YOON P. K.(2 ), TROGLIA M., TASIAS J. V., RODRIGUEZ J. N., AND FRUTOS D. T.
TECNAGRIND S. L., El Rebato, s/n° Finca Moli Coloma, 08739 Subirats, Barcelona, Spain
(1) This demonstration project in Murcia has been possible thanks to an European Union financial contribution under Rules 4256/88 art. 8 of the General Direction VI -Agriculture.
(2 ) 2 - P. K. YOON is the Vetiver consultant to Tecnagrind S. L. Contact Address: No.69 Jalan SS 3 / 39, Sungai Way Subang, 47300 Petaling Jaya, Selangor, Malaysia.
The establishment and growth of VGHR were tested in the hostile, aerial and edaphic environment of Murcia, Spain. The climatic condition consists of hot summer, cold winter with sub-zero temperatures, low precipitation and negative water balance over more than half a year. The soil is calcareous, mostly clayey. Hilly topography is common with serious erosion rate of more than 5000 Tm / km2 per annum.
The experimental sites were El Chopillo and Lorca. 5 trials were carried out to study the establishment and growth of Vetiver grass and the potential uses of VGHR for soil protection and moisture conservation under different conditions. Despite cold winter with frost, trials established by container plants from winter to early spring, had overall transplanting success of 95.9 %.
Plant growth during the growing season was good to vigorous. Harvesting of plant tops in El Chopillo, produced 1030 and 1388 gm per plant after 14 and 15 months respectively. In Lorca, the Malaysian Accession produced 305 and 489 gm per plant after 9 and 10 months respectively, while the American Accession produced 377 and 560 gm per plant respectively over the same two periods. In all cases, the cut-tops regenerated rapidly showing vigorous growth in autumn conditions.
Excavations showed that the root system in El Chopillo had reached a depth of 2.6 m after 14 months growth. In Lorca, the Malaysian and American Accessions had produced roots reaching down to 2.1 metres and 1.7 metres respectively after 9 months growth. In all cases, the major root masses were at the top 0.4 - 0.5 metres level.
In a 320 Highway slope of 11 metres height, 2 blocks of 20 metres were planted with VGHR at 1 metre vertical intervals in January 1995. The in-between block, left unplanted as control, suffered severe erosion by September 1995 despite the low rainfall. Significant cant soil had been trapped by the VGHR
Sub-zero temperatures in winter killed exposed tops but the buried crowns survived. In early spring, new tillers were formed, followed by good and vigorous growth in summer and autumn. The plant's response to the seasonal weather condition suggests 4 distinct phases
1. Frost Injury and Dormancy
2. Awakening and Tillering (Regeneration or Multiplication)
3. Rapid Growth and Biomass Production
4. Slow Growth or Sustenance period.
The tropical to sub-tropical Vetiver grass adapted well to the weather conditions and appeared to behave like a temperate plant. This, plus easy establishment, good growth and good root system suggest potential uses for Vetiver in the Mediterranean Regions. It also suggests that VGHR could be established for useful gains, in the cold highlands of the tropics and the subtropics.INTRODUCTION
In this project, an attempt was made to test the establishment, growth and potential uses of Vetiver grass hedgerows ( VGHR) in the hostile aerial and edaphic environments of Murcia, Spain. Two sites were selected for testing , viz. El Chopillo (Latitude 38° 22' 08" N Longitude 10 48' 06" E) and Lorca (Latitude 37° 42' 36" N Longitude 37° 37' 28" E). The climatic conditions consist of a long dry summer with absolute maximum temperatures reaching of 42°C in Lorca and 47°C in El Chopillo, and a cold winter with absolute minimum temperatures of - 4°C in Lorca and - 14°C in El Chopillo Precipitation is low with averages of 27.51 cm per annum in Lorca and 40.45 cm per annum in El Chopillo, and with few rainy days. The relative humidity is consistently low with high evapotranspiration. Negative water balance occur over 6 months in El Chopillo and 10 months in Lorca. The soil type is quite calcareous, mostly clayey but sometimes alluvial with negligible nutrient. Hilly topography is common with serious yearly erosion rates of more 5,000 Tm / Km2. The aim of the project is to use VGHR to minimise soil erosion and to enhance soil moisture. If successful, it will be tested as a means to improve crops, protect highway slopes and other embankments, as a source of biomass production and other applications.
