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On-farm seed priming reduces risk and increases yield in tropical crops

D. Harris1

1Centre for Arid Zone Studies, University of Wales, Bangor, Gwynedd, LL57 2UW, United Kingdom
Email d.harris@bangor.ac.uk

Abstract

Poor crop establishment is a major problem in many areas of the world, particularly for subsistence farmers in rainfed- and poorly-irrigated environments. ‘On farm’ seed priming – soaking seeds, usually overnight, before sowing – is a simple technology that farmers can use to improve crop establishment and increase yield. It has been tested, developed and refined in a range of crops, countries and agro-environments using a combination of in vitro, on-station and farmer-participatory research and regularly increases yield. In addition, priming has been associated with increased disease resistance in some crops and can also be used as a vehicle to alleviate some micronutrient deficiencies.

Media summary

‘On-farm’ seed priming is a low-cost, low-risk technique that is easily adopted by resource-poor farmers in developing countries and increases the yield of tropical crops.

Key words

On-farm seed priming, crop establishment, tropical crops.

Introduction

For resource-poor farmers in developing countries who grow annual crops from seed, good stand establishment is of paramount importance because patchy stands result in low yields and, often, crop failure. Even if sparse crops can be re-sown, it is expensive and can lead poor farmers into crippling debt. Good crop establishment is especially difficult in marginal, rainfed environments where many poor farmers live. Unpredictable and erratic rainfall, poor soils, low-quality seed and limited availability of labour or draft power all contribute to a situation in which good crop establishment is often the exception rather than the rule (Harris, 1992; 1996). Since 1990, on-farm priming of seeds of a range of tropical and sub-tropical crops has been tested as a means to promote rapid germination and emergence and to increase seedling vigour and hence yield.

Methods

Initially, in vitro experiments to determine the optimum priming characteristics of the most important tropical and sub-tropical annual crops were implemented and the results are summarised by Harris and Mottram (2004). In essence, it is safe and effective to soak seeds of most of the crops listed in Table 1 (and also others reported by Harris and Mottram, 2004) for 8 to 10 hours, followed by surface drying and immediate sowing. Exceptions are rice and maize that can be soaked for longer, e.g. 16-18 hours.

A combination of on-station and participatory, farmer-managed, on-farm trials was then used to assess the performance of seed priming in various crops and countries. Further details and results of these trials series may be found in the references listed in Table 1.

Results and discussion

Development and yield

On-farm seed priming was found to be effective in increasing yields in all the crops and countries listed in Table 1. Crops include both cereals and legumes and mean yield increases due to priming range from zero to more than 200%, with an overall average increase of around 30%.

Table 1. Crops in which seed priming has been tested successfully, the countries involved and the references where the methods used and the results obtained can be found.

Crop

Countries

References

Wheat

India, Nepal, Pakistan

Harris et al. (2001b); Rashid et al. (2002)

Upland rice

India, Nigeria, Sierra Leone, Gambia, Ghana, Cameroon

Harris et al. (1999); (2002); Harris (2003)

Maize

India, Nepal, Pakistan, Zimbabwe

Harris et al. (1999); (2001a); (2001c)

Sorghum

Pakistan, Botswana, Zimbabwe

Harris (1996); Chivasa et al. (1998); (2001); Rashid et al. (2002)

Pearl millet

Pakistan, India

Harris and Mottram (2004)

Finger millet

India

Kumar et al. (2002)

Chickpea

Bangladesh, India, Nepal, Pakistan

Harris et al. (1999); Musa et al. (2001); Rashid et al. (2002)

Mungbean

Pakistan

Rashid et al. (2004b)

Cowpea

Senegal

Braconnier and Bouru (2004)

Disease resistance

Musa et al. (2001) reported that seed priming in chickpea significantly reduced the damage caused by collar rot (Sclerotium rolfsii) in Bangladesh in two contrasting seasons. Recent work in Pakistan has demonstrated that mungbean (Vigna radiata) grown from seed primed in water for 8 hours before sowing showed significantly fewer serious symptoms of infection by Mungbean Yellow Mosaic Virus (MYMV) than a crop established without priming (Figure 1). The large differences in virus-related damage were associated with significant increases in pod weight (threefold) and grain weight (fivefold) due to priming (Rashid et al., 2004a). Rashid et al. (2004b) also observed similar differences in MYMV infection in other mungbean priming trials.

