This report describes standardized data for “Cowpea Yield Evaluation Trials - IITA Ibadan,1987 - 1993”. These data were standardized on 2024-09-20 by Robert Hijmans with this R script. The original data have a CC-BY license. Here you can download the standardized data.

This is the full citation of the data set:

Boukar, Ousmane; Christian Fatokun (1993). Cowpea Yield Evaluation Trials - IITA Ibadan,1987 - 1993. International Institute of Tropical Agriculture (IITA). Not versioned. doi:10.25502/20180920/0826/BO

The dataset has 1744 records and 21 variables for cowpea in Nigeria. The dataset has 1 treatment(s): variety.


These are the first 25 records:

records
trial_id planting_date harvest_date on_farm is_survey rep crop variety yield_part yield N_fertilizer P_fertilizer K_fertilizer irrigated country location longitude latitude geo_from_source
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 101 cowpea IT93K-734 seed 194.2 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 201 cowpea IT93K-734 seed 154.2 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 301 cowpea IT93K-734 seed 116.7 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 401 cowpea IT93K-734 seed 135.9 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 101 cowpea IT93K-699-1 seed 631.8 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 201 cowpea IT93K-699-1 seed 68.3 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 301 cowpea IT93K-699-1 seed 0.0 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 401 cowpea IT93K-699-1 seed 0.0 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 101 cowpea IT93K-573-5 seed 853.5 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 201 cowpea IT93K-573-5 seed 828.5 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 301 cowpea IT93K-573-5 seed 207.5 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 401 cowpea IT93K-573-5 seed 425.9 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 101 cowpea IT90K-277-2 seed 201.7 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 201 cowpea IT90K-277-2 seed 390.1 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 301 cowpea IT90K-277-2 seed 265.1 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 401 cowpea IT90K-277-2 seed 229.2 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 101 cowpea IT87D-885 seed 540.9 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 201 cowpea IT87D-885 seed 72.5 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 301 cowpea IT87D-885 seed 21.7 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 401 cowpea IT87D-885 seed 79.2 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 101 cowpea IT89KD-349 seed 290.9 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 201 cowpea IT89KD-349 seed 133.4 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 301 cowpea IT89KD-349 seed 133.4 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 401 cowpea IT89KD-349 seed 90.0 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE
ANMD9609 1987-04-18 1993-11-25 FALSE FALSE 101 cowpea IT89KD-245 seed 337.6 NA NA NA NA Nigeria IITA Ibadan 3.94704 7.37754 TRUE


The observations are for 1 locations, for which we have 1 unique mapped locations.


The standardization script emits the following non-compliance warnings.

message
1744 harvest_date more than 366 days after planting_date

The overall quality of the dataset, given the completeness of required variables was 5.6 on a scale of 10. See the table below

variable completeness (%)
planting_date 100
harvest_date 100
N_fertilizer 0
P_fertilizer 0
K_fertilizer 0
irrigated 0
latitude 100
longitude 100
location 100


The data are further summarized in the table below.

Variable Stats / Values Freqs (% of Valid) Graph Missing
trial_id [character]
1. C18812
2. T18713F
3. T18747S
4. ANMD9609
5. STUDY 755
6. C18922
7. C19006
8. C19035
9. ANS87IT
10. C19048
[ 33 others ]
64(3.7%)
64(3.7%)
64(3.7%)
60(3.4%)
60(3.4%)
48(2.8%)
48(2.8%)
48(2.8%)
40(2.3%)
40(2.3%)
1208(69.3%)
 0 (0.0%)
planting_date [character] 1. 1987-04-18
1744(100.0%)
 0 (0.0%)
harvest_date [character] 1. 1993-11-25
1744(100.0%)
 0 (0.0%)
on_farm [logical] 1. FALSE
1744(100.0%)
 0 (0.0%)
is_survey [logical] 1. FALSE
1744(100.0%)
 0 (0.0%)
rep [integer]
Mean (sd) : 11.4 (50.8)
min ≤ med ≤ max:
1 ≤ 3 ≤ 401
IQR (CV) : 2 (4.5)
1:405(24.1%)
2:405(24.1%)
3:406(24.2%)
4:404(24.0%)
101:15(0.9%)
201:15(0.9%)
301:15(0.9%)
401:15(0.9%)
 64 (3.7%)
crop [character] 1. cowpea
1744(100.0%)
 0 (0.0%)
variety [character]
1. LOCALCHECK
2. IT85D-3850-2
3. IT86D-719
4. IT82D-699
5. IT84S-2246
6. IT86D-1010
7. IT86D-472
8. IT87D-611-3
9. IT82E-32
10. IT86D-400
[ 149 others ]
116(6.7%)
48(2.8%)
36(2.1%)
28(1.6%)
28(1.6%)
28(1.6%)
28(1.6%)
28(1.6%)
24(1.4%)
24(1.4%)
1356(77.8%)
 0 (0.0%)
yield_part [character] 1. seed
1744(100.0%)
 0 (0.0%)
yield [numeric]
Mean (sd) : 780 (499.2)
min ≤ med ≤ max:
0 ≤ 710 ≤ 2602.5
IQR (CV) : 782.5 (0.6)
 1044 distinct values 131 (7.5%)
N_fertilizer [logical]
All NA's
 1744 (100.0%)
P_fertilizer [logical]
All NA's
 1744 (100.0%)
K_fertilizer [logical]
All NA's
 1744 (100.0%)
irrigated [logical]
All NA's
 1744 (100.0%)
country [character] 1. Nigeria
1744(100.0%)
 0 (0.0%)
location [character] 1. IITA Ibadan
1744(100.0%)
 0 (0.0%)
geo_from_source [logical] 1. TRUE
1744(100.0%)
 0 (0.0%)