Low-cost boost for crops in poor soils |
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| On-farm seed priming to improve plant nutrition in low fertility soil - Nutrient Seed Priming | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
A simple, low-cost way to boost crop yields in poor soils is now available. Farmers who till infertile land are often the poorest and can't afford fertilisers. Now, they can reap better harvests just by adding tiny amounts of nutrients to the water that they soak seeds in before sowing. Farmers in Bangladesh, India, Nepal and Pakistan added small amounts molybdenum, zinc, boron, phosphate and Rhizobia - the bacteria that help fix nitrogen - to priming water. In some cases, yields of chickpea, mungbean, maize and wheat improved by up to two-thirds. The simple 'nutrient priming' technology has almost unlimited potential. So many soils in less-developed countries are poor. Plus, the method can be used for many of the major tropical and sub-tropical crops. Project Ref: PSP30:
Research Programmes: Plant Sciences Research Programme (PSP). Relevant Research Projects: R7438, R8221, R8269
Research Outputs, Problems and Solutions: In marginal, rainfed areas, patchy plant stands often result from the failure of the crop to emerge quickly and uniformly. Yields of many crops are reduced because not enough seeds germinate and the plants that eventually emerge do so slowly and are susceptible to drought, pests and diseases. This is a particular problem for resource-poor farmers who can seldom command enough resources on a timely basis to ensure good establishment. Such farmers often also find it too expensive, or too risky, to apply sufficient, appropriate fertilizers to their crops to produce high yields. Huge areas of land in the world are deficient in macronutrients (e.g. Nitrogen, Phosphorus) and micronutrients (e.g. Molybdenum, Boron, Zinc, Calcium, Iron, etc.). A lack of these elements reduces yield and low densities of micronutrients such as Zn, Fe in grains adversely affect human and animal health. Although fertilizers can be used to mitigate effects of deficiencies on crop growth and foods can be supplemented to improve human and animal nutritional imbalances, such interventions are costly and their success is limited by poor infrastructure etc. On-farm seed priming is a simple, low-cost, low-risk technology that hastens germination and seedling emergence and promotes vigorous early growth so that transient resources (soil moisture, nitrogen, etc.) are captured and utilised. Seed priming simply involves soaking seeds in water, usually 'overnight', surface-drying them to facilitate easy handling, then sowing them in the normal fashion. Seed priming, including all work funded by PSP, has recently been reviewed by Harris (2006). Crop plants grown from primed seeds generally emerge earlier and in greater numbers, grow more vigorously, flower and mature earlier and often yield better than those from non-primed seeds. This simple, low-cost, low-risk technology has been developed, tested, refined and promoted using a combination of in vitro, on-station and participatory action research with farmers during the period 1996-2006. In addition, seed priming can be used to: · Add Rhizobia inoculum to legume seeds (chickpea, mungbean) to promote fixation of atmospheric N; · Provide small amounts of 'starter' P to crop seeds (maize, wheat, chickpea, pearl millet) to boost growth in low-P soils and to increase apparent recovery rates of expensive added P-fertilizer; · Provide Mo to legumes (chickpea, mungbean) grown in acidic soils where Mo is unavailable so as to increase yield; · Provide Zn to crop seeds (maize, wheat, chickpea) in alkaline or other soils where Zn is deficient, to increase yields and Zn nutrient density in grain. · Provide B to crops (maize, wheat, chickpea) in B-deficient areas to increase yields. · Improve the performance of seeds germinating in saline-affected soils All the above interventions are highly cost-effective because only very dilute solutions of the materials are used for priming seeds. Work specifically on nutrient seed priming was done during the period 2002-2006.
Nutrient seed priming has been developed and tested by PSP-funded research for maize, wheat, chickpea, mungbean and pearl millet so far but is potentially applicable to other crops once the appropriate optimum concentrations for priming solutions have been determined. There is some limited literature on the effects of nutrient priming with other crops but these generally have not been validated in the field.
