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Browsing Agriculture Books, Book Reviews and Book Chapters by Author "Kung’u, James"
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Item Fertilizer nitrogen recovery as affected by soil organic matter status in two sites in Kenya(Springer, 2007) Karunditu, M.W.; Mugendi, Daniel N.; Kung’u, James; Vanlauwe, B.Management of nitrogen (N) nutrition is a vital aspect in maize production systems ofKenya. In Central andWestern parts of Kenya, high population density has eliminated the use of traditional fallow farming systems for replenishing soil fertility while high unevenly distributed rainfall increase chances of N leaching. A study was conducted at Maseno, and Kabete to investigate the fate of fertilizer N in the soil-plant system using treatments that had been receiving leaf prunings of Calliandra calothyrsus and Tithonia diversifolia. Two microplots were installed in the main treatments to which labelled fertilizer was applied. At the beginning and at the end of 2002 long rains, soil was sampled to 200 cm for N and 15N enrichment analysis at the two trials. Also at the end of the season plant samples were collected for N and 15N analysis. At Maseno trial, evenly distributed rainfall and the influence of organic resource quality enhanced good fertilizer nitrogen recovery in the maize crop. Also substantial nitrate movement down the soil profile was observed in the control followed closely by calliandra at the end of the 2002 long rains season. At Kabete trial recorded the poorest fertilizer N recovery due to unevenly distributed rainfall. Limited soil moisture reduced both soil and fertilizer N uptake which was reflected in high N in the top soil and low recovery in plant. Most of the nitrate-N was left in the tp soil as a result of low rainfall which couldn’t move it into the lower soil depthsItem Improving food production using ‘best bet’ soil fertility technologies in the Central highlands of Kenya(Springer, 2007) Mugendi, Daniel N.; Mucheru-Muna, Monicah; Mugwe, Jayne; Kung’u, James; Bationo, A.Declining crop productivity is a major challenge facing smallholder farmers in central highlands of Kenya. This decline is caused by continuous cultivation of soils without adequate addition of external inputs in form of manures and fertilizers. With this background, an on-station trial was initiated at Embu in 1992 to evaluate the feasibility of using two leguminous shrubs; Calliandra calothyrsus and Leucaena leucocephala for improving food production. In 2000, an off-station farmers’ participatory trial aimed at offering farmers soil enhancing technologies for replenishing soil fertility was established in Meru South District. The results from the Embu on-station trial indicate that, over the 11 years of study, calliandra and leucaena biomass transfer with half recommended rate of inorganic fertilizer treatments gave the best average maize grain yields of 3.3 Mg ha-1. Treatment where calliandra was alley cropped with maize but the prunings removed recorded the lowest maize yield of 1.2 Mg ha-1. Treatments with calliandra and leucana biomass transfer had similar yields but treatments that were alley cropped with leucaena did better than those that were alley cropped with calliandra. On the other hand, results from the off-station trial in Meru South indicate that, on average, across the seven seasons, sole tithonia gave the highest maize grain yield followed closely by tithonia with half recommended rate of inorganic fertilizer with 6.4 and 6.3 Mg ha-1 respectively. Control gave the lowest yield of 2.2 Mg ha-1 across the seasons. On average, integration of organic an inorganic sources of nutrients gave higher yields compared to all the other treatments.