Rice is an excellent choice if you are looking for a food crop that will grow fast and produce a lot of food.
The only problem with growing rice is it can be difficult to get started without the right fertilizer or seed starter solution.
Just like all plants, rice needs the proper nutrients in order to survive and thrive after sprouting up out of the ground.
In order to increase productivity per unit area while keeping production costs low, farmers often use fertilizers on their crops. Organic manure can be used but due to its high demand and increasing prices, this isn’t always affordable or even available at times.
One option that has been shown effective time after time is chemical fertilizer which consists mostly of nitrogen (N), phosphorus (P), and potassium oxide (K).
Because soil fertility varies from region to region and even within one farm different areas may have varying levels of need for fertilization, it is important to know what the best fertilizer type and quantity are.
Best Fertilizer for Rice: Chemical or Organic?
The choice between chemical and organic fertilizers is an important one. While both types can increase yield substantially, they also have different effects on the soil ecosystem. Manure contains compounds that are difficult to measure but which play a very important role in maintaining fertility over time.
This means that before making any decisions it’s best to conduct experiments with various levels of nitrogen, phosphorus, and potassium oxide as well as varying ratios between them if possible depending on your location.
Because rice fields often require more nitrogen than other plants this should be taken into account when deciding how much fertilizer you need per hectare (about 0,0047 pounds). When used correctly either type will result in increased crop yields.
Here is a list of some of the best fertilizers for rice:
1). Soft Rock Phosphate
It contains 22% calcium phosphate, which makes it a very useful product during rice cultivation. It can be applied at any time during the crop cycle because it does not contain urea. The granules dissolve quickly in water and do not stick on hands while handling them.
A 50 lb bag will cover an area of about 1/2 acre (3′ x 150′). Soft rock phosphate is also useful in converting soils with high amounts of aluminum.
Soft Rock Phosphate can be used to balance the effects of nitrogen fertilizer, apply before transplanting or at early growth stages, and for general plant health.
2). Muriate Of Potash (Potassium Chloride)
Muriate of potash can be applied as basal fertilizer and may provide all required potassium to rice plants throughout the growing season.
It is water-soluble and fast-acting, which means that it can be easily absorbed by plant roots and can reach the intended area where needed. A 50 lb bag will cover an area of about 1/2 acre (3′ x 150′).
Muriate of potash may also contain calcium chloride, magnesium chloride, and sodium sulphate.
It is the most commonly used fertilizer for rice cultivation, mainly because it requires less storage space than other fertilizers. It acts slowly on the rice plant roots and may need to be applied every two weeks during the crop cycle.
Urea has an NPK ratio of 46-0-0, which means that it contains nitrogen (46%) that can help in improving plant growth and development, phosphorus (0%), helpful in promoting healthy root development, and potassium chloride (0%), which improves disease resistance.
When urea is applied to soils where phosphate levels are already high, it will generate excess nitrates in soil water or form insoluble compounds with calcium ions or aluminum ions in the soil solution. A 50 lb bag will cover an area of about 1/2 acre (3′ x 150′).
4). Ammonium sulphate
It contains 21% nitrogen and 12% sulphur. Being water-soluble, ammonium sulphate can be easily absorbed by rice plant roots. It is often used as a foliar fertilizer for rice cultivation, but it can also be applied at planting time or between harvests. A 50 lb bag will cover an area of about 1/2 acre (3′ x 150′).
5). Calcium Ammonium Nitrate (CAN)
Calcium ammonium nitrate has an NPK ratio of 16-0-0 and provides calcium, nitrogen, and potassium to the plant. CAN have high solubility in both acidic and alkaline soils due to its efficient ion exchange capacity.
A 50 lb bag will cover an area of about 1/2 acre (3′ x 150′).
Ammonium sulphate is often used to fertilize emerging rice seedlings, but it can also be applied at later growth stages. A 50 lb bag will cover an area of about 1/2 acre (3′ x 150′).
|Element||Soil test method||Critical value|
|Phosphorus||NaHCO3||6 ppm PO4-P(In cold years, may be as high as 9 ppm)|
|Potassium||NH4Ac||60 ppm K|
|Zinc||DTPA||0.5 ppm Zn|
Chemical fertilizer is probably the most effective and popular type of fertilizer on the market. It can be a dry or liquid form and is composed mostly of nitrogen, phosphorus, and potassium (N-P-K).
The amount of each nutrient determines the relative percentages found in a bag of fertilizer. For example, a 20-20-20 chemical fertilizer has 20% nitrogen, 20% phosphorus, and 20% potassium by weight. Some fertilizers contain trace elements as well as secondary nutrients such as calcium, sulfur, and magnesium depending on the manufacturer’s preference.
In order to maximize yield from a given field, rice growers typically apply at least 100 pounds per acre of actual nitrogen (from all sources) across the entire growing season with additional N applied during tillering and ripening stages for maximum yield. A common practice among some rice growers is to apply a combination of both organic and chemical fertilizers.
In this instance, the grower would first apply animal manure or compost as a cover crop which would provide early season nitrogen needs while supplementing soil fertility. Then, starting at tillering, a starter fertilizer such as ammonium polyphosphate may be applied to provide additional P and K along with N for maximum yield potential.