The application domain for this technology is so large (soils with low N, P, Mo, Zn, B, saline soils, acidic soils, alkaline soils, etc. and suitable for many of the major tropical and sub-tropical crops) that the potential for linkages with other research outputs is very great. Any work specifically relating to improving plant nutrition, crop establishment, integrated crop management, seed production or, more generally, initiatives to improve rural livelihoods and public health through better agricultural production could be linked to this output. A particularly appropriate linkage would be to explore the synergies between nutrient seed priming and the recent CGIAR Harvest Plus initiative to breed new varieties of crops that accumulate higher concentrations of beneficial micronutrients in grain. Specifically, links with other RNRRS outputs could include:
How the outputs were validated: Molybdenum and Rhizobium In Bangladesh, validation of priming chickpea seeds with Mo and Rhizobium was managed by PROVA in collaboration with DAE. Multilocation on-farm trials at three sites showed that seed priming with Mo and Rhizobium increased grain yield by about 60%, the same as adding much larger amounts of Mo to the soil. Farmer evaluations in large plots at 50 locations in 5 Upazillas in 2004-05 demonstrated that farmers could implement the technology and that there was a significant yield increase (mean 21%) in all 5 Upazillas. A similar exercise with 50 farmers in 2005-06 gave a mean yield increase of 22%. In India, pot trials using acidic soils in 2002-03 showed that Rhizobium added to chickpea seeds during seed priming increased the number of nodules and the level of nitrogenase activity in seedlings threefold, relative to the standard method of application. The response to priming chickpea seeds with 0.5 g Mo kg-1 seed litre-1 of water was tested in 2003-04 by 48 farmers in acid-soil areas of Orissa, Chattisgarh, eastern Madhya Pradesh, Jharkhand and West Bengal states. The mean yield increase over a control without Mo was 22% using the ICCV 2 variety and 17% using KAK 2. Molybdenum content in chickpea grain increased up to 2.4-fold using Mo-primed seed. The main advantages of Mo application through seed priming are ease and uniformity of application and about a 30-fold cost saving. In 188 on-farm trials during 2004-05 in the same states, priming improved chickpea nodulation by 62 percent. In a sub-set of 114 trials mean chickpea grain yield was increased by 9 percent and stover yield by 6 percent. Grain was sampled from a further sub-set of 63 trials and 54 showed increased concentrations of Mo. In Nepal, priming with Mo increased nodulation and yield (23%) in mungbean in on-farm trials in the three years 2003-05. Positive results in chickpea and field pea need further verification. Zinc In Pakistan on Zn-deficient soils, after preliminary experiments established that the optimum concentration for priming wheat seeds with ZnSO4 was 0.4% Zn, eight further on-station and on-farm trials produced a mean increase of 615 kg ha-1 in comparison with non-primed seed. The optimum concentration for priming chickpea seeds was much less, at 0.05% Zn. In nine trials, this treatment increased grain yield of chickpea from 1.1 t ha-1 to 1.6 t ha-1 in comparison with non-primed seed. Yield increases in individual trials ranged from 10-122%, with a mean of 48%. In seven trials with maize, mean grain yield was significantly increased from 3.0 t ha-1 in crops from non-primed seed to 3.8 t ha-1 (27%) using seeds primed with 1% Zn. Boron In Pakistan, the optimum concentration for priming maize was 10 mg L-1 B (as boric acid) which significantly increased mean grain yield by 23% from 3.9 to 4.8 ha-1. For wheat, the mean increase using 20 mg B L-1 in three trials was 22%. Salinity In Pakistan, priming with water alone improved the performance of wheat by 41%, 28%, 24% and 22% in four trials in saline soils and that of chickpea by 21% (Rashid et al., 2002). In barley, grain yield was increased by priming by an average of 18% at three sites with saline soils (Rashid et al., 2006). Phosphate There is a known correlation between the amount/concentration of P in seeds and subsequent crop vigour and yield. Priming seeds with 1% P (as KH2PO4) between 2003-06 boosted their P content by 30% and, in five trials with maize in Pakistan, increased mean grain yield significantly from 3.2 t ha-1 to 3.9 t ha-1 (24%). In four additional trials, the effect of P-priming was consistent over a range of rates of application of P-fertilizer (Fig 1, below). A similar response was also demonstrated for wheat (Fig. 2, below). Figure 1. Response of maize in Pakistan to seed priming with H2O and P over a range of P-fertilizer rates (np = not primed).
Figure 2. Response of wheat in Pakistan to seed priming with H2O and P over a range of P-fertilizer rates (NP = not primed).
