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Agronomy 2015, 5, 476-490; doi:10.3390/agronomy5040476
agronomy
ISSN 2073-4395
www.mdpi.com/journal/agronomy
Article
The Response of Sorghum, Groundnut, Sesame, and Cowpea to
Seed Priming and Fertilizer Micro-Dosing in South Kordofan
State, Sudan
Elgailani A. Abdalla 1, Abdelrahman K. Osman 1, Mahmoud A. Maki 1, Fadlalmaola M. Nur 1,
Salah B. Ali 1 and Jens B. Aune 2,*
1 Elobeid Research Station, Elobeid 611, Sudan; E-Mails: elgailani_ers@hotmail.com (E.A.A.);
arkosman@hotmail.com (A.K.O.); mahmekki@yahoo.com (M.A.M.),
fadelmoh75@yahoo.com (F.M.N.); salahbakor328@yahoo.com (S.B.A.)
2 Department of International Environment and Development Studies, Noragric, Norwegian
University of Life Sciences (NMBU) P.O. Box 5003, N-1432 Ås, Norway
* Author to whom correspondence should be addressed; E-Mail: jens.aune@nmbu.no;
Tel.: +47-9768-1283.
Academic Editor: Yantai Gan
Received: 8 July 2015 / Accepted: 18 September 2015 / Published: 29 September 2015
Abstract: This study was undertaken with the objective of evaluating micro-dosing of
mineral fertilizer combined with seed priming in sorghum, groundnut, sesame, and
cowpea. On-station and on-farm trials were conducted for two consecutive seasons
(2009/2010 and 2010/2011) at Al-Tukma village (12°00′57.60′′ N and 29°46′12.15′′ E) in
South Kordofan State, 15 km southeast of Dilling city. Heavy cracking clay soil is the
dominant soil type in the region with low fertility. The experiments for each crop consisted
of two priming levels (primed seeds vs. non-primed) and four micro-doses of NPK mineral
fertilizer (0, 0.3, 0.6 and 0.9 g per planting pocket or hole). On-farm trials in 15 fields
consisted of control, seed priming, and seed priming + micro fertilizer (0.3 g/planting
hole). Data collected included plant vigor, stand count, plant height, grain and straw yield,
seed weight, and other relevant agronomic traits. This study shows that it is possible to
increase productivity of sorghum, sesame, groundnut, and cowpea in the semi-arid
cracking clay of South Kordofan State at a low cost and with a moderate risk for farmers
through seed priming and micro-dosing of fertilizers. Seed priming combined with
micro-dosing NPK mineral fertilizer of 0.9 g was the best treatment for plant
establishment, seedling vigor, grain yield, and hay yield in sorghum and groundnut,
OPEN ACCESS
Agronomy 2015, 5 477
whereas the combination of seed priming and 0.3 g micro-doing of fertilizer was the best in
sesame. Seed priming and micro-dosing of fertilizer of 0.6 g was the best combination for
cowpea. On-farm trial results indicated that priming alone and priming combined with
fertilizer application significantly increased the yields of sorghum, groundnut, and cowpea
over the control (P = 0.01). Of the crops tested, groundnut responded most favorably to
micro-dosing and seed priming, with a value to cost ratio (VCR) of 26.6, while the highest
VCR for sorghum, sesame, and cowpea was 12.5, 8.0 and 4.4, respectively. For the best
productivity and profitability, we recommend using seed priming in combination with the
micro-dosing of 0.9 g/hole of 15:15:15 NPK fertilizer for sorghum and groundnut, of 0.3
g/hole for sesame, and of 0.6 g/hole for cowpea grown in the semiarid South Kordofan State
of Sudan.
Keywords: seed treatment; fertilization; yield; gross margin; on-farm; intensificaton
1. Introduction
Traditional dry-land farming is the major production system and source of livelihood for more than
75% of the population in Western Sudan. The major food crops grown are millet and sorghum while
groundnut and sesame are the major cash crops. Other crops grown are cowpea, maize, cotton, and
okra. The productivity of the main crops are very low compared to other parts of the world [1]. This is
due to a magnitude of natural and socio-economic constraints. Poor crop establishment and low soil
fertility are particularly constraining for crop productivity.
The study site, South Kordofan State, falls in the semi-arid zone where heavy cracking clays
constitute the dominant soil type. The region is characterized by seasonal variation in rainfall and low
soil fertility. The maintenance of soil fertility is becoming one of the most important interventions
required to increase crop productivity in the dry areas. Application of small amounts of mineral
fertilizer in the planting hole is a more efficient way to apply mineral fertilizer compared to
broadcasting. This method increases both yield and the efficiency of fertilizer application [2–6].
Another low-cost approach to increase yield under marginal dry land conditions is seed priming, a
process of soaking seeds in water for a specific period prior to sowing [5,7,8]. Seed priming and
fertilizer micro-dosing are recommended in the sandy soils of North Kordofan State as these methods
have significantly improved crop establishment and increased the yield of rain-fed sorghum, pearl
millet, groundnut, sesame, and cowpea [6,9,10]. The objective of the study was to evaluate the effect
of placing small amounts of mineral fertilizer in the planting hole (micro-dosing) in combination with
seed priming for sorghum, groundnut, sesame, and cowpea in South Kordofan State in Western Sudan,
a location with heavy cracking clay soil and higher rainfall, compared to North Kordofan.
