1. Effects of micronutrients on maize grain yield and macronutrients uptake
Tafadzwa Chipangura

2. Introduction and Justification
Micronutrients are essential for plant growth and play an important role in balanced crop nutrition. They promote the strong ,steady growth of crops that produce higher yields and increase harvest quality- maximizing a plant’s genetic potential.
Most micronutrients are immobile in soils and plants. There is therefore need to supply additional micronutrients to the soil.

3. Main Objective
To determine the additional effects of micronutrients on maize grain yield and macronutrients uptake.

4. Specific Objectives
1. To determine the effect of adding Cu,Fe, Zn micronutrients on maize grain yield.
2. To determine the effect of adding Cu,Fe, Zn micronutrients on N, P,K,Ca and Mg uptake.

5. Approach
Soils were sampled and characterised before the start of the experiment
Treatments consisted of plots measuring 1m*1.5m laid out in a CRBD with treatments replicated 3 times. Soil pH was 5.9
Compound D was applied at a rate of 400kgs/ha. All treatments except control were top dressed with AN(split application at 4 and 6 weeks) at a rate of 300kgs/ha. Foliar application of micronutrients Zinc, Iron and Copper were applied at a rate of 5kgs/ha.

6. Approach Cont The following treatments were used: (i) Control
(ii) Cpd D
(iii) Cpd D + Zn +Cu
(iv) Cpd D + Zn + Fe
(v) Cpd D + Cu + Fe
(vi) Cpd D + Zn +Cu+ Fe

7. Approach Cont
Maize grain yield was determined at 12.5% moisture content and analysed for N,P, K, Ca,Mg, Zn, Fe, B & Cu. These will be evaluated against FAO/WHO standards for maximum permissible limits in maize grain.

8. Preliminary results for 2017/2018 season (1st Year)
Table 1: Average maize grain yield for 2017/2018 Season
Treatment
Grain yield(T/ha)
1(Control)
3.2
2(Cpd D)
4.60
3(Cpd D +Zn+Cu)
5.00
4(Cpd D+Zn+Fe)
5.33
5(Cpd D+Cu+Fe
6.07
6(Cpd D+Zn+Cu+Fe)
6.13

9. Preliminary results Cont
Fig 1:Average maize grain yield for 2017/2018 season

10. Maize grain analytical results
Table 3: Maize grain quality analytical results 2017/2018
Treatment
Analytical Results N
(%) P Ca K Mg Fe
(ppm) Mn Zn B Cu
1(Control)
0.17
0.14
0.15
1.9
0.16
35.5
23.4 18 16
4.6
2(Cpd D)
1.20
0.21
2.3 37 24 20 21
4.5
3(Cpd D +Zn+Cu)
1.24
0.35
0.38
3.11
0.19 38 22 36
17.7 6

11. Maize grain analytical results Cont
Table 3: Maize grain nutritional analytical results 2017/2018
Treatment
Analytical Results N
(%) P Ca K Mg Fe
(ppm) Mn Zn B Cu
4(Cpd D+Zn+Fe)
1.33
0.34
0.41
3.47
0.20
123 25 34
20.7 5
5(Cpd D+Cu+Fe
1.39
0.31
0.39
3.28
0.18
118 23 21 16
6.4
6(Cpd D+Zn+Cu+Fe)
1.41
0.46
0.43
3.51
0.22
127 24
34.5
18.7
6.1

12. FAO permissible standards
Element
Low
Sufficient
High N%
<3.5
>5 P%
<0.3
>0.5 K%
<2.5
>4.0
Ca%
>0.7
Mg%
<0.15
>0.45
Fe ,ppm
<50.0
50-250
>250
Mn, ppm
<20.0
20-300
>300
Zn,ppm
20-60
>60
Cu,ppm
<5.0
5-20
>20
B,ppm
5-25
>25

13. Inference of the grain nutritional value to FAO permissible standards
Overally elements such as P, K, and Ca have shown sufficient levels as compared to when Compound d was sorely applied.

14. What then can we infer from the results?
Initial results show there are additional benefits in adding micronutrients both in terms of yield and nutritional value of the grain

15. Thank you
Tatenda