Potential of Weeds for Ruminant Feed on Rice Fields in Java
N.R. Kumalasari1,*, E. Bergmeier1,& L.Abdullah 2
1Faculty of Biology, University of Göttingen, Göttingen 37073, German,
*e-mail: nurrkumala@gmail.com
2Faculty of Animal Science, Bogor Agricultural University, Bogor 16680 Indonesia
Abstract
Weeds compete with rice for sunlight, nutrients and water, and may reduce the yield. However, in traditional rice farming systems farmers utilize many kinds of weeds for food, forage or household purposes. Rice weeds are also utilized to feed ruminants.The aims of this research were to explore the weed diversity of rice field in various regions and rice farming systems in Java. Field researches were conducted in November 2011 – January 2012. Designated research areas: West Java: Cianjur (upland) and Karawang (lowland); Central of Java: Karanganyar (upland) and Brebes (lowland); East Java: Malang (upland) and Gresik (lowland). Locations of plots have been selected according the principles of stratified random sampling. Weed assemblages were sampled in fields of intensive and extensive farming systems as well as in fallowed areas before weeding time in two seasons. The result showed that approximately 295 species of weeds growth in rice field and terrace area. Dominant weed species present at the terrace in experimental site were Cynodondactylon, Eleusineindica, and Fimbristylismiliaceae. Potency of weed for ruminant feed gains approximately 903,5 g/m2 at terrace area.
Keywords: potency, ruminant feed, weeds diversity
Introducton
Increasng the level of rce self-suffcency of Indonesa led to an ncrease n the ntensty of rce (Oryza sativa L.) croppng n many areas snce the 1970s. In Indonesa, rce cultvaton covers a total of about11.5 mllon hectares throughout the archpelago, on Java alone around 5.4 mllon hectares (Natonal Development Plannng Board, 2003).About 70% of the area comprse rrgated rce felds, whch have been estmated to be 100 tmes more productve than upland ran-fed rce farmng upland rce (Farhurst and Dobermann, 2002).
et al, 2000). Weed management therefore poses a sgnfcant challenge to Indonesan farmng systems. Herbcde treatments change the weed communty composton nterrelated to crop productvty (Ulber 2010). A new approach to bodversty frendly management s therefore to enhance the benefts derved from desrable weed speces wth hgh value for the farmer and the agroecosystem. The use of weed speces s possbly the most effcent management to overcome problems of polluton through herbcde usage, slow breakdown or burnng. Weed plants and vegetaton vary enormously n morphology, phytomass and speces composton dependng on habtat condtons and land-use (Soerjan et al., 1987). Due to ther chemcal and physcal characterstcs weeds may or may not be grazed by rumnants. The feedng value of rce feld weeds s lttle-known n scentfc lterature but the local farmers have consderable knowledge whch should be combned. The man objectves of the present study were to assess characterstcs of farmng systems n Java and to evaluate the potental of rce weed bomass as rumnant feed.
Materals and Methods
The research was done n October 2011 untl March 2012 n lowland (0-100 m) and upland areas (>400 m)of rce feld n Java, .e. Karawang (33 – 53 masl), Brebes (26 – 44 masl), Gresk (14 – 41 masl), Canjur (527 – 856 masl), Karanganyar(403 – 714 masl) and Malang (526 – 684 masl). In each of the stes, sutable landscape sectons of ca. 5 km x 5 km sze were selected and 15 plots located theren.The weeds were sampled n cultvated areas, fallowed areas and on rce feld terraces.
Fresh bomass was measured from weed sources n each plot by placng squareframes szed 30 cm x 30 cm. The weeds were sampled on three plots on each rce feld and terrace n each dstrct. Weed samples were collected n each plot, cut and weghed as fresh bomass. The samples were dred at 60°C for 48 h and weghed
as dry bomass.
Results and Dscusson
Overview
usually done two tmes, specfcally 20 and 40 days after transplantng of rce plants, wth the excepton of Gresk.