Figure 1. Proportion of mungbean (Vigna radiata) plants showing no symptoms (stippled), mild symptoms (solid) and severe symptoms (line shading) of Mungbean Yellow Mosaic Virus in Peshawar, Pakistan. Crops were grown either without seed priming (left) or seeds were primed in water for eight hours before sowing (right)

Micronutrient provision

Many legumes are relatively unproductive in acid soils because nodulation is limited by poor availability of molybdenum (Mo). In particular, chickpea is known to respond to added Mo but soil application is problematic for resource-poor farmers because of the relatively high rates of application required (at least 0.5 kg/ha) and because uniform application is difficult to achieve. Several authors have shown that it is possible to introduce Mo into seeds in aqueous solution, i.e. by priming (Johnson, 2004; Kumar Rao et al., 2004). The effect of sodium molybdate added to soil (500 g/ha) was compared to priming seeds with the same material but using only 0.5 g/l (approximately equivalent to 40 g/ha) in 19 trials in 5 villages in Jharkhand and West Bengal states in India in the 2003-2004 rabi season. Large areas of these and other eastern Indian states are used to grow rice during the rainy kharif season but are generally left fallow during the following rabi season, even though there is abundant residual soil moisture (Subbarao et al., 2001). The soils are mostly acidic and chickpea is known to respond to Mo when grown in pots containing soils from this area (Kumar Rao et al., 2004).

Each trial contained three plots – the two Mo treatments and a plot without any added Mo. Seed in all plots was primed for eight hours and was inoculated with Rhizobium culture. Nodulation was assessed in each plot using a standardised index based on photographs of a range of nodule abundance with values from 0 to 5. There was a clear response to Mo added during the priming operation (Table 2)

Table 2. Nodulation of chickpea in response to added molybdenum in 19 farmers’ trials in five villages of Jharkhand and West Bengal states, India.

Molybdenum treatment

Mean nodulation index
(0 -5)

No added Molybdenum

0.95

Molybdenum added to priming water

1.61

Molybdenum added to soil

1.18

SE diff. (36 df)

0.143

whereas the effects of soil application were not significantly different from the control treatment. Yield data are not available at the time of writing but observations suggest that yield will be significantly increased in both Mo treatments.

Risk

Conducting large numbers of farmers’ trials allows the risk of failure in priming seeds to be assessed (e.g. Harris, 2002; 2003). Figure 2 shows that the risk of a negative consequence of seed priming in chickpea was less than 2%, which suggests that seed priming is a very safe practice. A similar estimate of the risk associated with seed priming for upland rice has been calculated using data from more than 900 farmers’ trials in West Africa (data not shown).

Figure 2. Yield advantage (%) of using primed seed over non-primed seed of chickpea in 253 farmer-participatory, paired plot trials in Bangladesh and Nepal.

Conclusions

On-farm seed priming is safe, effective and easily adopted by resource-poor farmers and has the potential to benefit such farmers in many ways. More work is required to clarify the mechanisms by which priming affects development, growth and disease resistance and to refine methods for low-cost alleviation of some micronutrient deficiencies.

References

Braconnier S and Bourou S (2004). Etude du pr-trempage des graines de nib dans l'eau comme solution technique simple pour amliorer la tolrance la scheresse du nib. Centre d'tude rgional pour l'amlioration de l'adaptation la scheresse (CERAAS), Thies, Senegal.

Chivasa W, Harris D, Chiduza C, Nyamudeza P and Mashingaidze AB (1998). Agronomic practices, major crops and farmers’ perceptions of the importance of good stand establishment in Musikavanhu Communal Area, Zimbabwe. Journal of Applied Sciences in Southern Africa 4 (2): 9-25.

Chivasa W, Harris D and Nyamudeza P (2001). On-farm seed priming: a key technology to improve crop establishment and yield in semi-arid tropics. Sorghum and Millet Improvement Network News 3 (1): 17-18.

Harris D (1992). Staying in control of rainfed crops. In: Proceedings of the First Annual Scientific Conference of the SADCC/ODA Land and Water Management Programme. Private Bag 00108, Gaborone, Botswana, October 8-10, 1990, pp. 257-262.

Harris D (1996). The effects of manure, genotype, seed priming, depth and date of sowing on the emergence and early growth of Sorghum bicolor (L.) Moench in semi-arid Botswana. Soil and Tillage Research 40, 73-88.

Harris D (2002). On-farm seed priming to increase yield of crops and reduce risk of crop failure in marginal areas of developing countries. Pages 1509-1511 in: Second International Agronomy Congress on Balancing Food and Environmental Security – A Continuing Challenge (Extended Summaries) held New Delhi, India, 26-30 November 2002. Indian Society of Agronomy, Indian Council of Agricultural Research and Indian National Academy of Sciences.

