Study of Root Zone Thickness and Growth Response of Zoysia japonica, Zoysia matrella, and Paspalum vaginatum

Research Article
Sahrul Nugroho1Geun-Mo Yang2*


The thickness of a root zone is still a basis for football field constructors for good field performance along with saving root zone material. This research is a column pot experiment and placed in an open space to know the thickness of the root zone that is acceptable with the variable warm season grasses growth. The root zone used was a mixture of loamy sand, 75% sand, 10% soil, and 15% compost with a thickness of 15, 20, 25, and 30 cm. The grasses used were Zoysia japonica, Zoysia matrella, and Paspalum vaginatum and planted with sprigging, maintenance of watering, fertilization, and manual weed control. Harvesting was done after the plant is 34 weeks after planting. The results showed that the thickness of the root zone 25 and 30 cm had the same results on shoot density, time to 100% ground coverage, recovery rate from damage, plant height, clipping weight, root length, plant fresh weight, and root dry weight, and efficiency of use air. In all thicknesses of the root zone, Paspalum vaginatum had the highest yield on shoot density, 100% ground coverage, recovery power, plant height, cutting weight, root volume, leaf fresh and dry weight, root fresh and dry weight, and air efficiency.



Athletic field constructions commonly adopt the United State Golf Association (USGA) Green Section Recommendations. USGA has recommended 30 cm root zone since 1960, and no such recommendation has ever changed, mainly because of drainage and water retention (Frank et al., 2005). However, many golf courses are made of green by reducing the thickness of the root zone to 25 cm above the native soil to reduce costs (Davis et al., 1990). The main key to success even reducing thickness is proper attention to particle size distribution, physical performance criteria, and drainage spacing (Ho, 2003). One of the popular systems for constructing athletic fields is the The Prescription Athletic Turf (PAT) system. The PAT is a flat subgrade with 30 to 50 cm of sand placed over the plastic barrier with the majority sand particles in the 0.5 to 0.1 mm range, and the surface 5 to 10 cm is modified by adding peat, well composted organic matter, soil, and fertilizer. The Hy-play system is using excavated to a depth of 30 cm area, and after drainage installation, a 30 cm sand-based root zone medium is placed over the subgrade, the fertilizer distributes through the irrigation system (Kowalewski et al., 2015). The area of the soccer field according to FIFA (2007) is 7,140 m2 (105 m×68 m). Each increase in root zone thickness of 5 cm means that it requires 357 m3 of sand similary for the root zone thickness of 15 cm requires 1.071 m3 of sand, a thickness of 20 cm requiring 1,428 m3 of sand, 25 cm of thickness requiring 1.785 m3 of sand, and 30 cm of thickness requiring 2,142 m3 of sand. This study aims to determine the response of the warm season turfgrasses to the thickness of the root zone growing media of river sediment media.

