Impact of Organic Fertilizers on Plant Growth

By Julio P. Yap Jr.

A graduating agriculture student conducted research on the production and shelf life of lettuce (Lactuca sativa L.) and found out the impact and beneficial effects of using vermicompost coupled with amino foliar fertilizer in relation to the plant’s growth and development.

The study focuses on the impact of organic fertilizers in the growth and productivity of lettuce plants. The Lollo Rossa variety was used in the study.

Bernadette Capa Cacho, who will receive the degree of Bachelor of Science in Agriculture from the De La Salle Araneta University at the Salikneta Farm, Upper Ciudad Real, San Jose del Monte City in Bulacan, conducted the study. She says that this became possible through the support provided by her adviser, Dr. Pedrito S. Nitural.

Procedure

A single factor experiment arranged in Randomized Complete Block Design (RCBD) with six treatments and three replications was used in the study. Results of the study revealed that lettuce applied with vermicompost and supplemented with Amino Plus Foliar Fertilizer (APFF) produced the tallest plant at harvest (17.38 centimeters or cm), most number of leaves (9.00), longest (14.98 cm) and widest (12 cm) leaves per plant, as well as the highest yield per plot (2.96 kilograms or kg).

On the other hand, lettuce applied with vermicompost and APFF has a longer shelf life, whether under ordinary room temperatures or inside the chiller of a refrigerator.

Cacho’s research included soil analysis of the experimental plots, pricking of lettuce seedlings in plastic seedling trays, preparation of experimental plots, basal application of vermicompost on the experimental plots, transplanting of lettuce seedlings, watering of experimental plots, weeding, application of APFF, harvesting, and post-harvest handling under room temperature and inside the refrigerator (chiller). The Lollo Rossa variety of lettuce was used in her study. The variety is characterized by having a distinct compact rosette of blood violet fan-shaped leaves with a non-hearting pale green base, says Cacho.

Importance of the Study

Lettuce is one of the world’s most important salad crops, and in order to achieve the highest productivity of lettuce as well as to prevent pest infestations and diseases that will cause reduction of yield, supplemental application of nutrients is needed.

Nowadays, the cost of commercial fertilizer is constantly increasing, and vermicompost can be a good substitute for, or a supplement to supply, the nutrients needed by plants at a much more affordable cost.

According to Cacho, the study was conducted to gain information about the supplementation of APFF at varying levels of vermicompost that can be used by farmers who want to venture in lettuce farming.

Weeds growing in the experimental plots were immediately removed by hand-pulling to keep the area clean.

Growing lettuce is very easy, she says. But to achieve good yields, proper cultural management practices must be practiced and the right amount of fertilizer should be provided.

High production costs due to the increasing cost of commercial fertilizer is one of the main problems of small scale farmers. Cacho says that one way to solve this problem is to apply organic fertilizers through the use of vermicompost. In lettuce production, vermicompost can be used as organic fertilizer. It improves the soil structure by increasing porosity and reducing the bulk density.

Pest Management 

No chemical spraying was used in this study. Larvae of the common cutworm that were observed to be attacking the plants were collected.

On the other hand, weeds growing in the experimental plot were immediately removed by hand-pulling to keep the area clean and to prevent the weeds from competing with the main crop for nutrients, water, sunlight, oxygen, and other abiotic factors that affect the growth and development of lettuce.

Harvesting

Lettuce plants were harvested 25 days after transplanting by gently pulling the plants from the experimental plot; the roots were cut and washed in tap water to remove the soil adhering to them.

Results of the study appeared to show that lettuce plants are relatively good users of the nutrients NPK (nitrogen, phosphorus, and potassium). The number of leaves produced per plant was greatly influenced by the application of vermicompost supplemented with APFF at weekly intervals.

It is probable that the lettuce absorbed a sufficient amount of nutrients supplied with vermicompost which was enhanced through the application of APFF.

Soil Productivity

Nowadays, an alarming problem is the gradual reduction of the yield of crops due to deficiencies in the soil organic matter. The cost of inorganic fertilizers is very high and sometimes it is not available in the market; hence, farmers fail to apply inorganic fertilizers to a crop on time.

Application of organic material prevents erosion, cracking, and crusting. It also helps retain soil humidity and improve soil internal drainage. Crops fertilized with organic matter have greater resistance to pests and diseases. The humus acid and growth substances are absorbed into the plant tissue through the roots and they favor the formation of proteins by influencing the synthesis of enzymes that will increase the vigor and insect resistance of the plant.

Cacho says the purpose of foliar feeding is not to replace soil fertilization. Supplying a plant’s major nutrient needs (NPK) is most effective and economical via soil application. However, foliar application has been proven to be an excellent method of supplying plant requirements for secondary nutrients (calcium, magnesium, sulfur) and micronutrients (zinc, manganese, iron, copper, boron, and molybdenum).

As APFF contains compounds that promote plant growth and does not contain toxic or carcinogenic materials, it is a good source of fertilizer. It is high in L-Amino acids that are easily absorbed by plants. It also contains effective microorganisms that have long-term beneficial effects on the physical, chemical, and biological condition of the soil.

This appeared in Agriculture Monthly’s February 2018 issue.