Annals of Sri Lanka Department of Agriculture. 2007.9:71-80.
EFFECT OF HIGH GRADED EPPAWALA ROCK PHOSPHATE (HERP) ON THE PERFORMANCE OF BANANA UNDER LOW AND HIGH PHOSPHORUS CONTAINING RHODUDALTS SOILS J.M.P.B. JAYASUNDARA and H.M.N.K. HURUGGAMUWA Horticultural Crop Research and Development Institute, Gannoruwa, Peradeniya
ABSTRACT Selectively mined High Graded Eppawala Rock Phosphate (HERP) was tested as a P source for five crop cycles of Ambon banana under low (<5ppm) and high (>10ppm) available P containing Reddish Brown Latosolic soils (Rhodudalts) and compared with full and partial replacement of Triple Super Phosphate (TSP), normal Eppawala Rock Phosphate (ERP), Cattle Manure (CM) and with no P as a control treatment. In the high P containing soil, continuous depletion of available soil P was observed in the control treatment where as fully and partial use of HERP maintained optimum soil P levels up to the third crop and then declined. Under low available soil P situation, continuous decline in available soil P was observed in all treatment at the second crop stage except TSP, which maintained soil P continuously. Leaf P contents also followed almost similar trends as soil P. Under high soil P situation, no yield difference was observed between TSP and HERP up to the third crop stage but at the fourth and fifth crop stages it was 31.9 and 24.5% respectively. This yield reduction was further enhanced in low available soil P conditions at the fourth and fifth crop stages accounting to 48 and 43% respectively. The total yields of five crop cycles revealed that all the treatments except ERP and the control, induced higher yields under high available soil P conditions; under low available soil P conditions, TSP and partial use of TSP with HERP produced similar and higher yields. Results suggested that either HERP or ERP can be used as P sources for three crop cycles under rich available soil P conditions and for two crop cycles under poor available soil P conditions. Cattle manure produced similar yields as HERP in both conditions. Partial use of TSP with HERP was found to be better than HERP alone for five crop cycles of banana under both available soil P conditions. KEYWORDS: Available P, Banana, Cattle manure, ERP, HERP, TSP, Yield.
INTRODUCTION Banana is the major fruit crop grown in Sri Lanka and the current extent is about 50,000 hectares. The majority is grown in home gardens but is now gradually moving towards commercial scale cultivation. Nutrient management practices for banana at home garden level is neglected but market oriented growers use adequate amounts of chemical fertilizers which is estimated as high as 1/3 of cost of cultivation (Jayasundara and Gunathilake, 2006). Banana is a heavy feeder of plant nutrients but it draws nutrients from a very limited soil volume as it has a shallow root system. Phosphorus is an important nutrient for banana but reserve P in the rhizome may be sufficient to sustain early growth. The importation of phosphate fertilizer for various crop sectors in Sri Lanka in 2002 was about 50,000t
72 JAYASUNDARA AND HURUGGAMUWA
which costed Rs. 800 million. This causes a heavy drain on the foreign exchange reserves. It is therefore necessary to find an effective alternate source of locally available material. In this context the locally available Eppawala Rock Phosphate (ERP) has an important role to play. The cost of Triple Super Phosphate (TSP) and Imported Rock Phosphate (IRP) are 400 and 200% higher than the cost of ERP. The P2O5 content in ERP is between 33–40% but soluble P is about 1.5% compared to 98% in TSP. The current consumption of ERP in Sri Lanka is about 40,000t/year and is used mainly by the plantation sector and a smaller amount by the fruit crop sector. Phosphorus in Rock Phosphates (RP) are expected to be more available to plants grown on acid soils. They are recommended to be applied to slow growing crops such as perennials on neutral and acid soils (Wijewardena and Amarasiri, 1990). Under these conditions the rate at which P is supplied by the RP is usually sufficient to meet the crop requirements. Experiments conducted by Chien and Hammond (1978) showed that, in an initial crop of bean, all phosphate rock sources were less effective than TSP. However, during the second and the third cropping periods, the response of bean to residual P in rock phosphate sources was becoming increasingly significant. This behavior may be directly applicable to semi perennial crops such as banana. The production of crude ERP frequently includes some percentage of soil particles around the apatite rock as apatite is ground together with soil to produce ERP. As a result, the quality of the product may not be the best for agronomic purposes. However, selective mining and washing off soil particles from apatite rocks and the final ground product, which is known as High Graded Eppawala Rock Phosphate (HERP) may be an efficient product compared to ERP. On the other hand, research conducted using cattle and poultry manures on availability of soil P revealed that cattle manure (CM) was more effective than poultry manure (PM) but less effective than TSP in increasing available soil P. A unit of P in TSP seems as effective as 2.5 and 3.5 units of P in cattle and poultry manure respectively (Maraikar and Amarasiri, 1989). The main objective of this study was to test the long term effect of HERP on banana in comparison to TSP, ERP and CM. MATERIALS AND METHODS Field experiments were carried out to study the long term effect of HERP as a source P for five cropping cycles of tissue cultured Ambon banana on Reddish Brown Latosolic soils (Rhodudalts) containing high (>10ppm) and low (<5ppm) available P, when compared to full and partial replacement of TSP by HERP. Comparisons were also made using ERP and CM as sources of P. The experiments were carried out as individual units in adjacent fields containing Rhodudalt soils at the Horticultural Crop Research and Development Institute, Gannoruwa where field ‘A’ was poor (<5ppm) and the field ‘B’ was rich (>10ppm) in available soil P. The following treatments were tested in these two fields as P sources.
