AEB 6933
 Spring 1995
 Exercise FA1

Below are data generated from a fertilizer trial on maize conducted on 8 farms by personnel from
CIMMYT in Mexico. Notice that in this trial, there are four levels of N and three of P205. It is a 3 x 4
factorial (with 12 plots per block). There were three blocks or replications per farm, but only the
average of the three blocks for each treatment are available and shown in the table.

 Maize yields (kg ha-1 of 14 percent moisture grain) by fertilizer treatment, 8 farms.


 Fertilizer treatment (kg ha1)
 N: 0 50 100 150 0 50 100 150 0 50 100 150

 P205 0 0 0 0 25 25 25 25 50 50 50 50 Avg.

 Farm:
 1 400 1240 3630 3760 0790 2580 4230 4720 1670 2510 3280 3660 2710
 2 1530 2600 5140 5320 1670 3790 5100 6830 1410 4130 5890 6270 4140
 3 4150 4860 4800 4870 4440 5000 4970 5280 5120 5660 6360 6620 5180
 4 2420 3820 5230 4480 2360 4540 6260 7170 1610 4410 5380 6580 4520

 5 1640 1920 2080 2190 2040 3210 3120 2930 1440 3440 3320 3620 2580
 6 1610 2940 4140 4340 1810 3920 3610 3810 1180 3890 5380 4920 3460
 7 4740 5410 4290 4920 4910 5220 5380 5140 5100 4880 4540 5280 4980
 8 1210 2330 1970 2230 1530 2780 2490 2800 1370 3510 3750 4350 2530
 Avg. 2210 3140 3910 4010 2440 3880 4400 4840 2360 4050 4740 5160 3760

 Source: Perrin, Richard K., et al. 1976. From Agronomic data to farmer recommendations. An economics
 training manual. CIMMYT. Information bulletin 27.

 1. First look at the data. Are the farms quite similar or are they different? If they are quite different,
 we should probably look at them as if there were going to be more than one recommendation domain.

 2. Either way, let's begin to examine the data by looking at the overall average for all farms. First,
 let's look at the response of the maize to P20s. Notice that we have three levels of P20 for each of
 the four levels of N. Begin by summarizing the average data for different levels of N as follows:


Maize response for:

 0
 25
 50


N = 0


2.21
2.44
2.36


N = 50 N = 100
Yield (Mcr ha-l


3.14
3.88
4.05


3.91
4.40
4.74


3. Now, plot the P20, response data for N = 0 on a graph and calculate a quadratic the response
equation (production function) using the visiographic procedure.


4. Repeat this process for the other three levels of N.


N = 150


4.01
4.84
5.16