(parties are neighboring ranchland owners with drainage ditch running from plaintiff’s property to defendant’s property; defendant allowed cattle to tromp in dirt such that ditch backed-up and flooded plaintiff’s hay meadow causing significant damages for plaintiff; state court found defendant in violation of state law which required defendant to clean out ditch on annual basis in accordance with grade at or below level of bottom of road culvert installed by county in 1988; in retaliation, defendant got USDA to investigate potential Swampbuster violations of plaintiff due to flooded meadow; U.S. Court of Appeals for Eighth Circuit ruled for plaintiffs holding that plaintiffs were entitled to use meadow as they did before effective date of Swampbuster provisions and that USDA to determine necessary dredging and cleaning of ditch to maintain land in pre-Swampbuster status; USDA established sawtooth gradeline which failed to adequately drain ditch to allow plaintiff pre-Swampbuster use of meadow, and defendant used USDA gradeline when annually cleaning ditch; present action involved plaintiff’s claim that defendant not following state law in terms of adequately cleaning-out ditch which caused meadow to flood; plaintiff’s expert testified that USDA errors in established sawtooth gradeline which would not allow meadow to drain to extent that plaintiff could have pre-Swampbuster use of meadow; trial court determined that state law (Neb. Rev. Stat. Sec. 31-224) did not require yearlong obligation to keep ditch clean, but only required necessary cleaning from March 1 to April 15 annually; trial court also determined that plaintiff failed to establish that defendant failed to perform statutory duty to clean ditch and that plaintiff had failed to prove damages; on appeal, court affirmed; required cleaning need only occur from March 1 to April 15; court held that clean-out of ditch in compliance with USDA’s erroneous gradeline satisfied state law and then stated that issue of USDA’s survey establishing sawtooth gradeline not before trial court).