Agronomy 2015, 5 478
2. Materials and Methods
Four field experiments were conducted for two consecutive seasons (2009/2010 and 2010/2011) at
Al-Tukma village in South Kordofan State (29°46′12.15′′ E and 12°00′57.60′′ N), 15 km southeast of
Dilling city and 145 km north of Kadugli, the capital city of the state. This area is part of the central
clay plain, where soils are dark, heavy cracking (vertisol), with high water-holding capacity and low
nitrogen and phosphorus content.
Soil cores were taken to the depth of 0–10 cm prior to planting. The soil analysis showed a clay
fraction of 74%, very low nitrogen content (0.02 ppm), moderate phosphorus content (30 ppm) and
low potassium content (0.78 ppm). NPK mineral fertilizer (15:15:15) was used to compensate for low
contents of the soil NPK.
The experiments were carried out under rain-fed conditions on sorghum (Sorghum bicolor (L.)
Moench), groundnut (Arachis hypogea L.), sesame (Sesamum indicum L.), and cowpea (Vigna unguiculata
(L.) WLAP). The experiments consisted two levels of priming (primed seeds vs. non-primed) and four
levels of micro-dose of NPK (15:15:15) mineral fertilizer (0, 0.3, 0.6 and 0.9 grams per planting
pocket or hole) giving eight (2 × 4 factorial) treatment combinations. The treatments were laid out in a
randomized complete block design (RCBD) with four replications. The experimental plots were five
meters long and three meters wide with 60 cm between-row spacing and between-plant spacing of 40,
20, 40 and 30 cm for sorghum, groundnut, sesame, and cowpea, respectively. Total annual rainfall at
the nearest main meteorological station at Dilling was 675 mm and 562 mm during 2009/2010 and
2010/2011 seasons, respectively. The varieties used were Yarwasha, Gubeish, Obeid-1, and Ainelgazal
of sorghum, groundnut, sesame, and cowpea, respectively. The fertilizer type was NPK (15-15-15)
(Yara). Seeds of the four crops were soaked in water for eight hours (overnight) and then surface-dried
for less than an hour for planting the next day. Before sowing, the seeds were treated with Apron Star
(20% Metalaxyl–m, 20% Thiamethoxam and 2% Difenoconazole) at a dose of 3 g/kg seed. Two seeds
per hole were planted for groundnut and cowpea, while 4–5 seeds were planted for sorghum and
sesame, then thinned to 2–3 plants per hole two weeks after planting. The planting hole was opened
using a traditional hoe and the seed and fertilizer were placed together in the planting pit at a depth of
5 to 7 cm. The microdosing rates applied were 0.3, 0.6 and 0.9 g per pocket which corresponded to
6–7, 12–14, and 18–21 fertilizer granules per pocket, respectively.
The amount of fertilizer utilized per hectare for each crop differed according to the crop spacing
(Table 1). Manual hand-weeding was conducted three times, the first before planting, the second,
approximately two weeks after planting, and the third, three weeks after the second weeding. Data
collected included:
1) Plant vigor: The plant vigor score was measured at two and four weeks after planting using a
1–4 rating scale (score): 1 = Low, 2 = Moderate, 3 = Vigorous, and 4 = Highly Vigorous.
2) Stand count: Number of plants per four central rows, two weeks after planting.
3) For sorghum: Plant height (average of five random plants, pre-harvesting), panicle length (cm),
weight of straw, grain yield, and 1000 seed weight.
4) For groundnut: Number of pods per plant, shelling percentage, hay yield, pod yield, and 100
seed weight.
5) For sesame: Plant height, number of capsules per plant, hay yield, seed yield, and 1000 seed weight.
Agronomy 2015, 5 479
6) For cowpea: Pods per plant, seeds per pod, pod yield, hay yield, seed yield and 100 seed weight.
Table 1. Calculated fertilizer quantity in kg·ha−1 corresponding to fertilizer micro-dose
level per planting hole.
Crop
Spacing (cm)
Micro dose (g/hole)
0
0.3
0.6
0.9
Equivalent dose (kg/ha)
Sorghum
60 × 40
0
12.5
25.0
37.5
Groundnut
60 × 20
0
25.0
50.0
75.0
Sesame
60 × 40
0
12.5
25.0
37.5
Cowpea
60 × 30
0
16.7
33.4
50.1
On-farm trials were also conducted to study the effect of priming and micro-dosing. Each of the
15 selected farmers (men and women) was provided with 3 kg of 15-15-15 NPK fertilizer. The
treatments in each field of the selected farmers consisted of:
1. Control
2. Seed priming
3. Seed priming + micro-dosing (0.3 g/planting hole).
Plot size for each treatment in the on-farm experiment was 360 m2 (15 × 24 m) with all cultural
practices carried out by the farmers according to their preferences. Yields obtained from farmers’ plots
were analyzed according to the randomized complete block design, considering each farmer as a
replicate [11]. The combined analysis was carried out over two seasons and means were separated
using Duncan Multiple Range Test (DMRT) at levels of 0.01 and 0.05 [12]. The partial budgeting
technique was used to assess and compare the economic returns and net benefits of the different
treatments [13]. The average yield over seasons and replications in each treatment were used.
