(concurring in part and dissenting in part).
In this long-lasting legal war several parties were injured, but a major casualty was the Clayton County farm. The wholly believable evidence in this case shows that with proper care it may recover in about fifty years.
Although this record reflects they were careless farmers, defendants Schmitts farmed this 285-acre tract only in “patches” and rotated crops.1 In fact, the weeds they tolerated on the farm diminished the risk of soil loss. There was little evidence of erosion when they left the farm.
Defendants Woods took over this property in March 1975, under a contract containing a special money-back provision if the seller did not get title. Trial court found they were not good faith purchasers. They called this the “Hill Farm” because it was hilly. In his testimony Donald J. Woods referred to the “extreme steepness of the side hills.” Nonetheless, the Woods converted pasture to row crops and fall-plowed the soil with a moldboard plow to a depth of six to seven inches for three successive years. In 1976 and 1977 they planted the total tillable acres in corn with the rows running up and down hill, making no provisions for grassed waterways.
Plaintiffs Mosers were farmers who had always planted row crops on the contour (level) and on their other land had terraced es, early as 1951 and had practiced minimum tillage since 1966.2 When they finally gained rightful possession of this farm and saw the soil erosion that had been created by Woods’ treatment of the land, they called on Roger Koster, district conservationist,3 for assistance in developing a conservation plan for the farm.
Roster’s observations, made in the fall of 1977, were from an expert’s perspective. He was born and reared on a farm, graduated from Iowa State University with a Bachelor of Science Degree in Agronomy, and had postgraduate courses in soil conservation. He was a member of several professional organizations and had been employed as a soil conservationist for twenty-two years, the last thirteen years in Clayton County. Roster’s qualifications classify him as an expert on soil erosion control under our definition in Karr v. Samuelson, Inc., 176 N.W.2d 204, 209 (Iowa 1970).
Koster testified Woods had planted corn rows up and down hill, which doubled the erosion, and that there were no grassed waterways except in two instances. He described the rills, or small gullies, two to ten inches deep that had been cut by water runoff between the corn rows. All of this testimony was supported by photographs he had taken. Using the “universal soil loss equation,”4 Koster computed the average soil loss for this farm for the years 1975, 1976, and 1977 at sixty-three tons per acre *904per year. This loss, in his opinion, could be replaced in about fifty years if the land was withheld from cultivation and placed in good permanent pasture.
Koster also testified the maximum soil loss limitation established for Clayton County by the commissioners of the Clayton County Soil Conservation District was five tons per acre per year. See generally Woodbury County Soil Conservation District v. Ortner, 279 N.W.2d 276, 277 (Iowa 1979); § 467A.42(1), The Code; Comment, Regulatory Authority to Mandate Soil Conservation in Iowa After Ortner, 65 Iowa L.Rev. 1035, 1036 n.7, 1040 n.42 (1980). As Koster testified, these soil loss limits were promulgated by the soil conservation district to set the maximum amount of soil erosion that can be tolerated while preserving the Clayton County soil and water resources. See §§ 467A.42(1), 467D.1, The Code.
Although a better procedure would have been to offer a certified copy of the soil loss limit regulations, Koster worked for the district when this limit was established, employed it in his Clayton County soil conservation work, and in any event ultimately testified without objection. Because no violation of the regulation was being prosecuted in this case, the district’s soil loss limits were proved well enough to establish a norm for reasonable conduct by the Woods. The Woods, as long as they claimed to be owners of the farm, had a duty to know these regulations and comply with them. § 467A.43, The Code.
Donald J. Woods testified the erosion during the Woods’ possession was “nearly nil.” He also testified fall plowing with a moldboard plow (which turns all the crop residue under the surface) is “a generally accepted practice.” This practice, however, is so generally and publically recognized in this state as a major contributor to wind and water erosion that the court should have judicially noticed this fact and rejected this testimony. Woods’ other witness was a feed salesman, without formal or practical experience in soil conservation, who testified that when in his part-time employment he checked corn yields on the farm in 1976 he observed only “minimal” erosion.