Harris D (2003). Reducing risk and increasing yields from rainfed crops in Africa using 'on-farm' seed priming. Pages 87-88 in Abstracts: ‘Harnessing Crop Technologies to Alleviate Hunger and Poverty in Africa’, 6th Biennial Conference of the African Crop Science Society, Hilton Nairobi Hotel, Kenya, 12th – 16th October, 2003.

Harris D, Joshi A, Khan PA, Gothkar P, Sodhi PS (1999). On-farm seed priming in semi-arid agriculture: development and evaluation in maize, rice and chickpea in India using participatory methods. Experimental Agriculture 35, 15-29.

Harris D. and Mottram A. (2004). Practical hydration of seeds of tropical crops: ‘on-farm’ seed priming. In ‘Seed Science and Technology: Trends and Advances’, ed. A.S. Basra. The Howarth Press (in press).

Harris D, Pathan AK, Gothkar P, Joshi A, Chivasa W and Nyamudeza P (2001a). On-farm seed priming: using participatory methods to revive and refine a key technology. Agricultural Systems 69 (1-2): 151-164.

Harris D, Raghuwanshi BS, Gangwar JS, Singh SC, Joshi KD, Rashid A and Hollington PA (2001b). Participatory evaluation by farmers of ‘on-farm’ seed priming in wheat in India, Nepal and Pakistan. Experimental Agriculture 37 (3): 403-415.

Harris D, Rashid A, Hollington PA, Jasi L and Riches C (2001c). Prospects of improving maize yields with ‘on-farm’ seed priming. Paper presented at the Nepal Maize Symposium, December 3-5, 2001, Hotel Narayani, Kathmandu, Nepal. CIMMYT.

Harris D, Tripathi RS and Joshi A (2002). ‘On-farm’ seed priming to improve crop establishment and yield in dry direct-seeded rice. Pp. 231-240 in: Pandey, S., Mortimer, M., Wade, L., Tuong, T.P., Lopez, K., and Hardy, B., editors. 2002. Proceedings of the International Workshop on Direct Seeding in Asian Rice Systems: Strategic Research Issues and Opportunities, 25-28 January 2000, Bangkok, Thailand. Los Banos (Philippines): International Rice Research Institute. 383 pp.

Johnson SE (2004). Improving micronutrient nutrition of various crops in the rice-wheat-grain legume system of Nepal: Enrichment of legumes with boron and exploration of zinc redox chemistry in paddy rice soils. Cornell University PhD Dissertation. 165 pp.

Kumar A, Gangwar JS, Prasad SC and Harris D (2002). ‘On-farm’ seed priming increases yield of direct-sown finger millet (Eleusine coracana) in India. International Sorghum and Millets Newsletter 43: 90-92.

Kumar Rao JVDK, Harris D, Johansen C and Musa AM (2004). Low cost provision of molybdenum to chickpeas grown in acid soils. Poster presentation, International Fertiliser Association Symposium on Micronutrients, New Delhi, India, 23-25 February 2004.

Musa AM, Harris D, Johansen C and Kumar J (2001). Short duration chickpea to replace fallow after aman rice: the role of on-farm seed priming in the High Barind Tract of Bangladesh. Experimental Agriculture 37 (4): 509-521.

Rashid A, Harris D, Hollington PA and Ali S (2004a) On-farm seed priming reduces yield losses of mungbean (Vigna radiata) associated with Mungbean Yellow Mosaic Virus in the North West Frontier Province of Pakistan. Crop Protection (submitted).

Rashid A, Harris D, Hollington PA and Khattak RA (2002). On-farm seed priming: a key technology for improving the livelihoods of resource-poor farmers on saline lands. Pp 423-431 in: R. Ahmad and K.A. Malik (eds.) ‘Prospects for Saline Agriculture’. Kluwer Academic Publishers. The Netherlands.

Rashid A, Harris D, Hollington PA and Rafiq M (2004b). Improving the yield of mungbean (Vigna radiata) in the North West Frontier Province of Pakistan using on-farm seed priming. Experimental Agriculture 40 (2) in press.

Subbarao GV, Kumar Rao JVDK, Kumar J, Johansen C, Deb UK, Ahmed I, Krishna Rao MV, Venkataratnam L, Hebbar KR, Sesha Sai MVR, and Harris D (2001). Spatial distribution and quantification of rice-fallows in South Asia – potential for legumes. Patancheru 502324, Andhra Pradesh, India: International Crops Research Institute for the Semi-Arid Tropics. 316 pp. ISBN 92-9066-436-3.

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