Most sports fields in Indonesia are built from existing native materials. Soils with textures of silt loams or silty clay loams have been used in construction of sports fields for many reasons. In order to get proper play, it needs proper aerification, overseeding to maintain dense populations of grass, careful watering to avoid soil saturation, better nutritional programs to ensure growth and recovery from wear (Kowalewski et al., 2015). On a football field, periodic fertilization is needed to maintain the visual and functional quality of turfgrass. FIFA (2007) explains fertilization is needed for grass growth and closure. Fertilization is affected by soil type and temperature, root zone in the form of sand requires more fertilization. FIFA (2007) recommends fertilizing intervals for the root zone in the form of sand between two to four weeks for soccer fields in tropical climates. The root zone is a part of the soil where roots can grow and stand. The different root zone depths of the turfgrass species have very different rooting potential. According to Turgeon (1996) different turfgrass species have different leaf textures and colors that affect turfgrass quality. According to Harivandi et al. (2009) turfgrass species have differences in root depth and are also influenced by water patterns, soil characteristics, management practices such as cutting and fertilizing, and compaction. The nature of the root zone used will determine the quality of turfgrass produced in addition to environmental conditions and maintenance factors (Duble, 2014). The root zone is the part of the soil where roots can grow and stand. The soil profile of a root zone ranges from the soil surface to the depth that the root can reach. The thickness of the root zone in the turfgrass determines the volume of the soil to hold water for plants to use. Therefore deep root turfgrass requires less irrigation than shallow roots (Wu, 1985). Good drainage and irrigation is needed to keep the grass dense and fertile (Emmons, 2000). The USGA provides specifications for green field construction, first published in 1960, designed to improve the quality of green courts. Although USGA published a revision in 1973, 1989, 1993, and the most recent in 2004, recommendations for a root zone thickness of 30 cm remain unchanged. The root zone in the form of sand above the gravel layer maintains optimal moisture throughout the green field (Frank et al., 2005). According to Huang (2006) soil compaction can increase specific gravity, water retention and soil strength. However, it can also reduce the porosity, aeration, and oxygen needed for root growth. Harivandi et al. (2009) explained that soil compaction reduces the growth of root and shoot turfgrass and also decreases the level of water infiltration. Declining water use makes turfgrass growth slower and worse. According to Hardjowigeno (2007), sandy soil has problems with higher macropored structure, single grained loosening, high volume weight, low ability to absorb and store water so that it is less dry, and sensitive to nutrient leaching, and sensitive to erosion.

The selection of turfgrass species chosen for football fields must be resistant to intensive use on the field (Pawluczuk and Grabowski, 2014). FIFA (2007) recommends turfgrass species for soccer fields in tropical climates such as bermudagrass (Cynodon species), zoysiagrass (such as Zoysia japonica and Zoysia matrella) and seashore paspalum (Paspalum vaginatum). Zoysiagrass is a warm season turfgrass that spreads stolons and rhizomes to produce grass that is very dense and resistant to trampling. This grass has been developed and adapted to wider environmental conditions. There are three Zoysia species that are suitable as a turfgrass namely Zoysia japonica, Zoysia tenuifolia, and Zoysia matrella. The weakness of zoysiagrass is thatch has thick so periodic renovation is needed. These grasses are susceptible to nematodes, billbugs, and some diseases, and tend to have shallow roots when growing on low potassium soils (Romero and Dukes, 2009). A manilagrass has strong stolons and rhizomes which branch out in all directions. This grass has a uniform long stolon segment. Usually, the tips of the leaves of the manilagrass always roll inward. Leaves are smooth and dark green or bluish green. This grass has flowers that form a grain (Christians, 2004). A Paspalum vaginatum is a warm season turfgrass originating from tropical and sub-tropical regions throughout the world. This grass produces high quality turfgrass with relatively low fertility inputs. The shortage of this grass has poor shade tolerance (Romero and Dukes, 2009).

