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Root traits of different crops under rainfed conditions in the High Barind Tract, Bangladesh

M. Yusuf Ali1, Selim Ahmed2, Chris Johansen3, D. Harris4 and J.V.D.K. KumarRao5

1 Senior Scientific Officer, On-Farm Research Division, BARI, Gazipur 1701, Bangladesh, email: yusuf709@yahoo.com, ofrdjoy@bttb.net.bd
2
Scientific Officer, On-Farm Research Division, Barind station, BARI, Rajshahi, Bangladesh
3
Apartment 2B, Palmdale, Plot 6, Road 104, Gulshan-2, Dhaka 1212, Bangladesh
4
Centre for Arid Zone Studies, University of Wales, Bangor, Gwynedd LL 57 2UW, UK
5
International Crops Reseach Institute for the Semi-Arid Tropics, Patancheru 502324, A. P. India

Abstract

Root traits of six different crops grown rainfed in the post-rainy season in the High Barind Tract of Bangladesh were investigated for the purpose of identifying alternative crops to diversify the rainfed rice-chickpea cropping system. In general, crop yield was related to rooting ability below 30 cm soil depth. In the 2000-01 season, roots of barley, mustard and chickpea penetrated deepest, to 90-105 cm, whereas in 2001-02 roots of linseed penetrated deepest, to 120-135 cm. Barley developed the highest root length density (RLD) at depth (30-90 cm) in 2000-01, a growing season devoid of rainfall. Chickpea, mustard and linseed, in that order, had the next highest RLD at depth. In 2001-02, linseed and chickpea produced greater RLD at depth (30-105 cm), followed by barley. Lentil had least RLD with depth and the crop could not set seed in either year due to drought stress. Wheat had intermediate RLD, between lentil and other crops, and produced yields well below its potential had it been irrigated. Barley had the smallest root diameter but mustard had the thickest roots. The large variation in root traits between seasons was attributable to the different rainfall patterns experienced and bulk density characteristics of the soil profile at different locations. Economics of cultivation of barley, linseed and mustard were favorable when compared with chickpea, even if they were not as remunerative as chickpea. These three crops could be considered as alternatives to rotate with chickpea in the High Barind Tract, to mitigate against build-up of pests and diseases of chickpea. It is suggested that more suitable genotypes of these crops should be sought, ones having grater rooting ability at depth and hence adaptation to rainfed cropping in the High Barind Tract.

Media summary

Root traits of barley, linseed, wheat, Brassica, lentil and chickpea were studied in the High Barind Tract of Bangladesh for selection of alternatives to chickpea.

Key words

Participatory crop selection, sustainable crop sequence

Introduction

Chickpea (Cicer arietinum L.) is well adapted to growing on residual soil moisture in a post-rainy season because of its deep and prolific root system (Saxena and Singh 1987). This crop has proved to be particularly suitable as a post-rice crop under rainfed conditions of the High Barind Tract (HBT) in the north-west Bangladesh (latitude 24o 25’to 25o 10’ N and longitude 88-89o E at about 30 m above sea level). This is an uplifted, terraced landscape of calcareous alluvial origin modified by weathering in a sub-tropical environment. It has high bulk density, low organic matter, and low available nitrogen (N) and phosphorus P (Ali 2000). Traditionally, the area had grown only rainfed rice during June-November and the puddling for rice cultivation without recycling of organic matter made the soil particularly unsuitable for cultivation of post-rice crops. However, research of the On-Farm Research Division (OFRD) of the Bangladesh Agricultural Research Institute (BARI) from the early 1980s showed that post-rice cropping of chickpea was feasible and remunerative. The area of chickpea in the HBT has increased from <1,000 ha in 1980s to > 10,000 ha recently (Saha 2002). The success of chickpea in the HBT has been attributed to the availability of short duration varieties, rapid initial growth rate, deep rooting capability and other drought resistance characteristics (Rahman et al. 2000; Musa et al. 2002). Differences among chickpea genotypes in their drought tolerance have been attributed to root proliferation at depth (Krishnamurthy et al. 1996).

