Published in: Field Crops Research, 172: 85–98, 2015.
Rice–maize (R–M) systems are rapidly expanding in South Asia and Bangladesh due to higher yield andprofit potential from rabi (winter) maize, its reduced water requirement compared to rice–rice systems,and increasing demand from poultry and fish feed industries. The current practice of growing puddledtransplanted rice and maize with conventional, repeated tillage degrades soil structure, delays maizeplanting, and reduces its yield potential, increasing energy and labour requirements, ultimately leadingto high production costs. Conservation agriculture (CA)-based tillage and crop establishment options suchas strip or reduced tillage, and raised beds, may hold potential to increase yield, reduce crop establishmentcosts, and increase income of the farmers. The objective of this study was to evaluate the productivity andprofitability of R–M systems under CA-based tillage and crop establishment options across a gradient of69 farmers’ fields in Northwest Bangladesh. We evaluated four tillage and crop establishment options:reduced tillage; strip tillage; fresh beds; and permanent beds. Conventional-tilled (puddled) transplantedrice on flat followed by conventional-tilled maize on flat was included as a current practice. ANOVA foradjusted 4-year pooled mean revealed no significant treatment effects for yield and economic analysisparameters for rice (P ≥ 0.05), but they were significant for maize and the R–M system (P ≤ 0.05). Riceyields across tillage and establishment treatments over four years ranged from 4.6 to 4.9 t ha−1whilemaize and R–M system yields ranged, respectively, from 7.8 and 12.5 t ha−1under conventional tillage to9.0 and 13.8 t ha−1on permanent beds. Compared to conventional tillage, the average maize and systemyield across fresh beds, reduced tillage, and strip tillage, was greater by 9.1% and 6.1%, respectively. Maizeproduction costs ranged from US $922 ha−1with fresh beds to US $1,027 ha−1for conventional tillage.Maize net returns and benefit cost ratio (BCR), however, ranged, respectively, from $945 ha−1and 1.9under conventional tillage to $1350 ha−1and 2.4 under permanent beds. We conclude that while CA-basedtillage and establishment options may not have significant yield advantage over conventional tillage inrice, they have significant advantages in terms of reduced production cost and labour use, and increasednet returns. For maize as well as for R–M system, while most options can provide yield benefits similarto conventional tillage, permanent beds exhibit a significant advantage (yield, net returns, etc.) overconventional tillage. Profitability was consistently greatest and significantly different (P ≤ 0.001) underpermanent raised beds compared to all other treatments. Considering our assessment of the profitabilitydistributions and risk analysis, we conclude that both rice and maize planted sequentially on permanentbeds and strip tillage can result in higher net income and BCR compared to conventional tillage practice.
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