Materials and Methods

This research was a pot experiment conducted from May 2017 to February 2018. The research location is at the Center and Development of Sebelas Maret University Surakarta Dry Land in Sukosari Village, Jumantono District, Karanganyar Regency. The geographical location is 7º, 30', S and 110º, 50' E with a height of 180 m above sea level. A daily temperature at the study site around 24-35℃, and humidity around 55-82%. The pot is a column with a diameter of 37 cm and a height of 35 cm. The root zone used is a mixture of sand, alfisol soil, and leaf litter compost, with a ratio of 75% sand, 10% soil, and 15% compost. The sand texture used is river sediment, with 84.5% sand content, 7.9% dust and 7.6% clay. The highest texture of alfisol in klei is 75.78%, dust 21.14% and sand 3.07%, thus the mixture growing media was sandy clay texture. The root zone is made with different thicknesses, namely as Z1: 15 cm, Z2: 20 cm, Z3: 25 cm, and Z4: 30 cm. Then under the root zone is filled with gravel to fill the pot as deep as 35 cm. The bottom of the pot is given a hole for irrigation channels. Turfgrasses tested were S1: Zoysia japonica, S2: Zoysia matrella, S3: Paspalum vaginatum. Zoysia matrella has a leaf texture of 1.42 mm, Zoysia japonica of 2.82 mm, and Paspalum vaginatum of 2.38 mm. This study uses a completely randomized design with turfgrass type factor and root zone depth and with 3 replications. Planting is done by sprigging propagation method, namely cutting stolons or rhizomes along 3 sections, each pot contains 30 sprigs. Maintenance includes watering, fertilizing, and controlling weeds manually. Watering is done once every day. Fertilization for maintenance namely NPK Mutiara 16:16:16 compound fertilizer as much as 0.5 g per pot every two weeks. Harvesting is done after the plant is 34 weeks after planting. Soil samples are taken randomly at each root zone thickness, then analysis of soil texture, pH, ECP, and soil organic matter was conducted in the laboratory. Soil texture was analyzed by the pipette method Miller and Miller (1987). The pH measured with pH meter (Eutech Alkestron PT, Gagas Envirotek, Cibinong, Indonesia) with a ratio of media soil and distilled water 1:2.5. An ECp was measured using an EC meter (Eutech TDS 6 Plus Alkestron PT, Gagas Envirotek, Cibinong, Indonesia) with a ratio of media soil and distilled water 1:2.5. Organic matter content was analyzed in the laboratory by organic C firing using a spectrophotometer. Permeability is measured using a permeameter (Sebelas Maret University Modification, Surakarta, Indonesia) and soil ring sample. Soil moisture is measured using a soil moisture meter in the root zone. Holding power of water is done by measuring changes in moisture content in each root zone thickness using a soil moisture meter (PMS-714, Lutron, Taiwan) that is immersed into the root zone at the same depth of 10 cm and measured at 10:00 am for 3 consecutive days.

The shoot density was observed by counting the number of shoots in an area of 100 cm2 at each treatment. A turfgrass color was observed with a tissue plant color book counsel. Aspects of leaf texture are observed by measuring the average width of grass leaves taken randomly. Percentage of grass cover was observed using photos from digital cameras from each grid plot. Power recovery was observed as the ability of grass to turn green again after short cuts (0 cm) was then calculated as the number of days needed for grass to grow to reach 100% grass cover. Observation of grass height using the bar 14 weeks after planting. The weight of clipping is measured by cutting the surface of the grass at a sample area of 100 cm2 once a week in a row for 3 weeks. Root length was measured using a plug cutter and using a ruler 14 weeks after planting. Root volume using a plug cutter is cleaned then measured with a measuring cup filled with water, then drained and angina rings are weighed for fresh roots weight. Fresh weight of leaves was obtained by weighing clipping, and leaves were dried in the oven for 48 hours at 60℃ and then weighed to get the dry weight. The calculation of the efficiency of water use according to Suryanti et al. (2015) is calculated by the ratio of plant dry weight (g) divided by water requirements. The grass is irrigated every day manually as much as 0.26 L day-1 at the crop water requirements. The water crop requirement was calculated using the formula ETc=ET0×Kc (Harivandi et al., 2009). The average evapotranspiration (ET0) in May-August at the study site was 3.84 mm per a day. The crop coefficient value (Kc) of warm season turfgrass is 0.6 (Croce et al., 2001). So that the water needed for turfgrasses per pot of 2.30 mm per a day. Analysis of the research data using the F test and continued using Duncan’s multiple range test (DMRT) at 5% level.

Results and Discussion

The root zone thickness gives a significant effect on pH, ECp, soil moisture and soil organic matter (Table 1). The root zone 15 and 20 cm produce equally low organic matter, pH and ECp are significantly higher at thicknesses of 25 and 30 cm. The effect of root zone thickness on water storage does not occur on the first day, but it is significant on the second and third days. All root zone thicknesses have very fast permeability. According to Sutanto (2005), land with a permeability value of 16-25 cm hr-1 is fast and more than 25 cm hr-1 is very fast category. Sandy soils have weak soil structural characteristics, poor water retention, high permeability, and rapid water loss (Bruand et al., 2005). According to Emmons (2000), a sports field with sand root zone is the safest field because it is easier to maintain grass density and not dense surfaces. The thicker of root zone resulted in higher soil moisture and water retention capacity. Root zone 15 cm gives the lowest soil moisture, while root zone 30 cm gives the highest yield in first and second day irrigation. On the third day the root zone 15 and 20 cm gives the same low yield, while root zone 30 cm gives the highest. Zhou et al. (2013) reported that meanwhile turfgrass can avoid water shortages by extracting water from deeper soil profiles.

