MSc.

The experiment entitled “Silicon and boron nutrition of rice (Oryza sativa L.) in wet land soils of northern Kerala” was carried out to standardize the dose and method of application of silicon and boron to rice crop in paddy soils, to evaluate its effect on available nutrient status and yield and to study the effect of silicon in alleviating the toxicity of Fe, Mn and Al in laterite derived paddy soils.
The treatments were a combination of boron source as borax (soil and foliar application) and silicon sources as calcium silicate (soil application) and potassium silicate (foliar application). Two experiments, a pot culture and a field experiment were conducted with rice variety Aishwarya as the test crop.
Application of silicon and boron fertilizers improved the availability of silicon and boron in soil. Soil application of calcium silicate along with borax was superior in maintaining the available silicon and boron status of soil than foliar application of potassium silicate and borax.
The study revealed that the application of silicon and boron as soil and foliar application had a synergistic effect on the availability of N, P, K, Ca, Mg, S, Zn and Cu in the soil.
Application of silicon as foliar application of potassium silicate 0.5 % along with borax 0.5 % spray was effective in reducing iron toxicity in the soil while the use of calcium silicate 100 kg Si ha-1 and borax 10 kg ha-1 proved to be more effective in reducing manganese and aluminium toxicity in the soil.
The content and uptake of N, P, K, Ca, Mg, and S in rice were significantly improved by the application of potassium silicate 0.5 % foliar spray along with borax 0.5 % spray 3 rounds.
Foliar application of silicon and boron as potassium silicate 0.5 % spray and borax 0.5 % spray was more efficient on improving the content and uptake of silicon and boron compared to soil application of calcium silicate and borax.
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Application of potassium silicate @ 0.5 % spray + borax 0.5 % spray 3 rounds was significantly superior with respect to yield and yield attributes of rice.
In a nutshell, both the pot and field experiments clearly indicated that application of Si and B significantly improves the available nutrient status of soil, nutrient uptake, grain and straw yield of rice. Foliar application of potassium silicate and borax (0.5 % each) 3 rounds at 15 days interval significantly improved the available nutrient status of soil, yield and yield attributes of rice. It was also effective on alleviating toxicity of Fe, Mn and Al in laterite derived paddy soils