REPORT TO
TRIOMF
ON
EVALUATION OF THE EFFICACY OF DIFFERENT TRI-CALCIUM PHOSPHATE AND MAP SOURCES ON GROWTH OF MAIZE
MAY 2013
BY
Dr J A Janse van Vuuren, Prof A S Claassens
TABLE OF CONTENT
1. INTRODUCTION 3
2. SCOPE 3
3. METHODS AND MATERIALS
3.1 Soil 3
3.2 Trial layout and application rates 3
3.3 Plant and soil sampling 4
3.4 Plant and soil Analyses 4
4 RESULTS AND DISCUSSION 5
4.1 Yield results 6
4.2 Plant analysis 6
4.3. Soil analyses 7
4 CONCLUSIONS 8
5 Statistical Analyses 10
6 PHOTOS 12
1. INTRODUCTION
This trial was conducted to evaluate the efficacy of the different P sources such as Tri-Calcium P alone and in combination with superphosphate at different levels compared to MAP as P sources for Maize production.
2. SCOPE
To evaluate the performance of maize when different sedimentary Tri-Calcium Phosphates are partially replace with superphosphate as P source in comparison with MAP on the bio-mass production of Maize after six weeks growth period under controlled greenhouse conditions.
3. METHOD
3.1. Soil
An acid sandy “Babsfontein” soil was used as growth medium in pots. The sandy acid soil was ameliorated with Lime, MgSO4 KCl to increase the pH and supplement the Ca, Mg and K contents that were very low.
3.2. Trial layout and application rates
Maize (PANNAR 6671) was planted on 07 February 2013.
Seed germinated on the 11th of February 2013.
The basic reference fertilizer is a bulk blend (3:2:1(20)), consisting of LAN, phosphate sources, KCl plus Zinc-Sulphate-Hepta-hydrate as well as ZnO, applied at the rates below in a band in the centre of the pot.
Additional treatments at double the application rate were also included in the treatments.
As a reference treatment a zero fertilizer treatment was added.
Each treatment was replicated 4 times.
A topdressing of Urea (4.34grams) plus K2SO4 (5grams) per Litre was mixed and 100cm3 applied per pot.
Table1. Different treatment applications
Treatment No. / Grams/potZinc Sulphate
1 / No Fertilizer
2 / LAN 1.17, Duiker-P 1.74 , KCl 0.22, ZnSO4.7H20 0.022
3 / LAN1.15, Duiker-P 1.28, Super-P 0.48, KCl 0.21, ZnSO4.7H20 0.022
4 / LAN 2.34, Duiker-P 3.48, KCl 0.44, ZnSO4.7H20 0.044
5 / LAN 2.30, Duiker-P 2.56, Super-P 0.96, KCl 0.42, ZnSO4.7H20 0.044
6 / LAN 1.19, ChIn.1.71, KCl 0.23, ZnSO4.7H20 0.023
7 / LAN 1.17, ChIn.1.25, Super-P 0.49, KCl 0.22, ZnSO4.7H20 0.022
8 / LAN 2.38, ChIn.3.42, KCl 0.46, ZnSO4.7H20 0.046
9 / LAN 2.34, ChIn.2.50, Super-P 0.98, KCl 0.44, ZnSO4.7H20 0.044
10 / LAN 1.08, Langfos 1.84, KCl 0.21, ZnSO4.7H20 0.023
11 / LAN1.09, Langfos 1.38, Super-P 0.45, KCl 0.21, ZnSO4.7H20 0.022
12 / LAN 2.16, Langfos 3.68, KCl 0.42, ZnSO4.7H20 0.046
13 / LAN 2.34, Langfos 2.76, Super-P 0.90, KCl 0.42, ZnSO4.7H20 0.044
14 / LAN 0.77, MAP 0.98, KCl 0.22, ZnSO4.7H20 0.023
15 / LAN1.54, MAP 1.96 0.44, KCl 0.21, ZnSO4.7H20 0.04
Zinc Oxide
2 / LAN 1.17, Duiker-P 1.74 , KCl 0.22, ZnO 0.01
3 / LAN1.15, Duiker-P 1.28, Super-P 0.48, KCl 0.21, ZnO 0.01
4 / LAN 2.34, Duiker-P 3.48, KCl 0.44, ZnO 0.02
5 / LAN 2.30, Duiker-P 2.56, Super-P 0.96, KCl 0.42 ZnO 0.02
6 / LAN 1.19, ChIn.1.71, KCl 0.23, ZnO 0.01
7 / LAN1.17, ChIn.1.25, Super-P 0.49, KCl 0.22, ZnO 0.01
8 / LAN 2.38, ChIn. 3.42, KCl 0.46, ZnO 0.02
9 / LAN 2.34, ChIn..2.50, Super-P 0.98, KCl 0.44, ZnO 0.02
10 / LAN 1.08, Langfos 1.84, KCl 0.21, ZnO 0.01
11 / LAN1.09, Langfos 1.38, Super-P 0.45, KCl 0.21, ZnO 0.01
12 / LAN 2.16, Langfos 3.68, KCl 0.42, ZnO 0.02
13 / LAN 2.34, Langfos 2.76, Super-P 0.90, KCl 0.42, ZnO 0.02
14 / LAN 0.77, MAP 0.98, KCl 0.22, ZnO 0.01
15 / LAN1.54, MAP 1.96 0.44, KCl 0.21, ZnO 0.02
The plants were harvested after 6 weeks on the 25nd of March 2013.