The average field prices of the crops during 2011/2012 were taken from the markets in which the
farmers sell their produce. Production cost, or the sum of all of the variable costs including labor and
inputs costs (without fertilizer), was taken from the surveys, which were conducted annually by the
Ministry of Agriculture, South Kordofan State, Sudan. In the micro-fertilizer treatment, the fertilizer
cost was added based on the amount of fertilizer applied (Table 1. The fertilizer use efficiency (FUE)
was computed according to the formula:
FUEt = (Yt − Ct)/Ft
where FUE is the fertilizer use efficiency for the treatment level, Yt is the grain yield for the treatment
level, Ct is the grain yield from the control, and Ft is the fertilizer rate used in kg·ha−1 for the treatment level.
The value cost ratio was calculated as:
VCRt = (Yt − Yc) × PGt/CFt
where VCRt denotes the value cost ratio for the treatment level, Yt − Yc denotes the incremental grain
yield resulting from fertilizer use in the treatment and the control, respectively, PGt denotes the grain
price per kg and CFt denotes the cost of fertilizer per hectare of the treatment level.
Agronomy 2015, 5 480
The total production cost including labor and input costs, was calculated by adding the fertilizer
cost for each treatment to the production cost for each crop. The production cost for sorghum,
groundnut, sesame, and cowpea was 353, 428, 283 and 179 SDG/ha, respectively. The production
costs data were obtained from North Kordofan State Ministry of Agriculture 2010–2011 annual survey
reports. The prices in kg ha−1 of sorghum, groundnut, sesame, and cowpea, according to ElObeid
Auction Market 2010–2011, were 1.25, 4.7, 2.83 and 3 SDG, respectively. Hay prices from the local
market were 0.41, 1.6, 0.2 and 1.0 SDG for the above crop order, respectively. The market price of
15-15-15 NPK fertilizer was 200 SDG per 50 kg sack (4 SDG/Kg).
3. Results
3.1. Sorghum
Results of the combined analysis over the two seasons (2009/2010 and 2010/2011) are shown in
Table 2. Differences in stand count (plant population), plant vigor score (two and four weeks after
planting), and plant height were highly and significantly affected by seed priming and micro-dose of
mineral fertilizer (p = 0.01). Seed priming increased plant vigor, plant stand and plant height by 28%,
14%, and 3%, respectively (p < 0.05), when compared to the control.
Table 2. Effect of seed priming and fertilizer micro-dosing on some traits of sorghum
(combined across two seasons).
Treatments
Plant
pop./ha
Vigor score 2
WAP
Vigor score 4
WAP
Plant height
(cm)
No. of
heads/plot
No. of
seeds/head
1000 seed
weight (gram)
Seed Priming
Non-primed
67842
2.16
2.88
179
97
751
40.9
Primed
78446
3.00
3.35
185
113
930
42.7
SE±
2260 **
0.21 **
0.17 **
3.0 **
4.6 **
33 **
0.54 **
Fertilizing micro-dosing (gram/planting hole)
Control
69252
2.19
2.94
175
97
699
41.2
0.3 g/hole
68261
2.44
3.13
178
96
739
40.5
0.6 g/hole
75572
2.75
3.25
186
110
791
42.1
0.9 g/hole
79492
2.94
3.50
190
117
1134
42.5
SE±
1598 **
0.15 **
0.12 *
2.1 **
3.2 **
47 **
0.38 **
C.V%
8.74
23.11
14.77
4.60
12.30
15.66
3.68
Ns = not significant; * significant at p ≤ 0.05; ** significant at p ≤ 0.01, WAP = weeks after planting.
Plant stand, plant vigor score, and plant height also increased with micro-dosing. The highest
increments were recorded for the application of 0.9 g of fertilizer, which increased plant stand, plant
vigor, and plant height by 13%, 25%, and 8%, respectively. A similar effect of seed priming and
micro-dosing (p < 0.01) was also observed in heads per plot, and 1000 seed weight. Number of heads
per plot increased due to seed priming and micro-dosing by 30% and 16% respectively and number of
seeds per head by 24% and 27%, respectively (p < 0.01). Seed weight (g/1000 seeds) was significantly
improved by seed priming and fertilization (p < 0.01).
Agronomy 2015, 5 481
The yield differences in sorghum were significantly (p < 0.01) affected by seed priming and
micro-dosing (Table 3). Seed priming increased average grain yield from 619 kg/ha to 949 kg/ha.
Compared to the control, micro-dosing of 0.3, 0.6, and 0.9 g/hole fertilizer increased grain yield by
12%, 42%, and 84%, respectively. Yield increased from 512 kg/ha in the control treatment to 1371 kg/ha
in the “seed priming and 0.9 g fertilizer/pocket” treatment. This corresponds to a 167% yield increase.
Seed priming and micro-fertilization also significantly increased straw yield by 21% and 23%,
respectively (Table 3). The highest straw yield of 7700 kg/ha was recorded at the dose 0.9 g/hole,
while the lowest straw yield of 4750 kg/ha was obtained from the control, without seed priming or
fertilization. The interaction between priming and micro-fertilization was only significant for
plant height.
Table 3. Effect of seed priming and fertilizer micro-dosing on sorghum grain and straw
yields (kg/ha) combined across two seasons.