Woods also testified they planted the com “straight row up the hill, over the hill, and then down the hill,” and that this was an “accepted practice.” This testimony was controverted, of course, by Mosers and district conservationist Koster. The latter not only testified the practice was a major cause of erosion, but provided statistics that the practice was used on less than sixteen percent of the tillable land in Clayton County that needs contour farming.
There is a strong public policy that should cause courts to scrutinize carefully testimony that farming practices are “accepted” when general experience and knowledge relating to the natural effect of wind and water on exposed soil red-flag the danger of soil erosion. See generally Comment, Regulatory Authority to Mandate Soil Conservation in Iowa After Ortner, 65 Iowa L.Rev. 1035, 1035 & n.1 (1980). In Woodbury County Soil Conservation District v. Ortner, 279 N.W.2d at 278, we said “[t]he state has a vital interest in protecting its soil as the greatest of its natural resources, and it has a right to do so.” Iowa courts have long recognized that agriculture, for which soil is a sine qua non, is of utmost importance in this state. See id. at 278 (citing Benschoter v. Hakes, 232 Iowa 1354, 8 N.W.2d 481 (1943)). This public policy also has been codified by Iowa’s legislature in sections 467A.2, 467A.43, and 467D.1, The Code. In section 467D.1 the legislature stated:
It is hereby declared to be the policy of the state of Iowa ... to preserve and protect the public interest in the soil and water resources of this state for future generations ... and ... to mandate the conservation and proper control and use of the soil and water resources of this state, by measures including but not limited to ... the control of erosion by water or by wind ....
By legislative definition, soil and water conservation practices include strip-cropping, contour planting, and minimum tillage. *905§ 467A.42(2)(b), The Code. Straight up- and-down-hill cultivation and fall-plowing cannot be classified as conservation practices and, therefore, should not be found to be “acceptable” by the finder of fact when the issue is establishing damages to hilly farmland in Iowa and the physical injury to the land is well established.
Nonetheless, trial court found that “there are two different views of soil use involved here and there is nothing to show that the method in which Defendants worked the soil was different from that employed in many other corn fields in the community or that it was contrary to principles of good husbandry.” The majority “agree[s] with the trial court that Mosers failed to prove damages or the liability of Woods by a preponderance of the evidence.” (Emphasis added.) These findings fly in the face of the overwhelming evidence. Woods should become liable for damages here because while claiming to be landowners they did not manage the farm in a reasonable manner. See § 467A.43, The Code. In our de novo review we should find that the farm, and consequently Mosers, sustained damages by Woods’ farming procedures.
It is true that the evidence relating to the deterioration and damages to the buildings on this farm was unsatisfactory and provided no basis for arriving at a judgment in any sum. With respect to the land, the Mosers had obvious difficulties in the unusual circumstances of this ease while attempting to apply the ordinary measures of damages set out in the majority opinion. Restatement (Second) of Torts section 929(1) provides four components of total damages due to a past invasion of real property. The two of interest to the immediate problem of determining damages on this farm are alternatives and are “the difference between the value of the land before the harm and the value after the harm, or at his election in an appropriate case, the cost of restoration that has been or may be reasonably incurred.” Restatement (Second) of Torts § 929(l)(a) (1979). Grell v. Lumsden, 206 Iowa 166, 169-70, 220 N.W. 123, 125 (1928), established the following rules concerning damages to real property, which generally comport with the Restatement (Second) section 929(1):
Where the character of the injury is such that the premises may be reasonably restored to as good condition as they were before, the measure of recovery is the fair and reasonable cost and expense of such restoration.
If the character of the injury is such that the property cannot be repaired or restored to its former condition at a reasonable expense, or is to the soil, . . . the measure of recovery is the difference between the value of the real property immediately before and after the injury.
