The effects of Lake Ol’Bolossat’s Sediments Application on the Productivity of Swiss Chard (Beta vulgaris L.), and Soil-Chemical Characteristics

Abstract

Sediments dredged from the lakes have emerged as successful soil amendment solutions, especially in alleviating soil fertility in poor soils. This study aimed to assess the effect of deposits from Lake Ol'Bolossat on soil quality and the growth, development, and yield of Swiss chard (Beta vulgaris L.). A pot experiment was carried out in 2020 in a polyethylene greenhouse using a completely randomized design at the Jomo Kenyatta University of Agriculture and Technology main campus, Juja. Swiss chard (Ford hook) giant variety was grown in experimental pots. To achieve the study’s objective, several treatments were applied; (T1)- Sediments from lake depth of 0-30 cm + forest soil, (T2)- Sediments from lake depth of 30-60 cm + forest soil, (T3)- Sediments from lake depth of 60-90 cm + forest soil, (T4)- Inorganic fertilizer (NPK 150kg acre^-1) + forest soil, (T5)- forest soil with no lake sediments or inorganic fertilizers which acted as the control experiment. The sediments were mixed with forest soil at a ratio of 1:4 (lake sediments: soil). The experiment was carried out between January and April, and repeated between July and October the same year.

The results of the study showed that the lake sediments had a significant impact on the soil major nutrients. After soil amendment, T1, T2, and T4 resulted in a significantly higher N value than T3 and T5. Phosphorous and potassium were significantly higher in T1 in the two growing seasons, followed by T4 and T2. Nitrogen and Phosphorus were in significantly lower quantities in T3 and T5, and Potassium was in significantly lower quantities in T5. Total Organic Carbon values were significantly higher in treatments with lake sediments. T4 treatments had lower pH values and higher E.C. than treatments with lake sediments.

This study also showed that plant height, leaf length, leaf width, number of leaves, and Swiss chard dry matter were significantly higher in T1 and T2 in both growing seasons. The lake sediments obtained from 0-30cm and 30-60 cm depth showed a positive impact. It resulted in better productivity and subsequently higher dry matter of Swiss chard compared with the productivity of Swiss chard grown using lake sediments from 60-90 cm depth. The study demonstrated that sediments play an essential role in improving the productivity of Swiss chard and the quality of agricultural soils.