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Grain yield (t ha –1 )3.02.51989-99PrimedNot primedGrain yield (t ha –1 )3.02.52000-012.02.01.51.51.01.00.50.5015 20 25 30 35 40 45 50 5500 5 10 15 20 25 30 40 45 50 553.01999-20003.02001-022.52.52.02.01.51.51.01.00.5015 20 25 30 35 40 45 50 55Days after 1 November0.50 0 5 10 15 20 25 30 40 45 50 55Days after 1 NovemberFig. 1. Effect of sowing date on grain yield of chickpea, as measured in seed-priming trialsconducted across the HBT during 1998-99 to 2001-02 (see Musa et al 2001). Fitted trendlines are shown.Effect of sowing date on chickpea yieldThe effect of delayed sowing on chickpea in South Asia is well established, withyield decreasing as the shortest day is approached (Saxena 1987). The reasons whythis should also occur in the HBT include slow seedling growth due to declining temperaturesinto winter, drying of surface soil, delayed flowering and podding, whichincreases the risk of terminal drought and heat stress, damage by chickpea pod borer(Helicoverpa armigera), and storm damage from mid-March. A comprehensive set ofon-farm trials to measure the effect of seed priming (soaking seed in water overnightprior to sowing) on chickpea growth and yield (Musa et al 2001) offers an opportunityto quantify the effect of sowing date on chickpea yield specifically for the HBT. Thetrials were conducted in paired plots of 666-m 2 plot size in farmers’ fields across theHBT. There were 30 trials in 1998-99, 99 in 1999-2000, 101 in 2000-01, and 50 in2001-02. Sowing dates ranged from early November to mid-December.Yield tended to decrease in each season (Fig. 1). With seed priming, yields werehigher (see Harris et al, this volume) and the decline in yield with sowing date wasless. However, there was a large scatter of points, with some early-sown crops givinglow yields and some late-sown crops high yields. This scatter could be attributed toother factors besides sowing date that affect yield, such as suboptimal moisture atIntegration of chickpea and other rabi crops into rainfed rice-based systems of the High Barind Tract 137
sowing, biotic stresses including collar rot (caused by Sclerotium rolfsii), Fusariumwilt, Botrytis gray mold (BGM, caused by Botrytis cinerea) and pod borer, andnutrient deficiencies (e.g., N, P, and Mo). Reasons for low yield with early sowingcould include collar rot (which affects early-sown crops more), excessive vegetativegrowth inducing BGM or early attack of pod borer, and nutrient deficiencies limitingbiomass formation. High yields with late sowing could be attributed to sowing inniches where soil moisture remained favorable throughout growth, escape from podborer attack, and adequate soil fertility with good nodulation.The data of Figure 1 do confirm the general benefit of being able to sow chickpeawithin November, thus showing the value of growing rice that can be harvestedearlier in November, whether it be direct-seeded rice or short-duration rice varieties.However, the decline in chickpea yield with sowing date is linear and gradual, andit is not necessarily disastrous for chickpea to be sown into December, for example,after the harvest of Swarna. In conditions of favorable soil moisture and with soundagronomic management, it is possible to achieve good yields of December-sownchickpea. Likewise, good agronomic management is also necessary if high yields areto be obtained from November-sown chickpea.Increased cropping options through earlier harvest of riceThe prospect of being able to harvest rice earlier, through direct seeding (see Mazidet al, this volume) or short-duration varieties (see Joshi et al, this volume), increasescropping options in the HBT. Under a purely rainfed system, harvest of rice by earlyNovember would make it feasible to grow lentil (Lens culinaris Medik) and rapeseedmustard (Brassica juncea L. Czerni et Cosson), crops that require earlier sowingthan chickpea in Bangladesh (Fig. 2). Early harvest of rice would also increase yieldprospects for chickpea and rainfed cereals such as wheat and barley. The use of shortdurationrice varieties (e.g., 2.5 t ha –1 , as has occasionally beenobtained with BARI chola 5 in particular plots in the HBT where biotic and abioticconstraints were minimal. However, such yields are rarely achieved; they are usuallyin the range of 0.5–1.0 t ha –1 due to these constraints. Thus, the challenge is to close138 Johansen et al
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Improving AgriculturalProductivity
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Bangladeshi experiences with a drum
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AcknowledgmentsIRRI is most gratefu
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The High Barind Tract: a challengin
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irrigation across the entire Barind
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Workshop synthesis
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and, with representatives from the
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Subsistence pressureLand pressure,
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HerbicidesEarlier efforts to introd
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volume). PVS is an effective way to
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Farmers may use wet-seeded DSR as a
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process and distributing HNPV to fa
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an NGO, have successfully collabora
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Workshop discussionParticipants dis
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How can we identify a short-duratio
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to fixed tenancy. The implication i
