenya

Level : PhD

Year: 2007

Holding Libraries: Kenya Agricultural Research Institute Headquarters Library ; University of Nairobi Chiromo Library ;

Subject Terms: Soils/Maize/Beans/Crops/Crop rotation/ ;

Abstract:

Declining crop productivity is a big challenge to both the smallholder farming community and the researchers in crop production in Kenya. Nitrogen (N) is recognized as one of the most limiting nutrients to agricultural productivity in subSaharan Africa. The high cost of mineral fertilizers and the adverse effects of continued fertilization have led to a search for alternative sources of nutrient supply. The effect ofland management on soil nitrogen dynamics, microbial diversity and land sustainability in a long-term field experiment situated at the National Agricultural Research Laboratories, Kabete, near Nairobi, forms the subject of this thesis. The trial was established in 1976 to study the effect of continuous use of farmyard manure (FYM), crop residues and chemical fertilizers on crop yields and soil properties in a maize-bean rotation. A study was carried out to assess the effect of land management on soil physio-chemical properties and microbial populations, Soil chemical properties declined over time, while acidity and bulk density increased under continuous cropping with no inputs. The effect of organic and inorganic inputs on soil microbes, number and activities of various groups of microorganisms was monitored for one year in the 0 -15 and 15 -30 em soil layers. Use ofFYM alone or combined with chemical fertilizers gave significantly higher (p=0.05) numbers of microbes, microbial respiration and soil enzymatic activity than plots with no-inputs or with chemical fertilizers alone. The topsoil layer had significantly (p=0.05) higher microbial activity than the sub-soil regardless of treatment. Bacteria were more numerous (1 x 105 g dry soil -I) than fungi (l x 103 g dry soil -I), which may lead to more SOM mineralization and less SOM retention in this cropping system. To study the dynamics of fertilizer nitrogen (N), labeled 15N fertilizer as calcium ammonium nitrate (10 % atom excess) at the rate of 60 kg N ha -I yr -I was applied in 1 x 2 m2 micro-plots and monitored at various depths for a 2-yr period. A substantial amount of mineral N (NO-3-N + NH/-N) was found in the 0 - 300 em soil profile (114 mgNkg soil') at the start of the experiment. Of this, 19.3 mg N kg soil' was held in the plough layer (20 em). Mineral N within the first 1 m (43 mg N kg soil') decreased with depth as the crop matured (39 mg N kg soil'), which was attributed to plant uptake and loss through leaching. A bulge of 81 mg N kg soil' was found below 1 m soil depth, which increased as the crop matured (94 mg N kg soil') probably due to mineralization and further leaching, but was not significantly different between the treatments. The leached N was beyond the reach of annual crops and therefore considered lost to the cropping system. The most prevalent form of inorganic N was NO -3 -N. Data on yields, plant N content and soil N content was used to calculate N balances. Biomass production and crop N yield was higher in treatments with combined inorganic fertilizers and FYM than with inorganic fertilizers alone. The amount of crop N derived from fertilizer (%ndff) was about 13 - 20 % and was higher in fertilized plots than in those with combined organic and inorganic inputs. Fertilizer N utilization ranged from 10 - 55 %, depending on rainfall distribution, which is comparable to other tropical regions. All treatments, except the treatments with combined inorganic and organic inputs (+39 kg N ha -I yr -I), gave a negative N balance (-39.5 to -150 kg N ha -I yr -I), which was highest in the no-input control plots (-150 kg N ha -I yr -I). These results indicate that continuous cropping of annual crops is not sustainable as it leads to substantial loss ofN from the soil through leaching and continuous N crop uptake. There is need for interventions in farmer fields to reduce nitrogen leaching, enhance sub-soil N recovery and improve N utilization. Combined use of both inorganic and organic inputs is recommended to maintain productivity, reduce acidit