(a) Semi-direct: soil preparation is done in September or October
(45–60 days before sowing) when the soil is not inundated. This
early soil preparation with a disc plough and disc harrow permits
the incorporation of the rice straw and the germination of
weeds. A herbicide is used to kill these weeds, and rice is sown
without seedbed preparation to prevent regrowth of weeds.
Fields are inundated after emergence of the rice seedlings, as
in the case of the conventional system.
(b) Conventional: just before sowing, the fields are prepared when
the soil is not yet inundated. Deep tillage is employed using a
disc plough followed by superficial operations with a disc harrow
with the aim to level the soil and prepare a seedbed with a
fine tilth. Sowing (drilling) is done with a conventional sowing
machine. Water is let onto the field after the rice seedlings have
reached a height of approximately 10 cm.
(c) Pre-germinated: the fields are inundated (early August) before
tillage operations start. Tillage is done in September and October.
Usually, the same disc implements are used as in the
conventional system, often complemented with a pass of a special
leveller to smoothen and level the wet surface layer. Seeds
are pre-germinated by soaking until the coleoptile is 2–3mm
long. The seed is broadcast in the shallow (5–10 cm) water layer,
either by hand or sowing machine, depending on the size of the
farm. The water layer allows amore precise levelling of the field
and controls weeds.
(a) Semi-direct: soil preparation is done in September or October
(45–60 days before sowing) when the soil is not inundated. This
early soil preparation with a disc plough and disc harrow permits
the incorporation of the rice straw and the germination of
weeds. A herbicide is used to kill these weeds, and rice is sown
without seedbed preparation to prevent regrowth of weeds.
Fields are inundated after emergence of the rice seedlings, as
in the case of the conventional system.
(b) Conventional: just before sowing, the fields are prepared when
the soil is not yet inundated. Deep tillage is employed using a
disc plough followed by superficial operations with a disc harrow
with the aim to level the soil and prepare a seedbed with a
fine tilth. Sowing (drilling) is done with a conventional sowing
machine. Water is let onto the field after the rice seedlings have
reached a height of approximately 10 cm.
(c) Pre-germinated: the fields are inundated (early August) before
tillage operations start. Tillage is done in September and October.
Usually, the same disc implements are used as in the
conventional system, often complemented with a pass of a special
leveller to smoothen and level the wet surface layer. Seeds
are pre-germinated by soaking until the coleoptile is 2–3mm
long. The seed is broadcast in the shallow (5–10 cm) water layer,
either by hand or sowing machine, depending on the size of the
farm. The water layer allows amore precise levelling of the field
and controls weeds.
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