Statement I: Incorrect.
The Krishi Parasaram is an ancient text on agriculture but it doesn't focus on the classification of forests.
Statement II: Correct.
Hieroglyphics were used in ancient times to depict agricultural practices and crop plants through symbolic pictures.
Statement III: Correct.
Both Jatropha and Pongamia are biofuel plants rich in hydrocarbons, which makes them suitable for biodiesel production.
Statement IV: Incorrect.
C.G.K. Ramanujan is not associated with the study of urease crystallization. That work is credited to James B. Sumner.