Fertilizer
dose/hole
Grain yield (kg/ha)
Straw yield (kg/ha)
Non-primed
Primed
Mean
SE±
Non-primed
Primed
Mean
SE±
0.0 g
512 g
652 f
582
104 **
4752 h
5251 f
5002
323 **
0.3 g
500 g
799 c
650
4822 g
5513 d
5168
0.6 g
688 e
974 b
831
5485 e
7200 b
6342
0.9 g
776 d
1371 a
1074
6164 c
7701 a
6932
SE±
73 **
228 **
Ns = not significant; * significant at p ≤ 0.05; ** significant p ≤ 0.01. Different letters signify statistically different.
3.2. Groundnut
Seed priming and micro-fertilization positively affected crop establishment in groundnut by
increasing plant population and vigor score (p < 0.01, Table 4). Seed priming affected crop
establishment in groundnut by increasing stand count by 16%, plant vigor score two weeks after
planting by 25% and plant vigor score four weeks after planting by 15%. The number of pods per plant
was not significantly affected by seed priming, but was by fertilization. Shelling out-turn and
100 seed weight were not significantly affected by neither seed priming nor fertilizer application
(p < 0.05). Micro-fertilization significantly improved stand count (plant population) and vigor score
from 4% to 24% and from 3% to 34%, respectively. The plant characteristics were improved with
increased levels of fertilizer.
Agronomy 2015, 5 482
Table 4. Effect of seed priming and micro-dosing on some traits of groundnut (combined
across two seasons).
Treatments
Plant pop./ha
Vigor 2 WAP
Vigor 4 WAP
Shelling%
No. of pods/plant
100 seed wt.
Seed priming
Non-primed
102475
2.34
3.06
67.1
42.0
31.8
Primed
118984
2.94
3.59
66.8
42.8
32.2
SE±
7288.1 **
0.21 **
0.17 **
0.98 ns
0.74 ns
0.57 ns
Fertilizer micro-dose (gram/planting hole)
Control
96468
2.38
3.00
66
39
32.2
0.3 g/hole
100340
2.44
3.38
67
41
31.9
0.6 g/hole
126361
2.56
3.38
67
43
31.9
0.9 g/hole
119750
3.19
3.56
67
47
32.3
SE±
5153.4 **
0.15**
0.12 *
0.70 ns
1.05 **
0.41 ns
C.V%
18.62
22.9
14.31
4.16
7.02
5.07
Ns = not significant; * significant at p ≤ 0.05; ** significant p ≤ 0.01, WAP = weeks after planting.
Seed priming and micro-fertilization significantly increased pod and hay yields (p < 0.01, Table 5).
Seed priming increased average pod yield from 1995 to 2404 kg·ha−1, corresponding to a 20% yield
increase, while micro-fertilization increased pod yield by 35% on average, from 1865 to 2629 kg·ha−1.
Groundnut pod yield increased from 1716 kg·ha−1 in the control to 2955 kg in the treatment “priming
and 0.9 g fertilizer per pocket”, equivalent to a 72% increase in yield. Hay yield was also significantly
increased by seed priming and micro-fertilization (p < 0.01). The best hay yield of 2637 kg·ha−1 was
obtained from a micro-dose of 0.9 gram fertilizer per hole. There was no significant interaction
between priming and micro-fertilization for all traits, with the exception of shelling out-turn.
Table 5. Effect of seed priming and micro dosing on groundnut pod and hay yields (kg/ha)
combined across two season.
Fertilizer
dose/hole
Pod yield (kg/ha)
Hay yield (kg/ha)
Non-primed
Primed
Mean
SE±
Non-primed
Primed
Mean
SE±
0.0 g
1716 f
2013 d
1865
95 **
1737 h
2170 f
1954
97 **
0.3 g
1931 e
2291 c
2111
1915 g
2270 c
2092
0.6 g
2030 d
2354 b
2193
2076 f
2752 b
2414
0.9 g
2303 c
2955 a
2629
2212 d
3061 a
2637
SE±
67 **
69 **
Ns = not significant; * significant at p ≤ 0.05; ** significant p ≤ 0.01. Different letters signify statistically different.
3.3. Sesame
Results showed a strong and significant (p ≤ 0.01) effect of seed priming and micro fertilizing on
plant stand, which increased by 56% with priming and 25% with micro-dosing, compared to the
control (Table 6). Seed priming increased vigor score by 57% (p ≤ 0.01), while there was no effect of
micro-dosing on plant vigor score. Plant height increased by 3% and 8% due to seed priming and
micro-dosing, respectively. The number of capsules per plant increased (p < 0.05) by 12% and 15%
Agronomy 2015, 5 483
with priming and micro-dosing, respectively. Seed priming showed no significant effect on sesame
1000 seed weight, while micro-dosing significantly increased 1000 seed weight by 8% (p = 0.05).
Sesame seed yield was significantly increased by priming and micro-dosing (p < 0.01). Seed yield
increased from 276 to 383 kg·ha−1 with priming and from 276 to 393 kg/ha with micro-fertilizer
application (Table 7). Seed priming and micro fertilization improved sesame hay yield by 55% and
24%, respectively. The best seed and hay yields of 524 and 1942 kg·ha−1, respectively, were obtained
from the combination of seed priming and micro-dosing of 0.9 g per pocket. Significant interaction
between priming and micro-fertilization was observed for plant height, 1000 seed weight, and seed
yield (p < 0.05). Although the highest seed yield was recorded for a 0.9 g micro-dose in combination
with seed priming, the difference between 0.3 g and 0.9 g micro-dosing rates in combination with seed
priming was not significant for seed yield.
