NEW YORK (TheStreet) -- A drought in Russia has hammered wheat production and the crop just saw its largest one-month gain in more than 50 years. Agricultural ETFs such as PowerShares DB Agriculture (DBA - Get Report) are benefitting from the move and a broader move in soft commodities.

Investors with a penchant for commodities may find that, in preparation for the expected slowdown in economic recovery worldwide, now may be an opportune time to move away from funds focusing on industrial metals and into investments in the agricultural sector.

Since I do not advocate for investment in individual agricultural commodities, as their performance is often too volatile for most investors, an ETF that provides broader exposure to multiple agricultural commodities, such as PowerShares DB Agriculture Fund , is a better approach. I recently added it to the portfolio in my ETF Action Newsletter.

DBA has gone up by 7.8% in the past month, roughly in line with the S&P 500, and has outperformed the S&P 500 in the past three months. However, on a year-to-date basis the fund underperformed the broader U.S. equity indices.

Commodities that DBA tracks include wheat, soybeans, sugar, coffee, and livestock. The strong performance of wheat and sugar, in particular, help explain the fund's move higher in July and the past three months.

Looking at the performance of sugar, as reflected by iPath Dow Jones-AIG Sugar Total Return Sub-Index ETN ( SGG), shows a steep increase in July, followed by a steep fall since the start of August. This helps explain why DBA has stalled somewhat this month.

Speculation that top producing nations such as Brazil and India are increasing production of sugar also contributed to stiff declines after a prior period of solid gains.

Dow Jones-AIG Grains Total Return ETN ( JJG) also saw an impressive July, and although it has not dropped off since the start of August like SGG, it has flattened out. This is due to the relatively stable soybean prices, which make up nearly 40% of the fund. Much of JJG's gains came from the explosion in wheat prices, which continue to rise, with another 4% gain in morning trading today.

The trend behind the rise in wheat is expected to continue, which should help DBA's forward momentum (wheat makes up 12.5% of DBA's index). Supply reductions from Canada, as well as a continuation of bad weather in Europe, most notably a severe drought in Russia, will hurt the supply of wheat and could continue to drive prices higher.

The drought's severity has incited talk of a Russian ban on grain exports, in order to allow suppliers to prioritize domestic contracts over international demand.

The drought has helped fuel a tremendous jump in wheat prices, the largest monthly gain (of more than 40 percent) since 1959. Worse still, the drought looks to continue well into the season, threatening winter wheat production. All in all, this climatic anomaly may have an effect on prices further down the line, as the drought cripples future yields as seed-planting periods for future harvests fast approach.

Over the short term, corn is also in low supply and strong demand, a situation that may provide DBA with long-term support as well. Ethanol continues to receive government support and since corn is the main ingredient in the production of this fuel, an increase in its usage could drive up the long-term prices of corn.

Investors should be aware that the performance of agricultural commodities can change at a lightning pace, such as when a weather report for a region changes. For investors that don't want to get burned by a shift in the weather or market conditions in a single crop, DBA is a safer way to play the generally positive outlook for agricultural commodity prices.

-- Written by Don Dion in Williamstown, Mass.

At the time of publication, Dion Money Management was long PowerShares DB Agriculture.

Don Dion is president and founder of Dion Money Management, a fee-based investment advisory firm to affluent individuals, families and nonprofit organizations, where he is responsible for setting investment policy, creating custom portfolios and overseeing the performance of client accounts. Founded in 1996 and based in Williamstown, Mass., Dion Money Management manages assets for clients in 49 states and 11 countries. Dion is a licensed attorney in Massachusetts and Maine and has more than 25 years' experience working in the financial markets, having founded and run two publicly traded companies before establishing Dion Money Management.

Dion also is publisher of the Fidelity Independent Adviser family of newsletters, which provides to a broad range of investors his commentary on the financial markets, with a specific emphasis on mutual funds and exchange-traded funds. With more than 100,000 subscribers in the U.S. and 29 other countries, Fidelity Independent Adviser publishes six monthly newsletters and three weekly newsletters. Its flagship publication, Fidelity Independent Adviser, has been published monthly for 11 years and reaches 40,000 subscribers.