effect of foliar fertilizer in shallot and potato · ml/l of supergro for potato) was weekly...

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Herman de Putter, Witono Adiyoga, Tonny K. Moekasan,

Laksminiwati Prabaningrum and Joko Sugiharto

vegIMPACT Report 41

September 2017

Effect of foliar fertilizer in shallot and potato

vegIMPACT Report 41 – Effect of foliar fertilizer in shallot and potato

vegIMPACT is a program financed by The Netherlands’ Government promoting improved vegetable

production and marketing for small farmers in Indonesia, contributing to the food security status and

private sector development in Indonesia. The program builds on the results of previous joint Indonesian-

Dutch horticultural development cooperation projects and aligns with recent developments in the

horticultural private sector and retail in Indonesia. The program activities (2012 – 2016) include the

Development of Product Market Combinations, Strengthening the Potato Sector, Development of

permanent Vegetable Production Systems, Knowledge Transfer and Occupational Health.

Wageningen University & Research, the Netherlands:

- Wageningen Plant Research, Lelystad

- Wageningen Centre for Development Innovation (CDI), Wageningen

- Wageningen Plant Research, Wageningen

- Wageningen Economic Research, Den Haag

Wageningen University & Research

Contact person: Huib Hengsdijk, [email protected]

Indonesian Vegetable Research Institute (IVEGRI, Indonesia)

Contact person: Witono Adigoya, [email protected]

Fresh Dynamics (Indonesia)

Contact person: Marcel Stallen, [email protected]

Website: www.vegIMPACT.com

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Effect of foliar fertilizer in shallot and potato

Herman de Putter, Witono Adiyoga, Tonny K. Moekasan, Laksminiwati Prabaningrum and Joko Sugiharto


Table of Contents

Abstract ........................................................................................................................................................ 5

1. Introduction .......................................................................................................................................... 6

2. Materials and methods ........................................................................................................................ 7

2.1 Shallot ........................................................................................................................................... 8

2.2 Potato ........................................................................................................................................... 8

2.3 Observations and analyses ........................................................................................................... 9

3. Results ................................................................................................................................................ 10

3.1 Shallot ......................................................................................................................................... 10

3.1.1 Climatic data ....................................................................................................................... 10

3.1.2 Plant development ............................................................................................................. 10

3.1.3 Pests and diseases .............................................................................................................. 11

3.1.4 Yield .................................................................................................................................... 12

3.2 Potato ......................................................................................................................................... 12

3.2.1 Plant development ............................................................................................................. 12

3.2.2 Pests and diseases .............................................................................................................. 13

3.2.3 Yield .................................................................................................................................... 16

4. Conclusions ......................................................................................................................................... 18

5. References .......................................................................................................................................... 19

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Abstract

The effect of foliar fertilizer on the yield of shallot and potato was tested during the dry season of 2015. Shallot was grown in the lowland and potato in the highland of West Java, Indonesia. Crops were grown using standard granular fertilizer soil applications. Foliar fertilizer (2ml/l of HCS(SOT) for shallot and 2 ml/l of Supergro for potato) was weekly applied to the crops with and without a pesticide spraying solution.

The use of foliar fertilizer in shallot and potato did not result in higher yields. The use of foliar fertilizer even resulted in a lower fresh yield of shallot, but no differences were observed in the dry shallot yield. No differences were observed in crop development, pest and disease development and yields of potato and shallot by applying foliar fertilizers with or without pesticides.

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1. Introduction

Plant nutrition is crucial for optimal plant growth and production. The most common way to provide nutrients to the plants is by applying organic or inorganic fertilizers through soil treatments. Since the last decades, the agro-industry has strongly promoted the use of relatively expensive foliar fertilizers for vegetable crops in Indonesia. This has led farmers to believe that it is necessary to use foliar fertilizer to obtain high yields. Foliar fertilizers are sprayed onto the crops and consequently are taken up by the plants through the leaves. These foliar fertilizers, next to the macronutrients N, P and K, contain a range of micronutrients that are not present in the standard inorganic fertilizers such as Urea, SP-36 and KCl. The most widely used NPK fertilizer by vegetable farmers is NPK 15-15-15 (Phonska) that only contains sulphur and zinc. Farmers usually apply the foliar fertilizers in a mix with pesticides used to control pests and diseases. This may affect the uptake of fertilizer or efficacy of foliar fertilizer. Another problem is that farmers commonly spray with high water volumes that might result in high amounts of spray solution running off the plants to the soil (Van den Brink et al., 2015) Potato (Solanum tuberosum) and shallot (Allium cepa var. aggregatum) are two important crops in Indonesia in which high volumes of foliar fertilizers are applied (unpublished data Permveg). The leaf structure of these crops is different: Potato has broad leaves almost perpendicular to the spray direction ensuring good contact of the sprayed droplets. In contrast, shallot has waxy small upright standing round leaves that make contact with droplets difficult. This report describes the results of an experiment in potato and shallot to test the effect of foliar fertilizer on crop development, pest and disease development and yields of potato and shallot.

