SSNM Technique for Higher Rice Yield

By Dr. Sosimo Ma. Pablico

A TECHNIQUE that advocates the optimum use of indigenous nutrient sources like crop residues and manures as well as the timely application of fertilizers to meet the deficit between rice demand for nutrients and the supply of nutrients from the soil and organic inputs appears as one way of increasing rice yields in six Asian countries, including the Philippines.

Called the SSNM [Site-Specific Nutrient Management] technique, this crop management approach stresses that nutrient management should be based on specific location, crop needs, and season since soil condition varies from one farm land to another. This technique is also called Site-Specific Crop Management.

In its initial regional evaluation, the Irrigated Rice Research Consortium in Asia noted that on the average, the SSNM increased yields and gross income by 7 percent in a period of four years. Here in the Philippines, yields ranged from 5 tons to 9 tons a hectare.

At PhilRice [Philippine Rice Research Institute], studies on the SSNM continue to be conducted with the leadership of Hermenigildo Gines even as he has already retired from government service. He started this research at PhilRice as a collaborative project with IRRI (International Rice Research Institute) when he was still a senior researcher.

Gines said farmers can expect higher yields from their farms with timely application of fertilizer to solve nutrient deficiency.

At the outset, the SSNM technique looks complicated but Gines said it is actually simple. Farmers just have to identify the needed nutrients, set a target yield, and apply the fertilizer that is deficient in the soil.

To derive the benefits from this technique, Gines advises farmers to determine the nutrients available in the soil and irrigation water before setting a target yield for SSNM. This is done through the nutrient omission plot technique (NOPT) or the minus-one element technique (MOET).

The NOPT determines the natural capacity of the soil, water and other materials like manures and crop biomass in the field to provide the right nutrients for the rice plant. To do the NOPT, three plots are established in the field. The whole field is fertilized with complete fertilizer (consisting nitrogen or N, phosphorus or P, and potassium or K), while each of the plots is applied with only two nutrients each. Thus, the minus-N plot receives only P and K; minus-P plot receives only N and K; and the minus-K plot receives only N and P.

Gines said, however, that the NOPT would take a whole season before results are known. Thus, farmers may resort to the use of the MOET [minus-one element technique], which is completed at a much shorter time.

On the other hand, the MOET can be used before the growing period or at land preparation stage in areas where farmers take time to prepare their fields very well in at least one month before transplanting. It is done in seven plastic containers using the puddled soil of the field as growing medium. The MOET kit comes with seven fertilizer formulations. One formulation contains all the macronutrients nitrogen (N), phosphorus (P) and potassium (K) and the micronutrients zinc (Zn), copper (Cu) and sulfur (S).

The MOET shows the status of these six essential nutrients in soils. It simulates actual field condition of a flooded or submerged soil, is farmer friendly, and does not require sophisticated equipment. The farmer can do the testing right in his field using the same variety to be planted on his field. The method is easy to use with fast and reliable results. The kit costs cheaper than other methods.

Gines said that farmers must consider their financial capability when they set a target yield. If the farmer opts to achieve the maximum yield, he must be able to apply all the fertilizers needed. Otherwise, he should settle for the yield option that he can afford. Although the minimum yield that could be derived through SSNM is 5 t/ha, this is already way above the usual yield obtained by most farmers, according to PhilRice soil expert Wilfredo Collado.

He adds that the use of the SSNM ensures higher productivity even at a minimum target yield if farmers follow the management practices specifically recommended for their respective field conditions. (With report from Myriam G. Layaoen)

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