Transplanting into non-puddled soils with a small-scale mechanical transplanter reduced fuel, labour and irrigation water requirements for rice (Oryza sativa L.) establishment and increased yield

Abstract

Mechanizing the transplanting of rice can decrease labour requirement and costs for crop establishment. The cost of crop establishment can also be reduced by changing from conventional tillage with puddling to reduced tillage in non-puddled soil. However, mechanized rice transplanters for suitable for the small-scale fields of Asia have not been evaluated on non-puddled soils. This study was conducted to evaluate the performance of a 4-row walking-type mechanical rice transplanter under different tillage options for rice establishment. Field experiments were conducted on a clay loam soil in Gazipur and on a loam soil in Kushtia during the irrigated dry (Boro) season in 2012–13 and the non-irrigated wet (Aman) season in 2013. Three non-puddled soil treatments (shallow beds, strip tillage on the flat, zero tillage on the flat) were compared with conventional puddled tillage (‘puddling’). The non-puddled plots were flooded 18 h before transplanting to soften the soil.Strip tillage reduced tillage time and fuel consumption for tillage by 50–70% relative to puddling. Strip and zero tillage also reduced the irrigation water input for transplanting by 22 and 28%, respectively. The transplanter had a significantly higher rate of area coverage in strip and zero tilled soil (0.131–0.134 ha/h) than in puddled soil and beds (0.115–0.121 ha/h). Non-puddled strip and zero tillage also reduced fuel consumption for mechanical transplanting by 11–18 % compared to puddling. The proportion of missing hills was lower in strip tilled soil than in puddled soil, and there were fewer missing hills due to less floating and burial of plants. Transplanter slippage significantly reduced the plant to plant spacing during transplanting in puddled soil compared to the spacing in non-puddled soil.All non-puddled tillage treatments gave similar or significantly higher yield of rice compared to puddling. On the clay loam soil, strip tillage and zero tillage gave significantly higher yields (5.4–5.6 t/ha) than bed tillage and puddling (5.1–5.2 t/ha). On the loam, yields with strip tillage (5.1 t/ha) and bed tillage (4.9 t/ha) were similar, and yield with strip tillage was significantly higher than that of zero tillage and puddling (4.7–4.8 t/ha). Operating the mechanical rice transplanter in non-puddled soil reduced labour and fuel costs and irrigation water input for rice establishment. Crop production was profitable with mechanized transplanting into all tillage treatments at both sites in both seasons, with gross margin ranging from US$273 to US$582/ha, and BCR from 1.3 to 1.7. Strip tillage and zero tillage were more profitable than puddling at Gazipur, while strip tillage was also the most profitable treatment at Kushtia. Mechanized transplanting into non-puddled soil is thus a promising option for smallholder wetland rice farmers in Asia.