* Wheat down 1.6% this week on improved weather across U.S. Plains
* Soybeans down after four weeks of gains, corn falls for 2nd week (Recasts with move in wheat prices, adds quote in paragraph 3)
By Naveen Thukral
SINGAPORE, March 12 (Reuters) - Chicago wheat futures were little changed on Friday, with the market set for a second straight weekly decline as expectations of improved weather across the U.S. Plains weighed on prices.
Soybeans lost ground and were on track to end the week with losses after climbing for the last four weeks. Corn fell and is poised for a second weekly drop.
"The upcoming rainfall to the U.S. Hard Red Winter wheat regions, including the very western third, continues to weigh on prices," said Tobin Gorey, director of agricultural strategy at the Commonwealth Bank of Australia in Sydney.
The most-active wheat contract on the Chicago Board Of Trade (CBOT) Wv1 has lost 1.6% this week, the second straight weekly loss. The market was unmoved at $6.42-1/2 a bushel by 0302 GMT.
Soybeans are down 1.3% for the week, their first weekly loss in five and the biggest slide in nearly two months. Corn Cv1 is down 1.8%, its second straight weekly fall.
Weekend storms are set to soak the U.S. Plains wheat belt, much of which has endured dry conditions for several months.
The region's winter wheat is just starting its key spring growth phase, when the crop's need for water increases.
Losses in the soybean market were curbed by South American crop worries.
The Buenos Aires Grains Exchange lowered its estimates of Argentina's soybean harvest to 44 million tonnes and its corn forecast to 45 million tonnes, below its previous forecasts of 46 million tonnes for each crop, citing dry conditions. funds were net buyers of CBOT corn, soyoil and soybean futures contracts on Thursday and net sellers of wheat and soymeal futures, traders said. COMFUND/CBT