MST-Department of Agricultural Resources Management (ARM)

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Browsing MST-Department of Agricultural Resources Management (ARM) by Author "Mochoge, B. O."

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    Effect of Cattle Manure, Mineral Fertilizer and Rhizobium Inoculation on Climbing Beans Production and Soil Properties in Burera District, Rwanda.
    (2014-02-24) Musaninkindi, Nadia; Mochoge, B. O.; Muhinda, Jean Jacques Mbonigaba
    Agriculture is the major engine of Rwandese economy, accounting for about 40% of the GDP, 85% of employment and 80% of exports. Known as “meat for the poor”, beans constitute a predominant source of proteins in Rwandese diet since they supply 65% of national dietary proteins compared to 4% from animal sources. However, the on-farm bean productivity is about 0.8 – 1.0 tons/ hectare which is quite low compared to 5 tons/hectare that is achieved under optimal management conditions. The aim of this study was therefore to determine the effect of cattle manure, mineral fertilizer and Rhizobium inoculation on production of climbing beans and subsequently the soil properties in Burera District. The experimental design was a split plot in completely randomized design (CRD) with two main plots (with and without Rhizobium inoculum); four sub-plots (Cattle Manure, DAP, Cattle manure + DAP, untreated control) with quantities applied at single level for each treatment, i.e. 20t/ha for Cattle manure, 50 kg/ha for DAP and 100 g of inoculum which was mixed with 15 kg of beans. The experiment involved 8 treatments which were replicated three times to give 24 plots. The mean bean grain yields from inoculated treatments and non-inoculated treatments showed statistically significant difference (P< 0.0001), that is 3900 kg/ha from inoculated plots and 2946 kg/ha from non-inoculated. Statistical significant differences were also found among treatments (P<0.0001) with the highest mean yield of 4782 kg/ha obtained from treatment Inoculum + DAP + Cattle Manure against 2640 kg/ha from untreated (control) plots. The mean number of nodules was significantly different (P< 0.0001) between inoculated (60 nodules) and non-inoculated (15 nodules) plots. The highest number of nodules (95) was recorded from plots that were treated with Inoculum + DAP + Cattle Manure and the lowest (14) in the untreated control plots (P<0.0001). Regression analysis between yield and nodule number showed a coefficient of determination R2 of 0.8 and a p value of < 0.0001, which confirmed the dependence of the yield on nodules number. In terms of cost-benefit analysis, in the highest yielding treatment (I+FYM+DAP) scenario, a farmer is likely to earn around 1,330 USD per season per hectare; while in the middle and lowest yielding treatment (I and UNTREATED CONTROL), the farmer is likely to lose 43.8 USD and 388 USD per season per hectare, respectively. On the effect of treatments on soil chemical properties, no tangible changes were observed in pH, CEC and organic matter at the end of season. According to these results a combination of mineral fertilizer, inoculum and cattle manure application gave the best results in terms of bean yield, nodulation and nitrogen uptake and therefore could be better considered for recommendation to climbing bean growers in the region.
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    Effect of Tithonia Biomass and Mineral Fertilizer Application on Soybean Perfomance in Degraded Technosols from Tantalum Mining in Gatumba, Rwanda
    (2014-02-26) Ndoli, Alain; Mochoge, B. O.; Naramabuye, F.
    Large areas of the Gatumba Mining District (GMD) in Rwanda are covered by Technosols (pegmatite or pegmatite-soil mixtures) resulting from coltan mining activities. These substrates are poor in soil plant nutrient contents and are low in soil productivity. Due to agricultural land shortage in Rwanda, almost all the available land is farmed. The present study was conducted to evaluate the effect of tithonia and inorganic fertilizers on plant nutrient uptake and biomass production of soybean grown in Gatumba soils that are affected by the previous coltan mining activities. A greenhouse pot experiment and a field trial were conducted using pegmatite substrate alone and pegmatite-Lixisol Bt mixture in a completely randomized design (CRD). Another experiment was set on cambisol in a farmer’s field to compare the treatments from the technosols (affected by mining). Tithonia biomass (T) was applied at 5 tonnes (t) dry matter (DM) ha-1 alone and combined with triple superphosphate (TSP), Matongo rock phosphate (MtRP) (for the greenhouse), Minjingu rock phosphate (for the field trials) and ammonium sulphate (AS). Soybean biomass, grain yield as well as its total N, P and K were measured at harvest while soil total nitrogen (N), available phosphorus (P), potassium (K) and carbon (C) were analyzed before and after the trials. The results demonstrate that soybean DM, grain yield, N, P and K accumulation were higher on pegmatite than on the mixture, The combination of T, MtRP and TSP also gave higher grain yields on both pegmatite (2.1t ha-1) and mixture (1.7 t ha-1) in the greenhouse. In the field, T+MRP and AS treatments, compared to other treatments, gave highest grain yields (1.5 ha-1) followed closely by T+MRP+TSP (1.49ha-1) on pegmatite while on the mixture, T+MRP+AS gave highest grain yields (0.87 ha-1) followed closely by T+MRP+TSP (0.7 ha-1). At the end of the greenhouse experiment, all treatments on both pegmatite and the mixture showed a general increase in pH, total N, exchangeable K and total organic C with the exception of the available P in the mixture which had declined. The same increase in soil nutrients was observed also in the field trial with the exception of total N that declined in all soil types and treatments. The combination of tithonia green manure and different inorganic fertilizers significantly (<0.05) increased the N, P and K accumulation of soybean grain, shoot and root biomass over tithonia alone. The results indicate that soil plant nutrients generally increased in all treatments in both greenhouse and field trials which is a good indication that these technosols can be reclaimed for agricultural use.