Table 6. Effect of seed priming and micro-dosing of fertilizers on sesame combined across
two seasons.
Treatments
Plant pop./ha
Vigour 2 WAP
Plant ht. (cm)
Av. no. of caps/plant
1000 seed wt. (gm)
Seed priming
Non-primed
166683
1.97
132.6
61.2
2.37
Primed
259836
3.09
137.3
68.6
2.41
SE±
19264 **
0.22 **
3.3 *
3.2 **
0.10 ns
Fertilizer micro-dose (gram/planting hole)
Control
180199
2.31
129
58
2.26
0.3 g/hole
204993
2.56
135
63
2.43
0.6 g/hole
246007
2.50
138
70
2.43
0.9 g/hole
221838
2.75
139
68
2.44
SE±
13261 *
0.15 ns
2.3 *
2.3 *
0.03 *
C.V%
25.55
24.48
6.88
14.15
6.58
Ns = not significant; * significant at p ≤ 0.05; ** significant p ≤ 0.01, WAP = weeks after planting.
Polp./ha = population/ha, Plant ht (cm) = plant hight in cm, 1000 seed wt. (gm) = weight of 1000 seeds
in gram.
Table 7. Effect of seed priming and micro-dosing on sesame seed and hay yields (kg/ha),
combined across two seasons.
Fertilizer
Dose/hole
Seed yield (kg/ha)
Hay yield (kg/ha)
Non-primed
Primed
Mean
SE±
Non-primed
Primed
Mean
SE±
0.0 g
276 e
383 c
330
19 **
935 h
1335 d
1135
100 *
0.3 g
243 f
507 a
375
970 g
1801 b
1385
0.6 g
348 d
467 b
408
1058 f
1430 c
1244
0.9 g
393 c
524 a
458
1223 e
1942 a
1582
Mean
SE±
13 **
70 **
Ns = not significant; * significant at p ≤ 0.05; ** significant p ≤ 0.01. Different letters signify
statistically different.
Agronomy 2015, 5 484
3.4. Cowpea
Differences in plant stand (plant population) and 100 seed weight were highly affected by seed
priming and micro-dose of mineral fertilizer (p < 0.01, Table 8). Seed priming improved plant stand by
23% compared to non-primed, while micro-dosing treatments increased plant stand (plant population)
by up to 26%. Seed priming improved vigor score by 32% compared to non-primed, while no
significant differences were observed among micro-dosing treatments for vigor score (p < 0.05). Seed
priming did not affect the number of pods per plant, while micro-dosing increased pods number from
11 to 13 per plant. The number of seeds per pod was not significantly affected by either seed priming
or fertilizer application (p < 0.05). Hundred seed weight was significantly increased due to seed
priming and fertilizer micro-dose application.
Cowpea seed yield was significantly (p < 0.05) increased by 11%, 38% and 16% compared to the
control with a micro-dose application of 0.3, 0.6 and 0.9 g, respectively, while seed yield increased by
36% with seed priming (Table 9). Hay yield highly and significantly (P = 0.01) increased with priming
(115% increase) and fertilization (51% increase) compared to the control. There was no significant
interaction between priming and micro fertilizing for grain and hay yields.
Table 8. Effect of seed priming and micro fertilizing on cowpea combined across
two seasons.
Treatments
Plant pop.
Vigour 2
WAP
No. pods/plant
No. seeds/pod
100 seed wt. gram
Seed priming
Non-primed
37938
2.31
13
9.1
18.2
Primed
46656
3.06
13
9.0
18.4
SE±
3570 **
0.23 **
0.74 ns
0.51 ns
0.10 *
Fertilizer micro-dose (gram/planting hole)
Control
34438
2.44
11
9
18.1
0.3 g/hole
39813
2.56
14
9
18.2
0.6 g/hole
48563
2.69
13
9
18.4
0.9 g/hole
46375
3.06
13
9
18.4
SE±
2524 **
0.17 ns
0.52 **
0.36 ns
0.10 **
C.V%
23.87
24.86
16.36
16.02
1.19
Ns = not significant; * significant at p ≤ 0.05; ** significant p ≤ 0.01, WAP = weeks after planting. 100 seed
wt. gram=weight of 100 grains. Different letters signify statistically different.
Table 9. Effect of seed priming and micro-dosing on cowpea seed and hay yields (kg/ha),
combined across two seasons.
Fertilizer
Dose/hole
Seed yield (kg/ha)
Hay yield (kg/ha)
Non-primed
Primed
Mean
SE±
Non-primed
Primed
Mean
SE±
0.0 g
191 e
240 c
215
20 *
219 g
414 d
316
41 **
0.3 g
203 de
275 b
239
216 g
488 c
352
0.6 g
239 c
356 a
297
283 f
657 b
470
0.9 g
217 d
283 b
250
395 e
831 a
613
Mean
212
288
250
278
597
438
SE±
14 ns
29
Ns = not significant; * significant at p ≤ 0.05; ** significant p ≤ 0.01. Different letters signify
statistically different.
Agronomy 2015, 5 485
3.5. On-Farm Trials
Priming alone and priming combined with fertilizer application significantly increased the yield of
sorghum, groundnut, and cowpea over the control in the two seasons (p = 0.01), while in sesame the
increase was only significant in one season (Table 10).
