Sugarcane

Compost


Composting Sugarcane Trash and Pressmud

  • There is increasing dearth of farm yard manure (FYM) in most agricultural farms because of two main reasons. viz., the cattle population is dwindling as more and more farmers are switching over to machinery to carry out various farm operations and the cattle dung is increasingly diverted to make fuel cakes as availability of fire wood is becoming scarce.
  • This is why these days farmers either do not apply FYM or apply only limited quantities. Long lasting improvements in soil physical and chemical characteristics are possible only by the additions of sufficient amounts of organic manures.
  • Sugarcane produces huge quantity of foliage, about 40 percent of the total biomass. On an average the cane trash produced amounts to 15-20 t/ha. However the quantity varies with varieties and crop growth.
  • The trash contains on an average 0.35% N, 0.13% P2 O5 and 0.65% K2 O.
  • For every tonne of cane trash and nutrient availability is 3.5 Kg N, 1.3 Kg P2 O5 and 10 Kg K2 O.
  • From a hectare of sugarcane crop, around 50 Kg N, 20 Kg P2 O5 and 100 kg K2 O O can be recovered from trash alone.
  • Usually sugarcane farmers dispose off the trash by burning in the field itself. This is mainly because of the requirement of huge number of labourers to remove trash out of the field, and, also due to lack of appreciation of the value of the trash as a source of organic carbon and nutrients.
  • When the trash is burnt in the field, the environment is polluted by smoke, carbon dioxide and carbon monoxide. Certain nutrients are lost in gaseous form. The organic matter is burnt and thus lost.
  • Secondly burning trash generates intense heat ranging from 600 to 800 degree C which kills favourable soil micro-organisms and earthworms. Thus favourable soil biological activity is affected.
  • Intense heat generated also kills sugarcane buds present in the stubbles. Therefore severe gaps in the field occur finally leading to less stalk population and yield.
  • All these undesirable effects on soil, environment, loss of nutrients, etc., could be avoided by recycling trash through composting.

Trash composting

  • After the cane harvest, the trash is collected and removed to a corner of the field or to any other convenient place. A pit measuring 9 m x 5m x 1m is dug out. The size of the pit may vary according to the availability of trash and convenience of the farmer.
  • In the pit a layer of about 500 kg trash is spread in 8m x 5m area. Over this, about 500 kg pressmud is spread (if pressmud is not available soil can be used). Above these layers, 25 kg fertilizer mixture prepared by mixing rock phosphate, gypsum and urea in the ratio 2:2:1 )i.e., 10 kg rock phosphate + 10kg gypsum + 5 kg urea) is sprinkled.
  • These layers are then moistened with about 500 litres of slurry made up of soil, cow dung and decomposted FYM in 500 litres of water (i.e., 5 kg soil + 5 kg cow dung + 5 kg FYM for every 100 litres of water).This way 10-15 layers of trash + press mud + fertilizer mixture + slurry are laid.
  • Over the final trash layer, a layer of pressmud or soil is spread to a thickness of 15cm and the head is covered. The heap must be moistened once in a week from above and allowed to decompose for 3 months. After 3 months, a turning must be given, mixing the layers and reheaping the partially decomposed material.
  • To facilitate this operation, one metre space must be left in the pit. Moistening from above must be continued for another 3 months at 7-10 days interval. By around 6 months, a well decomposed manure rich in nutrients is obtained.

Composition of cane trash compost

Nutrient
Per cent composition
Nitrogen (N)
1.60
Phosphorus (P)
1.10
Potassium (K)
0.50
Calcium (Ca)
1.00
Magnesium (Mg)
0.60
Sulphur (S)
0.48
Iron
2710 ppm
Manganese
450ppm
Zinc 370ppm
Copper 80 ppm
C:N ratio 22:1

Pressmud

  • The pressmud produced in a sugar mill is about 4 percent of the cane crushed. The pressmud contains considerable amount of major and minor nutrients.
  • Application of pressmud improves, iron availability. It also improves availability of zinc, calcium, magnesium and manganese. In calcareous soils, it reduces soil pH, EC and ESP and increases available status of the soil.

Enrichment of pressmud by composting

  • Immediate and direct application of press mud is not desirable as it has a wide C:N ratio and its decomposition generates lot of heat.
  • Composting of press mud using micro-organisms helps in enriching it and makes it easier and safer to apply to the field.
  • For composting one tonne of pressmud, a pit measuring 2m x 1m x1m is dug out. One tonne of pressmud is divided into 3 portions. One portion is spread in the pit.
  • Over this 2 bags (500 g) of Trichoderma viridae or 2 bottles of Pleurotus sp. culture is added. Then 5 kg urea and 50 kg cow dung or well decomposed FYM are added. In this way, two more layers are laid and the top is covered.
  • It is allowed to decompose for 45 days. Sufficient moisture level is maintained throughout by periodical sprinkling of water over the heap.

Nutrients content of enriched pressmud

Enriched pressmud
Total N (%)
Available N (ppm)
Total P (%)
C:N ratio
Pressmud enriched by Trichoderma viridae
1.19
856
2.90
8.10
Pressmud enriched by Pleurotus sp.
1.26
988
3.13
7.75
Pressmud-non enriched
1.03
775
2.76
8.55

  • The pressmud could be further enriched by the addition of rock phosphate and zinc sulphate. Use of this pressmud helps in improving soil organic carbon content, nutrient availability and soil physical properties like porosity, water holding capacity and soil structure.

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Sugarcane Management