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In the city of Tromsø in northern Norway, invasive Tromsø palm (Norwegian: Tromsøpalme; English: Persian hogweed) is widespread. Although Tromsø palm has negative impacts on biodiversity and contains a phototoxic sap that burns human skin, it is also considered to be a local symbol of Tromsø city and is appreciated by many inhabitants. This study examined private landowners’ characteristics, perceptions, and landowners’ regulation of invasive Tromsø palm on their parcels on Tromsø Island in 2012 (vegetation season: May–September) to provide information concerning which landowner groups could be assisted by official regulation. Eleven key informants and 17 landowners were interviewed. Afterward, Tromsø palm on Tromsø Island was mapped using aerial photos and street-level photos from Google Maps®/Google Street View® and fieldwork verification. This distribution map was superimposed on a property map in a geographic information system to produce a map showing private parcels that contained Tromsø palm and associated neighboring parcels that did not contain Tromsø palm. Questionnaires were mailed to the 441 owners of the selected parcels, and 199 of the returned questionnaires were analyzed. Tromsø palm was more likely to be fully regulated/absent on a parcel that was inhabited (particularly if the owner lived on-site) and less likely to be fully regulated/absent if the parcel was jointly managed by several households. These findings indicate that authorities could focus their management efforts on supporting regulation efforts of those private landowners who own currently uninhabited or rented-out parcels and landowners of parcels jointly managed by several households. Furthermore, those landowners who found regulation measures against the plant on Tromsø Island important tended to have partly or fully regulated Tromsø palm on their plots. This might imply that information campaigns from authorities might encourage more landowners to regulate Tromsø palm.
Intensification of maize production is imperative to improve food security for the rising population in the central rift valley (CRV) of Ethiopia, whose livelihood is principally based on rainfed maize that operates under shrinking landholding and high seasonal rainfall variability. This study examined different levels of intensification options in maize production by sequentially introducing minimum tillage and seed priming, phosphorus (P) fertilizer microdosing, surface mulching and nitrogen (N) fertilizer microdosing. Field experiments were conducted with five treatments, steps or levels consisting of conventional tillage (farmers practice as a control); minimum tillage + seed priming, unfertilized (step 1); step 1 + microdosing 53 kg ha−1 P (step 2); step 2 + 4 ton ha−1 maize stover as surface mulch (step 3) and step 3 + 53 kg ha−1 N (step 4). These steps represented increasing levels of intensification. Except at the lowest level (step 1), agronomic and economic responses improved with increasing levels of inputs. Relative to the very high and increasing gross margin, production costs were low but slowly increased with increasing levels of inputs. Except at the lowest level, the value cost ratio was above 4 even at the highest levels of inputs, demonstrating that such kind of intensification can be achieved with low risk. Likewise, the fertilizer use efficiency was quite high even at the highest of levels of inputs signifying the efficiency of the pocket application of fertilizer through the microdosing method. The improvement in maize establishment and yield and the reduction in the days to maturity could contribute to make maize production more adaptive to the existing seasonal rainfall variability. Depending on the affordability to the external inputs and their feasibilities, the different technology packages in the intensification ladder may give different choices for the farmers to improve maize production in the CRV of Ethiopia.
An on-farm study was conducted from 2009 to 2012 with communities in the Manjawira, Mpingu and Zidyana Extension Planning Areas in the Ntcheu, Lilongwe and Nkhotakota districts of central Malawi. The aim of the study was to evaluate the effects of the principles (no-tillage and mulching) and components (fertilization and weeding) of conservation agriculture (CA) on crop productivity and weeds, and the interactions between principles and components, and to suggest strategies for introducing CA to smallholder farmers. The treatments consisted of tillage, fertilizer application, residues management and weed control strategies. While combined analysis showed that mulching is as effective as tillage in controlling weeds, the interaction between site and treatment revealed that in the more humid environment of Zidyana, weed dry matter obtained under no-tillage and residues plus fertilizer (NT+F+R) was 0.6 mg ha−1 lower than under CP+F. Results suggest that about 6.0 mg ha−1 of mulch is required to have a similar effect as tillage in controlling weeds. Fertilizer had an overriding effect on maize yield, regardless of tillage and crop residue management. Mulching was beneficial over tillage in the drier environment of Manjawira, where maize yield obtained under NT+F+R was 1.2 mg ha−1 greater than under CP+F. Our results show that the introduction of no tillage has benefits only if it is accompanied by fertilizer application, retention of crop residues as surface mulch, and improved weed control. Increasing availability and accessibility of inputs (fertilizers and herbicides) to farmers is critical for adoption of CA at scale in Malawi.