EFFECT OF HERP ON BANANA UNDER LOW AND HIGH SOIL P 73
Treatment 1. No. P 2. 100% HERP 3. 100% ERP 4. 100% TSP 5. 50% TSP 6. 50% TSP + 50% HERP 7. Cattle Manure (CM)
Description Control Recommended (Rec.) levels of P as HERP Rec. P as ERP Rec. P as TSP 50% Rec. P as TSP Rec. P as 50% TSP + 50% HERP P as CM (10kg/clump/6 month intervals)
The above treatments were tested in a Randomized Complete Block Design (RCBD) with five replicates in each experimental field. The current fertilizer recommendation (N-150, P2O5-135 and K2O-350g/clump/ year) was used for this study with three split applications per year. However, N and K were applied at a rate 150% higher than recommended level to avoid any possible deficiencies. Planting space was 3m x 3m and number of plants per treatment was four. Composite soil samples were collected from each field and analyzed for pH, organic matter %, available P, exchangeable K and electrical conductivity before commencing the experiment. Random samples of HERP, ERP and cattle manure used for the experiment were also analyzed for available P. The composite soil samples collected from every treatment after harvesting the crop were analyzed for available P. The centre part of the fifth leaf (Walmsley and Twyford, 1968) was analyzed for leaf P content during vegetative phase for five crop cycles in every treatment. The experiment was carried out under rainfed conditions. Yield parameters were recorded after each crop and statistically analyzed. Treatment comparisons were made using Duncanâ€™s Multiple Range Test (DMRT). RESULTS AND DISCUSSION General characteristics of the soils The soils at two adjacent experimental fields was classified as Reddish Brown Latosolic (Rhodudalts) soil and chemical analysis are presented in Table 1 together with analyses of HERP, ERP and CM used in this study. Table1. Some important chemical characteristics of soils at two adjacent fields and of P sources. Parameter Content Field A Field B CM HER ERP P pH (1:1) water Olsen P (mg kg-1) Exch. K (mg kg-1) Organic matter (%)
4.9 4.5 93.0 1.9
5.3 13.6 132.0 2.2
74 JAYASUNDARA AND HURUGGAMUWA EC (m mhos cm-1) Total P2O5%
The initial soil parameters (Table 1) showed that field B had higher pH, P, K, organic matter and EC when compared to field A. Phosphorus content of the soil in field B was more than three times compared to field A. Therefore, field B was considered to posses high (>10ppm) and field A as low (<5ppm) available soil P contents. Cattle manure contained 1.58% P at almost neutral pH. HERP had higher total P% compared to ERP. Soil P status High available soil P situation (Field B) The available soil P of each plot in field B after each crop are given in Figure 1. A trend with significant decline of available soil P was observed in the control where as high levels were maintained in TSP treated soil. On the other hand, soil P was maintained up to the third crop and then gradually declined in treatments where TSP was fully and partially replaced by HERP. Soil P was maintained only up to the second crop stage when only ERP was used. A continuous, but a marginal decline of soil P was noticed with 50% TSP. Cattle manure was found to be superior to ERP but inferior to HERP. 13 12
Soil P (ppm)
11 10 9 8 7 6 5 1 2 No P 100% ERP 50% T SP Cat t le Man ure (CM )
Crop 4 5 10 0% HERP 10 0% T SP 50 % T SP + 50% HERP
EFFECT OF HERP ON BANANA UNDER LOW AND HIGH SOIL P 75 Figure 1. Available soil P status after each crop in different treatments in field B.
Low available soil P situation (Field A) The available soil P contents in field A after each crop relevant to each treatment are illustrated in Figure 2.
Soil P (ppm)
No P 100% ERP 50% T SP Cat tle Manure (CM)
100% HERP 100% T SP 50% T SP + 50% HERP
Figure 2. Available soil P status after each crop in different treatments in field A.
