Department of Soil and Geological Sciences

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Climate Impacts on Agricultural and Natural Resource Sustainability in Africa
(Springer, 2020) Singh, Bal Ram; Safalaoh, Andy; Amuri, Nyambilila A; Eik, Lars Olav; Sitaula, Bishal K; Lal, Rattan
The major challenge related to sustainable management of natural resources, agricultural and livestock production, and the assessment of innovative technologies and policies is to identify solutions for these problems. Soil degradation, a serious problem in sub-Saharan Africa, is affected by climate change through emission of greenhouse gases (GHGs). Thus, restoration and sustainable management of soil to minimize risks of soil degradation are important to adaptation and mitigation of climate change and to advancing sustainable development goals of the United Nations. Livestock is a source of animal proteins for humans on the one hand and a source of nutrients and energy (biogas) on the other. However, livestock is vulnerable to many climate change-induced disasters such as prolonged droughts and floods, resulting in loss of animals and feed resources. In order to fully benefit from livestock, the targeted interventions needed include adoption of feed preservation technologies, including hay and silage for use during lean periods, controlled planning and management of com- munal grazing areas, rehabilitation of degraded communal grazing areas, and range- lands as a way of improving pasture availability. Research and development priorities and emerging issues include conservation agriculture (CA), use of legume-based crop- ping systems, integrated nutrient management (INM), climate-resilient livestock and feed systems, value addition policies, and adoption of innovative technologies.
Effects of tillage and cropping systems on maize and beans yield and selected yield components in a semi-arid area in of Kenya
(Tropical and Subtropical Agroecosystems, 2016) Karuma, Anne N; Gachene, Charles K. K; Gicheru, Patrick T; Mtakwa, Peter W; Amuri, Nyambilila A
Conservation of soil moisture through tillage practices is an important management objective for crop production in semi-arid areas. A study to evaluate the effects of tillage practices on maize and bean yields was conducted in Mwala Sub County, Eastern Kenya, in the long (LR) and short rains (SR) of 2012/13. The tillage treatments were: Disc Ploughing (DP), Disc Ploughing and Harrowing (DPH), Ox-ploughing (OX), Subsoiling – Ripping (SSR), Hand hoeing with Tied Ridges (HTR) and Hand hoeing (H) only. There were three cropping systems of Sole Maize (SM), Sole Bean (SB) and Maize - Bean intercrop (M + B), which were investigated in a Split-Plot Design field experiment with four replications. Data on maize and bean yield and yield components were monitored throughout the four cropping seasons. Maize plant height, leaf area and leaf area index, maize and beans grain and biomass yields were significantly affected by tillage (P < 0.05). No significant effect of cropping systems on the maize height was observed. Higher maize grain yields (P < 0.05) were obtained in the sole maize plots in LR 2012 (5.01 Mg ha -1 ), SR 2012 (4.19 Mg ha -1 ) and in the SR 2013 season (2.82 Mg ha -1 ). A three - season bean grain yield average by tillage shows that DPH > SSR > DP > OX > HTR > H, with values ranging from 0.75 Mg ha -1 to 1.46 Mg ha -1 (P < 0.05). Intercropping reduced the seasonal means of bean grain yields (P < 0.05) with a 54 % decrease by intercropping (0.73 Mg ha -1 ) compared to the sole bean (1.6 Mg ha -1 ). Thus, the DP and DPH improved crop yield and yield components and can be recommended as tillage practices in the semi-arid region.
Farmer-Focused tools to improve soil health monitoring on smallholder farms in the Morogoro region of Tanzania
(The American Phytopathological Society, 2018-01) Testen, Anna L; Mamiro, Delphina P; Nahson, Jackson; Amuri, Nyambilila A; Culman, Steven W; Miller, Sally A
A participatory approach was used to improve smallholder tomato farmers’ understanding of and access to soil health monitoring in the Morogoro Region of Tanzania. Baseline soil characteristics were gathered from 50 tomato fields in the region, local soil knowledge was elicited from farmers and used to de- velop a soil health card to qualitatively assess soil health, and farmers (n = 32) were trained on the use of a low-cost soil test kit to quantitatively assess soil health. Farmers most often described local indicators of soil health in terms of soil texture and tilth, soil color, soil water relations, and soil fertility. Following use of the soil test kit, farmers indicated increased awareness of soil testing services (Wilcoxon signed rank Z = –3.0, P = 0.001), more agreed they had access to soil testing services (Z = –2.7, P = 0.004), and more agreed that soil management recommendations were easy to understand (Z = –3.4, P < 0.0001) compared with pre-exposure results. Farmers continued to use the soil health test kit and soil health card based on a follow-up survey administered 1 year after project completion. Participatory soil health monitoring projects can improve farmers’ ability to monitor and manage soil health, potentially impacting sustained soil and plant health.
