Potentials ofIntegrated Nutrient Managementsystems inRice Cultivation in Sri Lanka
Content1) Integrated nutrient management (INM) is..2) Why we must practice it in rice fields3) nutrient requirement for rice plant4) how to practice INM5) what are the limitations in INM6) how to overcome those7) what are the potentials in Sri Lanka
IPNS is a holistic approachto plant nutrition by obtainingthe nutrients available fromdifferent sources such asinorganic and organic sourcesto maintain and sustain soil fertility.This will enhance crop productivity in aframework of an ecologicallyaccommodated, socially acceptableand economically viable situation.
There are many Advantages …- Enhances the availability of applied nutrientsas well as native soil nutrients.- Synchronizes the nutrient demand of the crop,with nutrient supply from native and appliedsources.- Provides balanced nutrition to crops andminimizes the antagonistic effects resulting fromhidden deficiencies and nutrient imbalance.- Improves and sustains the physical, chemicaland biological functioning of soil.
- Minimizes the deterioration of soil, water andecosystem by promoting carbon sequestration,reducing nutrient losses to ground and surfacewater bodies and to atmosphere- Increase fertilizer use efficiencychemical fertilizer yield from only chemical fertilizer+ > ororganic manure yield yield from only organic manure- Generally rice growing soils in SL are low inorganic matter and poor in available P amount soapplication of organic manure is definitely increasethe yield….!!
There are 17 essential elements for a rice plant togrow and develop properly.These elements can be grouped intomacro-elements : C, H, O, N, P, S, K, Mg, Caandmicro-elements : Fe, Mn, Cu, Zn, Mo, B, ClModern high-yielding rice varieties producingaround 5 t/ha of grain, in general, can removefrom the soil about..
Removals of Si and K2O areparticularly large if thepanicles and straw are takenaway from the field atharvest.However, if only the grainsare removed and the straw isreturned and incorporatedback into the soil, theremoval of Si and K2O isgreatly reduced, althoughsignificant amounts of N andP2O5 are still removed.Nutrient Weight (kg per 5ha)N 110P2O5 34K2O 156MgO 23CaO 20S 5Fe 2Mn 2Zn 0.2Cu 0.15B 0.15Si 0.25Cl 25
Use combinations of- synthetic fertilizers (Urea, TSP, MOP),- mineral (ERP, Dolomite)- organic fertilizers (farmyard manure,green manure, crop residues etc.)obtained on farm and off farm forrecycling of nutrients.Using proper application methodssuch as Broadcasting, Placement,Foliar application and Fertigation.
( I ) Artificially synthesized fertilizersTriple Super Phosphate(TSP)Urea
“…Paddy consumes the largestproportion of imported chemicalfertilizers,It accounts for approximately 50%of the overall use of chemicalsfertilizers in Sri Lanka….”
( II ) Organic manureThere are various sources of organicmanure to be used for INM. Some ofthese are mentioned below- Compost- Farm Yard Manure (FYM)- Poultry Manure- Piggery manure- Urban and rural solid and liquid waste- Wastes from agro based industries- Crop wastes- Vermicompost
(III) Crop residues- Rice straw- Rice husk- Bean straw- Sugarcane trash- Cowpea stems- Wood ashes-1/3 of N required by Rice plantcould be provide by Rice straw- Rice straw can provide almostall K Requirement (30-40 g/ha)
(IV) Green Manure- Provide N, organic matter and improve soilfertility. Grown before and after rice crop.- Can be broadcast in to standing rice cropshortly before harvesting.- Also can be broadcast into rice stubble withoutcultivation.- Can grown in bunds of rice fields or in fallowlands during the off season and their leaves areincorporated.
- Financial credit is available only formineral fertilizer.- No organized credit system to promoteorganic fertilizer- Farmers who have domesticatedanimals, do not have facilities to collect,store and market their animal waste.- Low awareness about using biofertilizers- Non-availability of water
- Chemical fertilizers are easilyavailable and easy to use- Organic manure is not available inown holdings most of time- Storage and retail marketing oforganic manure is limited, is not easilyaccessible to most farmers- Scarcity of labour
- Initiatives have to be directed to utilizeall available organic materials such asrice straw, animal manure and paddyhusk, and incentives have to be givenfor the popularization of same- Large scale on farm and off farmproduction of organic manure should beencouraged in Island wide- Planting of Gliricidia, or Ipil Ipil on themajor bunds and hedge rows to supplygreen manure.
- Use of charred rice husk.- Cultivation of sandwich crops.- Encourage farmers who practicingIPNM methods by providing subsidiesand monetary prizes.- Make new rules and regulations toboost organic manure usage.- Introducing new green manurecrops and latest composting methods