Although the principle of priming seeds with P was established using NaH2PO4 we have developed an even more cost-effective and practical protocol using a combination of two cheap and widely available materials - Na2CO3 (washing soda) and Single Super Phosphate fertilizer. Used to prime maize seeds before sowing, this mixture can give yield gains equivalent to priming with NaH2PO4. Where the Outputs were Validated: See above for additional details. In Bangladesh, validation has been ongoing with Mo/chickpea in the High Barind Tract (HBT) since 2002-03, targeted towards the resource-poor farmers of the rainfed rice fallows system (semi-arid, smallholder rainfed humid/dry). The same systems and farmer categories are targeted in the eastern states of India for chickpea and in Nepal for chickpea and mungbean. In Pakistan, maize/Zn, maize/P, maize/B, wheat/Zn, wheat/P and wheat/B have been validated in both high potential/irrigated and semi-arid, smallholder rainfed dry systems. Chickpea/Zn was found suitable for the semi-arid, smallholder rainfed dry system. Seed priming is low-cost and low-risk and so is suitable for all social groups (except the landless who may, nevertheless, benefit from additional opportunities afforded by greater yields). Validation of nutrient priming in Pakistan was done at the Research Farm of NWFPAU, Peshawar and in on-farm trials in 8 Districts of NWFP (Peshawar, Nowshera, Mardan, Kohat, Karak, Lakki, Banu, D.I.Khan). On-farm trials involved close collaboration between project staff and farmers. Additional research on various aspects of seed priming was implemented by: Barani Agri. Research Station, Kohat; Barani Agri. Research Station, Karak; Sugar Research Station, Mardan; Central Cotton Council, D.I.Khan; Pakistan Oil Seed Board; Agri. Faculty Gomal University, D.I.Khan. Seed priming has been the subject of student theses at the following Universities: Agri. Uni. Peshawar; Agri. Uni. Faisalabad; Arid Agri. Uni., Rawalpindi; Gomal University, D.I.Khan. Who are the Users? See above for additional details. In Bangladesh, priming with Mo + Rhizobium in acid surface soils of the HBT is now recommended for chickpea by PROVA and DAE. Further evaluations and demonstrations on a limited scale will continue in 2006-07 supported by other non-DFID-funded projects. After extensive testing CRS in India has adopted priming with Mo + Rhizobium for its forthcoming (2006-07) activities promoting rainfed rabi cropping in rice fallows. Around 200 tonnes of chickpea seeds with Mo and Rhizobium are being distributed/sold to resource-poor farmers in eastern India. Around 9000 farmers are currently growing chickpea as a new crop on land left fallow after rainfed rice. In Pakistan, nutrient priming is a relatively recent innovation and there is little adoption yet by farmers, although the earlier technology of priming with water was quickly adopted by farmers in target areas after they had tested it for themselves. Similarly, in Nepal promotion of nutrient priming is at a relatively early stage and adoption is limited. Where the outputs have been used: Farmers in Bangladesh, India and Nepal are priming chickpea with Mo and Rhizobium (see above). Priming crops with zinc and with phosphate is just beginning in Pakistan. Scale of Current Use: See above for additional details. In 2004-2005 around 1900 farmers in eastern India were involved in the CRS programme and, in 2005-2006, 6624 new farmers were inducted into the programme. Adoption has been rapid after farmers have tested the technology for themselves. Although access to inputs, including Mo and Rhizobium, is still being facilitated for many farmers by CRS this still represents substantial use of the technology package (including nutrient priming). Use of nutrient priming by farmers is at a relatively early stage in Pakistan, Bangladesh and Nepal but, based on the Indian experience, adoption can be rapid and widespread if the technology is included in a well-resourced and targeted promotional programme. Policy and Institutional Structures, and Key Components for Success: Institutional structures for promotion and extension of agricultural information exist in all four target countries (and in other countries where such a cross-cutting technology could be applied) but our experience with water priming (and with Mo and Rhizobium in the CRS programme) has been that potential institutional collaborators are generally unwilling to promote seed priming on evidence gathered elsewhere. In addition, nutrient (and water-) seed priming is often viewed as being too 'simple' to extend on its own. Successful adoption has been achieved when priming is promoted as part of a 'package' and the 'integrated' approaches (IPM, ICM, ICNM, etc., often implemented through Farmer Field Schools or something similar) offer a good platform for such an approach. Lessons Learned and Uptake Pathways Promotion of Outputs: There is a large ongoing promotional programme in eastern India for the chickpea production package that includes nutrient priming (see "Scale of current use"). Around 200 tonnes of chickpea seeds (plus Mo and Rhizobium) are being distributed