Weeding Effect of Free-Ranging Goslings in a Tea Field

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1 日本暖地畜産学会報 61(1):21-26,2018 Weeding by goslings in tea fields Full paper Weeding Effect of Free-Ranging Goslings in a Tea Field Koji TAKAYAMA, Yuko MIZOGUCHI, Ichiro OSHIMA and Yoshitaka NAKANISHI Faculty of Agriculture, Kagoshima University (Received 5 July 2017:Accepted 10 October 2017) ABSTRACT We evaluated the effects of free-range goslings on weeds in a tea field from May 24 to July 7, Two treatments were applied: 1)no goslings, on a control plot of 0.3 a, and 2)four free-ranging goslings (body weight, 570 g; age, 24 days)on an experimental plot of 0.9 a. The goslings were provided with supplementary feed every morning (50% of nutrient requirement). The goslings spent the most time grazing on Day 6. The goslings grazed preferentially on Bromus catharticus Vahl and Trifolium repens L. The percentage of bare ground in the experimental plot was significantly larger than that in the control plot on Day 44 (P < 0.05). There was also a significant difference in the herbage mass between the two treatments on Day 44 (P < 0.05), with an average of 330 kg dry matter/10 a and 43 kg dry matter/10 a in the control and experimental plots, respectively. The average body weights of the goslings on Days 22 and 44 were 1,506, and 2,073 g, respectively. In conclusion, free-ranging goslings effectively weeded a tea field, making it an appropriate context in which to raise them. Journal of Warm Regional Society of Animal Science, Japan 61 (1): 21-26, 2018 Keywords:free-range, goslings, tea fields, weeding INTRODUCTION Tea (Camellia sinensis L.) is the most commonly consumed beverage in Japan and is an important part of Japanese cuisine. Most tea leaves are produced with synthetic chemicals, including pesticides, fungicides, herbicides, and chemical fertilizers. Use of these chemicals has increased over the last few decades in order to maximize production. However, it is clear that the excess inputs of nutrients are causing environmental pollution (Nagayama et al. 1989; Miura 2012). Organic tea for both domestic and export markets is receiving increasing attention (Miura 2012). Weed management is essential for organic cultivation of tea. Takayama et al. (2004) indicated that freeranging Aigamo ducks were effective for weed control in tea fields. However, biological control of weeds by other domestic birds in tea fields has rarely been investigated. Geese, the only poultry species that can live and reproduce on a diet of grass, are prolific grazers (Cowan 1980; National Research Council 1991; Takayama et al. 2010, 2011). Geese are also effective weeders and have been successfully employed as biological control agents for weeds. For example, they have been used to control weeds in apple orchards (Clark and Gage 1996), in pear orchards (Takayama et al. 2009a, 2009b), and on blueberry orchards (Mizoguchi et al. 2012). To date, no studies have examined their use in tea fields. The objective of the present study was to assess the potential of these domestic birds as biological control agents in a tea field. MATERIALS AND METHODS The study was conducted in a tea field (1.2 a) (Fig. 1) at the experimental farm of Kagoshima University from May 24 to July 7 (44 days) in There were two treatments: 1) no goslings, on a control plot of 0.3 a, and 2) four free-ranging goslings (Anser cygnoides domesticus) (average body weight, 570 g; age, 24 days) on an experimental plot of 0.9 a. The experimental plot was surrounded by electric and net fences. The goslings were provided with 105 g/bird/day of grain-based formula feed every morning (crude protein: 15%, metabolizable energy: 2,800 cal/g). The amount of feed was about 50% of Figure 1 Experimental tea field. Correspondence: Koji TAKAYAMA, , Korimoto Kagoshima-shi, , Japan. TEL: +81-(0) , takayama@agri.kagoshima-u.ac.jp 21