MATERIALS AND METHODS
Planting Materials used for Various Look - See Trials
i. Planting Materials for El Chopillo
A small consignment of 300 bare-root tillers was obtained from Malaysia and sent directly to El Chopillo in May 1994. They were raised in 12.5 cm x 17.5 cm polybags in a glasshouse for 11 weeks before being planted into the ground in El Chopillo on 29 July 1994.
ii. Planting Materials for Lorca
Large consignments of tillers were obtained from Malaysia in June 1994 and America in July 1994. They were planted in plastic planting trays of 37 x 30 cm; with 20 containers, of 22.5 cm deep and each container holding 800 cc of standard potting mixture (Composition 25% peat + 65% pine bark and other forest materials + 10% rice husk. Fertilization Osmocote 1.5 kg / m3, 16-8-12-2, 6-8 months). The plants were kept in a glasshouse near Barcelona with the controlled environment maintained at 180° C to 350° C and 60% - 80% R. H. Plants were irrigated for 5 to 10 minutes with a overhead mist for 1 - 3 times per day depending on the prevailing climatic conditions. They were also flooded with nutrient solution of "10-1 0-20-oligoelements" at a rate of 0.5 gm./1 once every 3 days. The bare-root tillers produced roots within 2 weeks. After 3 1/2 months, the roots had enmeshed the core of the potting mixture with the tops having 2 - 5 tillers newly produced in-site. The plants were cut to. 20 cm height before sending it to Lorca (Photo 1). They were then reconditioned in an open air container nursery (Photo 2). These container plants were used in all the field trials in Lorca.
Irrigation and Fertilization System Used In The Look - See Trials.
In Phase I of the project, the main concern was to ensure establishment of the Vetiver plants in the hostile environments of Murcia. It was therefore decided from the onset to reduce the stresses from water deficit and low nutrients by adequate supplies. Irrigation and fertilizer were applied as follows
i. Ground Nursery in El Chopillo.
The plants were drip-irrigated every 1, 2 or 3 days depending on the season. Water consumption was equivalent to 6,670 m3/ha from February to October 1995. Soluble fertilizer was distributed regularly through irrigation water; from February to October 1995; the total amount used was 170 kg/ha KNO3 + 70 kg/ha H3P04 75% + 500 kg/ha KN03 59%.
ii. Container Nursery in Lorca.
Irrigation was supplied by overhead sprinklers at a rates of 2 l/m2 day to 9 l/m2/day, adjusting it according to the climatic conditions. Fertilizer was applied at rates of 0.156 gm./m2/day, KNO3.
iii. Ground Nursery in Lorca.
Irrigation was by flooding. The amount of water used was equivalent to 700 m3/ha over 10 occasions from February to October 1995. Fertilizer was applied by adding the equivalent of 500 kg/ha N15P15K1, before planting; and 500 kg/ha KNO3 distributed with the irrigation water over the 10 applications.
iv. Highway Slope
Irrigation was by drip-irrigation at rate 4 l/hr/m of VGHR. The total amount of water applied from February to October 1995 was 948 l/m of hedgerow. Fertilizer was through the irrigation pipes, using a total of 151 gm/m KNO3 over the recorded period. This area was not linked to the farm's irrigation system. The pipe system was connected to a mobile tank of 6,000 litres placed at a higher level. Drip-irrigation was by gravity, at a rate of 4 l/hr/m of VGHR. The amount of water used was about 500 l/m from April to October 1995. Fertilizer, at a rate of 180 gm/m of KNO3 was distributed in the irrigation water over the same period.
Design For Look - See Trials.
