IMPROVING SOIL HEALTH AND FERTILITY THROUGH INTEGRATED NUTRIENT - PowerPoint PPT Presentation

IMPROVING SOIL HEALTH AND FERTILITY THROUGH INTEGRATED NUTRIENT MANAGEMENT G Umrit 07 May 2014 MAURITIUS SUGARCANE INDUSTRY RESEARCH INSTITUTE

Soil Health • Capacity of a soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental quality and promote plant and animal health. • In the context of agriculture, it may refer to its ability to sustain productivity. • A healthy soil would ensure proper retention and release of water and nutrients, promote and sustain root growth, maintain soil biotic habitat, respond to management and resist degradation

Measure of Soil Health • Governed by a number of physical, ORGANIC MATTER chemical and biological attributes and processes. CHEMICAL ENVIRONMENT ENVIRONMENT BIOLOGICAL SOIL • Expressed by different quantitative and HEALTH INDICATORS qualitative measures of these attributes as also by outcomes that are governed by the soil such as productivity, nutrient and water use efficiencies and quality of PHYSICAL ENVIRONMENT produce.

Declining Soil Health – A Cause of Concern Trend in sugar productivity in Mauritius (1970 to 2010) Tonnes sugar per hectare 10 8 6 4 2 0 1970 1980 1990 2000 2010

THE YIELD DECLINE PHENOMENON Increasing evidence of decline in productive capacity of sugarcane soils Attributable to: long term monoculture poor soil management

Need for an integrated nutrient management (INM) approach. Goal of INM: Integrate the use of all natural and man ‐ made sources of plant nutrients, so that crop productivity increases in an efficient and benign manner without sacrificing soil productivity of future generations. Maintaining soil Biological, Chemical and Physical fertility are critical components of INM

Development of an integrated approach to sugarcane fertilization This integrated approach will accommodate nutrient inputs form organic sources, industrial wastes etc where necessary Foliar diagnosis will be used as a tool for monitoring the effectiveness of this approach

Tapping alternative sources of nutrients GREEN MANURING, BIOLOGICAL NITROGEN FIXATION ORGANIC MANURES BIOFERTILIZERS

Total N accumulation by LGM biomass (kg ha ‐ 1 ) Medine Union Belle PSES Park Rive Lablab var Rongai 257 a 267 ac 264 a 215 a Lablab var Highworth 232 a 235 a 132 b 170 b Cowpea var Ebony 182 b 101 b 115 bc 124 c Soybean var Leichardt 106 c 287 c 98 c * Cowpea var Caloona 116 c Crotalaria 175 d 190 ab

LGM LGM contributes substantial N to sugarcane crop in Plant cane and 1 st r atoon but not in 2 nd ratoon N application to plant cane following LGM may be omitted Reduction in N rates to half the Recommended dose for 1 st ratoon cane

ORGANIC SOURCES Value of organic manures as a fertilizer for sugarcane Treatments 1 Control – Unfertilized (No NPK) 2 Scums + molasses (factory byproducts) 3 Poultry manure 4 Mineral fertilizer

Mineral v/s Organic sources on cane yields 80 Yield data 70 Cane Yield (TCH) averaged over 60 PC + 5R 50 and 3 crop cycles 40 30 20 10 0 Unfertilized Scums & Poultry Mineral Molasses manure NPK

ORGANIC SOURCES ORGANIC FERTILIZER SOURCES ARE AS GOOD AS MINERAL SOURCES TO SATISFY SUGARCANE NUTRITIONAL NEEDS VERY HIGH RATES (> 40 T Ha ‐ 1 ) ARE NEEDED TO SUBSTITUTE FOR MINERAL FERTILIZERS USEFULNESS AS FERTILIZER IMPEDED BY TRANSPORTATION COSTS

MICROBIAL BIOFERTILIZERS WHAT ARE BIOFERTILIZERS? Biofertilizers, more commonly known as microbial inoculants , are products containing living micro ‐ organisms, which are applied to seeds, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant, and are claimed to promote crop growth by increasing the supply or the availability of primary nutrients to the host plant

MICROBIAL BIOFERTILIZERS Some uncertainties associated with application of microbial biofertilizers to non ‐ legumes, including sugar cane: � Unpredictability/inconsistency of field performance � Perform less than the exaggerated claims made by manufacturers � reliable data showing conclusive impacts of biofertilizers on cane and sugar yield are still lacking. � Farmers more enthusiastic than the scientific community Studies carried out at MSIRI have shown that prospects of using three tested microbial biofertilizers as an alternative means of harnessing N by sugar cane are remote

MICROBIAL BIOFERTILIZERS Reasons for lack of response Inability of the inoculated bacteria to survive in the rhizosphere or host plant tissue due to biological and environmental factors There exists a strong sugarcane genotype x diazotrophic strain interaction Generally, nitrogen fixing endophytes are effective only in very low N input systems Deficiencies in handling procedure are a major cause of lack of performance in field applications

MICROBIAL BIOFERTILIZERS OUTLOOK FOR BIOFERTILIZER USE IN SUGARCANE If at all microbial biofertilizers are to enable the sugarcane crop to access N derived from N2 ‐ fixation as well as to harness soil reserves of inorganic and organic P, this can only happen if the highest standards of quality control are maintained in their production, evaluation and application.

MICROBIAL BIOFERTILIZERS The success of integrating biofertilizers in sugarcane will depend on: Quality control to verify that there are sufficiently high viable numbers of the correct strains of micro ‐ organisms Field trials should also be part of the quality control, proving that the biofertilizer actually promotes crop yield with reduced chemical fertilizer inputs. Establishing minimum standards and testing protocols Carefully designed field research should be performed for product validation anddintegration into the current cane cropping system. Taking necessary actions on fake bio ‐ fertilizer products put on the market.

MICROBIAL BIOFERTILIZERS Because the amount of energy required to fix agronomically significant quantities of N per hectare could significantly reduce yields, an appropriate balance must be found between the benefits of BNF and the potential reduction in yield.

Conclusion • General trend towards a decline in soil health – the yield decline phenomenon • Need for adoption of site-specific balanced and integrated nutrient management approach involving synthetic fertilizers, organic manures, biofertilizers and amendments. • Utilizing all locally available nutrient sources to reduce dependence on imports. • Developing new efficient fertilizer products/ approaches through state of art R & D applications. • Farmers to take advantage of testing services in order to make precise fertilizer use. • Need for creating awareness amongst farmers on benefits of balanced fertilization.

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