If demand for agricultural prods is inelastic, a small increase in supply will cause...?

True - Any increase in supply will cause prices to decline, so the first part of the question is true. Price inelastic demand means that the percent change in demand is smaller than the percent change in price. Let's say the initial condition was such that the price was 5, demand was 200 and revenue was $1000. Let's also say that the increase in supply caused the price to drop to 4.5, a 10% decline. Holding with the condition of price inelastic demand the largest increase in demand is to 219 (a 9.5% increase), at the new price and demand farm revenue is 219*4.5 = $985.5. This is an illustration of why it is safe to raise prices if demand for your good is inelastic.