Environmental and economic impacts of pesticide treatment in the Yam Minisett Technique

AbstractWhite yam (Dioscorea rotundata) is an important tuber crop in a number of countries, but especially in West Africa where it serves as a food staple as well as a cash crop as excess production is sold in local markets. But the availability of quality planting material, most notably seed yams, for yam production remains an important constraint for farmers. Techniques have been developed to help address this limitation by cutting yam tubers into pieces (minisetts), treating them with the pesticide either via a seed dressing dust or pesticide ‘dips’ and planting to grow seed yams of the required size and quality. But while there have been many studies on the agronomy and adoption by farmers of these techniques, there have been fewer studies on their economic performance. Indeed, to date there have been no studies that compare the economic performance of treating setts compared to leaving them untreated, and neither has there been any analysis of the environmental impact of treating setts. This paper reports the results of a study designed to address these two gaps in knowledge and is based upon results from a series of farmer-managed seed yam plots established in the middle belt of Nigeria over 4 years (2013–2016). Results suggest that revenue and gross margin were higher for treated versus untreated setts although the latter still performed relatively well. Using the Field Use Environmental Impact Quotient (EIQ), the commonly recommended pesticide sett treatments were estimated to have a low-to-moderate environmental impact, and further research is needed to see how far pesticide use can be reduced to still be effective and minimise any environmental impact.

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Potential for clean yam minisett production by resource-poor farmers in the middle-belt of Nigeria

The Journal of Agricultural Science ◽

10.1017/s0021859609008740 ◽

2009 ◽

Vol 147 (5) ◽

pp. 589-600 ◽

Cited By ~ 10

Author(s):

S. MORSE ◽

N. McNAMARA ◽

M. ACHOLO

Keyword(s):

Cropping System ◽

Economic Viability ◽

Treatment Results ◽

Care Needs ◽

Gross Margin ◽

Dioscorea Rotundata ◽

Planting Material ◽

White Yam ◽

Household Labour ◽

River Niger

SUMMARYYam minisett technique (YMT) has been promoted throughout West Africa since the 1980s as a sustainable means of producing clean yam planting material, but adoption of the technique is often reported as being patchy at best. While there has been much research on the factors that influence adoption of the technique, there have been no attempts to assess its economic viability under ‘farmer-managed’ as distinct from ‘on station’ conditions. The present paper describes the results of farmer-managed trials employing the YMT (white yam: Dioscorea rotundata) at two villages in Igalaland, Kogi State, Nigeria. One of the villages (Edeke) is on the banks of the River Niger and represents a specialist yam environment, whereas the other village (Ekwuloko) is inland, where farmers employ a more general cropping system. Four farmers were selected in each of the two villages and asked to plant a trial comprising two varieties of yam, their popular local variety as well as another variety grown in other parts of Igalaland, and to treat yam setts (80–100 g) with either woodash or insecticide/nematicide+fungicide mix (chemical treatment). Results suggest that while chemical sett treatment increased yield and hence gross margin compared with woodash, if household labour is costed then YMT is not economically viable. However, the specialist yam growers of Edeke were far more positive about the use of YMT as they tended to keep the yam seed tubers for planting rather than sell them. Thus, great care needs to be taken with planning adoption surveys on the assumption that all farmers should adopt a technology.

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THE ADAPTED YAM MINISETT TECHNIQUE FOR PRODUCING CLEAN SEED YAMS (DIOSCOREA ROTUNDATA): AGRONOMIC PERFORMANCE AND VARIETAL DIFFERENCES UNDER FARMER-MANAGED CONDITIONS IN NIGERIA

Experimental Agriculture ◽

10.1017/s0014479714000428 ◽

2014 ◽

Vol 51 (3) ◽

pp. 467-482 ◽

Cited By ~ 4

Author(s):

STEPHEN MORSE ◽

NORA McNAMARA

Keyword(s):