Finally, split applications of urea or muriate of potash (potassium chloride) are commonly used from mid-season to ripening for finish applications of nitrogen. The effectiveness of all these practices will have more to do with timely application than the particular chemical being applied since it is so important in rice production.
Pros of Chemical Fertilizers:
- The most effective type of fertilizer available commercially to increase rice yields.
- Provides quick uptake for an immediate response (2 – 3 weeks).
- Contains all three macronutrients (N, P, and K) in proper ratios.
Cons of Chemical Fertilizers:
- Can be expensive; typically cost $250-$400 per ton depending on local commodity prices and transportation costs to the farm.
- High risk for environmental contamination including groundwater and surface waters through leaching and runoff at high rates, as well nitrogen volatilization while applying during hot weather (>90°F) or high humidity or while lightning is nearby.
- Large amounts applied early in the season can inhibit rice tillering.
- Can impact organic matter decomposition if the soil is not well aerated and to the extent that microbial activity has been reduced by overuse of pesticides or herbicides the previous year due to the presence of residual chemicals.
Organic fertilizers such as animal manure and composts are typically applied at rates similar to chemical fertilizers (100 lbs/ac) depending on availability, cost, and nutrient content. The use of organic fertilizers serves two purposes for rice growers:
1) provide N through mineralization or breakdown of organic materials which then become available for plant uptake.
2) provide a ‘salary’ to maintain soil fertility throughout the growing season instead of using up soil fertility in a single application, since all organic fertilizers release N at varying rates depending on the composition of the material.
Animal manures typically have a high initial concentration (>10%) of N when fresh but have lower mineralization rates compared to composts with similar nutrient content.
In general, animal manure is applied to rice fields in the fall after harvest and incorporated into the soil prior to planting while compost is often used as a top-dress in spring.
Pros of Organic Fertilizers:
- Provide long-term nutrient availability through ‘salary’ payments with minimal risk for leaching or runoff with proper management practices.
- Can be generated inexpensively using rice straw and/or weed-free grass hay as residues following harvest.
- Can be used to boost fertility in fields with low organic matter content.
Cons of Organic Fertilizers:
- Long-term availability means translocation of N and other nutrients can occur over many months; consequently, there is a risk for leaching or runoff when it rains before mineralization has been completed.
- May contain weed seeds which could reduce stand establishment in the following season if not well incorporated into the soil prior to planting rice. – Manure and compost can vary widely in nutrient composition and quality depending on their source (i.e., animals, bedding material, ingredients added by the producer).
You may have been asked which type of fertilizer is best for the crop. The answer to this question depends on what the grower wants from his or her rice crop.
Nitrogen is a very important nutrient for all plants and none more so than rice. Rice does not need as much N as other crops because it initiates grain formation early in its growth cycle.
Once a significant amount of carbohydrates begin to accumulate in the plant tissue then little additional will be used for grain production.
Since a rice plant initiates grain formation early in its growth cycle, an application of fertilizers containing N will increase the yield potential of a crop. However, it should be noted that there is a point where additional N can become counterproductive.
This would be from an excessive supply being applied greater than the ability of the plant to use it for increased yields. In this case, there is little benefit from overapplication because too much will leach out which could pollute waterways and eventually end up as nitrate in groundwater, rivers, and lakes.
The need for nitrogen might also depend on what type of fertilizer was used to produce the seed you are planting.
If seed manure or compost were used then less N may be needed than if synthetic fertilizers such as mono ammonium phosphate (11-52-0) or diammonium phosphate (18-46-0) were used.
Phosphorus is needed by plants in very small amounts compared to nitrogen and potassium; however, it plays a very important role in the development of plant root systems and shoots vigor. If phosphorus is deficient, rice will be stunted and produce poorly until P supply is increased.
Application of too much phosphorus can affect the soil pH which could make it more difficult for rice plants to take up other nutrients such as nitrogen, manganese, and zinc.
Excessive applications could also cause excessive vegetative growth at the expense of grain production. Growers should remember that P does not move around in soil as easily as other nutrients, so it should be applied to the entire field.
Chloride is needed by rice plants in small amounts and usually occurs naturally at levels considered adequate for maximum growth and yield. Excess chloride may cause damage to sensitive crops if present in the soil solution after application of irrigation water containing Cl.
High-Cl soils tend to reduce yields and produce lower quality grain because Cl tends to accumulate on leaf surfaces which hinder gas exchange during photosynthesis. Although there is little direct evidence that chloride toxicity affects rice yields, many researchers believe that high Cl in the soil solution during reproductive growth negatively impacts rice yield potential.
Chloride toxicity can be reduced by leaching with water which will move Cl off the root surface and into the subsoil where it will not harm plant tissue. As a general rule, soils with less than 2 ppm Cl are considered high for most crops.
Rice is arguably the most important cereal crop for human nutrition.
It provides more calories and protein than wheat or maize, and those who depend on rice as their staple food supply need only half as much land to do so as those who depend on wheat or maize.
In addition, rice requires less water than other cereals, even though it yields more calories per unit of water used.