2 TAKAYAMA MIZOGUCHI OSHIMA NAKANISHI the standard requirement according to the National Research Council (1994). The goslings free-ranged during the day (6:00-18:00) and were confined inside at night. Behaviour of the free-ranging goslings was observed on Days 6 and 38 (May 30 and July 1, 2014, respectively) and classified into grazing, browsing, eating (supplementary feed), resting, walking, preening, exploring, drinking, and other behaviours. Observations were performed at 1-min intervals, resulting in 720 observations each day over a 12-h period (6:00-18:00). Body weight (BW) of free-ranging goslings was measured on Days 0, 22, and 44 (May 24, June 15, and July 7, 2014, respectively). Vegetation was investigated on Days 0, 12, and 44 (May 24, June 5, and July 7, 2014, respectively). Plant coverage and percentage of bare ground were measured at fixed points ( m quadrat) in the control (n = 4) and experimental (n = 8) plots. Herbage mass was randomly sampled using a quadrat ( m) in the control (n = 4) and experimental (n = 8) plots. The herbage over 3 cm in height was cut and oven-dried at 60 C for 48 h to determine dry matter (DM). The behaviour of the free-ranging goslings was compared between two observation days using t-tests. The differences in body weight of goslings among the three measurements were analyzed using one-way ANOVA. If the effect of the ANOVA was significant, post-hoc analyses were conducted using Fisher s protected least significant difference (PLSD). The plant coverage, percentage of bare ground, and herbage mass were compared between the control and the experimental plots using t-test. RESULTS AND DISCUSSION The time budget of the maintenance behaviour of the free-ranging goslings is shown in Table 1. On Day 6, the time budget for grazing behaviour was the largest (38.6%) and that for drinking was the smallest (1.9%). On Day 38, grazing behaviour significantly decreased to 6.5% (P < 0.05). In contrast, eating, resting, preening, and exploring behaviour significantly increased between Day 6 and Day 38 from 4.8% to 16.6%, 37.9% to 50.8%, 4.6% to 8.6%, and 4.6% to 9.9%, respectively (P < 0.05, respectively). Walking behaviour of the goslings changed little between Days 6 and 38. Goslings did not browse the leaf or bark of tea plants during the experimental period. Plant coverage in the two plots is shown in Table 2. The number of plant species observed in the control and experimental plots on Day 0 were 6 and 11 (representing 4 and 6 families), respectively. The dominant species in both plots on Day 0 was Bromus catharticus Vahl. The coverage of B. catharticus Vahl on Day 44 tended to be greater in the control than in the experimental plot (P < 0.10; 22.5% in the control plot and 5.9% in the experi- Table 1 Time budget of maintenance behaviour of freeranging goslings in a tea field Days after grazing (Date) Behaviour 6 (May 30, 2014) 38 (July 1) -%- Grazing 38.6±4.7 a 6.5±3.1 b Browsing 0 0 Eating 4.8±1.1 a 16.6±5.3 b Resting 37.9±6.5 a 50.8±4.2 b Walking 7.6± ±1.2 Preening 4.6±1.0 a 8.6±1.0 b Exploring 4.6±1.8 a 9.9±1.2 b Drinking 1.9±0.5 a 0.7±0.1 b Others 0 0.9±0.1 a, b Means with different superscripts within the same row differ significantly (P < 0.05). Table 2 Effect of free-ranging goslings on plant coverage in a tea field Days after grazing (Date) Family Species 0 (May 24, 2014) 12 (June 5) 44 (July 7) control plot experimental plot control plot experimental plo control plot experimental plot -%- Commelinaceae Commelina communis L ± ±3.8 0 Compositae Kalimeris yomena (Kitam.) Kitam ± ± ±6.4 Cyperaceae Cyperus microiria Steud ±0.4 Geraniaceae Geranium carolinianum L. 0.5± Gramineae Alopecurus aequalis Sobol. var. amurensis (Kom.) Ohwi 1.0± ± ± ± Bromus catharticus Vahl 21.0± ± ± ± ± ±8.3 Digitaria adscendens (H.B.K) Henr. 20.8±24.7 a 0.9±2.5 b 8.8± ±9.3 0 Echinochloa crus-galli (L.) Beauv. var. crus-galli 0 2.5± ±6.0 0 Paspalum thunbergii Kunth ex Steud ± Poa annua L ± ± Setaria viridis (L.) P. Beauv ± ±0.4 Leguminosae Amphicarpaea edgeworthii Benth. var. japonica Oliver 0 0.3± ± Trifolium repens L ± ± ±3.6 Ranunculaceae Ranunculus silerifolius Lév ± ± ±0.7 Oxalidaceae Oxalis corymbosa DC. 1.0± ± ± Vitaceae Cayratia japonica (Thunb.) Gagn. 2.8± ± ± ± ± ±17.0 No. of family and species 4 and 6 6 and 11 4 and 6 5 and 8 3 and 7 6 and 7 a, b Means with different superscripts within the same row differ significantly (P < 0.05). 22

