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Addressing poor nodulation and molybdenum deficiency in chickpea through seed priming

C Johansen1, AM Musa2, David Harris3, JVDK Kumar Rao4, JG Lauren5 and AKM Shahidullah6

1 15 Westgate Court, Leeming, WA 6149 Email cjo41802@bigpond.net.au
2
People’s Resource Oriented Voluntary Association (PROVA), B/251, Kazihata, Rajshahi, Bangladesh Email musaprova@librabd.net
3
Centre for Arid Zone Studies (CAZS), Plant Sciences Programme, University of Wales, Bangor, Gwynedd LL57 2DG UK Email d.harris@bangor.ac.uk
4
International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Andhra Pradesh 502 324 India Email j.kumarrao@cgiar.org
5
Department of Crop and Soil Sciences, Cornell University, Ithaca, New York, USA Email jgl5@cornell.edu
6
People’s Resource Oriented Voluntary Association (PROVA), B/251, Kazihata, Rajshahi, Bangladesh Email musaprova@librabd.net

Abstract

A major limitation to chickpea grown on residual soil moisture after the harvest of rice in the High Barind Tract (HBT) of Bangladesh is acidic surface soil. Multilocational on-farm trials in the 2002-03 season established that grain yield responses to soil-applied 500 g Mo ha-1 were 58-173%. However, to develop an application method suitable for resource-poor farmers it was tested if Mo and Rhizobium could be added in the seed priming process. Multilocational trials in farmers’ fields in 2003-04 confirmed that this was as effective as soil application of Mo, giving yield responses of 37-90 %. In each of 2004-05 and 2005-06 seasons, 50 farmer-implemented on-farm evaluations of adding Mo + Rhizobium in the priming solution were conducted in operational scale plots (666 m2) across the HBT and mean responses of up to 50 %, compared to priming in water only, were obtained. These results suggest that the severe N deficiency of chickpea commonly observed in the HBT can be effectively alleviated by a simple low-cost technology within the scope of resource-poor farmers.

Key Words

Acid soil, Rhizobium, nitrogen fixation, on-farm trials, High Barind Tract

Introduction

The High Barind Tract (HBT) in north-western Bangladesh is suitable for growing chickpea (Cicer arietinum L.) on residual soil moisture following harvest of rainy season rice in late November to early December. However, surface soils (0-20 cm) are acid (pH<5.5) and this poses limitations to nitrogen fixation. Indeed molybdenum (Mo) deficiency in chickpea in the HBT was demonstrated in 2002, in a nutrient omission experiment at one location, and addition of Mo increased nodulation and N content (Johansen et al. 2004). Subsequently, under a DFID-funded Project (R8269) managed by the University of Wales, on-farm experiments were conducted to determine the extent of Mo deficiency in the HBT and to develop a method of applying Mo and Rhizobium inoculum suitable for resource-poor farmers who cultivate chickpea.

Methods

On-farm trials were conducted in 2002-03 at sites with acid surface soils in the northern (Porsha), central (Gomostapur) and southern (Amnura) regions of the HBT. Treatments were applied as follows: 1) Control with recommended agronomic practices for chickpea, including seed priming; 2) As for control, but Mo broadcast on the soil, mixed with river sand, as sodium molybdate at 500 g Mo ha-1; 3) As for control but with soil-applied Mo and Rhizobium inoculation of seed. The experiment was laid out in 10 x 10 m plots in a randomized block design in farmers’ fields with 5 dispersed replications at each location. Due to absence of compound fertilizers containing Mo in Bangladesh and difficulties of evenly applying the low rates of Mo salt required to the soil, it was tested as to whether Mo and Rhizobium could be added in the seed priming process. Seed priming, soaking seed in water overnight prior to sowing, had previously been shown to be beneficial for chickpea in the HBT, and had been readily adopted by farmers (Musa et al. 2001). In 2003-04, further on-farm trials were conducted using treatments 1) and 2) as above and also: 3) As for control, but Mo added to the priming water @ 0.5 g sodium molybdate L-1 priming solution, ensuring that all seeds were covered with the priming solution and that most of the priming water was absorbed by the seeds after 8 hr; 4) As for 3), but Rhizobium inoculum also added to the priming solution at 4 g L-1. Plot size was 7 x 7 m in a randomized block design with 5 dispersed replicates at locations in north (Porsha), central (Gomostapur) and southern (Tanor) HBT. These on-farm trials were researcher-managed and in order to determine if farmers could implement seed priming with Mo and Rhizobium, farmer-managed evaluations were conducted. Farmers were given pre-season training in the technology and provided sachets of Mo and Rhizobium inoculum. They conducted on-farm evaluations of priming alone versus priming with Mo + Rhizobium in paired plots of 666 m2. There were 10 such paired comparisons in each of 5 upazilas (sub-districts) in fields having surface soil pH<5.5, in both 2004-05 and 2005-06 seasons. However, due to plot damage by extraneous factors, 7 comparisons had to be discarded from the analysis in 2004-05.