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2. Materials and methods

The experiment with foliar fertilizers in shallots (cv. Bima Curut) was carried out in Sumber lor, one of the lowland areas in West Java (10 m ASL). The experiment with foliar fertilizers in potato (cv. Granola) was carried out in Lembang, a highland area in West Java (1225 m ASL). See Table 2.1 for typical soil characteristics of both test sites. Table 2.1. Soil nutrient status of fields typical for the test locations Sumber lor and Lembang.

Lembang Sumber Lor

pH (KCl)

5.05 5.15

NO3-N mg/kg 41.3 110.3

NH4-N mg/kg 16.7 10.6

C % 0.24 0.31

P-Bray1 mg/kg 7 12

K mg/kg 247 433

Na mg/kg 21 182.5

Ca mg/kg 1340 6219

Mg mg/kg 134 1583

CEC

Ca++ % 78.8 67.6

Mg++ % 12.8 28.2

K+ % 7.4 2.4

Na+ % 1.1 1.7

Fe HCl mg/kg 8.2 9.1

Mn HCl mg/kg 41.6 91.9

Cu HCl mg/kg 3.5 3.0

Zn HCl mg/kg 13.6 3.2

Clay % 9 43

Silt % 20 50

Sand % 71 8

We used three treatments (Table 2.2): A Foliar fertilizers and pesticides simultaneously applied in a mix, B Pesticide only applied without the use of foliar fertilizers, and C Foliar fertilizers and pesticides applied in different sprays. The two treatments with foliar fertilizers (A) and (C) received weekly a fertilizer application. Treatment (C) with the separate application of pesticides and foliar fertilizers was only given in potato: Foliar fertilizer and pesticides were applied on the same day but the fertilizer in the morning hours between 9 and 11, and the pesticides in the late afternoon. Table 2.2 Foliar fertilizer treatments in shallot and potato.

shallot Potato

A Foliar + pesticide spray YES YES

B No foliar only pesticide spray YES YES

C Foliar and separate pesticide sprays - YES

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In shallot, the foliar fertilizer HCS (SOT) was used, and in potato, the foliar fertilizer Supergro was used

(Table 2.3). In treatment A and B of potato also the nitrophenolates-based plant stimulant Atonik was

sprayed. It is believed to enhance the uptake of nutrients, but Przybysz et al. (2014) observed no

increase in yield, despite a higher calcium and phosphorus content in cucumber leaves.

Table 2.3 Nutrient content of the foliar fertilizer HCS (SOT) and Supergro used in shallot and potato,

respectively.

nutrient N P2O5 K2O SO4 Mg Fe Cu Mo Zn

unit % % % % % ppm ppm ppm ppm

HCS (SOT) 13.0 5.1 14.2 3.2 0.03 42.0 0.6 0.5 27.8

Supergro 20.0 5.3 5.6 y 3.7 y y y y

y= present but no data on quantity.

The experiments were carried out in a randomized block design with five blocks for shallot and a randomized block design with nine blocks for potato. Data were analysed by using Genstat.

2.1 Shallot

The planting date of shallot was 21 August 2015 and the harvesting date was 13 October 2015. The plot size was 1.5 x 9 m. Basal fertilization was applied two days before planting with 533 kg/ha NPK 15-15-15, 59 kg/ha SP-36 and 37 kg/ha KCl. Ten and 30 days after planting a side dressing with 185 kg/ha urea and 407 kg/ha Ammonium Sulphate, respectively, was given. The total amount of N-P2O5-K2O given was 250, 101 and 102 kg/ha, respectively. Starting 10 days after planting the foliar fertilizer HCS (SOT) (Table 2.2) was weekly applied at a rate of 2 ml/l with 400 l/ha for eight weeks. This resulted in a total of 6.4 litre HCS and an equivalent of 0.8 kg/ha N, 0.3 kg/ha P2O5 and 0.9 kg/ha K2O. This amount is relatively small compared to the total amounts applied with granular fertilizer. Nevertheless, Treatment (B) without foliar fertilizer received a comparable amount of N, P2O5 and K2O on top of the side dressings using Urea or ammonium sulphate, SP 35 and KCl only on top of the fertilizer rates stated before. Thus, the differences in applied nutrients among the three treatments were the amount of trace elements (only applied with the foliar fertilizer) and the method of application. There were no differences for macronutrients applied among the treatments. For controlling pests and disease, shallots were sprayed with Dithane or Delsene (fungicide) and Starelle (insecticide). Unfortunately, due to miscommunication, also, hand picking of caterpillars took place and infected leaves with the caterpillars were removed and destroyed.