3.3. Plant and soil sampling
3.3.1 Plant sampling
At harvesting the plants in each pot were cut above the ground and weighed (wet mass) and after drying at 65ºC, weighed again (dry mass). The four replicates were then pooled and sent for a standard plant analyses. The dried mass was analysed for N, P, K, Ca, Mg, Na, Cl, S, Fe, Mn, Cu, Zn, B and Mo.
3.3.2 Soil sampling
The soil in the pots of the four replicates of each treatment was pooled, mixed thoroughly and then a representative sample was taken and sent for a standard soil analysis.
3.4. Plant and soil analyses
The plant and soil analyses were done by NviroLAB, Brits utilizing standard AgriLASA methods, (Handbook of Standard Analysis Methods for Plants and Feeds, Handbook of Standard Analysis Methods for Soils respectively), were utilized for the plant and soil samples.
4. RESULTS AND DISCUSSION
4.1 Yield results
Table2. Wet and dry bio-mass production after six weeks.
Treatment (gram/pot) / ZnSO4 grams/pot / ZnO grams/potWet / Dry / Wet / Dry
1. Control / 14.045 / 2.5075 / 14.045 / 2.5075
2. Duijker P1.74 / 12.94 / 2.71 / 8.43 / 1.6835
3. Duijker P1.28, SuperP0.48 / 37.8425 / 5.9025 / 44.7275 / 6.4475
4. 2xDuijker P3.48, / 11.065 / 2.5025 / 14.9 / 2.855
5. 2x Duijker 2.56g + SP 0.96g / 50.0725 / 6.905 / 43.8275 / 6.105
6. Chin. 1.71g / 10.47 / 2.195 / 13.035 / 2.5175
7. Chin.1.25g +SP 0.49g / 27.4925 / 4.5725 / 8.265 / 2.25
8. 2x Chin.3.42g / 10.9625 / 2.515 / 12.4575 / 2.8425
9. 2x Chin. 2.5g +SuperP 0.98g / 27.8475 / 4.035 / 20.945 / 3.9475
10. Langfos P1.84g / 14.7725 / 2.59 / 8.1775 / 2.365
11. Langfos P 1.38g +SuperP 0.45g / 35.45 / 4.32 / 48.575 / 8.4175
12. 2x Langfos P 3.68g / 12.71 / 2.015 / 13.5475 / 3.0475
13. 2x Langfos P 2.76g+ SuperP0.9g / 82.1675 / 8.8825 / 60.95 / 7.8575
14. MAP 0.98g / 133.975* / 22.16* / 127.055* / 18.278*
15. 2xMAP 1.96g / 144.25* / 20.865* / 156.75* / 22.295*
SUM / 626.0625 / 94.6775 / 595.6875 / 93.4085
AVERAGE / 41.7375 / 6.311833 / 39.7125 / 6.227233
STD.DEV. / 44.07998 / 6.480188 / 45.2185 / 6.140238
Statistically significantly higher/lower than average bio-mass production
From Table2, the following observations can be made:
Only the MAP treatments and the higher application of the Langfos treatment
ameliorated with Superphosphate gave significantly higher bio-mass productions
compared to the average. The MAP treatments were “highly significantly*” (Two
standard deviations compared to the average. At least 25% amelioration of the
Langfos with a water soluble phosphate source is required.
The symbiotic effect of the combined Nitrogen and Phosphate is clearly illustrated
when bio-mass production (indicative of potential yield) of the MAP is compared to
applications of separate commodities of Nitrogen and Phosphate such as the
LAN and the different phosphate sources.
