Net Returns 



Gross returns were calculated by multi- 

 plying the tons of alfalfa produced (table 6) by 

 an assumed price of $17 per ton. 11 Net re- 

 turns were obtained by subtracting total costs 

 from gross returns. Details of the calculations 

 for 42-foot benches on 4-percent slopes are 

 shown in table 7. Net returns are $468 per 

 100 acres for benches with contributing areas 

 and $699 for benches without, indicating that 

 the use of contributing areas does not increase 

 net returns for the slope and bench width illus- 

 trated in this table. However, alfalfa production 

 on benches — either with or without contributing 

 areas — is substantially more prof itable than on 

 natural slopes, where there is a net loss of 

 $120 per 100 acres. 



Net returns were calculated for five bench 

 widths and 10 different slopes, for systems 

 both with and without contributing areas. The 

 highest net returns were found on the gentlest 

 slopes, and for each width of bench the net 

 returns decreased as the slope increased 

 (table 8). On slopes of 1 percent, the 42-foot 

 benches had the highest net returns, while on 

 2-, 3-, and 4-percent slopes the 2 8 -foot benches 

 showed the highest returns. On all slopes of 

 5 percent or more, the returns decrease as 

 the bench width increases. On the steepest 

 slopes the returns are negative on the widest 

 benches, largely because of higher construction 

 costs. 



For benches on a 1 -percent slope with 

 contributing areas, the net return is lowest on 

 the 14-foot width and highest on the 42-foot 

 width. On 2-, 3-, and 4-percent slopes returns 

 are highest on the 28-foot benches. On slopes 

 of 5 percent and over, the net returns decrease 

 as the bench width increases. The relationship 

 between bench width and net returns is much 

 the same for benches with contributing areas 

 as it is for benches without. 



Slope appears to have more effect than 

 width of bench on net returns. For every bench 



1 * This is the expected long-term price currently 

 used in North Dakota by various State and Federal agen- 

 cies for river basin planning. 



width, either with or without a contributing 

 area, the net returns decrease as the slope 

 increases. The level of net returns is generally 

 higher for benches without contributing areas 

 than for those with contributing areas — except 

 for some of the widest benches on the steepest 

 slopes. Variations in width of bench and in 

 percentage of slope have less effect on net 

 returns for benches with contributing areas 

 than for those without. Because the investment 

 is smaller for situations with contributing 

 areas, the net losses are not as high as is the 

 case without contributing areas. 



The data on net returns are useful as a 

 guide in deciding whether to build a level 

 bench system on a particular field, and if so, 

 what width of bench. For example, if the field 

 has a slope of only 1 percent, a 42-foot bench 

 appears to be most profitable, though net re- 

 turns are almost as large on 28-, 56-, and 

 70-foot benches, and the latter two have an 

 advantage because they are easier to farm. 

 Benches without contributing areas seem to 

 have a convincing advantage over benches with 

 contributing areas. For slopes of more than 

 4 percent, 14-foot benches seem to be most 

 profitable. With a 10-percent slope, only the 

 narrowest benches have favorable net returns. 



Relationships of Available Water and Alfalfa 

 Yields 



As mentioned earlier, soil water readings 

 were taken at intervals during each growing 

 season. While it is not part of the purpose of 

 this report to analyze in detail the soil water 

 data, it is relevant to show the economic im- 

 portance of conserving as much precipitation 

 as possible. At Mandan, and in areas with 

 similar climate, the amount of available water 

 is one of the major factors influencing crop 

 yields and profits; therefore, it was the prin- 

 cipal variable in this set of level bench ex- 

 periments. There were differences between 

 benches in the water-holding capacity of the 

 soil, but water readings were corrected for 

 this difference by calculating the soil water 

 available to plants. The lowest water value 

 for each 1-foot increment of soil throughout 

 the study period was selected as the minimum 

 point of exhaustion for alfalfa (3). Any water in 



11 