Table 10. On-farm evaluation of seed priming and fertilizer micro-dosing at three villages
(15 farmers from each village) in South Kordofan.
Treatment
Sorghum
Groundnut
Cowpea
Sesame
1st season: 2009/2010-(yield kg/ha)
Control
686 c
586 c
128 b
272 b
Primed seeds
860 b
731 b
207 a
-
Primed+ fertilizer (0.3 gram)
1022 a
906 a
233 a
405 a
2nd season: 2010/2011-(yield kg/ha)
Control
607 c
886 b
253 b
181
Primed seeds
837 b
1237 a
353 a
-
Primed + fertilizer (0.3 gram)
986 a
1438 a
415 a
198
# of participating farmers
15
15
15
15
# of participating villages
3
3
3
3
Ns = not significant; * significant at p ≤ 0.05; ** significant p ≤ 0.01. Different letters signify
statistically different.
4. Economic Analysis
An economic analysis was undertaken to assess economic performance of the different treatments
(Table 11). Generally, the highest returns were obtained in all crops when both seed priming and
micro-fertilization were used. Micro-dosing without seed priming, even at low doses, negatively
affected gross margin in sorghum, sesame and cowpea.
Table 11. Economic analysis of the different seed priming and micro-dosing treatments.
Treatments
Net return (SDG/ha)
Sorghum
Groundnut
Sesame
Cowpea
Non priming no fertilizer (control)
287 f
7637 h
498 g
394 e
Non priming + 0.3 g per planting hole
222 g
8548 g
355 h
363 f
Non priming + 0.6 g per planting hole
596 c
8913 f
602 f
404 e
Non priming + 0.9 g per planting hole
407 e
10096 d
719 e
272 g
Priming no fertilizer
462 d
9033 e
801 d
541 c
Priming + 0.3 g per planting hole
765 b
10240 c
1102 a
580 b
Priming + 0.6 g per planting hole
467 d
10436 b
939 c
755 a
Priming + 0.9 g per planting hole
1211 a
13161 a
1050 b
470 d
SE±
112
591
95
53
* 15-15-15 NPK fertilizer price is 200 SDG per 50 kg sack (4 SDG/Kg); ** Note: sorghum, groundnut,
sesame and cowpea production costs are 353, 428, 283 and 179 SDG, respectively [14]; *** Note: sorghum,
groundnut, sesame and cowpea price according to Obeid Auction Market, 2010–2011, are 1.25, 4.7, 2.83, and
3 SDG, respectively. Hay prices from the local market were 0.41, 1.6, 0.2 and 1.0 for the above crop order,
respectively. Different letters signify statistically different.
Agronomy 2015, 5 486
Sorghum seed priming and application of 0.9 g fertilizer per hole increased the gross margin from
462 to 1211 SDG/ha, while the treatment of non-priming with application of 0.9 g fertilizer per hole
increased the net revenue from 278 to 407 SDG/ha.
For groundnut, the net benefit increased from 9033 in the control to 13161 SDG/ha with the
application of priming and 0.9 g fertilizer per hole. Priming with micro-dosing gave a higher return
than non-priming with micro-dosing. However, unlike in other crops, groundnut yield increased with
increasing micro-dosing rates up to 0.9 kg fertilizer per pocket. The revenue increase from micro-dosing
and seed priming was much higher in groundnut compared to the other crops.
Sesame gross margin increased from 498 SDG/ha in the control to 1102 in the treatment “priming
combined with application of 0.3 g fertilizer per hole”. Priming alone with micro dosing also gave a
good return in sesame.
For cowpea, the gross margin increased from 541 in the control to 755 SDG/ha with the application
of 0.6 g fertilizer per hole combined with seed priming. Fertilizer use efficiency (FUE) and value cost
ratio (VCR) for grain yield and the total biological yield were the highest at the treatment
combinations with the highest yields for all crops (Tables 12 and 13). FUE and VCR were always the
highest in treatments which combined micro-dosing with seed priming, and were higher in sorghum
and groundnut compared to sesame and cowpea. Adding the hay value to the grain value increased the
FUE and VCR. It is worth mentioning that hay yield is a valuable agricultural bi-product which is
utilized for animal feed in the dry months of the year. Sorghum straw is also utilized as building
material in rural areas.
Table 12. Value cost ratio (VCR) of NPK fertilizer micro-dose rates with and without
seed priming (VCR1-grain yield, VCR2-grain + hay yield). a = non-primed seed,
b = primed seeds.
NPK rates
gram/hole
Sorghum
Groundnut
Sesame
Cowpea
VCR1
VRC2
VCR1
VCR2
VCR1
VCR2
VCR1
VCR2
0.3a
−0.3
0.27
10.11
12.96
−1.70
−1.56
0.54
0.41
0.6 a
2.2
5.21
7.38
10.09
2.04
2.29
1.08
2.44
0.9 a
2.2
6-06
9.20
11.70
2.21
2.69
0.39
3.02
0.3b
3.68
5.78
13.07
14.67
7.02
8.02
1.57
2.68
0.6 b
4.03
11.83
8.01
19.65
2.38
2.60
2.60
4.42
0.9 b
5.99
12.52
14.76
26.64
2.66
3.26
0.64
2.72
Table 13. Fertilizer use efficiency (FUE kg·kg−1) of NPK fertilizer micro-dose rates with
and without seed priming (FUE1-grain yield, FUE2-grain + hay yield). a = non-primed
seed, b = primed seeds.