Of the three Tri-Calcium sources, Langfos performed the best on its own, followed
by the control, Duijker Eil. and Chin., for both zinc sulphate and
oxide applications. When ameliorated with Superphosphate Duijker Eiland-P
numerically performed the best followed by Chin. At the higher application
Langfos performed the best on the wet basis but not on the dry basis.
At the higher ameliorated applications the Langfos again out-performed the other
two products.
When comparing the efficacy of the two zinc sources the zinc sulphate
outperformed the zinc oxide. This confirms earlier and recent findings as to the
efficacy of the two products.
4.2 Plant analyses
From Tables 3 and 4 of the plant analyses data the following observations are clear.
The MAP over-all had the lowest nutrient content as would be expected as the
higher bio-mass production caused a dilution of nutrients. Except for the fact that in
all treatements where the Tri-calcium P was supplemented with Super phosphate
the nutrient content in the leaves were lower due to the dilution effect when the
yields were higher, no clear patterns emerged from the rest of the nutritional
elements.
The phosphate levels in the MAP treatments were significantly higher than the rest again confirming the better P source and perhaps the symbiotic effect of the Nitrogen and Phosphate because with MAP most of the nutrient contents were higher at the higher P levels although the yields were higher. It also indicates that the supply rates of the Tri-Calcium Phosphates are inadequate for annual crop productions such as maize that require fresh water soluble (available) phosphate supply during the early growth stages.
Table3. Plant analysis results as influenced by P sources and Zinc Sulphate
N / Ca / Mg / K / S / P / Na / Fe / Mn / Cu / Zn / Mo / BZinc Sulphate / % / mg/kg
1. Conrol / 2.13 / 0.85 / 0.61 / 2.51 / 0.25 / 0.15 / 90 / 340 / 368 / 7 / 27 / 4.02 / 8
2. Duijker P1.74 / 3.53 / 1.21 / 0.66 / 3.80 / 0.23 / 0.08 / 108 / 254 / 396 / 8 / 42 / 1.83 / 10
3. Duiker P1.28, SuperP0.48 / 2.56 / 0.83 / 0.59 / 2.86 / 0.16 / 0.07 / 74 / 176 / 280 / 5 / 27 / 3.41 / 7
4. 2xDuiJker P3.48, / 4.12 / 1.32 / 0.55 / 3.66 / 0.25 / 0.08 / 133 / 238 / 389 / 8 / 39 / 1.33 / 9
5. 2x DuiJker 2.56g + SP 0.96g / 3.00 / 0.89 / 0.45 / 3.07 / 0.15 / 0.08 / 69 / 149 / 246 / 5 / 35 / 1.85 / 8
6. Chin. 1 1.71g / 3.66 / 1.30 / 0.62 / 3.74 / 0.23 / 0.07 / 89 / 255 / 474 / 8 / 33 / 0.90 / 11
7. Chin.1.25g +SP 0.49g / 3.22 / 1.13 / 0.64 / 3.23 / 0.20 / 0.07 / 97 / 182 / 318 / 6 / 32 / 3.40 / 11
8. 2x Chin.3.42g / 4.43 / 1.29 / 0.53 / 3.84 / 0.25 / 0.07 / 101 / 271 / 451 / 8 / 35 / 1.48 / 10
9. 2x Chin.2.5g +SuperP 0.98g / 3.68 / 1.20 / 0.54 / 4.01 / 0.19 / 0.08 / 85 / 183 / 352 / 6 / 44 / 2.25 / 8
10. Langfos P1.84g / 3.49 / 1.30 / 0.65 / 3.82 / 0.20 / 0.07 / 80 / 179 / 440 / 8 / 40 / 0.67 / 10
11. Langfos P 1.38g +SuperP 0.45g / 2.85 / 0.94 / 0.57 / 2.98 / 0.17 / 0.09 / 67 / 148 / 318 / 6 / 32 / 4.08 / 8
12. 2x langfos P 3.68g / 4.20 / 1.23 / 0.54 / 3.52 / 0.22 / 0.08 / 108 / 182 / 453 / 9 / 43 / <0.10 / 11