Increasing maize yields with soil testing and subsides in Tanzania
(FEED THE FUTURE, 2020-09) Harou, Aurélie P; Madajewicz, Malgosia; Michelson, Hope; Palm, Cheryl A; Amuri, Nyambilila A; Magomba, Christopher; Semoka, Johnson M; Tschirhart, Kevin; Weil, Ray
Though the use of fertilizers can enhance productivity and increase profits for small-scale farming families, two barriers to their adoption have proved critical. First, many farmers often cannot afford to buy fertilizers; second, use recommendations from government sources may not be appropriate for specific farms. In Tanzania, 1 our multi-disciplinary team used low-cost soil testing to pair field-specific recommendations with subsidy vouchers to help cover the cost of fertilizer purchase. Our results show that farmers benefitted significantly in both yields and profits when (1) fertilizer recommendations were calibrated to the needs of individual farms and (2) a subsidy made the recommended fertilizers affordable.
An overview of underutilized benefits derived from Azolla as a promising biofertilizer in lowland rice production
(cell press, 2023) Marzouk, Said H; Tindwa, Hamis J; Amuri, Nyambilila A; Semoka, Johnson M
Currently, there is no doubt that Azolla can compensate for the nitrogen requirements of rice in different agroecological zones. Compared to synthetic N-fertilizers, Azolla has various positive impacts on lowland rice production, including improving soil fertility, minimizing weeds, increasing soil organic carbon, improving microbial biomass, and thus nutrient cycling and enhancing rice growth and yield. However, Azolla has not been accepted globally by rice farmers for field use and so far, farmers are relying on increasing rates of synthetic N fertilizers instead of taking advantage of Azolla which will improve long-term soil fertility and health. This systematic literature review and scientific evidence could help policymakers, scientists and researchers to understand the benefits, limitations, and innovative ways of utilizing Azolla as a cost-effective and eco-friendly amendment in rice production. The paper uses Preferred Reporting Items for Sys tematic Review and Meta-Analysis (PRISMA) method to review the hidden potential of Azolla as a biofertilizer in paddy and summarizes its benefits and problems by collecting information from different sources and presenting under different subheadings such as critical factors affecting Azolla growth and nitrogen fixation, nitrogen fixation of Anabaena Azollae and their contribution in soil health, release and availability of Azolla-N to rice, amounts and time of Azolla inoculation, influence of Azolla on ammonia volatilization, contribution of Azolla to yield and yield compo nents of rice, and impact of Azolla on weed emergence in rice cropping system. Literature indi cated that the use of Azolla as green manure incorporated before rice transplanting or grown together with rice and left until a few days of harvest alone or in combinations with other syn thetic fertilizers in the lowland rice production saved the nitrogen requirement of rice up to 60 kg N ha− 1 , it enhances the availability of nutrients, improves physiochemical properties of soils, minimizes soil salinity, reduces the soil pH, and minimize weed germination. However, it was observed that incorporating Azolla as green manure is labor-intensive, and maintaining the Azolla inocula and phosphorous requirement are major restrictions for farmers. Therefore, under standing mechanism of spore production, educating farmers on cheaper alternative ways of Azolla application, and testing different species of Azolla over different agroecological zones will help in maintaining Azolla biomass and applying it at low cost for further environmental conservation.
Potential of soil fertility management to improve essential mineral nutrient concentrations in vegetables in Dodoma and Kilombero, Tanzania
(Scientific Research Publishing Inc., 2017) Amuri, Nyambilila A; Mhoro, Lydia; Mwasyika, Tumaini; Semu, Ernest
Collective efforts to fight mineral nutrient malnutrition in humans require consideration of soil fertility management practices (SFMP) in vegetable pro duction. This study aimed at establishing the relationship between SFMP and vegetable nutrient concentration for human health in farming systems of Tanzania. Soil and vegetable samples collected from vegetable growing areas in Kilombero and Dodoma were analyzed for chemical properties and mineral nutrient concentration. Descriptive statistics, analysis of variance and correla tion analysis were employed. The results showed that soil pH in Kilombero ranged from 6.04 to 6.8 and in Dodoma ranged from 6.23 to 8.58. The organic C was low, ranged from 0.10% to 1.87%. All soils studied had sufficient Zn (0.45 to 29.3 mg/kg), Cu (0.71 to 3.23 mg/kg), Fe (3.70 to 171.7 mg/kg) and Mn (2.84 to 41.38 mg/kg). Zinc concentration in all vegetables ranged from 12.57 to 134.54 mg/kg, 14% of vegetables had low Zn (<20 mg/kg) for human health. The Cu concentration in vegetables ranged from 0.07 to 52.37 mg/kg, and vegetables from Kilombero had very low Cu (<0.10 mg/kg) for plant and human nutrition. Vegetable Fe and Mn concentration ranged from 152.95 to 1780 mg/kg and 35.10 to 321.82 mg/kg, respectively. The SFMP used did not affect mineral micronutrients concentration in vegetables, but affected soil Zn, Cu, Fe and Mn concentrations. Soil pH, Zn, and CEC correlated with vegeta ble Cu, K, Mg, Zn, P and Fe concentrations, and differed among soils. There fore, soil properties differed with SFMP, and both determined mineral con centrations in vegetables for human health.

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Browsing Department of Soil and Geological Sciences by Author "Amuri, Nyambilila A"