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Opportunities for improving ricepro
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that the reliability and productivi
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Table 1. Planting dates, direct-see
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Table 2. (A) Mean effect of fertili
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Table 5. On-farm trials of a drum s
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Upper toposequenceYield (t ha -1 )7
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and perennial grasses (e.g., Ischae
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Direct-seeded rice in the HighBarin
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Table 1. Sample selection for costs
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Table 4. Variations in weed managem
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Table 7. Labor requirements (days h
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Table 10. Farmer perceptions of dis
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Farmers (no.)1412108DSRWet-seededDr
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able commercially. Other OFT farmer
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Box 1. Farmers’ comments on DSRPo
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NotesAuthors’ addresses: M.A. Jab
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This paper explores the role of som
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(Olsen method, atomic absorption),
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Mean biomass (g m −2 )1,000.000Fi
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Fig. 3. Log rank abundance of weed
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attested by Fig. 2). Diversity in t
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Bangladeshi experiences with a drum
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Table 1. Grain yield and crop durat
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Table 5. Grain yield and growth dur
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ACEy = 0.0001x + 0.7089Yield (t ha
Page 96 and 97: Table 11. Partial budget analysis f
Page 98: ConclusionsDirect wet-seeded rice u
Page 101 and 102: A 178% increase in rice production
Page 103 and 104: Table 1. Components of yield gaps d
Page 105 and 106: Table 3. Weed management in Comilla
Page 107 and 108: Table 5. Weed management practices
Page 109 and 110: Table 7. Significance (P H o ) of t
Page 111 and 112: Since 2000, there has been an incre
Page 114 and 115: Identifying varieties for the High
Page 116 and 117: Table 1. Rice varieties bred by cli
Page 118 and 119: Table 2. Grain yield advantage of J
Page 120 and 121: Table 3. Plant height and crop dura
Page 122 and 123: Table 6. Summary of adoption and sp
Page 124 and 125: Freeman GH, Perkins J.M. 1971. Envi
Page 126: Opportunities for improving rabi cr
Page 129 and 130: Grain yield (t ha -1 )2.0npp1.5LSD
Page 131 and 132: In each of the plots, numbers of He
Page 133 and 134: Table 2. Effect of IPM components o
Page 135 and 136: Unit plot size was 10 10 m and the
Page 137 and 138: Yield (t ha -1 )5Straw4321GrainP (g
Page 139 and 140: Nodulation score3AControl Soil Mo P
Page 141 and 142: even at low levels of production. B
Page 144 and 145: Integration of chickpea and other r
Page 148 and 149: Improved Improved Rainfed rainfed C
Page 150 and 151: Table 1. Preharvest and postharvest
Page 152 and 153: Greater resistance to Helicoverpa p
Page 154 and 155: wheat varieties). There is also sco
Page 156 and 157: Developing seed systems fordissemin
Page 158 and 159: This paper describes attempts to em
Page 160 and 161: seed needed to attain the recommend
Page 162 and 163: introduced to permit sale beyond th
Page 164: pesticides, inoculation with benefi
Page 168 and 169: for the rabi crop in 2001. Hence, b
Page 170: where farmers decided not to relay-
Page 174 and 175: Table 2. Mean dates of T. aman harv
Page 176 and 177: Table 4. Subsistence pressure and r
Page 178 and 179: Table 7. Subsistence pressure and r
Page 180 and 181: cite the absence of rent as a facto
Page 182 and 183: abi cropping in the HBT through ear
Page 184 and 185: Formulation and dissemination ofimp
Page 186 and 187: in India, for which shorter-duratio
Page 188 and 189: Applied researchOFTsAdaptive resear
Page 190 and 191: Table 1. Recommended package of pra
Page 192 and 193: Table 2. Grain yields (kg ha -1 ) o
Page 194 and 195: Table 4. Grain yields (t ha -1 ) of
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Table 6. Mean grain yields (t ha -1
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constraints present. This in itself
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Extending rabi cropping in rice fal
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Table 1. Estimates of rice area dur
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Yield (kg ha -1 )1,2001,00080060040
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Future disseminationThrough dialogu
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Direct seeding of rice andopportuni
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Table 1. Time of establishment and
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Table 3. Weed density and biomass a
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than in Central Java and many farme
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Proportion abundance (log scale)Ran
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CAN FIELD BE DRAINED?YesCAN FIELD B
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Johnson DE, Mortimer AM. 2005. Issu
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Zhao DL, Atlin GN, Bastiaans L, Spi
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