"Investing in agriculture-related companies has been one of our main themes for the past year, and we still favor it," say resource experts Roger Conrad and Yiannis Mostrous.

The co-editors of Vital Resource Investor note, "We're adding a new stock to the portfolio that should benefit from the increasingly higher global demand for fertilizer: Potash Corp. (NYSE: POT).

"Potash is the world's largest and lowest-cost publicly traded potash producer, the fastest-growing segment in the fertilizer business. Its potash reserves are sufficient for more than 100 years of production.

"The company controls about 70% of the world's excess capacity. Potash Corp is also the world's third-largest phosphate producer and fourth-largest nitrogen producer. Current phosphate reserves should last more than 50 years.

"As incomes around the world rise, so does demand for food; and the explosive growth in population is aggravating the situation even further," note Yiannis Mostrous and Roger Conrad.

The co-editors of Vital Resource Investor explain, "The big cycle in food demand has begun, and long-term-oriented investors will be rewarded handsomely." What's the best play? Among their favorites is Monsanto (NYSE: MON).

"Monsanto is the undisputed leader in the genetically modified (GM) seed industry. Its business consists of two segments: Seeds/Genomics and Agricultural Productivity.

"The Seeds/Genomics segment consists of the company's global seeds and traits business, and genetic technology platforms, including biotechnology, breeding and genomics.

"The Agricultural Productivity segment consists primarily of crop protection products, residential lawn-and-garden herbicide products, and the company's animal agricultural businesses.

"Monsanto shares have been affected by the market's shorter-term gyrations, but the underlying business is extremely healthy. In fact, the seed business is currently in a sweet spot as global food demand changes dramatically.

"People want to own more gold when there's a perception of growing global economic and political turmoil," explain resource experts Roger Conrad and Yiannis Mostrous.

In their Vital Resource Investor, the advisor offer their long-term bullish assessment for gold as well their favorite gold mining stock: "Goldcorp (NYSE: GG).

"Every commodity bull market eventually ends when consumers permanently reduce demand with conservation and switch to alternatives, and the producers ultimately over-expand. This, however, only happens over a period of many years.

"To be sure, we've seen demand in the US drop for many vital resources, from copper to energy, as the economy has slowed. Demand from developing nations, however, remains entrenched by necessity, as these suddenly more affluent nations struggle to upgrade their vital infrastructure.

"And although we may see Chinese economic growth slow from its current off-the-chart 10% rate, that country will still face critical needs to build out its cities to meet the millions of new migrants that come every year. And that's a huge call on raw materials.

Resource industry specialists Roger Conrad and Yiannis Mostrous are bullish on the agriculture and water sectors; in their model portfolio they already hold 6 stocks in these sectors.

The co-editors of Vital Resource Investor explain, "We see strong underpinnings for continued higher agricultural prices for many years to come." Here's their latest agrculture play: EI du Pont de Nemours (NYSE: DD).

"Recently the United Nations Food Agency warned of civil war in some countries because of global food shortages. With the rapid urbanization of Asian countries, we see a growing global dependence on a shrinking number of food producing nations, particularly with the world adding 78.5 million people each year.

"There will be ups and downs for prices along the way. A throttling back of America's efforts to develop ethanol so extensively or a move to use something besides corn to brew ethanol could take some of the upward pressure off corn prices.

"A real global recession could also cause food prices to back off for a time and it's also possible we'll see some form of US government intervention to curb food prices, particularly as the presidential election develops.

"There's no doubt about it: vital resources are in a bull market of gigantic proportions," note Yiannis Mostrous and Roger Conrad.

"The co-editors of Vital Resource Investor caution that "no market moves in a straight line, and in commodities, the action is often extremely violent." However, for long-term investors, they offer some favorites in iron ore, aluminum and copper.

"All commodity bull markets are ultimately gored by demand destruction, alternatives and new supply. But it will almost certainly be years before that happens to this one. And that means plenty of money will be made along the way.

"We're still extremely bullish on iron ore as the market remains in deficit and prices continue to rise. Chinese domestic supply has been falling and, if this continues, imports will make up the difference, thereby helping the miners.

"China consumes 51% of the world's iron supply. Portfolio holding Companhia Vale do Rio Doce (NYSE: RIO), the world's largest iron ore producer, will benefit from the shortage in iron ore supply.

"We favor aluminum in the industrial metals sector. We've been advocating aluminum for some time, and the market's finally going our way. Aluminum prices have been impacted by lack of available power in China and South Africa and higher alumina and bauxite prices.