Under low soil P situation, continuous declining of available P was observed in all treatments (Fig. 2) after the second crop stage, except in TSP and TSP + HERP treatments, where higher available P levels were maintained throughout the study. On the other hand, CM maintained a available P level lower than TSP and TSP + HERP but higher than in other treatments. HERP was found to be better than ERP or 50% TSP. On the other hand, 50% TSP + 50% HERP was found to be better than when used individually to maintain soil P levels. Leaf P status High available soil P situation (Field B) The leaf P content of the fifth leaf of each treatment for five crop cycles grown under high soil P condition is illustrated in Figure 3.
Leaf P (%)
76 JAYASUNDARA AND HURUGGAMUWA
Figure 3. Leaf P content of five crop cycles of banana grown under high available soil P situation.
Leaf P content under high available soil P situation revealed that TSP was able to maintained leaf P continuously (Fig. 3) whereas partial and full use of HERP was able to do so only up to the third crop stage. However, partial use of HERP and TSP exhibited higher P levels in the leaf than other treatments. On the other hand, CM behaved better than 50% TSP, HERP or ERP in maintaining leaf P levels (Fig. 3). Low available soil P situation (Field A) The leaf P levels of the control treatment gradually decreased where as TSP maintained at the highest levels throughout the study period under low available soil P situation too (Fig. 4). On the other hand, HERP maintained leaf P levels up to the third crop stage and then gradually declined. However, ERP did not maintain the leaf P levels continuously. Combined application of HERP and TSP was able to maintain P levels for five crop cycles at lower levels than 100% TSP. Behaviour of CM was intermediate between HERP and ERP (Fig. 4).
EFFECT OF HERP ON BANANA UNDER LOW AND HIGH SOIL P 77
Leaf P (%)
50% TSP + 50% HERP
Cattle Manure (CM)
Figure 4. Leaf P content of five crop cycles of banana under low available soil P situation.
Yield parameters High available soil P situation (Field B) Fruit yields of five consecutive crop cycles and total yields grown under high available soil P situation are presented in Table 2. Table 2. Fruit yield of five crop cycles under high available soil P situation. Treatment Crop yield (kg/bunch) 1st 2nd 3rd 4th 5th
No. P 100% HERP 100% ERP 100%TSP 50% TSP 50%TSP+50%HERP CM % CV
24.2 26.1 26.9 28.5 29.5 28.3 28.6 12.6
22.9 24.1 21.4 24.8 24.5 25.3 22.0 14.3
18.5 b 23.6 a 21.2 a 24.1 a 21.6 a 22.4 a 19.6.ab 10.2
14.5 c 16.6 b 15.8 bc 21.9 a 19.6.ab 20.8 a 17.6 b 13.5
15.6 c 18.3 b 14.3 c 22.8 a 18.9 b 20.6 a 17.3 b 11.6
Total yield (kg) 95.7 b 108.7 ab 99.6 b 122.1 a 114.1 a 117.4 a 105.1 ab 13.2
78 JAYASUNDARA AND HURUGGAMUWA Means followed by the same letter in each column are not significantly different at p=0.05.
EFFECT OF HERP ON BANANA UNDER LOW AND HIGH SOIL P 79
No yield differences were observed between treatments up to the second crop stage. However, all the P sources induced similar higher yields than the control at the third crop stage. The higher and comparable yields were recorded with TSP, TSP + HERP and 50% TSP at the fourth crop stage. On the other hand, at the fifth crop stage, only TSP and TSP + HERP gave comparable higher yields than other treatments while a further yield decline was observed in the control treatment. The leaf P contents of relevant treatments also exhibited similar trends which reflected their respective yields (Fig. 4 and Table 2). All the treatments gave comparatively higher yields than ERP and the control treatment. HERP induced similar yield as CM and slightly higher yield than the currently recommended ERP. Under low available soil P situation (Field A) Fruit yield of five consecutive crop cycles and total yields under low available soil P situation are shown in Table 3. Table 3. Fruit yield of five crop cycles and total yields under low available soil P situation. Treatment Crop yield (kg/bunch) 1st crop 2ndcrop 3rdcrop 4thcrop 5thcrop Total yield (kg) No P 23.5 16.2 b 15.4 c 13.1 c 11.6 c 79.8 c 100% HERP 22.0 19.4 a 16.8 b 15.2 bc 15.1bc 88.5 b 100% ERP 21.9 18.4 a 16.2 b 14.3 c 13.2 c 84.0 bc 100%TSP 25.6 22.7 a 20.1 a 22.5 a 21.6 a 112.5 a 50% TSP 21.7 20.7 a 17.0 ab 16.1 bc 16.5 b 92.0 ab 50%TSP+50%HERP 23.6 20.6 a 17.9 a 19.6 b 18.8 ab 100.5 a CM 23.8 19.5 a 16.5 b 14.6 c 15.0 bc 89.4 b % CV 9.86 12.3 10.2 11.8 12.9 15.5 Means followed by the same letter in each column are not significantly different at p=0.05.