Our main concern at the begining of the project was the establishment of the Vetiver plants; we were not even sure whether the plants would grow!! Thus only observational trials were set up.
i. Ground Nursery in El Chopillo
204 polybag plants were planted in a single block of 4 rows on 29 July 1994. The planting distance was 1 metre between rows and 0.33 metres between plants.
ii. Ground Nursery in Lorca.
The total trial consisted of 2 blocks of 2,917 and 2,478 plants of Malaysia Accession, and 3 blocks of 2,587 ; 2,685; and 2,745 plants of American Accession. They were planted into the ground nursery on 5 - 19 December 1994. The block size was about 0.1 hectare and the planting distance was 0.33 metres with 1.00 metre between rows. Because the blocks were of irregular shape, the number of rows varied from 12 - 16 per plot and the number of plants per row varied from 150 - 200.
iii. Highway Slope.
A trial was undertaken to test the effect of VGHR to prevent soil erosion on the Highway slope of 12 m vertical height and with 320 gradient. The slope construction used a rocky gyspic base covered with very irregular, unstable, not consolidated, clay soil. 3 blocks of 20 metres width were selected with the outer blocks planted with VGHR and the central block as control. Vetiver container plants were planted at 5 cm between plant distance and the VGHR were at 1.0 metre vertical intervals . 12 full length VGHR were planted in each block and the total plants used were 10,258. The VGHR were planted on 4 - 9 January 1995.
iv. Almond Plots.
Three VGHR of 90 metres length were planted between blocks of four almond rows on 7 April 1995. The between-plant distance was 5 cm and a total of 6006 container plants were used.
i. Serial photos of the container nursery in Lorca were taken weekly, while for all the other ground trials, photos were taken at approximately monthly intervals. Qualitative assessment of plant performance were from examining these collections of photos.
ii. Quantitative count of tiller production and dry weight production were done by harvesting the tops as follows :-
a) Ground Nursery El Chopillo 4 groups of 6 - 8 plants each were cut at 20 cm from the ground. The fresh weight was measured and numbers of tillers of each top were taken. Sub-samples were taken to obtain oven - dry weights.
b) Ground Nursery, Lorca To remove boundary effect, the boundary rows were topped by a mechanised grass cutter to facilitate sampling in the immediate adjacent rows. 3 groups are randomly selected and the plants were cut manually at heights of 20 cm. For the Malaysian Accession, 15 plants were sampled per group per row of each of the 2 blocks. For the American Accession, 10 plants were sampled per group per row of each of the 3 blocks. The fresh weight and tiller number of each top were noted in the field. Sub - sample's were taken to obtain oven - dry weights.
iii. Root Examination Excavations to examine the root systems were carried out in September 1995. A back-hoe was used to dig a large pit next to a group of plants ranging from 4 plants in El Chopillo to 7 plants in Lorca. To ensure the roots were not damaged, a gap of at least 20 cm were left between the hole and VGHR. A pressure pump, linked to a water tank, was used to wash away the soil and expose the roots.
iv. Meteorological Data were obtained from the official stations near the trials sites. For this paper, we concentrated on the maximum and minimum temperatures and rainfall as given in Appendices 1 and 2.
1. Establishment and Growth of Plants in Ground Nursery, El Chopillo
This was essentially our first observation block. The 11 week old polybag plants were transplanted into the ground in July 1995 in the warm weather of summer with very good transplanting success of 99.5%. Growth was good between August - September 1994 ( Photo 3 ) with very vigorous growth from October to early December 1994. Subzero temperatures occurred between 23 - 28 December 1994 and the frost killed all the exposed tops. However, the buried crown-portion survived and by early February 1995 new tillers started to emerge. ( Photo 4 ) From then to May 1995 there were rapid tiller productions. A census taken in June 1995 showed that 81.8% of the plants have fully recovered from the winter frost. Good growth was observed in June 1995 ( Photo 5 ) followed by very vigorous growth rates from August to November 1995.
( Photo 6 )
Harvesting of the tops were carried out on two occasions. ( Photo 7a ) The results are summarised below:
Date No. of Tillers Dry Weights ( gm per plant)
29/09/95 54.5 +/- 5.0 1030.6 +/- 132.0
04/11/95 66.7 +/- 8.7 1387.5 +/- 250.2
The differences between the dry weights obtained in the 2 harvests suggested rapid biomass production in autumn 1995. This was confirmed by the very rapid regeneration of the cut tops. (Photo 7b + 7c).
