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Puddling


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Puddling destroying the aggregates of soil by agricultural operations on it when it is too wet. Alternatively, a special way of management of water-saturated soil by plowing and harrowing. Puddling can be defined as the process of breaking down soil aggregates into uniform mud, accomplished by applying mechanical force to the soil at high moisture content. It may also be defined as the mechanical reduction of the apparent specific volume of soil. To a farmer, puddling is mixing soil with water to make it soft for transplanting and impervious to water. To put it simply, it is an act or method of making a puddle.

In most cropping systems, puddling is an unintentional effect of tillage at the wrong moisture content and usually results in severe yield decreases or delays in planting. In lowland rice systems, puddling is an important soil management practice, conducted with great care for the purpose of destroying the topsoil structure. It is almost synonymous with lowland rice culture in Bangladesh, as in other countries in Asia.

The process of puddling is accomplished by a series of tillage operations, beginning at soil moisture content above saturation and ending at moisture content closer to field capacity. In practice, farmers start their puddling operations at moisture contents above saturation. Applying force at this range does not cause maximum puddling, but it incorporates weeds and starts the aggregate destruction process. Farmers then continue to puddle the soil at progressively lower moisture content until they reach maximum puddling. The degree of puddling attained varies with soil type and management practices. High clay contents facilitate puddling and produce more aggregate destruction. Nevertheless, sandy soils with low clay contents can also be puddled. Montmorillonite families are puddled more easily and thoroughly than kaolinitic or oxide families. Similarly sodium saturated clays are puddled more easily than calcium saturated clays. In general, the higher the organic matter content or the iron and aluminium oxide content or both, the more difficult it is to puddle the soil.

The repeated cultivation of many soils in Bangladesh, especially the puddling of soils for transplanted rice, creates an impervious topsoil which considerably modifies the physical and chemical properties of this layer as well as its colour in many soils. The agricultural potential of Black Terai Soils generally is moderate or low because of the difficulty of puddling the topsoil for transplanted paddy cultivation. On the other hand, the low moisture holding capacity of the shallow ridge soils on the Old Brahmaputra Floodplain are used for transplanted aman cultivation because of the puddled topsoil and strong ploughpan. [Aminul Islam and Sirajul Hoque]