Continued cultivation of chickpea on the same land inevitably leads to build-up of pests (e.g. Helicoverpa pod borer) and diseases (e. g. soil fungal diseases such as Fusarium wilt). It is therefore desirable to identify alternative crops to chickpea, so as to be able to diversify the post-rainy season phase of the rainfed rice-chickpea cropping system in the HBT. As for chickpea, it is hypothesized that post-rainy season rainfed crops most likely to succeed in the HBT would have superior ability to root at depth and thus effectively exploit the receding soil moisture front. Therefore five crops with climatic adaptation to the post-rainy season of the HBT were compared with chickpea in their rooting ability with depth in natural soil profiles of the HBT in the farmer’s field.

Table 1. Comparative yearly total root length (TRL) and grain yield of different crops, High Barind Tract, Bangladesh, 2001-2002.

 

2001

2002

Crops

TRL
(km.m-2)

Yield
(t.ha-1)

TRL
(km.m-2)

Yield
(t.ha-1)

Chickpea

0.13

1.37

0.29

1.42

Wheat

0.07

0.85

0.17

1.01

Brassica

0.12

0.93

0.10

0.61

Barley

0.60

2.00

0.30

1.43

Linseed

0.08

0.57

0.33

1.42

Table 2. Comparative mean profitability of different crops in the High Barind Tract, Bangladesh, 2001-2002.

Crop

Productioncost
(Tk.ha-1)

Grossreturn
(Tk.ha-1)

Netreturn*
(Tk.ha-1)

Chickpea

7,660

34,750

27,090

Wheat

10,009

8,370

1,639

Brassica

6,554

11,550

4,996

Barley

8,637

11,970

3,333

Linseed

4,837

11,880

7,043

Lentil**

7,660

0

-7,660

1 USD = Around 59 Bangladesh Taka (Tk)

Conclusion

Deep and prolific rooting capability of individual crops was found to be important for survival and production of optimum grain for post rainy season rainfed and marginal soils. Among the tested crops barley, linseed and possibly Brassica could be regarded as alternatives to chickpea.

Future research work would be to find out genotypic variation in root system, drought tolerance and yield levels for barley, linseed and Brassica.


Fig 1: Root length density (RLD) of crops, High Barind Tract, Bangladesh, 2001-02

(error bars indicated SE of means of all crops of 3 replications).

References

Ali M Y (2000). Influence of phosphorus fertilizer and soil moisture regimes on root system development, growth dynamics and yield of chickpea. Ph. D. Thesis, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur, Bangladesh, 221 pp.

Krishnamurthy L Johansen C & Ito O (1996). Genotypic variation in root development and its implications for drought resistance in chickpea, In: Dynamics of Roots and Nitrogen in Cropping Systems of the Semi-Arid Tropics, eds O. Ito, C. Johansen, J. J. Adu- Gyamfi, K. Katayana, J. V. D. K. Kumar Rao and T. J. Rego, Japan International Center for Agricultural Sciences, pp. 235-250.

Musa A M Ali M Y and Johansen C (2002). Bangladesh experience on promotion of chickpea in rice fallows of the High Barind tract. Paper presented at the Stakeholders Review and Project Planning Workshop of the DFID / PSRP funded Project on Promotion of Rainfed Rabi Cropping in Rice Fallows of India and Nepal: Pilot Phase held during 28-30 May, 2002 at ICRISAT Center, Patancheru, Andhra Pradesh, India.

Rahman M M Bakr M A Mia M F Idris K M Gowda C L L Kumar J Deb U K Malek M A and Sobhan A (2000). Legumes in Bangladesh. In: Legumes in rice and wheat cropping systems of the Indo-Gangetic Plain Constraints and opportunities, eds C. Johansen, J. M. Duxbury, S. M. Virmani, C.L. L. Gowda, S. Pande and P. K. Joshi). Patancheru International Crops Research Institute for the Semi-Arid Tropics, and Ithaca: Cornell University, pp. 5-34.

Saxena MC and Singh KB (Eds) (1987). The Chickpea. Wallingford, UK: CAB International. 409 pp.

Saha AK (2002). Final Report on Impact Assessment Study for the DFID-funded Project R7540, Promotion of Chickpea Following Rainfed Rice in the Barind Area of Bangladesh. Report submitted to DFID Plant Science Research Programme, Centre for Arid Zone Studies, University of Wales, Bangor, UK 114 pp.

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