2.2 Potato

The planting date was 15 July 2015 with a planting distance of 60 x 30 cm, and the harvesting date was 14 November 2015. Plots were 2.6 m x 6 m containing 80 plants. Nutrients were applied with standard chemical fertilizers and manure. Basal fertilization was carried out

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two days before planting by applying 18.75 t/ha manure, 635 kg/ha NPK 15-15-15, 433 kg/ha SP-36 and 267 kg/ha KCl. Four weeks after planting a side dressing of 233 kg/ha Urea was applied. Total N-P2O5-K2O applied with chemical fertilizer in this way was 202, 251 and 255 kg/ha, respectively. The foliar fertilizer Supergro and the growth regulator Atonik (sodium nitro phenol compounds) were weekly sprayed, starting three weeks after planting up to harvesting, resulting in 14 applications. A total of 9 litre Supergrow was sprayed in this way resulting in 1.8 kg/ha N, 0.5 kg/ha P2O5 and 0.5 kg/ha K2O To apply the same amounts of macro elements to all treatments, for the treatment (B) without foliar fertilizer a comparable amount of N, P2O5 and K2O from Urea or ammonium sulphate, SP 35 and KCl was added as side dressing. Thus, the nutrient differences among the three treatments were only the amount of trace elements and the method of application. . Potato was sprayed starting three weeks after planting with the fungicide of Daconil 70 WP (chlorothalonil) and the insecticides of Kardan 50 WP and Endure 50 EC.

2.3 Observations and analyses

Every five days pests and diseases were observed using leaf, plant or plot counting. For plant and leaf observations, randomly 10 plants out of the plot were selected. These plants could be different for each observation date. For the leaf observation, randomly one leaf per plant was selected. Number of pests individuals was counted consequently per plant or leaf. For some pests and the diseases, the number of plants per plot with presence or a symptom of the pest or disease was counted and a percentage of attacked plants was calculated. In shallot, Spodoptera exigua was observed in different ways. Egg packages of this pest were counted per plot. Number of caterpillars present on the leaves were counted per plot. Number of leaves per plant from 10 selected plants with visible Spodoptera damage were counted and a percentage of damaged leaves of the total observed leaves present was calculated. Based on field observations the Area Under the Disease Progress Curve (AUDPC) or Area Under the Pest Progress Curve (AUPPC) was calculated with the following formula:

Where Yi is the disease or pest level at a certain date (ti) and Yi+1 at the following observation date (ti+1) (Madden et al. 2007). For shallot only the AUDPC for Spodoptera was calculated, while for potato both a AUDPC and AUPPC was calculated for a range of diseases and pests, respectively, observed during the growing season. During crop development, the number of leaves in the shallot crop were weekly counted and the plant height was weekly measured in the potato crop. At harvest, the total yield and yield per grade was weighed (kg) and the number of tubers or bulbs were counted. Grade A are the bigger tubers with 2-5 tubers per kg, B is 6-8 tubers per kg and Grade C has 10-12 tubers per kilogram.

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3. Results

3.1 Shallot

3.1.1 Climatic data

No precipitation was observed during the shallot test in Cirebon. Maximum temperature was about 40oC during the entire period form planting until harvesting (Fig. 3.1). Minimum temperature was mostly about 25oC with some lower temperatures towards 20oC at the end of September.

Figure 3.1 Daily maximum and minimum temperature (oC) at Cirebon during the shallot test period.

3.1.2 Plant development

Around October1, the number of plant leaves in the treatment without foliar fertilizer was slightly higher than in the treatment with foliar fertilizer possible because of more pests and diseases present. (Fig. 3.2).

Figure 3.2. Development of shallot leaves (number per plant).