There was no yield difference observed between treatments at the first crop stage (Table 3) as the native available soil P may be sufficient to obtain satisfactory yield. However, yield response to any kind of added P source was observed at the second crop stage and the control treatment gave lower yields than other treatments. At the third crop stage, differences between P sources appeared and TSP, TSP + HERP and 50% TSP gave higher yields than HERP, ERP and CM which gave similar and lower yields. The highest yield recorded at the fourth crop stage was with TSP, followed by HERP, TSP + HERP and 50% TSP. The similar trend was observed at the fifth crop stage. The highest total fruit yield was recorded by TSP and TSP + HERP. On the other hand, CM, HERP, ERP and 50% TSP gave similar but lower yields than the above treatments.
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Percent total yield increase The percent yield increases between the related P sources are given in Table 4 under low and high available soil P situations. It is suggested that application of HERP under both conditions was better than ERP. The percent yield increase recorded by HERP was almost double that of ERP under high P when compared to low P conditions. The percent yield increase recorded with TSP over HERP was more evident at low available soil P. On the other hand, a partial replacement of TSP by HERP at low available P situation was more evident than at high available P situation when compared to 100% TSP (Table 4). The yield differences between HERP and ERP was higher at high P situation than at low P situation. This information suggests that HERP would be a better P source than ERP but less effective than TSP. The partial replacement of TSP with HERP would be a sustainable solution for reasonable yields under both available soil P situations. These findings agree with the work carried out by Lin and Fox (1992) who illustrated that rock phosphates were less effective than TSP as P sources for banana. Table 4. Percent total yield increase. Treatment difference
% Yield increase Low P High P
HERP - No P 10.9 bc 19.6 a ERP - No P 5.3 c 4.1 c HERP- ERP 5.4 c 9.7 c (50%HERP + 50% TSP) - HERP 13.5 bc 8.0 c TSP - (50%HERP + 50% TSP) 17.9 b 4.0 c TSP - HERP 27.0 a 12.3 b TSP - ERP 33.9 a 14.5 ab CV% 12.8 14.3 Means followed by the same letter in each column are not significantly different at p=0.05.
CONCLUSIONS The study suggests that HERP is more effective than ERP under high and low available soil P situations as P source for banana. However, HERP has performed better under high available soil P situation than under low available soil P situation. The effectiveness of HERP could be further enhanced by partial replacement of recommended dose of TSP under high soil P situation. The effectiveness of CM was comparable to that of HERP under both soil P conditions. Therefore, it is suggested that use of HERP at the recommended levels is more effective than using ERP under these soil conditions. Banana yields could be further enhanced by partial replacement of TSP with HERP. No significant yield reduction is possible if cattle manure is used as a source compared to HERP. Therefore it is
EFFECT OF HERP ON BANANA UNDER LOW AND HIGH SOIL P 81
recommended that partial replacement of TSP with HERP is suitable for high available P containing soil and 100% TSP is suitable for low available P containing soil in order to obtain sustainable high yields of banana. ACKNOWLEDGEMENTS The authors are grateful to the laboratory staff, Division of Chemistry, Horticultural Crop Research and Development Institute and Institute of Fundamental Studies for analyzing soil and leaf samples. REFERENCES Chien, S.H. and P. Hammond. 1978. A comparison of various laboratory methods for producing the agronomic potential of phosphate rocks for direct application.Soil Science Society, American J. 42. 935-9. Jayasundara, J.M.P.B. and G.A.A.S.L. Gunathilake. 2006. Effect of in-situ decomposition of coir-dust and poultry litter in planting holes on yield and fertilizer use efficiency of banana. Annals of the Sri Lanka Department of Agriculture, 8: 57-68. Lin, M.L. and R.L. Fox. 1992. The comparative agronomic effectiveness of rock phosphate and super phosphate for banana. Fertilizer Research, Taiwan. 31: 131-135. Maraikar, S. and S.L. Amarasiri. 1989. Effect of cattle and poultry dung addition on available P and exchangeable K of a Red Yellow Podzolic soil. Tropical Agriculturist. 145: 51-55. Walmsley, D. and I.T. Twyford. 1968. Estimation of leaf P at different growth stages of Cavendish banana. Tropical Agriculture, Trinidad. 45: 223-8. Wijewardena, J.D.H. and S.L. Amarasiri. 1990. Comparisons of phosphate sources on growth of vegetables on an acid soil. Tropical Agriculturist 46: 57-66.