by CRS and its partners in the forthcoming 2006-07 rabi season. In Bangladesh, PROVA and DAE are continuing their programme of validation trials and demonstration plots in the HBT as part of another externally-funded project. A similar situation exists in Nepal where FORWARD are continuing with a limited testing and promotional programme in collaboration with some of the District Agricultural Development Offices in the Terai. As far as we know, no formal promotional activities for nutrient priming are planned in Pakistan, although discussions are ongoing between NWFPAU researchers and the Outreach Directorate that coordinates research and extension activities. There are a number of ongoing generic activities to promote seed priming widely. A website http://www.seedpriming.org/ is maintained and CAZS-NR receives many requests from visitors for additional information on seed priming, including that for nutrient priming. Several thousand copies of two colour brochures (DFID/PSP 2001; 2006) have been distributed to interested parties as well as many copies of specific research publications and customised protocols for testing seed priming. Seed priming has also been widely promoted during conference presentations around the world and at dedicated Technology Fairs (in Zimbabwe in December 2005 and in Uganda in February 2006). Potential Barriers Preventing Adoption of Outputs: Apart from the general issues relating to the need to use integrated approaches to promotion (see under "Policy and Institutional Structures, and Key Components for Success"), local access to the materials used for nutrient priming can be difficult in rural areas. Although nutrient seed priming is highly cost effective relative to using fertilizers applied to the soil, accessibility and up-front cost of some of the materials used can be a bottleneck to adoption. We have used two approaches to address this issue. First, measuring the correct quantities, re-packaging and selling the small quantities of micronutrients needed by farmers offers opportunities for disadvantaged people (landless, widows, etc) to generate income. CRS have been pursuing this approach on a trial basis in eastern India but it is, in theory, applicable anywhere. However, a holistic approach to rural development is necessary, which is something that sectoral line agencies may find difficult. A second approach has been pursued in Pakistan where cheaper, more readily available materials are being evaluated as an alternative source of P for priming. The need for commercialization of the supply of Mo and Rhizobium (and quality control) in Bangladesh and Nepal is a problem that will need to be addressed. There is also an opportunity for seed producers to develop a value-added process if the technology can be refined to allow longer-term storage of nutrient-primed seeds. The overarching constraint, of course, is lack of resources. For instance, although CRS and its partners in India could procure and distribute 200 tonnes of chickpea seeds this year without any external funding, their original target was for 600 tonnes of seed. Although the farmers are willing to bear the cost of seeds and inputs (recovered through a rolling fund) the up-front costs were simply too great for CRS to meet its original target. How to Overcome Barriers to Adoption of Outputs: There is already evidence that results-based advocacy by CRS, CAZS-NR and ICRISAT has persuaded the state government of Chhattisgarh to promote rainfed rabi cropping (including nutrient priming) by its Department of Agriculture. This is in addition to CRS' own ongoing efforts. This approach will be pursued with other state governments. A similar approach is being used in Bangladesh (see, for example, the Proceedings of a joint PSRP/CPP/IRRI/BRRI/BARI meeting held in Dhaka, 6-8 Feb, 2006) to advocate an integrated approach to rural development. A Business Development Services (BDS) approach to commercialization of resources such as Mo and Rhizobium, for which adoption and effective implementation of quality control legislation is essential. A commitment to the training of researchers, extensionists and farmers in integrated approaches is essential so that more widespread farmer evaluations and demonstrations can be accomplished. Lessons Learned: Direct involvement of farmers throughout the research-to-adoption process is essential as is access to (and acting upon) feedback from farmers - technologies are seldom adopted without being fine-tuned to local needs and circumstances. On-farm, farmer-participatory action research is essential, backed up by specific technical, problem-solving research as and when necessary. We have always found a twin-track approach to dissemination to be effective, i.e. supporting local 'validation' where it is necessary (both in 'new' countries and crops and in areas where priming has only recently been introduced) and supporting extension activities to promote wider uptake with farmers in countries where local 'validation' has been completed. Poverty Impact Studies: A recent study in India (Kankal et al., 2006) has surveyed the impact of the CRS rainfed rabi cropping