NPK rates
gram/hole
Sorghum
Groundnut
Sesame
Cowpea
FUE1
FUE2
FUE1
FUE2
FUE1
FUE2
FUE1
FUE2
0.3a
−0.96
4.64
8.60
22.84
−2.64
0.16
0.72
0.54
0.6a
7.04
36.36
6.28
13.06
2.88
7.80
1.44
3.36
0.9a
7.04
44.69
7.83
14.16
3.12
10.80
0.52
4.03
0.3b
11.76
32.72
11.12
15.12
09.92
29.92
2.10
06.53
0.6b
12.88
90.84
06.82
18.46
03.36
7.72
3.47
10.75
0.9b
19.17
84.50
12.56
24.44
3.76
15.68
0.86
09.18
Agronomy 2015, 5 487
The economic analysis of the on-farm experiment confirmed the positive impact of seed priming
and micro-dosing (Table 14). There was an increase for all crops, with the highest increase observed in
groundnut. The increase in gross margin from the control to the treatment combining seed priming and
micro-dosing was 2178, 444, 372, and 469 for groundnut, sorghum, cowpea, and sesame, respectively.
Table 14. The effect of seed priming and micro-dosing on gross margin in on-farm farmer
managed plots.
Treatment
Combined (30 farmers)
Groundnut
Sorghum
cowpea
Sesame
Control
3265
513
387
13
Priming
4662
824
690
P + M
5443
957
759
482
SE
283 **
40 **
54 **
74 **
CV
35
28
48
163
Ns = not significant; ** significant p ≤0.01.
5. Discussion
Seed priming and micro-dosing represent low-cost approaches to increase yields of small-holders
under marginal dry land conditions [5,8,9].
Seed priming is a simple strategy to improve plant establishment and alleviate the negative effects
associated with stress exposure. Seed priming has been shown to reduce germination time, improve
plant stand, increase vigor, shorten the growing cycle, and increase crop yield [5,7,8,15]. It is a
technology that is particularly suited to adverse environmental conditions. The results of the present
study have shown that seed priming significantly improved crop establishment and seedling vigor of
rain-fed sorghum, groundnut, sesame, and cowpea grown on clay soil in South Kordofan State. This is
important as seed priming and micro-dosing can reduce the need for re-sowing. Similar results were
obtained with these crops under rain-fed condition on sandy soils in North Kordofan State [10].
Previous studies have shown that seed priming and micro-dosing can increase yield at a low
cost [2–5,9,10,16]. Micro-dosing was also reported to improve the fertilizer use efficiency compared to
broadcasting of fertilizer [17]. The results from this study indicate that seed priming combined with
micro-dosing is not only an approach for sandy soils, but also works well on the cracking clay soil of
South Kordofan State. Most previous studies on micro-dosing have been with cereal crops, but this
study shows that micro-dosing and seed priming is also an appropriate technology in groundnut,
sesame, and cowpea. The yield increase observed for the best treatment compared to the control was
85%, 41%, 84% and 48% in sorghum, groundnut, sesame, and cowpea, respectively. The best
treatment with regard to net return in sorghum and groundnut was found to be seed priming in
combination with 0.9 g of NPK fertilizer, while 0.3 g and 0.6 g in combination with priming were the
doses with highest net returns in sesame and cowpea, respectively. These combinations were
significantly better than all other combinations including the control. Higher micro-dose response was
found in groundnut in the clay soils of South Kordofan State compared to the sandy soils of North
Kordofan State [10]. The highest fertilizer use efficiency (FUE) and value cost ratio (VCR)
corresponded with the combination which gave the highest total grain and biological yield, except for
Agronomy 2015, 5 488
sorghum. The results of this study show that the agronomic and economic benefits of micro-dosing can
be increased if it is combined with seed priming, as the VCR were generally higher when seed priming
was combined with micro-dosing, compared to when micro-dosing was used alone. Seed priming
therefore makes micro-dosing a safer investment. The on-farm study confirms that seed priming and
micro-dosing can greatly increase gross margin. This study shows that the type of crop onto which the
fertilizer is applied is of importance. If the objective is to have the highest possible economic return, it
is far better to apply the fertilizer in groundnut as the VCR for the best treatment in groundnut was
26.6, whereas the best VCR for sorghum, sesame, and cowpea were 12.5, 8.0, and 4.4, respectively.
This illustrates that applying micro-dosing combined with seed priming is a very safe investment as
the VCR should be above 2 and preferably above 4 under dry land conditions where the risk is
high [18]. This point can also be illustrated by looking at the increase in gross return from the control
to the best treatment. For groundnut, this increase was 5524 SDG/ha whereas it was 924, 607, and 285
for sorghum, sesame, and cowpea, respectively. The on-farm experiments also confirmed that the
highest return is found in groundnut. The main reason the return on fertilizer is higher in groundnut
compared to other crops is the high price of this crop compared to the other crops.
