News Release

I did a soil diagnosis

June 14, 2022

June 14, 2022

I did a soil diagnosis


Satake is a post-harvest machinery manufacturing industry. Nonetheless, we show interest and give support to the primary production of plant-based foods. Since the first stage of food production is cultivation and harvesting, our company launched "Satake College" in 2006, where young employees are taught rice cultivation through classroom lectures and hands-on training.

Unlike animals, plants such as rice cannot move about to obtain food, hence the soil is important for their growth. Even so, we do not know much about what happens in the soil beneath our feet. My hobby is vegetable gardening. I used to think that if a person plants seeds in the soil and watered them, the plants must grow. However, after several years of doing this, I found that examining and improving the soil is very crucial for cultivation. This is called "soil diagnosis". There are three types of soil diagnosis: physical, chemical, and biological. In this article, the basic physical diagnosis of my style is explained. Basically, what I do is to "dig", "look", and "touch". The purpose of the soil diagnosis is to ensure an optimal condition of the soil in which the young plants were grown.

The soil layer in which humans work to help plants take root is called the top soil layer. The appropriate depth is said to be 15 cm for rice cultivation and 25 cm for fields (deeper for root crops). In my case, it is a field, so I dug about 30 cm deep.


When observed, the soil looks darker up to about 15 cm. This shows that there is a lot of organic matter. It is assumed that compost has been applied to grow vegetables without pesticides and chemical fertilizers, which has been effective. However, I found that up to 25 cm of the crop soil layer has not turned black, and around 30 cm is brown. This is called hardpan, which is soil that is difficult for roots to penetrate, which needs to be broken up.

Soil hardness is closely related to rooting. An easy way to check is to poke it with a finger. A soft soil allows roots to easily penetrate and take up water and nutrients to the plant shoot.


On the other hand, around 25 cm, a little more than the first joint of my finger could get in to the soil. At this hardness, it is difficult for the plant to take root and absorb water and nutrients as it grows larger. This physical diagnosis revealed that there was not enough organic matter in the field down to 25 cm of the crop layer and that the soil was hard. The soil needs to be improved here. My prescription is to till well and add compost material. I am looking forward to growing vegetables in the future.