In Gresk, drect seedng was practced due to a shortage of labor and the hgher costs of rce transplantng. Manual weedng n Gresk would commonly be done smultaneously wth rce plant thnnng to reduce labor costs. Labor for manual weedng s becomng ncreasngly scarce. Therefore the applcaton of herbcdes n the frst tllage ncreases to eradcate all weeds that emerged n the tme of fallow. In addton, poor mantenance of the rrgaton nfrastructure reduces water avalablty for rce producton n the dry season and ncreases surface water sand floodng n rce feld areas n the rany season.
Weed Biomass
Weed bomass s the most mportant ndcator of feed avalablty for rumnant n rce feld area. There was a sgnfcant dfference n weed bomass among rce feld areas, wth upland areas (Canjur, Karanganyar and Malang) producng hgher bomass values than lowland areas (Karawang, Brebes, Gresk) (Table 2). There were no sgnfcant dfferences between the locatons of eastern, central, or western Java, respectvely. Fresh weed bomass n the frst rce growng season (early rany season) yelded 891-2369 g/m2(Table 2). Weed bomass vares enormously between
regons and even between small farms n the same vllage due to dfferences of envronmental factors and farmng management. The results showed that hgh values of fresh weed bomass had the potental to supply rumnant feed n Java although varablty n water regme affected the populatons and growth of weed speces.
Fresh weed bomass n Javanese rce felds dffered from that found byRoder et al. (1998) who measured 220-990 g/m2/year of fresh weed bomass over the rce
growng season n northern Laos. There are many factors affectng the weed bomass
Table 1. Characterstcs of rce farmng systems
Parameters
Dstrct
West Java Central of Java East Java
Karang-between countres, such as seasonal and clmatc varaton as well as dfferent farmng management systems (Machado, 2005). Yakup (2007) reported that weed nfestaton n rce farms ncreased along wth elevaton. Common weeds n the upland rce feld areas n West Java are Myriophyllum aquaticum and Sagittaria guayanenesis whle n lowland areas Leersia hexandra, Sacciolepis interrupta and Ipomea aquatic are common (Yakup, 2007).
The combnaton of herbcde applcaton and manual weedng n the lowland rce feld areas of Karawang, Brebes and Gresk resulted n a sgnfcantly hgher degree of weed suppresson. Varablty of surface water condton affects the growth ofrce weed communtes (Juram et al., 2011). Hence, weed bomass n upland areass concentrated on terraced stes snce weeds have been suppressed on about 70% of the rce feld areas through pondng surface waters. In all lowland areas, rce weeds were found to grow manly n tmes of fallow and the values were not sgnfcantly dfferent from each other.
There were bologcally small but statstcally sgnfcant dfferences n the comparson of dry matter percentage n each locaton. In the lowland areas hgher dry matter values were found than n the upland area. Cuttng tmes and plant structural composton seems to affect producton yelds (Yolcu et al., 2006).
Conclusons
Selectng weed speces sutable for rumnant feed supply and producton n a partcular regon (based on agro-pastoral farmng) s very mportant to sustan anmal producton both economcally and ecologcally. Rce weeds have the potental to yeld substantal amounts of bomass n fallowed areas and terraces. Rce weed bomass n upland areas s currently hgher than n lowland areas due to the combnaton of herbcde applcaton and manual weedng n the lowlands.
Table 2. Weed bomass n rce feld areas
Parameters
Dstrct
West Java Central of Java East Java
Canjur Karawang
Xnqng et al. (2006) suggested four prncples for selectng approprate speces as feed, .e. bogeographcal matchng of speces, ecologcal matchng, producton yeld and forage qualty.It s essental, therefore, to further study the phytogeographcal, ecologcal, bologcal and functonal trats of the Javanese wld plants of rce felds.
Acknowledgements
We are grateful to Prof. Em. Soeksman Tjtrosoedrdjo and Dr. Sr Sudarmyat for ther supervson durng N.R.K.’s laboratory works at the Herbarum BIOTROP. Ths paper s an output from feld research carred out thanks toErasmus Mundus Experts Asa (moblty program) and funded by BIOTROP (PhD grant 2012).
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