While mulch had positive effect in most cases, other treatments
of no-till, use of seed drill and higher planting density generally
had rather a small effect. No-till had no positive effect except at
one location; one of the difficulties with the use of no-till in rice
stubble areas, is that rice becomes a volunteer weed if not controlled
using herbicides. One option would be to wait until the rice
plants die, before planting of non-rice crops, but it is likely that
delayed planting will have reduced soil water content and therefore
more irrigation water would be required. One advantage of conventional
tillage is the incorporation of fertilizer to reduce losses
of urea-N through volatilisation. Another would be to reduce the
soil strength and to increase aeration for better root growth. The
fact that the use of seed drill resulted in similar crop establishment
and yield to the crop established from manual planting suggests
that the seed drill can be used when the labour cost exceeds and
approaches the depreciation cost of seed drill. In the year after
these experiments were completed, we further tested no-till using
seed drill at several locations. While crop establishment was not
affected in this method, crop growth was rather poor, perhaps soils
were too compacted and aeration was not sufficient. On the other
hand, general observation was that the seed drill was successful
when it was used after land was thoroughly prepared using conventional
tillage. This mechanised system of land preparation after
rice harvesting followed by drill seeding of mungbean may happen
rather quickly in the Mekong region where labour cost is increasing
rapidly.
While mulch had positive effect in most cases, other treatmentsof no-till, use of seed drill and higher planting density generallyhad rather a small effect. No-till had no positive effect except atone location; one of the difficulties with the use of no-till in ricestubble areas, is that rice becomes a volunteer weed if not controlledusing herbicides. One option would be to wait until the riceplants die, before planting of non-rice crops, but it is likely thatdelayed planting will have reduced soil water content and thereforemore irrigation water would be required. One advantage of conventionaltillage is the incorporation of fertilizer to reduce lossesof urea-N through volatilisation. Another would be to reduce thesoil strength and to increase aeration for better root growth. Thefact that the use of seed drill resulted in similar crop establishmentand yield to the crop established from manual planting suggeststhat the seed drill can be used when the labour cost exceeds andapproaches the depreciation cost of seed drill. In the year afterthese experiments were completed, we further tested no-till usingseed drill at several locations. While crop establishment was notaffected in this method, crop growth was rather poor, perhaps soilswere too compacted and aeration was not sufficient. On the otherhand, general observation was that the seed drill was successfulwhen it was used after land was thoroughly prepared using conventionaltillage. This mechanised system of land preparation after
rice harvesting followed by drill seeding of mungbean may happen
rather quickly in the Mekong region where labour cost is increasing
rapidly.
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