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3.1.3 Pests and diseases

In shallot, only Spodoptera exigua was observed. The treatment (A) with mixed pesticides and foliar fertilizers showed more Spodoptera egg packages than the treatment (B) without foliar fertilizer. (Fig. 3.3).

Figure 3.3 Number of Spodoptera exigua egg packages in shallot. There was no significant difference in the number of caterpillars between both treatments (Fig. 3.4).

Figure 3.4 The number of damaged shallot leaves per 10 plants by Spodoptera exigua caterpillars. Except for egg packages, all Spodoptora exigua AUPPC’s showed no significant differences between the two treatments (Table 3.1). Despite the higher number of egg packages in treatment A the AUPPC’s for larva and the number of infected leaves was the same as in treatment (B).

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Table 3.1 AUPPC of different Spodoptera exigua observation methods in shallot. AUPPC Treatment (B)

Without foliar

Treatment (A)

With foliar

Average p LSDɑ=0.05

Egg package (no./plot) 4.0 16.3 10.2 0.05 12.6

Caterpillars on plants (no./plot) 3.2 6.4 4.8 0.2 6.5

Damaged leaves (number) 151.7 124.7 138.2 0.1 37.1

Damaged leaves (% of total leaves) 44.2 35.0 39.6 0.1 12.7

3.1.4 Yield

Fresh shallot yield without foliar fertilizers (treatment B) was significantly higher than that with foliar fertilizer (Table 3.2). However, final dried and cleaned weight for both treatments was about the same. Table 3.2 Yield of shallot in two treatments, pesticides only (Treatment B) and pesticides applied in

combination with foliar fertilizer (Treatment A).

Product Treatment (B)

No foliar

Treatment (A)

With foliar


Fresh 13 Oct 2015 48.5 44.5 46.5 0.058 4.2

Dried 16 Oct 2015 36.2 32.6 34.4 0.037 3.2

Dried cleaned 22 Oct 2015 31.0 29.4 30.2 0.12 2.3

3.2 Potato

3.2.1 Plant development

Potato plants of all three treatments showed a similar plant height development (Fig. 3.5). A maximum height of approximately 43 cm was reached around September 1.

Figure 3.5 Plant height of potato plants (cm).

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3.2.2 Pests and diseases

Different pests and diseases were observed in the potato experiment: plants affected by virus, thrips, aphids, white fly, Liriomyza, Spider mite, potato tuber moth, Epilachna beetles, Phtorimaea opercullela, Spodoptera litura, Bacterial Wilt, Clavibacter, Fusarium and alternaria (early blight). For all these an AUDPC or AUPPC was calculated. Population development of some of them is shown in the following graphs. Development of the thrips population in potato was the same in all treatments with a peak of more than three thrips per leaf by the end of August (Fig. 3.6).

Figure 3.6 Number of thrips per leaf. Aphids were present in all treatments and a peak was observed early September (Fig. 3.7). No distinctive differences between the three treatments were identified.

Figure 3.7 Number of aphids per leaf. The white fly population in potato gradually increased from the beginning of August with a slight decrease at the end of August after which the population increased again to a number of 3 to 3.5

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whiteflies per leaf (Fig. 3.8). Between the three treatments were no differences in the number of white fly.

Figure 3.8 Number of white fly per leaf. Potato tuber moths showed a peak at the end of August (Fig. 3.9). After mid-September, the moth population increased again. Between the three treatments were no differences in the number of tuber moths.

Figure 3.9 Number of potato tuber moth (P. oppercullela) per plant. The population of Epilachna beetles was the highest at the end of August after which it decreased (Fig. 3.10). Differences among the treatments were small.

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Figure 3.10. Presence of Epilachna in potato (percentage plants attacked). In addition, Spodoptera litura was present in potato and increased until September after which the number of caterpillars decreased (Fig. 3.11).

Figure 3.11. Presence of Spodoptera litura in potato (percentage of plants attacked). Percentage of plants with early blight (Alternaria) showed a small peak by the end of August after which it showed a sharp increase until the harvest (Fig. 3.12). Differences among the treatments were small.

