by Christopher Teh Boon Sung, Fac. of Agriculture, Uni. Putra Malaysia, Serdang ([email protected])
How you manage your soil is very important. Even a low fertility soil can be made very fertile with proper soil management, and a soil, though initially very fertile, can degrade into a problematic one due to soil mismanagement. Below are five general key steps to have a healthy soil.
You need to determine what kind of soil you are using and its current fertility status. This information is vital to better manage your soil, particularly on how much and what type of fertilizers to apply. There are several soil testing labs to which you can send your soil samples. My faculty also has such facilities for soil testing. You should test your soil at least on the following: pH, organic matter, and major plant nutrients particularly nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg).
Malaysian soils are typically strongly to very strongly acidic, having pH values between 3 to 5. At these levels, the nutrients in the soils are less available for your plants. To make these nutrients more available, you need to raise your soil’s current pH level to about 6 to 6.5. Typically, about 600 g of lime should be added to every one square meter ground area. You can get lime in the form of hydrated lime (calcium hydroxide) or dolomite.
Adding organic matter to soils will virtually improve all soil properties. When organic matter is applied to the soil, the organic matter will decay, gradually releasing its nutrients. Soils rich in organic matter are more resistant to erosion, retain more water and nutrients for plant use, and encourage more soil microbial life. Organic matter can be applied in the form of compost or mulch. Several websites and even online videos show how you can make your own compost. Making your own compost is easy, is not expensive, and does not require any sophisticated equipment. Mulch, on the other hand, is the application of plant materials like leaf litter, twigs, and other plant waste materials on the soil surface. You should not apply more than 10 to 12 kg of organic matter per one square meter ground area.
One of the most common mistake gardeners do is to apply too much fertilizers. This often occurs when gardeners “experiment” with various types of fertilizers. Adding too much fertilizers can be worse than applying too little because correcting nutrient toxicity is much more difficult than correcting for nutrient deficiency. You should apply the fertilizers in the recommended amounts and time. Different plants require different types and amount of fertilizers, and you should refer to the internet (particularly from credible university sources) for such information for your specific plants.
Different plants require different amounts of water, but generally, plants only require about five liters of water per one square meter ground area per day. It is easy to over water our plants, and over watering causes root rot (often fatal to plants) and excessive nutrient losses where the soil nutrients are washed out. If you tend to over water, your soil should be freely draining so that the excess water can easily flow out, without risking root rot. But freely draining soils tend to more easily dry out, causing water stress for plants grown in such soils.
Finally, you need patience. Building up soil fertility takes time and often requires multi pronged approach.