The effect of seed priming and micro-dosing (the application of small amounts of mineral fertilizers) was studied in sorghum and pearl millet in on-station and on-farm experiments for three seasons under rainfed conditions in the North Kordofan State, western Sudan. Seed priming consists of soaking the seeds for eight hours in water prior to sowing. Seed priming increased sorghum grain yield in the on-station experiments across three seasons from 482 kg ha−1 to 807 kg ha−1. Micro-dosing of 0.3 g, 0.6 g and 0.9 g NPK fertilizer (17-17-17) per pocket increased sorghum grain yield by 50.4, 68.8 and 109.7% respectively compared to the control. Seed priming did not significantly increase pearl millet yield while the micro-doses of 0.3, 0.6 and 0.9 g fertilizer increased millet yield by 31.3, 30.7 and 47% respectively. On-farm seed priming increased sorghum yields by 32.6% while seed priming plus 0.3 g fertilizer increased yields by 69.5%. For millet, the corresponding yields increased by 29.8% and 71% respectively. Fertilizer use efficiency for both crops increased remarkably with seed priming, although this effect was more apparent in sorghum than in millet. In sorghum, seed priming and the application of 0.9 g fertilizer per pocket increased the gross margin from 49.5 to 206.5 US$/ha. For millet, the gross margin increased from 44.9 in the control to 90.0 US$/ha with the combination of seed priming and 0.3 g fertilizer per pocket. These technologies are simple to apply; they offer low financial cost and low risk and are affordable for resource-poor farmers.
The effect of seed priming and micro-dosing in groundnut, cowpea and sesame was studied for three years in on-farm and on station experiments under rainfed agriculture in North Kordofan, Sudan. The on-station trials showed that seed priming increased groundnut pod and hay yields by 18% and 20% respectively. Micro-dosing of 0.3, 0.6 and 0.9 g fertilizer per pocket increased groundnut pod yield across the three years by 36.7, 67.6 and 50.8% respectively compared to the control. The highest yield increases were consistently obtained when micro-dosing was combined with seed priming. A combination of seed priming and micro-dosing of 0.6 g increased groundnut yield by 106%. Priming alone did not significantly affect sesame seed or hay yield, but micro-dosing of 0.6 g per pocket increased the grain yield by 38% over the control. Cowpea grain yield in the on-station experiments was not significantly affected by seed priming or micro-dosing. However, both seed priming and micro-dosing increased cowpea hay yield. In the on-farm trials, seed priming increased groundnut and cowpea yields by 18.2 and 25.5% respectively, and seed priming combined with 0.3 g fertilizer increased their yields by 42.2 and 54.5% respectively compared to the control. For sesame the yield increase after 0.3 g fertilizer per pocket was 46.3%. The economic analyses of the on-station experiments showed that the highest gross margin was obtained when combining seed priming with 0.6 g micro-dosing for all the crops. These results show that the combination of micro-dosing and seed priming has the potential to increase productivity and improve net return in the crops tested.
This paper adopts soil scientific models of soil productivity and degradation in Tanzania into an intertemporal optimisation framework. The farmers choose labour input, capital investment and fertiliser input to maximise soil wealth, i.e., the present value of soil rent. First we focus exclusively on soil mining, considering the nutrient stocks as determinants of land productivity. Next, we focus on soil erosion, and include rooting depth as determinant of land productivity. We compute the soil wealth under the assumption that the opportunity cost of labour is equal to current wages, or alternatively equal to zero. Our estimates suggest that the potential gains from change in agricultural management are considerable. Moreover, the shadow price on root depth and hence the returns to land conservation investments are highly sensitive to our labour market assumptions. We also find that the value of the eroded soil amounts to 12–17 per cent of the value of Hicksian income, and the savings required to maintain consumption amounts to 13–29 per cent of the contribution to GDP.
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