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Figure 3.12. Presence of Alternaria in potato (percentage of plants attacked). Based on the pest and disease development, AUDPS or AUPPC’s were calculated for the described diseases and pests and a number of other observed diseases (Table 3.3). No significant differences were observed for all diseases and pests in potato. Table 3.3 AUDPC or AUPPC of different diseases and pests observed in potato. Pest or disease Foliar with

pesticide (A) Separate

pesticide (B) No foliar

(C) Average p LSDɑ=0.05

P. infestans (% plants) 0.0 9.3 3.1 4.1 0.5 17.4

Alternaria (% plants) 204.6 220.9 218.6 214.7 0.7 48.0

Fusarium (plants/plot) 2.4 1.0 5.4 2.9 0.4 6.7

Virus (% plants) 0.0 0.0 1.0 0.3 0.4 1.7

Spider mite (% plants) 9.1 11.2 17.3 12.5 0.5 15.5

Liriomyza sp. (% plants) 29.0 25.9 30.2 28.4 0.8 12.8

Thrips (no./leaf) 71.6 71.0 68.8 70.4 0.8 9.7

Aphids (no./leaf) 47.2 42.7 48.0 45.9 0.5 10.6

White fly (no./leaf) 107.4 103.4 103.8 104.9 0.5 7.8

Spodoptera litura (% plants) 129.2 123.6 128.3 127.0 0.9 47.3

Epilachna sp. (% plants) 208.7 221.7 223.8 218.1 0.7 39.8

Phthorimaea opercullela (no./plant) 15.9 14.9 14.2 15.0 0.6 3.6

P. opercullela (% plants) 8.2 9.9 15.6 11.2 0.2 7.9

3.2.3 Yield

No significant yield differences among the treatments were observed in potato, neither for total yield nor for the yield per class (Table 3.4). Without foliar fertilizers, the average tuber weight of Class A and Class B potatoes tended to be larger than with foliar fertilizer.

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Table 7. Yield (classes) of potato in three foliar fertilizer treatments.

Foliar with pesticide (A)

Separate pesticide (B)

No foliar (C)


Class A (t/ha) 2.7 2.8 2.9 2.8 0.9 0.9

Class B (t/ha) 6.7 6.3 6.3 6.4 0.8 1.4

Class C (t/ha) 8.0 8.1 8.3 8.1 0.9 1.4

Marketable yield (ton/ha) 17.2 17.5 17.5 17.4 0.8 1.1

Total yield/ha 17.7 17.9 18.0 17.9 0.9 1.1

Tuber weight Class A (g) 125.8 119.6 140.4 129.0 0.06 16.8

Tuber weight Class B (g) 65.1 67.5 72.2 68.2 0.08 6.2

Tuber weight Class C (g) 29.6 27.7 28.1 28.4 0.6 4.3

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4. Conclusions

Mixing pesticides with foliar fertilizer has little effect on pest and disease control in potato. In shallot, more Spodoptera egg packages and less plant leaves, possible because of Spodoptera, could be a result of reduced pesticide efficacy due to the mixed application of pesticides with foliar fertilizer. However, no clear impact of mixing foliar fertilizer with pesticides on the efficacy of the pesticides were found. However, the non-planned hand picking of caterpillars may have disturbed the results. No effects of foliar fertilizer on potato and shallot yield have been observed. Potato and shallot were both grown on fertile soils (Table 2.1), which could have reduced the effect of foliar fertilizers on yields. These soils contain enough trace elements and production is not limited by these nutrients. Furthermore, the amounts of granular fertilizer are more than sufficient to support optimal plant growth in terms of N, P2O5 and K2O requirements while the amounts applied with foliar fertilizer are minimal. The use of foliar fertilizer in shallot had even a significant negative effect on the fresh yield, but this yield difference disappeared after drying of the shallots (Table 3.2). The experiments with shallot in Sumber lor and potato in Lembang do not show the need for farmers to apply relatively expensive foliar fertilizers in vegetables. Further research may give insight in yield effects of foliar fertilizers under less fertile soil conditions.

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5. References

Van den Brink, L., Gunadi, N., Uka, Wustman, R., Moekasan, T.K., Hengsdijk, H., 2015. Agronomics and economics of potato production in West Java, Indonesia. Wet season 2013/2014. vegIMPACT External Report 17. Wageningen UR, The Netherlands. Madden, L.V., Hughes, G., Van Den Bosh, F., 2007. The Study of Plant Disease Epidemics. APS Press, Saint Paul, USA. Przybysz, A., Gawrońska, H., Gajc-Wolska, J., 2014. Biological mode of action of a nitrophenolates-based biostimulant: case study. Front Plant Sci. 5, 713: 1-15.

effect of foliar fertilizer in shallot and potato · ml/l of supergro for potato) was weekly...

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