3 Weeding by goslings in tea fields Figure 2 (Day 6). Grazing behaviour of free-ranging goslings in a tea field (Day 44) (P < 0.05; 33.3% in the control plot and 83.4% in the experimental plot). There was also a significant difference in the herbage mass between the two treatments at the end of the experiment (Day 44) (P < 0.05), with an average of 330 kg DM/10 a and 43 kg DM/10 a in the control and experimental plots, respectively (Fig. 4). Photographs of the experimental plot at the beginning and end of the experiment are shown in Figure 5. It was obvious that the experimental plot had less herbage mass at the end of the experiment. Clark and Gage (1996) reported that free-ranging geese in an agroecosystem consisting of an apple orchard with intercropped potatoes were more effective weeders mental plot). In contrast, there was no difference in the coverage of other plant species between the two treatments on Day 44. Takayama et al. (2004) reported that free-ranging Aigamo ducks hardly grazed grasses (Digitaria adscendens (H.B.K.) Henr.) in tea fields. Takayama et al. (2009b) pointed out that geese selected tender plants and tended to prefer grasses and legumes to other plants. In the present study, we observed that goslings grazed preferentially on B. catharticus Vahl and Trifolium repens L. (Fig. 2). However, the birds did not browse on the leaves or bark of tea plants. Plant coverage of B. catharticus Vahl and Trifolium repens L. in the experimental plot decreased from 27.5% to 5.9% and 17.8% to 2.3%, respectively, from Day 0 to Day 44. Goslings may have avoided grazing on tea plants because the bark is harder than that of other plants and the leaves contain more tannin, an astringent substance, than other plants (Nakagawa 1973). The percentage of bare ground in the control and experimental plots is shown in Figure 3. There was no difference in the percentage of bare ground between the two treatments on Days 0 and 12. However, a significant difference in the percentage of bare ground was found between the two treatments at the end of the experiment Figure 3 Effect of free-ranging goslings on percentage of bare ground in a tea field. a, b: Values with different letters in same date differ significantly (P < 0.05). Figure 4 tea field. Effect of free-ranging goslings on herbage mass in a a, b: Values with different letters in same date differ significantly (P < 0.05). Beginning (May 24, 2014; Day 0) End (July 7; Day 44) Figure 5 Experimental plot at the beginning (upper) and the end (lower) of free-ranging goslings. 23

4 TAKAYAMA MIZOGUCHI OSHIMA NAKANISHI Figure 6 field. than chickens. Takayama et al. (2009a, b) and Mizoguchi et al. (2012) revealed that free-ranging geese suppressed weeds without browsing the leaves and bark of fruit plants in the orchard (Japanese pears and blueberry). Although free-ranged goslings, rather than mature geese, were used in the present study, the results obtained coincide with their findings. The average body weights of free-ranging goslings on Days 0, 22, and 44 were 570, 1,506, and 2,073 g, respectively (Fig. 6). The body weights on Day 44 increased significantly by approximately 400% compared with that on Day 0 (P < 0.05). Geese consume large amounts of grasses, and they can digest 15%-20% of the fiber in the plant, which is three to four times the amount that any other poultry species can digest (National Research Council 1991). Therefore, geese can be reared solely on the nutrients supplied by their grazing, provided that the pasture is of good enough quality (Cowan 1980), although their growth may be slow. Takayama et al. (2010) reported that the body weights of free-ranging geese (4-30 weeks of age) in pear orchards without supplementary feed reached from 950 to 2,820 