13. 2x Langfos P 2.76g+ SuperP0.9g / 2.70 / 0.79 / 0.49 / 3.12 / 0.15 / 0.08 / 76 / 117 / 211 / 4 / 31 / 1.39 / 6
14. MAP 0.98g / 1.85 / 0.49 / 0.48 / 1.10 / 0.18 / 0.24 / 58 / 104 / 153 / 4 / 19 / 1.37 / 4
15. 2xMAP 1.96g / 2.57 / 0.54 / 0.54 / 1.60 / 0.16 / 0.46 / 58 / 123 / 180 / 5 / 19 / 0.71 / 4
Table4. Plant analysis results as influenced by P sources and Zinc oxide
N / Ca / Mg / K / S / P / Na / Fe / Mn / Cu / Zn / Mo / BZinc Oxide / % / mg/kg
1. Conrol / 2.13 / 0.85 / 0.61 / 2.51 / 0.25 / 0.15 / 90 / 340 / 368 / 7 / 27 / 4.02 / 8
2. Duijker P1.74 / 3.82 / 1.39 / 0.72 / 4.01 / 0.24 / 0.07 / 81 / 199 / 516 / 8 / 30 / 3.04 / 10
3. Duiker P1.28, SuperP0.48 / 2.71 / 0.92 / 0.59 / 2.96 / 0.15 / 0.07 / 61 / 112 / 254 / 4 / 31 / 1.70 / 6
4. 2xDuiJker P3.48, / 4.35 / 1.19 / 0.57 / 3.95 / 0.25 / 0.10 / 103 / 250 / 429 / 7 / 35 / 0.17 / 11
5. 2x DuiJker 2.56g + SP 0.96g / 3.06 / 1.00 / 0.47 / 3.52 / 0.18 / 0.09 / 71 / 114 / 263 / 4 / 43 / 3.50 / 8
6. Chin.. 1 1.71g / 3.31 / 1.06 / 0.62 / 3.75 / 0.20 / 0.08 / 77 / 144 / 388 / 7 / 30 / 1.21 / 10
7. Chin. 1.25g +SP 0.49g / 3.87 / 1.45 / 0.77 / 3.54 / 0.26 / 0.07 / 103 / 166 / 376 / 7 / 25 / 2.68 / 10
8. 2x Chin.3.42g / 4.48 / 1.35 / 0.56 / 4.04 / 0.24 / 0.08 / 116 / 174 / 495 / 7 / 31 / 2.31 / 10
9. 2x Chin.2.5g +SuperP 0.98g / 3.82 / 1.06 / 0.45 / 3.52 / 0.22 / 0.09 / 79 / 132 / 298 / 5 / 34 / 1.50 / 10
10. Langfos P1.84g / 3.00 / 0.96 / 0.60 / 2.55 / 0.20 / 0.09 / 86 / 140 / 303 / 5 / 33 / 1.99 / 7
11. Langfos P 1.38g +SuperP 0.45g / 2.44 / 0.88 / 0.60 / 2.24 / 0.17 / 0.09 / 69 / 112 / 289 / 5 / 30 / 2.10 / 6
12. 2x langfos P 3.68g / 4.34 / 1.16 / 0.62 / 3.64 / 0.26 / 0.08 / 101 / 172 / 358 / 7 / 34 / <0.10 / 8
13. 2x Langfos P 2.76g+ SuperP0.9g / 2.99 / 0.83 / 0.41 / 3.26 / 0.18 / 0.11 / 64 / 121 / 224 / 5 / 30 / 0.89 / 7
14. MAP 0.98g / 2.06 / 0.55 / 0.54 / 1.42 / 0.21 / 0.29 / 63 / 151 / 193 / 6 / 16 / 0.93 / 4
15. 2xMAP 1.96g / 2.79 / 0.59 / 0.55 / 1.77 / 0.21 / 0.51 / 46 / 119 / 198 / 5 / 11 / 0.53 / 5
4.3 Soil analyses
From the analyses results shown in Tables 5 and 6 the following was observed.
Soil pH:
No clear differences in the effect of the different P-sources on the pH’s of the soil
were observed. It was expected that the addition of water soluble superphosphate
which usually contains free acid, would lower the pH. The fact that the pH’s were
not effected could be explained by the buffering effect of P on soil as the H2PO4-
binds with free H+.
Soil P:
The only product which had an immediate effect in contributing to the
Bray1 plant available phosphate was MAP. The fact that even where the Tri-
Calcium Phosphate sources were ameliorated with Superphosphate, no increases
In Bray1 P was observed. It must be kept in mind that these observations are
short term. It is expected that the Tri-Calcium sources would over time add to the
Bray1 P under acid soil conditions. It is further clear that these sources of P are not
suitable for annual crops such as maize, especially in the short term.
Cations and S:
No clear patterns observed apart from the lower values of the MAP