Results

There were significant yield responses to soil application of Mo in 2002-03 across locations, with a further slight but non-significant response to Rhizobium application (Table 1). Priming with Mo alone improved yield, but not to the extent of Mo addition to the soil (Table 1). However priming with Mo + Rhizobium gave similar yields to soil applied Mo. Nodulation responses showed a similar trend (data not shown). In farmer implemented evaluations, significant yield responses to priming with Mo + Rhizobium were obtained across acid surface soil locations of the HBT (Table 2).

Table 1. Effect of adding Mo, with or without Rhizobium inoculum (Rh), to the soil or the priming solution on grain yield (t/ha) of chickpea (variety BARI chola 5) in multilocational on-farm trials in the High Barind Tract (HBT) of Bangladesh, in the 2002-03 And 2003-40 seasons.

Treatment

Season and location in HBT

2002-03

2003-04

North

Central

South

All locations

North

Central

South

All locations

Control

0.37

0.33

0.70

0.47

0.62

0.32

0.67

0.54

Soil Mo

1.01

0.54

1.10

0.88

0.89

0.68

0.96

0.84

Soil Mo+Rh

1.12

0.70

1.13

0.98

-

-

-

-

Primed Mo

-

-

-

-

0.66

0.48

0.93

0.69

Primed Mo+Rh

-

-

-

-

0.93

0.61

0.92

0.82

Standard Error

0.156

0.033

0.197

0.152

0.180

0.090

0.218

0.126

Significance

P<0.005

P<0.005

ns

P<0.001

ns

P<0.01

ns

P<0.01

Table 2. Response of grain yield (t/ha) of chickpea (variety BARI chola 5) to priming with Mo and Rhizobium (Rh) in on-farm evaluations in acid soil locations of the HBT in 2004-05 and 2005-06.

Season

Treatment

Upazila

Tanor

Nachole

Gomostapur

Porsha

Shapahar

2004-05

No Mo+Rh

0.599

0.601

0.750

0.513

0.593

 

Primed with Mo+Rh1

0.655**

0.738**

0.881***

0.637**

0.742***

2005-06

No Mo+Rh

0.762

0.499

0.160

0.700

0.707

 

Primed with Mo+Rh1

0.761ns

0.502 ns

0.197***

0.935***

1.058***

Significance of treatment difference: ns = not significant; ** = significant at P<0.01; *** = significant at P<0.001.

Conclusion

Mo deficiency severely limits chickpea in acid soils of the HBT. It can be corrected by adding Mo in the seed priming solution, through which Rhizobium inoculum can also be effectively delivered. Thus, severe N deficiency of chickpea commonly observed in the HBT can be alleviated by a simple low-cost technology within the scope of resource-poor farmers.

References

Johansen C, Musa AM, Kumar Rao JVDK, Harris D, Ali MY, and Lauren JG (2005). Molybdenum response of chickpea in the High Barind Tract of Bangladesh and in Eastern India. Pages 205-220 in Micronutrients in South and South East Asia. Proceedings of an International Workshop held 8-11 September, 2004, Kathmandu, Nepal. (Andersen P, Tuladhar JK, Karki KB, and Maskey SL, eds). International Centre for Integrated Mountain Development, Kathmandu, Nepal.

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: 509-21.

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