Overall Summary for Sengkuang

OVERALL SUMMARY FOR SENGKUANG

1. Observation of Sengkuang in four-week observation.

Figure 1: Average height of sengkuang in different soil sample

Figure 1 shows the average height of five different types of soil on a four- week observation. The five soils are soil samples from FSSA, PPIB, Mengkabung, Tepi Tasik and Tepi Tasik 2. The line graph of soil FSSA, PPIB, and Tepi Tasik shows a drastic increase of average height from week 1 to week 3 while the Sengkuang in Mengkabung does not show any sign of germination thus have no increase of average height from week 1 to week 4.

Sengkuang, or the Mexican turnip grows best in mildly acidic soil, ideally from pH 6.00 to pH 7.00.  As for soil texture, Sengkuang flourishes in sandy loam soil. The pH for soil FSSA is 6.00 which is mildly acidic and it has soil texture of sandy loam, which is very ideal for the growth of Sengkuang. This explains why the line graph of average height of Sengkuang in soil FSSA is the highest. pH of soil from Mengkabong is 3.00, which is extremely acidic and has soil texture of clay loam, thus no germination took place. 

Figure 2: Germination rate of sengkuang in different soil sample

Based on the Figure 2, the graph shows the germination rate of Sengkuang in different types of soil. There are 5 types of soil which is from Tepi Tasik FSSA, Mengkabung, FSSA, PPIB, dan Tepi Tasik FSSA 2. According the result, the highest germination rate is 33.33% which is from the FSSA soil while the lowest germination rate is from Mengkabung soil which is 0%. Besides that, the seeds from Tepi tasik FSSA and PPIB show the same germination rate at the fourth week. From the result, we can assume that the FSSA soil is the most suitable soil type for the Sengkuang to growth.

The conditions required for growing different root crops are all basically the same.
Sengkuang, or the Mexican turnip should be grown in full sun. They should be planted in deeply cultivated, well-drained but moisture retentive soil. Root crops will not tolerate alkaline soil, nor strongly acidic soil.

Turnips grow best in well-structured sandy loam. Loam is soil that contains roughly an equal amount of sand, silt and clay. Sandy loam has slightly more sand than silt and clay. Particles of sand, silt and clay come together in the soil to form what are called aggregates. If you dig up well-structured soil, it will break down into whole aggregates and broken aggregates but not individual particles. If the soil contains too much clay, it will cling to the roots. The types of soil determine the soil aeration and soil compaction. Soil aeration is an important factor in the normal growth of plants. The supply of oxygen to roots in adequate quantities and the removal of CO2 from the soil atmosphere are very essential for healthy plant growth. 

Soil compaction is the reduction of soil volume due to external factors; this reduction lowers soil productivity and environmental quality. Loamy soils or clay has fewer particles, thus easily compacted than soils with more particles.

The soil texture in soil FSSA is sandy loam. Sandy loam soils have visible particles of sand mixed into the soil. When sandy loams soils are compressed, they hold their shape but break apart easily. Sandy loam soils have a high concentration of sand that gives them a gritty feel. The particles in sandy loams give the soil a good aeration, and have very low soil compaction thus allow the root growth of the Sengkuang to flourish. 

Soil texture in soil PPIB is loamy fined sand. This type of soil is almost similar to sandy loam, only sandier meaning it has more particles. Sandy soils are light, dry, warm, low in nutrients and often acidic although it has good aeration because of the soil particles, it also means that the soil can tend to absorbs and dissolves in chemicals, thus root growth in this type of soil proves to be tricky.

Soil texture in soil Mengkabung is Clay loam. Clay loam is heavier, wet and cold in cold temperature and tends to baked dry in hot temperature. This type of soil has few particles, meaning it has poor aeration and tend to compact easily. It will be hard for the Sengkuang root grow as the soil is very denser.

Soil texture in soil Tepi Tasik is loam. Loams are mixtures of clay, sand and silt that avoid the extremes of each type. Loam soil has average air particles and average compaction. Most plants flourish in loam soil, but sengkuang prefer sandy loam, so loam would be a little bit compacted for root growth of sengkuang.

Tepi Tasik 2 has the same soil texture as FSSA, which is sandy loam-the perfect soil for growing a Sengkuang. However, the growth of Sengkuang in Tepi Tasik 2 soil is not as great as FSSA and this may be due to other factors, such as soil pH.

Soil texture is the relative proportion of sand, silt and clay found in the soil. This relative fraction of the soil is important because it can determine factors such as soil water, soil aeration and also soil compaction.

Clay particles are small and close to each other. Clay soil also has a high water holding capacity. As they are absorbing water, the particles are expanding. This will cause them to have a heavy mass and be heavily compacted with a few amounts of large pores. Hence, it is difficult for air, water and plant roots to move through the soil. This also causes it to have a poor aeration with a slow gases exchange process and must be loosened to support healthy root growth. This is why there is no growth in Mengkabong soil because it contains high amount of clay particles.

Loamy soil is made up of clay, silt and sand in fairly even amounts which means it has a good proportion for growing most of the plants. This type of soil can drain well, retain the right amount of moisture for the growth of root plants and are nutrient rich. But loam is a quite heavy soil that makes the compaction is likely to occur in it. When it is compacted, the soil aeration of loam is poor for the air movement required for root growth. This makes the soil from Tepi Tasik FSSA has low germination rate and also make it hard to measure its root length because of the low average height of the plant.

