Sample collection is the most critical part of soil testing for developing variable rate fertilizer consumption maps. Research is underway how to optimize sampling for various combinations of soil properties, cropping systems, and fertilisation/manuring histories.
Overlay Field with a Grid
! For the initial sampling, each grid cell should not be larger that 1 acre unless the field has a history of high soil test values and fertiliser applications in excess of normal crop removal. In the latter case a 2-acre cell may be acceptable. It may be necessary to sample portions of the field on a finer grid, if, responsive sites are identified with the first sampling pass.
! Future sampling of the field may be done using a larger grid size or by nutrient management areas, depending on the outcome of the initial sampling.
! Locate the sample point by counting rows and measuring distances, or preferably navigate to the point using GPS.
! Taking samples in straight rows across the field may be biased by previous management such as fertiliser application patterns. A systematic but unaligned pattern may be better choice, especially, if, GPS-referencing is available.
! Collect at least 5-8 soil cores for each grid cell, taking the cores from within a radius of 10 feet of the sample point.
Sample at a Uniform Depth
Soil tests are usually calibrated on the basis of an acre furrow slice approximately 2 million pounds of soil. Check with the analytical lab for its recommendation on sampling depth, because some labs use their own calibration data set that is based on a sampling depth different from the 62/3- inch standard. For no-till fields, consider collecting a set of samples at the standard depth and another set to represent the top 2 inches. This will help identify stratification of nutrients, and is especially important for pH determination. A goal of every farmer should be to develop a strategic plan that works toward detailed, site-specific nutrient management:
! Make a commitment to keep accurate, detailed records of production inputs and yields for each field, including variability within the field.
! Begin collecting soil test, nutrient application and crop yield data on a grid basis. Identify each sample with its exact location in the field. Use GPS location- referencing, if, possible.
! Analyse records and develop a nutrient management plan that takes into account the variability within a field. Use spot spreading a variable rate application where appropriate.
! Measure yields for each field. Using on-the-go yield measurement to develop a yield map of each field is even better. Individual field yield records are a good starting point, but yield variation across the field must be measured to get an accurate check on response to site-specific management.
! Continue to add information each year and begin more detailed analysis of the records to refine the site-specific nutrient management plan. Even though the level of detail of different data sets will vary, each point in the field can be associated with each data set, if, all of the records are properly geo-referenced. As technology improves, some data sets can be replaced with more accurate or more detailed data sets for the same parameters.
Nutrient Management Plan
Every field should have a nutrient management plan that integrates the information from all sources of data available for the farm. The plan should integrate the specific experience, preferences and goals of the farmer. Yield goals should not only be realistic and profitable, but also progressive. Assessment of potential environmental impact and compliance with applicable regulations should be a part of the plan.
Site Specific Nutrient Management for High Yield and Quality of Fruit Crops
Plans should be written out in detail, with appropriate supporting records and other information. Nutrient management plans should include proper credits for previous crops, manure, sludge or industrial by product applications. Consider all of the nutrient resources available and select the best combination for each field. Good nutrition may be expensive, but inadequate nutrition can be even more costly in terms of lost
yield potential...and lost profits!
Start Now—Build for the Future
A site-specific nutrient management (SSNM) system begins with a commitment to develop a good record keeping system that will document the past and help plan the future management practices and crop responses. Other components, including yield monitoring, grid soil sampling, and variable rate fertiliser application, can then be added as best fits the management and economics of the operation.
To begin the process, it requires no major capital investment of specialized equipment. Computers and satellite-based positioning systems may be important tools in the long run, but they are of little value until the basic management strategy is established. Much can be done to implement site-specific management, even before new technology is added. The important step is to make a commitment and get started with accurate, detailed records and careful attention to management details.
SSNM Treatments : An Example 1. NP3K3SZnB 2. NP2K3SZnB 3. NP1K3SZnB 4. NP0K3SZnB 5. NP3K2SZnB 6. NP3K1SZnB 7. NP3K0SZnB 8. NP3K3SZnB0 9. NP3K3SZn0B 10. NP3K3S0ZnB
11. State recommended dose 12. State recommendation++
Importance of Nutrient Management in Horticultural Crops
! Higher yield, quality and returns.
! Improving nutritional standards of the people.
! Greater and better quality raw materials for fruit and vegetable processing industries. ! Generate foreign exchange earnings through the export of high quality produce. Balanced and Efficient Nutrient Management
! Add all deficient nutrients
! Replenish the amount removed by crops
! Add nutrients to compensate for nutrient losses from the soil
! Consider quantities "locked up" in perennial growth and removed in prunings ! Adopt BMP
The Basic Difference
! Long pre-bearing period
! Needs vary with age and productivity ! Deep root system
! Remain at the same place for years ! Large structure
! Distinct and lengthy phases of vegetative growth and fruit development Site-Specific Nutrient Management: Ensures
! Balance ! Efficiency ! Top yield ! Top quality ! Top profits
Objectives of Site-specific Management
Site Specific Nutrient Management for High Yield and Quality of Fruit Crops
! Understand the impact of soil variability on crop growth, yield and profitability ! Manage soil variability to improve production, increase profits, and reduce
environmental impact
Benefits of Site-specific Management
! Improved input efficiency
! Reduced potential for environmental impairment
! Documentation of "what, where, when, why"…of management ! Identification of within-field variability in yield potential
The Potash and Phosphate Institute of Canada (India Programme) is the partner of the fertilizer industry, Agricultural Universities/Institutes, State Department of Agriculture in achieving balance through its network of research and educational programmes which help to achieve maximum economic yields through site-specific nutrient management in different soil-crop-climatic situations of India. Lessons learnt from PPIC's site-specific nutrient management programme are rewarding and emphasize the need for practicing balanced and efficient fertilizer use considering site-specific nutrient deficiencies and crop's nutrient requirements for targeted yield goals.
Sustainability of Indian agriculture to maintain food self-sufficiency will depend on the 'high input-high output' principle. The 'low input-high output' concept is merely a dream, and adherence to this invalid view would prove fatal for food security and nutritional security. In the Indian context, this is more true now than ever before because of emerging demands for horticultural, floricultural, and plantation crop products. The founding father of the green revolution in India, Dr. Norman Borlaugh, has rightly stated that without the use of chemical fertilizers, India and China would have needed 2-3 times more land under cereals to meet food needs of 1991, if, they used the technology of 1960…and not increase the, fertilizer input to sustain its present level of production. This is very true for horticulture sector also.
CONCLUSION
High yield agriculture must be at the top of India's agenda for food and nutritional security, and environmental safety. Maximum economic yield goals can be achieved on irrigated land by using improved genetics, yield targeted site-specific nutrient management, and improved crop husbandry practices. Attention must be paid to quantities of nutrients being removed by crops and quantities of nutrients supplied by all sources. To minimize India's current annual negative nutrient balance of 8-10 million
tonnes of N+P2O5+K2O, increased use of fertilizers along with possible use of organic manures and biofertilizers would be essential and inevitable. Organics, which can supply a portion of P and K along with the secondary and micronutrients required by crops can help offset the negative nutrient balance and slow down nutrient depletion processes; however, it cannot meet the nutrient requirements of crops. Proponents of strictly organic farming systems tend to overlook three important factors, i.e. (a) the adequacy of supply of organic materials on a national basis, (b) the nutrient content and rate of supply to growing crops, and (c) the high labor costs to collect and apply organic materials. The importance of organics in improving soil physical and biological properties cannot be denied, their efficient use to the extent possible should, therefore, be promoted and integrated nutrient management be practised.