g (DG: 10.3 g/ day) during the grazing period. Although goslings were provided with supplementary feed (50% of nutrient requirement) in the present study, they did actively graze in the tea field, showing a steady increase in body weight (DG: 34.2 g/day). All geese consume large amounts of grass, and the most voracious grazers are goslings (Ashton 1999). Our data suggested that free-ranging goslings can control weeds in a tea field and that it is an appropriate location in which to rear them. In conclusion, free-ranging goslings effectively weeded a tea field and could be reared there. REFERENCES Ashton C Domestic geese. pp The Crowood Press, Wiltshire. Clark MS, Gage SH Effects of free-range chickens Effect of free-ranging goslings on body weight in a tea a-c Values with different letters differ significantly (P<0.05). and geese on insect pests and weeds in an agroecosystem. American Journal of Alternative Agriculture, 11(1): Cowan PT The goose: an efficient converter of grass? A review. World s Poultry Science, 36: Miura N Dynamics of soil organic nitrogen in tea field and its uptake by tea plants (Camellia sinensis L.). Bulletin of the Kagoshima Prefectural Institute for Agricultural Development, Agricultural Research, 5: (in Japanese with English abstract) Mizoguchi Y, Takayama K, Mizumoto A, Nakanishi Y Use of domestic geese for weed control in a blueberry orchard. Journal of Warm Regional Society of Animal Science, Japan, 55(2): (in Japanese with English abstract) Nagayama T, Maki T, Kan K, Iida M, Tamura Y, Nishima T Residues of organophosphorus pesticides in commercial tea and their leaching into tea. Journal of Pesticide Science, 14(1): (in Japanese with English abstract) Nakagawa M Relation of the constituents with taste of green tea. Tea Research Journal, 40: 1-9. (in Japanese) National Research Council Microlivestock: littleknown small animals with a promising economic future, pp National Academy, Washington, D.C. National Research Council Nutrient Requirements of Poultry (Ninth Revised Edition), pp National Academy, Washington, D.C. Takayama K, Yamashita K, Nakanishi Y, Manda M, Edar E, Takesaki T The influence of free-ranging Aigamo ducks on weeds and pest insect infestations in the tea fields. The West Japan Journal of Animal Science, 47: (in Japanese with English abstract) Takayama K, Igata M, Hagiiwa Y, Manda M, Nakanishi Y. 2009a. Use of geese for weed control in an orchard. Journal of Warm Regional Society of Animal Science, Japan, 52(2): (in Japanese with English abstract) Takayama K, Igata M, Nemoto H, Mizoguchi Y, Hagiiwa Y, Manda M, Nakanishi Y. 2009b. Free-ranging geese for weed control in an orchard of Japanese pears. Japanese Journal of Organic Agriculture Science, 1(1): (in Japanese with English abstract) Takayama K, Igata M, Mizoguchi Y, Nemoto H, Hagiiwa Y, Manda M, Nakanishi Y The growth and meat productivity of free-ranging geese in pear orchards. Japanese Journal of Organic Agriculture Science, 24

5 Weeding by goslings in tea fields 2(1): (in Japanese with English abstract) Takayama K, Mizoguchi Y, Nemoto H, Nomura T, Taura I, Kido M, Tominaga A, Nakanishi Y The egg production of free-ranging geese in pasture. Japanese Journal of Organic Agriculture Science, 3(1): (in Japanese with English abstract) 25

6 TAKAYAMA MIZOGUCHI OSHIMA NAKANISHI 要約 茶園におけるガチョウ雛の除草利用 髙山耕二 溝口由子 大島一郎 中西良孝 鹿児島大学農学部 連絡責任者 : 髙山耕二 (TEL: , takayama@agri.kagoshima-u.ac.jp) 本研究では, 茶園におけるガチョウ雛の除草利用の可能性を検討した. 試験地内にガチョウを放飼した試験区 (0.9 a) と放飼しない対照区 (0.3 a) を設け, 試験区には 24 日齢のガチョウ雛 4 羽 ( 平均体重 570 g) を 2014 年 5 月 24 日から 7 月 4 日の 44 日間放牧した. なお, ガチョウには養分要求量の 50% 相当量の補助飼料を給与した. ガチョウは活発な食草行動を示し, イヌムギ (Bromus catharticus Vahl) とシロツメクサ (Trifolium repens L.) を好んで採食し, その一方で茶の葉や幹の採食は観察されなかった. 放飼後 44 日目における裸地率は, 対照区に比べ, 試験区で有意に大きかった (P < 0.05). 放牧終了時の植物現存量についても, 対照区の 330 kgdm/10a に対し, 試験区で 43 kgdm/10a となり, 両区間で有意差が認められた (P < 0.05). 放飼開始後 22 および 44 日目におけるガチョウの体重は 1,506 および 2,073 g に増加した. 以上より, 茶園でのガチョウ雛放飼による除草効果は顕著であり, 茶園で飼養可能であることが示された. 日本暖地畜産学会報 61(1):21-26,2018 キーワード : ガチョウ雛, 除草, 茶園, 放飼 26