Sand particles are generally round and large. This makes sandy soil tend to resist compaction and has more space for water and air to go through the soil. With a large air space between the particles, sandy soil provides a good aeration for the root growth. The roots also are able to move through the pores in the soil as they are growing. Thus, this is why the soil with high amounts of sand particles is able to growth sengkuang plant and their length of root is able to measure. The soils with good root growth are from PPIB, FSSA and Tepi Tasik FSSA 2. Their soil textures are loamy fined sand and sandy loam respectively.

Figure 3: The graphical representation of a comparison between result from pH paper and pH Meter.

Based on the graph, the soil sample from the FSSA has the highest pH soil value compared to other soil sample. The lowest which is Mengkabung shows that this soil sample has the most acidic soil compared to other soil sample. PPIB is the second highest pH value among the soil sample and both Tepi Tasik and Tepi Tasik 2 is the fourth highest as their pH value are nearly similar.

The availability of some plant nutrients is greatly affected by soil pH. Based on the highest result of pH soil is from FSSA, it showed that pH value of FSSA is 6 which are slightly acid. It has been determined that most plant nutrients are optimally available to plants within this 6.5 to 7.5 pH range, plus this range of pH is generally very compatible to plant root growth. Nitrate (NO3-), the nitrate uptake system in plants must be versatile and robust because plants have to transport sufficient nitrate to satisfy total demand for nitrogen in the face of external nitrate concentrations that can vary by five orders of magnitude. To function efficiently in the face of such environmental variation, plants have evolved a transport system that is active, regulated, and multiphasic. For phosphate nutrient, Soil phosphate (PO4) is quite pH dependent. Plants take up soluble PO4 from the soil solution, but this soluble PO4 pool tends to be extremely low, often less than one lb./ac. For nutrient of sulphate it got over reading or an error during the nutrient analysis, but Sulfate (S042-) sulfur, the plant available form of S, is little affected by soil pH.

Based on the lowest result of pH result is from Mengkabung, it showed that pH value of Mengkabung is 3 which are most strongly acid. Strongly acid is not for growth of plant and soil organism. The soil pH also influences plant growth by its effect on activity of beneficial microorganisms. Bacteria that decompose soil organic matter are hindered in strong acid soils. This will prevent organic matter from breaking down, resulting in accumulation of organic matter and tie up nutrients, particularly nitrogen, that are held in the organic matter.

Finally, To get a better germination of seeds, it is important to choose a location with a full sun which means direct sunlight is available for at least six to eight hours per day to support the growing of its vine. Bottom heat also is needed because the seeds require warm temperatures to germinate. Sengkuang grow best in moist but well-drained soil. Water the plant daily and it is highly recommended to not overwatering the plant as this will affect the germination of seed. Hence, it is important to choose a suitable soil texture to grow sengkuang especially the one that has a good drainage.

Based on the data that we obtained, the best soil texture for growing sengkuang is sandy loam. Sandy loam is known for being a good soil to plant the root vegetables, and sengkuang is one of them. Sandy loam has a good texture, without heavy clods of clay or accumulations of rock. Sengkuang need a good drainage, good aeration and a non-compacted soil that help in germination of seeds. Thus, sandy loam is a good choice because it has a high amount of large pores that help in the movement of water, air and roots in the soil.

After a month, the germination rate in Mengkabong soil is still zero. Therefore, we suggest that in order to get better germination rate of sengkuang, avoid using a clay loam soil as what the Mengkabong soil is because clay loam soil composed of mostly clay particles and offers an unfavourable growing environment for most of the plants including sengkuang. Clay has high water holding capacity and it drain water slowly. It also lack in large pores that causes poor soil aeration with a slow gases exchange process. This will affect the germination of seed because the   process is just too slow.

Based on background research, we found that suitable soil pH for growing sengkuang is acidic, neutral and basic. But from what we had observed in the data, sengkuang can grow in the soil with pH from 4 to 6. It grew best in soil pH 6 which is near to neutral. Thus, we suggest using soil with pH 6 to get better germination of seed. Nutrient rich soil is needed to grow a good sengkuang plant. Nutrient rich soils contain phosphate and other nutrients such nitrogen and potassium. Those nutrients are vital nutrient for plant growth, development and reproduction. Hence, soil with sufficient amounts of nutrient can help in increasing the germination of seed of sengkuang.

In conclusion, the soil samples used in this experiment are safe for growing sengkuang except Mengkabong soil. This is because Mengkabong soil is composed of mainly clay particles which are quite not suitable for growing sengkuang. Its soil pH is 3 which is too acidic. Although nitrogen is a good nutrient in the soil, low level of nitrogen is needed in order to grow a tuber of sengkuang. This is because nitrogen encourages foliage growth at the expense of the tubers. The above ground parts are poisonous so any parts of the sengkuang plant other than the tuber should not be eaten. Mengkabong soil has the highest level of nitrogen compared to the others. Thus, it is not safe to be used to get a nice tuber to be eaten.