Excavation showed the root system to have reached 2.6 metres deep, with very dense root mass on the first 0.5 metre depth. ( Photo 8 )
2. Establishment and growth of Container Plants in Lorca.
The plants in planting trays, in the glasshouse in Barcelona, were cut back to 20 cm height and transplanted on 2 occasions viz.: 27 October 1994 and 10 November 1994, to a open air container nursery in Lorca ( Photo 2 ). The plants transported well with no sign of transporting shock and practically no casualty. They stayed a healthy green colour but with little growth; the young tillers barely increased in height over the next few weeks. With the decreasing cold temperature in December 1994, the matured green leaves became bleached, turned yellowish and finally after sub-zero minimum temperature over 7 days in end December; they were killed and turned straw colour. Throughout this period, the young tillers continued to retain the green colour and turned dull green only after the sub-zero minimum temperature. On site examination showed that, whereas the matured leaves were killed, the young tillers and the crown region was alive. The dull green colour of the young tillers persisted through to March 1995, when, with the warmer weather, a healthy green colour was re-attained and growth resumed. Then, new tillers were also noted. Container plants were taken out for planting at various times, into the ground starting from 5 December 1995 and ending 7 April 1995. Towards the end, each container plant had a few actively growing tillers. The overall establishment success of field planting 32,498 container plants was 95.9 %.
3. Establishment and growth of plants in Ground Nursery, Lorca.
At the time when the container plants were taken out, the cold weather had already turned the matured leaves to bleached yellow colour, but the young tillers were still green. After the transplanting and after the frost in late December 1994, the matured leaves dried up into straw colour ( Photo 9a ); even the young tillers turned a purplish-green to straw colour. This condition persisted into the cold period of January - March 1995. With warmer weather in April 1995, the young tillers regained a healthy green colour and there were new tillers. By May 1995, there were good tiller production, followed by growth in June and July 1995. Very rapid growth was observed from August 1995 onwards (Photo 9b + 9c). Census taken on 4 July 1995 showed the overall establishment success to be 89.1 %. On two occasions, assessments of growth were carried out by topping the plants (Photo 10a)
Date No. of Tillers Dry Weights (gm per plant)
Malaysia American Malaysia American
30/09/95 45.2 +/- 3.2 79.0 +/- 4.9 304.7 +/- 36.6 376.9 +/- 23.8
03/11/95 46.6 +/- 3.4 65.0 +/- 3.2 488.8 +/- 50.6 559.8 +/- 42.9
The dry weights between the 2 harvests were substantially different indicating vigorous growth. Observations of rate of regeneration of cut tops confirmed this view (Photo 10b). Excavation of roots were carried out. The roots of the American Accession has reached a depth of 1.7 m while those of the Malaysian Accession was 2.1 m (Photo 11). However, the main and pronounced root mass was in the upper 0.4 metres, and there was no apparent difference between the 2 accessions.
4. VGHR to protect Highway slope
Planting was done on 13 - 17 January 1995, at which time the plants in the containers was suffering from the cold December weather; the mature tillers were dead and the young tillers were dull green in colour (Photo 12). However by late March, the young tillers had turned a healthy green colour and by April / May, new tillers were being formed. Very rapid tiller formation and good growth occurred between April and July followed by vigorous growth from August 1995 onwards (Photo 13). The overall establishment success was 98.8%. Observations in late September 1995 showed that the VGHR had effectively reduced soil erosion in the planted plots (Photo 13). Severe erosion had occurred in the control plots despite the low rainfall of 740 mm over 24 days since the establishment of the trial (Photo 14a + 14b).