(Citations omitted.) See Oak Leaf Country Club, Inc. v. Wilson, 257 N.W.2d 739, 747-48 (Iowa 1977) (erosion damage). Further, if a record is made that these measurements are inapplicable, the landowner may pursue other measures because our damage law is flexible enough to develop means to compensate those who have suffered an injury. Long ago this court established the following policy concerning damages to land:
The question as to the measure of damages for a continuing injury to the land and its manner of application is one of those which arise under such an endless variety of circumstances that a rule effectuating substantial justice in one instance would often work manifest injustice in another. As a result, we find the courts making use of various rules by which, when injury has been shown, the amount of compensation may be determined. . . . The foregoing is not an exhaustive statement of thi various measures of damages which have been recognized, but is sufficient to indicate the tendency to make the legal remedy sufficiently flexible to provide reasonably adequate compensation to the injured party.
Harvey v. Mason City & Fort Dodge Railroad, 129 Iowa 465, 479-80, 105 N.W. 958, 963 (1906).
The Woods produced evidence to show the farm increased in value from 1974 to the date of the hearing. The obvious explanation for this was inflation and the gener*906al increase in farm prices, conditions that, in various contexts, we have considered before. E. g., In re Marriage of Stutsman, 311 N.W.2d 73, 76 (Iowa 1981) (effect of inflation on cost of raising children); Hulse v. Wifvat, 306 N.W.2d 707, 713 (Iowa 1981) (effect of inflation on cost of providing counsel to indigents); In re Marriage of Kehrli, 241 N.W.2d 923, 926 (Iowa 1976) (effect of inflation on land values). Mosers were not precluded from proving damage because the farm was worth more in 1978 than in 1974.
In these circumstances, in which damages are occasioned over a period of time, and in order to factor out the elements of inflation or deflation of the value of the dollar and of real estate, an accurate measure of damages could have been developed by using our existing real property damage rules tempered slightly by concepts from the law of bailments.
[T]he measure of damages is the difference between the value of the property immediately before, and its value immediately after, it was damaged. In adapting this rule to the bailment relationship, however, it is generally held that the measure of damages (if the property has a market value) is the difference, in the locality where it was injured, at the time of return of the property to the bailor or other termination of the bailment (which is, in legal contemplation, the time the injury occurred), between its market value in its damaged condition and such value in the condition in which it would have been but for the bailee’s negligence; or, as sometimes stated, the difference at such time and place between the market value of the damaged goods and that of goods of like kind and quality in undamaged condition.
8 Am.Jur.2d Bailments § 334, at 1222 (1963) (footnotes omitted); see Halferty v. Hawkeye Dodge, Inc., 158 N.W.2d 750, 753 (Iowa 1968); Jones v. O’Bryon, 254 Iowa 31, 38, 116 N.W.2d 461, 465 (1962).
Using this measure of damages, Mosers could have established that when they took possession the farm was worth less in the eroded condition than it would have been worth in an unexploited condition. The difference between the eroded and unerod-ed land values would be the Mosers’ damages. This sum could be established through expert testimony. Of course the landowner would be qualified to express an opinion about the value of the farm at the time its possession was returned to him had it not sustained the erosion damage, and its value in its eroded condition. See Holcomb v. Hoffschneider, 297 N.W.2d 210, 213 (Iowa 1980); Oak Leaf Country Club, 257 N.W.2d at 748. Other local farmers may have qualified to express the same opinions. See Brown v. Mostoller, 167 Iowa 568, 581-82, 149 N.W. 908, 912-13 (1914).
Mosers attempted to demonstrate the dollar amount of damages by capitalizing a per acre decrease in productive value based on a reduction in corn suitability rating caused by the erosion. Their expert testified that this method indicated a per acre decrease in value of $62.42. Trial court evidently did not accept this estimate over defendants’ objections that it was speculation and that no proper foundation had been laid for the expert testimony.