initiative in eastern India. Although not specific to nutrient priming, the study concludes that the package has been effective in persuading large numbers of farmers to grow chickpea and reports case studies highlighting various beneficial effects on incomes and quality of life of the farming community. There have been no impact studies yet specific to nutrient priming. However, a number of simple benefit: cost analyses have been done using information from research trials. Given the simple nature of seed priming, such analyses are deemed to be valid. As examples, using yield and cost data from Pakistan, benefit: cost ratio for wheat/Zn was about 360, for chickpea/Zn was 1500 (Harris et al., 2005) and for maize/Zn was 290. Benefit: cost ratio for priming with fresh water in saline areas was very large because extra cost was essentially zero. Priming wheat and maize with P was also very cost effective, exact values depending on the source of P used. As long as steps are taken to facilitate access to priming materials and to provide appropriate training, nutrient priming could make substantial positive impacts on the livelihoods of poor farmers. How the Poor have Benefited (including gender and other poverty groups): No impact analyses specific to nutrient priming have been done. Case studies in Kankal et al. (2006) demonstrate that chickpea cultivation in rice fallows is profitable, popular and accessible to men and women alike. Direct and Indirect Environmental Benefits: There are many environmental benefits associated with growing legumes, particularly as a second crop where none was possible before. These include: improved soil fertility through N-fixation and increased biomass; reduced soil erosion through longer duration of crop cover; increased agro-biodiversity; reduced incidence of pests and diseases (and thus use of pesticides) through rotation of crops. Nutrient priming with Mo and Rhizobium in, e.g. acid soils, can allow legumes to be grown where it was not possible before or can increase the profitability of poorly-performing legumes. For all crops, nutrient priming will increase biomass and ground cover and increase fertilizer use efficiency, through more precise delivery of nutrients. For P, this could reduce surface- and groundwater pollution due to runoff and leaching of phosphate fertilizers. Increased production per unit of land may dissuade people from cultivating more marginal, less suitable land. Adverse Environmental Impacts: Some of the materials used can be toxic to plants if seeds are exposed to high concentrations during the priming operation. Protocols for nutrient priming have been carefully developed with wide margins for error to minimise this risk. Nevertheless, training is essential to ensure maximum benefit with minimum risk. There is little or no potential for risk to humans and animals through eating high concentrations of micronutrients in grain and fodder as accumulation in tissues is largely self-limiting. In addition, and as noted above, accidental use of toxic levels on seeds results in little or no growth and hence no opportunity for harm to consumers. Coping with the Effects of Climate Change, or Risk from Natural Disasters: A greater choice of farming options will improve the resilience of poor farmers to shocks due to climate change or other natural disasters. Nutrient priming can allow farmers to grow additional crops (e.g. legumes in marginal environments) and to produce crops more cost-effectively, thus minimising the risk of loss of investment. References DFID/PSP (2001). 'On-Farm' Seed Priming. A key technology to improve the livelihoods of resource-poor farmers in marginal environments. DFID/PSP information booklet, English language version. Centre for Arid Zone Studies, University of Wales, Bangor, UK. DFID/PSP (2006). 'On-Farm' Seed Priming. A key technology to improve the livelihoods of resource-poor farmers in marginal environments. Second edition. DFID/PSP information booklet, English language version. Centre for Arid Zone Studies, University of Wales, Bangor, UK, pp 20. Harris, D. (2006). Development and testing of 'on-farm' seed priming. Advances in Agronomy 90: 129-178. Harris, D., Rashid, A., Arif, M. and Yunas, M. (2005). Alleviating micronutrient deficiencies in alkaline soils of the North-West Frontier Province of Pakistan: on-farm seed priming with zinc in wheat and chickpea. In Andersen, P., Tuladhar, J.K., Karki, K.B., Maskey, S.L. (eds) Micronutrients in South and South East Asia, pp 143-151. Kathmandu: ICIMOD Kankal, M., Basu, I, Gupta, B., Mishra, K., Gupta, A., Peter, R. and Dash, P. (2006). Agricultural Alternatives- Experiences of Rain-fed Rabi Cropping in Rice fallows of India. October, 2006. Catholic Relief Services-USCCB, pp 33. Rashid, A., Harris, D., Hollington, P.A. and Khattak, R.A. (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., Hollington, P.A., Harris, D. and Khan, P. (2006). On-farm seed priming for barley on normal, saline and saline-sodic soils in NWFP, Pakistan. European Journal of Agronomy 24 (3): 276-281. Relevant Research Projects,
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