5. VGHR to improve Almond Plots
At the time of planting in April 1995, the container plants had fully recovered from the frost injury; the young tillers were actively growing with healthy green colour and there were also new tillers being formed (Photo 15a). The plants established very fast with a good success of 99.3 %. From the beginning of transplanting new tillers were produced and by July, useful hedgerows had been formed. Growth from August 1995 was rapid (Photo 15b). In this trial, it is hoped that the VGHR will serve to slow down the surface rain wash thus improving infiltration and conserving moisture. There were also plans to cut the tops of the VGHR to mulch the almond plants. The effect of VGHR on almond production will be studied using the 2 adjoining plots as controls.
6. General Field Observations.
In the field, some interesting observations were made
( i) Both the Malaysian and the American Accessions had not flowered though plants had many morphologically matured culms with distinct nodes.
(ii) The morphology of the Malaysian Accession in Spain seemed to be different from the same Accession in Malaysia. The culms of plants in Spain were clearly bigger and taller than the same Accession grown in Malaysia. However, the internodes were surprisingly shorter. In addition, there were very few culm-branches in the plants grown in Spain.
( iii) Plants in the boundary of blocks of Vetiver grass tended to be less vigorous and showed more stress symptoms of dying of the leaf tips, when compared with plants growing in the centre.
There do not appear to be any documented record of Vetiver grass having been successfully grown in Mediterranean climate. Dr. Francoise Dinger reported his failed attempt to grow Vetiver in Draix ( Haute-Provence Alps, France ) in the Vetiver Newsletter # 6. We are happy to have successfully established Vetiver grass and to be able to study the performance of VGHR in Murcia.
Field Establishment of VGHR Under Mediterranean Climate
Due to various logistic requirements, the large number of container plants were transplanted to the ground beginning 5 December 1994 and ending 7 April 1995. This, fortuitously, allowed the study of plant development stages on the transplanting success, establishment and growth under different weather conditions. It also permitted observing container plants over a longer period. Observations from the various trials in Lorca showed that new tillers were largely produced in May regardless of the time of the first transplanting into the field. The same time of new tiller production also occurred in the container plants. In addition, there was a distinct trend that plants taken out during the warmer weather have better establishment success. This ranged from 89.1% in the Ground Nursery (planted December 1994) through 98.8% in the Highway slopes (planted January 1995) to 99.3% in the Almond Plot Trial (planted April 1995). Therefore, it would appear that plants should not be taken out too early. In addition to better establishment success, the plants would be easier to irrigate and maintain in the container nursery. Based on this first set of results, it appears that the best time to take out container plants may be in the spring months of March / April. However, this gain in ease of management and less water usage must be weighted against the advantage of winter planting with its least competition for labour; spring planting is normal for the main crops.
Growth and Biomass Production
A most interesting field observation was that the plants in the boundary rows were smaller than those in the central rows and showed more stress symptoms. This occurred in all 5 ground nursery blocks and in the 2 Highway slope blocks. This is different from observations noted in the tropics where the central rows consistently performed poorer because of the shade sensitivity of Vetiver. This new observation may be due to the high solar intensity and the long sunlight hours during the growth period of May - September 1995 and the negative stress effect of low relative humidity. If so, moisture and water stress have become a stronger limiting factor when compared with light effect. Due to the growth pattern, biomass determination of the tops were not done until the plants have gone through some months of the active growth period. Active growth of plants in ground nurseries started in May 1995 in El Chopillo, but commenced in June / July in Lorca. This difference was most likely due to the different times of planting. Though the El Chopillo plants were damaged by winter frost, they already had an established root - system, and plant growth can take off faster. On the other hand, plants in the ground nursery in Lorca were only transplanted to the ground just before the winter 1994-5 and the plants will take time to establish first. Harvesting of plant tops in El Chopillo produced 1030 gm and 1388 gm per plant after 14 and 15 months respectively. For the same 2 periods, the number of tillers per plant were
55 and 67 respectively. In reality, as the tops of plants were killed during the frost of winter
1994-5, this biomass production was over a growth period of 5 and 6 months. These values
were high and showed good growth of the Vetiver plants.