Attempting to show restoration cost, Mosers resorted to showing the cost of fill dirt, even though expert testimony indicated the soil must be replaced in the same manner it was created — by natural weathering and decaying vegetation over many years.
The majority does not question that the Woods “could have been” liable for damages caused. They were essentially trespassers, who are responsible for all injurious consequences flowing from their trespass as a natural and proximate result of their conduct. 75 Am.Jur.2d Trespass § 52 (1974). There is an implied covenant that even a tenant, who has an estate in the land, must farm the premises in a husband-like manner. See Brown Land Co. v. Lehman, 134 Iowa 712, 719, 112 N.W. 185, 188 (1907). According to our common law, a tenant is required to cultivate the farm according to the course of good husbandry and must return the premises in the same *907general condition in which they were at the time of the letting, subject to such general deterioration as is caused by a reasonable use and lapse of time. 49 Am.Jur.2d Landlord and Tenant § 230, at 249, § 263 (1970). The Woods did not comply with these rules of the game.
In the case before us on de novo review, where the evidence established the extreme physical damage to the farm, I would accept Mosers’ expert’s computation of $62.42 per acre diminution in productive value, albeit somewhat obscure and speculative, multiplied by 185 tillable acres.
Even if this measure is rejected, there was no reason for trial court to withhold nominal damages. See Watson v. Lewis, 272 N.W.2d 459, 465 (Iowa 1978); Johnson v. Scott, 258 Iowa 1267, 1271, 142 N.W.2d 460, 463 (1966); Harvey v. Mason City & Fort Dodge Railroad, 129 Iowa 465, 482, 105 N.W. 958, 964 (1906) (nominal damages for injury to land).
Justice Douglas once raised the question whether the public interest should justify conferring standing upon environmental objects to sue for their own protection, pointing out that a ship has a legal personality, a fiction found useful for maritime purposes. Sierra Club v. Morton, 405 U.S. 727, 741-43, 92 S.Ct. 1361, 1369-70, 31 L.Ed.2d 636, 647 (1972) (Douglas, J., dissenting). Perhaps before the current and exacerbating disaster in Iowa’s hill country becomes irreversible the genius of the common law will devise procedures by which an abused farm through a next friend will be accorded standing to enjoin practices like those in the record before us, and to enforce remedial measures.
I concur in all divisions of the majority opinion except division VII, to which I dissent for the reasons above stated.
McCORMICK and SCHULTZ, JJ., join this concurrence in part and dissent in part.
. A crop rotation is “the practice of growing different crops in succession on the same land chiefly to preserve the productive power of the soil.” Webster’s Third New International Dictionary 540 (unabr. 1976).
. Minimum tillage, also called conservation tillage, is any tillage system that reduces the amount of soil and water runoff from the amount that would occur if clean tillage were used. See Soil Conservation Society of America, Resource Conservation Glossary 15g (1976).
. Mr. Koster is an employee of the Soil Conservation Service, United States Department of Agriculture. See 16 U.S.C. § 590e (1976). He is stationed at the Clayton County Soil Conservation District, which is a creation of state law. See §§ 467A.5-.7, The Code. The interaction of federal and state governments within soil conservation districts is partially explained in Ferguson, Nation-Wide Erosion Control: Soil Conservation Districts and the Power of Land-Use Regulation, 34 Iowa L.Rev. 166, 168-70 (1949), and Comment, Regulatory Authority to Mandate Soil Conservation in Iowa After Ortner, 65 Iowa L.Rev. 1035, 1037 (1980).
.The universal soil loss equation is used to design water erosion control systems. It is a mathematical equation that estimates average annual soil loss in tons per acre. Variables in the equation include rainfall intensity, soil ero-dibility, length of the slope, steepness of the slope, existing conservation practices, and land management factors. Soil Conservation Society of America, Resource Conservation Glossary 58g (1976). See generally W. Wischmeier & D. Smith, Predicting Rainfall Erosion Losses — A Guide to Conservation Planning (USDA Agri. Handbook No. 537, 1978).