6. Conclusions
This study showed that it is possible to increase the productivity of sorghum, sesame, groundnut,
and cowpea in the semi-arid cracking clay of South Kordofan State at a low cost and at a very
moderate risk for farmers through seed priming and fertilizer micro-dose application. Seed priming
with micro-doses of 0.9 g improved crop establishment and seedling vigor of sorghum and groundnut,
while the combination of seed priming and 0.3 g micro-fertilization improved crop establishment,
seedling vigor and grain yield in sesame. Seed priming and micro-fertilization of 0.6 g improved crop
establishment and grain yield in cowpea. The highest economic return, FUE, and VCR corresponded
to the treatment which produced the highest grain and total biological yield in each crop. Seed priming
and micro-dosing can be considered as a safe option for farmers, particularly if used in groundnut
and sorghum.
Acknowledgments
Sincere thanks are due to the Sudan and Norway Drylands Coordination Group (DCG) for their
assistance and support that made this work possible. Our thanks are also extended to the Dry Lands
Research Center (ARC) and ADRA (Sudan) for their cooperation and facilitation. Thanks are due to
Mutaz M. Elsadig, Sudan, DCG coordinator, for his keen follow up and for facilitating the
implementation of the project. Special thanks to Edaw Mohamed Idris, technician at El-Obeid
Research Station, for his help in trial conduction and data collection. Sincere thanks are also extended
to Khalid Ali Issa and Faiz Ali Ahmed, the drivers who made the journeys to and from trial sites easy
and enjoyable. We are very grateful to the members of the communities who participated in the
implementation of the activities.
Agronomy 2015, 5 489
Author Contributions
The authors contributed to the design, implementation, analyzing and write-up of the paper.
Conflicts of Interest
The authors declare no conflict of interest.
References
1. Osman, A.K.; Ali, M.K. Crop production under traditional rain-fed agriculture. In Proceedings of
the National Symposium on: Sustainable Rain-Fed Agriculture, Khartoum, Sudan, 17–18 November
2009; pp. 113–131.
2. Hayashi, K.; Abdoulaye, T.; Gerard, B.; Bationo, A. Evaluation of application timing in fertilizer
micro-dosing technology on millet production in Niger, West Africa. Nutr. Cycl. Agroecosyst.
2008, 80, 257–265.
3. Klaij, M.C.; Genard, C.; Reddy, K.C. Low input technology options for millet based cropping
systems in the Sahel. Exp. Agric. 1994, 30, 77–82.
4. Aune, J.; Doumbia, M.; Berthe, A. Microfertilization sorghum and pearl millet in Mali. Outlook
Agric. 2007, 36, 199–203.
5. Aune, J.; Bationo, A. Agricultural intensification in the Sahel: The Ladder Approach. Agric. Syst.
2008, 98, 119–125.
6. Aune, J.B.; Ousman, A. Effect of seed priming and micro dosing of fertilizer on sorghum and
pearl millet in western Sudan. Exp. Agric. 2011, 47, 419–430.
7. Harris, D.; Pathan, A.K.; Gothkar, P.; Joshi, A.; Chivasa, W.; Nyamudeza, P. On-farm seed
priming: Using participatory methods to revive and refine a key technology. Agric. Syst. 2001, 69,
151–164.
8. Harris, D. Development and testing of “on-farm” seed priming. Adv. Agron. 2006, 90, 129–178.
9. Osman, A.K.; Abdalla, E.A.; Mekki, M.A.; Elhag, F.M.A.; Aune, J. Effect of seed priming and
fertilizer micro dosing on Traditional Rain-Fed Crops of North Kordofan. In Proceedings of the
49th National Crop Husbandry Committee Meeting, Wad Medani, Sudan, 21 December 2010.
10. Osman, A.K.; Aune, J.B. Effect of seed priming and micro dosing of fertilizer on groundnut,
sesame and cowpea in western Sudan. Exp. Agric. 2011, 47, 431–443.
11. Gomez, K.A.; Gomez, A.A. Statistical Procedures for Agricultural Research; Wiley: New York,
NY, USA, 1984; p. 680.
12. MSTAT-C. User’s Guide to MSTAT-C; MSTAT Development Team, Michigan State University:
East Lansing, MI, USA, 1983.
13. CIMMYT. From Agronomic Data to Farmer Recommendations: An Economics Training Manual;
CIMMYT: Batan, Mexico, 1998
14. MOA. Ministry of Agriculture, North Kordofan State, Department of Planning and Agricultural
Statistics, Agricultural Season Evaluation Report; MOA: Auckland, New Zealand, 2011.
15. Ashraf, C.M.; Abu-Shakra, S. Wheat seed germination under low temperature and moisture stress.
Agron. J. 1978, 70, 135–139.
Agronomy 2015, 5 490
16. Buerkert, A.; Bationo, A.; Piepho, H.P. Efficient phosphorus application strategies for increased
crop production in sub-Saharan West Africa. Field Crop. Res. 2001, 72, 1–15.
17. Tabo, R.; Bationo, A.; Hassane, O.; Amadou, B.; Fosu, M.; Sawadogo-Kabore, S.; Ndjeunga, J.;
Fatondji, D.; Korodjouma, O.; Abdou, A.; et al. Fertilizer Micro Dosing for the Prosperity of the
Resource Poor Farmers: A success story. In Proceedings of Increasing the Productivity and
Sustainability of Rainfed Cropping Systems of Poor Smallholder Farmers, Tamale, Ghana, 22–25
September 2008.
18. Koning, N.; Heerink, N.; Kauffman, S. Integrated Soil Improvement and Agricultural Development
in West Africa: Why Current Policy Approaches Fail; Wageningen Agricultural University:
Wageningen, The Netherlands, 1998.
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