In the ground nursery in Lorca, the Malaysian Accession produced 45 and 47 tillers after 9 and 10 months growth respectively. Over the same periods the dry matter were 305 gm and 489 gm per plant respectively. The American Accession yielded 377 gm with 79 tillers and 560 gm with 65 tillers after 9 and 10 months respectively. After deducting for establishment time, the growth periods were only 4 and 5 months. It would appear that the American Accession was more vigorous than the Malaysian Accession but it must be noted that the trials were not designed for such comparisons; also the plants were rather variable as there were no stringent selection of container plants used for field planting.
In both El Chopillo and Lorca, the cut tops regenerated rapidly confirming the good growth of Vetiver grass m autumn. Whether the impressive growth during the growing seasons is sufficient to compensate for negligible growth during the dormant and sustenance seasons to give good annual biomass production, will be the subject of future investigation.
The good growth of Vetiver grass and the rapid regeneration of cut tops point to potentially abundant in-site mulch to improve the main crops; this will be tested in the almond plots. Also the toppings may be considered for fuel, fodder, animal bedding, etc. The fast establishment of quality VGHR could be used to prevent surface soil erosion, as was clearly demonstrated in the observation trial on Highway Slopes.
Root System And The Need For Irrigation.
Excavation to study the root systems showed that the roots of the plants in El Chopillo had reached a depth of 2.6 metres after 14 months in the field. In Lorca, the Malaysian Accession and the American Accession had produced roots reaching down to 2.1 metres and 1.7 metres respectively after only 9 months. However, m all 3 cases the massive root system was at the top 0.4 - 0.5 metres. The root Systems observed were not inferior to the condition experienced in Malaysia.
In this project, there was an attempt to grow Vetiver grass in the Mediterranean climate of Murcia. Vetiver grass originated mainly from the humid tropics and it will therefore be most challenging to try to establish it in such an alien and hostile aerial conditions. For the first Phase of the project, Vetiver grass was irrigated to allow it to have a better chance of establishment so that its growth performance may be studied. However, irrigation is expensive and m certain locations, water may not be readily available. The ultimate economic success may ultimately be determined by its tolerance to water stress.
With the good root system produced, the plants may be able to tap into the sub-soil moisture during drought and that VGHR, once established, may be tolerant of dry weather conditions. This is a very important speculation as the need for continued irrigation may make VGHR not economically viable. Therefore, more experience is needed in order to confirm this key aspect of the project. Phase II Trials will be targeted to achieve this objective.
Plant Response to Climatic Conditions.
Since there is no easy nor economical way to modify the temperature in the field, we decided, in Phase I of the project, to concentrate on studying its effect on the establishment and growth of Vetiver plants. The responses of the plant to the seasonal weather conditions showed very interesting results. With plants established in the ground in El Chopillo, frost killed the tops but the crown-portions were not injured. With the coming of the warmer weather, new tillers were formed. In the Container Trial in Lorca, the cold winter killed the matured tillers but not the newly emerged ones. This recovery from cold damage was not surprising as the Vetiver Newsletter had carried such observations made in China, U.S.A., South Africa, Zimbabwe, etc. The plants in El Chopillo recovered from frost injury and cold weather much faster and produced tillers earlier than the plants in Lorca. The main reason may be, that the plants in El Chopillo were well established with a good root system while the plants in Lorca were being established in the field or were in containers exposed to the aerial environment. The depth of root in the warmer ground could be of importance in the plant's tolerance to cold as well as water stress. These observations, documented by serial photos, suggest that there seem to be distinct plant performance periods (at least under irrigation) viz.
1. Frost injury and dormancy
2. Awakening and tillering (regeneration or multiplication)
3. Rapid growth and biomass production
4. Slow growth or sustenance period.
The last period need to be verified during the coming 1995 - 6 late August to early winter months. If these observations were correct, the tropical to sub-tropical Vetiver Grass is behaving more like a temperate plant, adapting to the prevailing climatic conditions. This adds on to the documented great range of adaptabilites of Vetiver Grass, a very unusual plant indeed. It also points to the possibility of using VGHR in the Mediterranean regions as well as up m the cold highlands of the tropics and sub-tropics.