Small Scale ◽

Agronomic Performance ◽

Economic Returns ◽

Dioscorea Rotundata ◽

Pesticide Treatment ◽

Planting Material ◽

Clean Seed ◽

Small Scale Farmers ◽

Major Factors ◽

First Time

SUMMARYWhite yam (Dioscorea rotundata) is a major root crop grown throughout West Africa but one of the major factors that limits its production is the availability of good quality planting material. This paper described the results of farmer-managed demonstration plots established in 2012 and 2013 designed to promote the Adapted Yam Minisett Technique (AYMT) in Nigeria. The AYMT was developed between 2005 and 2008 to produce quality seed yam tubers at a cost that is viable for small-scale farmers. Since its development the agronomic performance of AYMT has not been explored across a large sample of farmers, and neither has there been any attempt to explore possible varietal effects although farmers have often alluded to this. This papers seeks to address these gaps in the literature and the results suggest that the AYMT does succeed in producing seed yams of the required size and the economic returns are also good. Results also suggest that there is a varietal affect with AYMT, including a significant interaction with pesticide treatment; the first time this has been demonstrated.

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The influence of minisett size and time of planting on the yield of seed yam (Dioscorea Rotundata)

Experimental Agriculture ◽

10.1017/s0014479720000095 ◽

2020 ◽

Vol 56 (3) ◽

pp. 469-481

Author(s):

Beatrice Aighewi ◽

Norbert Maroya ◽

Djana Mignouna ◽

Daniel Aihebhoria ◽

Morufat Balogun ◽

...

Keyword(s):

Food Security ◽

West Africa ◽

Production Systems ◽

Seed Tuber ◽

Block Design ◽

Dioscorea Rotundata ◽

Trade Off ◽

Planting Material ◽

Tuber Crop ◽

Equivalent Area

AbstractIn traditional yam (Dioscorea spp.) production systems in West Africa, finding sole seed yam producers is rare and up to 30% of harvested tubers from the ware tuber crop is reserved to plant an equivalent area of the harvested crop during the next season. Many farmers typically must make a trade-off between food and seed in the use of available tubers. A study was carried out using a factorial experiment in a randomised complete block design to investigate the influence of planting different minisett sizes at different planting periods on the yield of seed yam with the aim of improving the availability of this expensive input and saving more ware tubers for food or sale. Results showed that by doubling or tripling the minisett size from 30 to 60 or 90 g, yields of seed yam increased by 61.1 and 103.3%, respectively. The 90 g minisetts had the highest values for all traits studied but had the least sett multiplication ratio. The early planted crop yielded 137% more than the late-planted crop. Significant interactions between minisett size, planting period and season were found. In 2016, although the highest yield of seed tubers was from early planted 90 g minisetts (35.6 t ha−1), the yield of early planted 30 g minisetts (23.8 t ha−1) was similar to those of 60 g planted mid-season (28.7 t ha−1) and 90 g planted late (20.0 t ha−1). To produce a high proportion of seed size tubers with less planting material, early planting of 30 g minisetts is recommended. Such practice will enhance seed tuber availability and food security by saving 1–2 t ha−1 of tubers that would have been used as seed instead of food.

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IMPACT OF THE ADAPTED YAM MINISETT TECHNIQUE ON WARE YAM (DIOSCOREA ROTUNDATA) PRODUCTION UNDER FARMER-MANAGED CONDITIONS IN NIGERIA

Experimental Agriculture ◽

10.1017/s0014479716000120 ◽

2016 ◽

Vol 53 (1) ◽

pp. 131-143 ◽

Cited By ~ 4

Author(s):

STEPHEN MORSE ◽

NORA MCNAMARA

Keyword(s):

West Africa ◽

Dioscorea Rotundata ◽

Pests And Diseases ◽

Planting Material ◽

Published Evidence ◽

White Yam ◽

Funded Project ◽

Work Done ◽

Farmer Income ◽

Water Yam

SUMMARYWhite yam (Dioscorea rotundata) is a major root crop grown throughout West Africa and a major limitation on its production is the availability of good quality (i.e. free of pests and diseases) planting material, notably seed yams. One of the methods developed to address this limitation is the Adapted Yam Minisett Technique (AYMT) and since 2012 the AYMT has been promoted in both Nigeria and Ghana via a Bill and Melinda Gates funded project entitled Yam Improvement for Income and Food Security in West Africa (YIIFSWA). While previously published studies have focussed on the agronomy of the sett-to-seed yam process, there has been no work done on the seed-to-ware yam stage which is critical in terms of farmer income and livelihood. This paper provides the first published evidence obtained under entirely farmer-managed conditions in Africa that shows seed yams produced via the AYMT can generate agronomic benefits in the water yam stage, including better germination, tuber numbers and weights.

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