soybean, also known as the soy bean or soya bean, is a species of legume native to East Asia that is widely produced for its edible bean, which has a variety of uses. Soy milk, from which tofu and tofu skin are formed, is a traditional unfermented dietary usage of soybeans. In recent years, Soyabean has become quite popular, its area is constantly growing, due to steady demand and the high cost of a grain of this crop. This attracts farmers who are trying to increase the profitability of their enterprises.
However, successful cultivation is impossible without knowledge of the biological characteristics of this culture, the intricacies of technology, and a creative approach.
One important aspect of soybean cultivation technology that is often neglected is the use of fertilizers. There is an opinion that soy does not need fertilizers. Moreover, it actively accumulates nitrogen in the soil due to the activity of nodule bacteria. Unfortunately, not everything is so simple.
The need for Soybean in nutrients is determined by its biological characteristics. At the beginning of the growing season, the culture develops slowly, from seedlings to flowering, it requires a small number of nutrients. From flowering to the mass filling of beans, the greatest need for batteries is observed (65% of NPK is absorbed).
Soybeans require 14 nutrients for successful Growth:
|Nitrogen (N)||Phosphorus (P)||Potassium (K)||Sulfur (S|
|Iron (Fe)||Manganese (Mn)||Zinc (Zn)||Boron (B)|
|Calcium (Ca)||Copper (Cu)||Magnesium (Mg)||Nickel (Ni)|
|Chloride (Cl)||Molybdenum (Mo)|
Soybeans have a large requirement for nitrogen but can obtain the majority of this from the air via Rhizobium bacteria forming nodules on their root system. Soybean seed needs to be inoculated with Group H rhizobia to get effective nodulation and ensure adequate nitrogen nutrition to the plant. Rhizobium bacteria need low nitrogen soils for optimum effectiveness and soybeans are grown after cereal crops rather than pasture provide these conditions.
Once established the nitrogen-fixing bacteria (rhizobia) in the root nodules can supply soybean plants with all their nitrogen requirements, provided soil mineral N is low. Soybean N fixation tends to decrease as soil mineral N increases, as the plant prefers to accumulate ‘easy’ soil nitrate rather than support rhizobium to fix atmospheric N2. High mineral N in the early stages of crop establishment can delay early nodule development (possibly causing an N deficiency when the soil N runs out and the plant has to then allow nodules to develop), while mineral N late in the season (e.g. from a decomposing cane trash blanket) can prematurely shut down N fixation but also contribute to high yields and grain protein.
A small amount (up to about 15 kg of N per hectare) of ‘starter’ nitrogen may be beneficial when the crop is sown into high crop residue loads with high C: N ratios (e.g. wheat straw or sugarcane trash), as the establishing soybeans, need some soil N to grow while nodules are developing. Another situation where some starter N may benefit is in late sown crops, as it helps to ensure good early growth of seedlings and adequate height to the lowest pod. Care must be taken not to apply too much starter N as this will raise soil mineral N concentrations and have a detrimental effect on the growth of nodules that supply nitrogen to the plant later in its growth cycle
Nitrogen is especially necessary if one or more of the following conditions occurs:
- Crops do not have a uniform dark green colour throughout the field (but their colour does not contain signs of chlorosis)
- Acidic soil (soil pH below 5.5);
- Low organic matter, soil eroded or compacted;
- Active nodules (dark pink in the centre) on the roots are absent or few
- Soybean was not inoculated, there are symptoms of nitrogen deficiency.
Phosphorus plays an important role in soybean production. The soy fertilizer system, like any other crop, consists of three application methods: main, sowing and top dressing, and, most importantly, their correct combination.
The critical period for phosphorus for soy is the first month of life, for nitrogen – 2-3 weeks before flowering and 2 weeks after flowering. The lack of nutrients in these periods leads to a noticeable decrease in soybean productivity and cannot be compensated by the introduction of fertilizers in the later phases of plant growth and development.
Soybeans require large amounts of potassium (K) to achieve good yields and so soil K-status is important. Soils that have low exchangeable K-levels prior to planting (i.e. <0.3 meq/100g) are likely to respond to K-fertiliser applications. In coastal areas with sugarcane-dominant cropping systems, K is usually one of the main nutrients required for good soybean growth during a fallow. Soybeans are capable of accumulating large amounts of K in the plant material (100- 150 kg K/ha), and if the soil K-status is good, this accumulation may be well in excess of the minimal requirements for growth and yield.
Boron is important for pollen tube growth and pollen grain germination. Thus, its deficiency leads to low flower set and malformation of soybeans grains. Boron deficiency causes malformation of the pollen tube and results in an increase of flower abortion, thus reducing soybean yield potential. Therefore it very important nutrient to ensure a good yield. Flower abortion can cause low seed production because there are no seeds in the pods that would have been formed if the flower had not been aborted. Flower abortion can also give rise to flat or empty pods which reduce yields
As a secondary nutrient, sulfur (S) plays a critical role in the growth and development of high-yielding soybeans:
- Necessary for optimum growth during the vegetative and reproductive stages
- Required to fixate nitrogen from the soil
- Plays a large role in soybean seed development and the photosynthesis process
- A part of every living cell and is important to the formation of proteins
One of the difficult things with sulfur is that it’s often found in insufficient quantities for the needs of high-yielding crops, which is where supplementing becomes important.
learn More About Soybean
- Soybean Flower Abortion its Causes and Solution
- Insect pest of soybean and Their Control
- Characteristics and Uses of Soybean
- Maize Soybean Intercropping | Different stages view | UAF | Faisalabad | Pakistan