Means with the same letters within the columns are not significantly difference at a P=0.05 level by the Duncan multiple range test.

Table 1. Rootzone characteristics after turfgrass harvesting.

Root zone thickness has a significant effect on the efficiency of water use. The thickness of rooting zones 15 and 20 cm gives the same low yield on water use efficiency, while the thickness of root zone 20, 25 and 30 cm also gives the same high results. Demirel and Kavdir (2012) explain the use of water by turfgrass depending on species, climate conditions, irrigation programs, and management such as pruning and fertilizing. Species have a significant influence on the efficiency of water use. Z. matrella has the lowest water use efficiency of 0.38 g mm-1, while P. vaginatum gave the highest yield of 1.22 g mm-1, thus meaning that with the same water, the seashore paspalum will resulted more yield than Z. matrella. According to Lee (2011) each turfgrass species has different water needs, the use of cultivars and species with superior drought resistance is one way to reduce water use while maintaining good quality in turfgrass growth.

Root zone thickness affects plant shoot density (Table 2). Root zones 15, 20, and 25 cm gives the same low yield at shoot densities, while the thickness 20, 25, and 30 cm give the same high results. The shoot density of Z. matrella and P. vaginatum plants at root zone 30 cm is higher than the thinner root zone, whereas Z. japonica there is no significant difference between root zone thickness (Table 3). All root zone thicknesses are included in the intermediate shoot density or the number of shoots 100-200/100 cm2 (Beard, 1973). Table 3 shows that Z. japonica has the lowest shoot density which is 95 shoots 100 cm-2, while Z. matrella and P. vaginatum give the same high results, and are included in the medium category. The density of shoots can be increased by mowing (FIFA, 2007). Schild (2013) reported that turfgrass increases density by developing tiller or tiller from parent plants. Z. japonica has the highest color contrast difference between the top and back leaf blade. The color of the back leaf blade P. vaginatum is greener than the color of the upper leaf blade. Based on Tjitrosoepomo (2007), chlorophyll causes the green color of the leaves, so regular fertilization is needed to keep the colors. In addition, the discoloration can also be due to symptoms of lack of water. According to Schild (2013) due to symptoms of turfgrass drought will experience brownish and yellowish discoloration. The greener color of P. vaginatum may be related to irrigation. Harivandi et al. (2009) reported that P. vaginatum has a good drought avoidance mechanism.

Means with the same letters within the columns are not significantly difference at a P=0.05 level by the Duncan multiple range test.

Table 2. Mean growth and quality of turfgrass species on different root zone depth.

Root zone thickness affects the soil surface coverage. Table 3 shows the thickness of root zone 25 and 30 cm which results in 100% coverage speed and high recovery rate, while root zone 15 and 20 cm results in slow surface coverage and recovery rate. Table 4 showed that speed of coverage on the ground surface of P. vaginatum is faster than Z. matrella and Z. japonica. Z. matrella and Z. japonica are not significantly different. Z. matrella with root zone 15 cm showed very slow surface coverage. P. vaginatum with 15 and 20 cm recovery speed is lower than the thickness of 25 and 30 cm. The number of days of P. vaginatum recovery root zone thickness of 15 and 25 cm is relatively the same with Z. japonica at thicknesses of 25 and 30 cm. Duble (2014), reported growing media prone to compaction resulted in low drainage, shallow roots, slow growth and recovery rate of plant. Species have a significant effect on 100% closing speed and turfgrass recovery power (Table 5). P. vaginatum has the fastest surface coverage and recovery rate, while Z. japonica and Z. matrella provide the same slow results. Croce et al. (2001) reported that P. vaginatum has better vegetative growth than Zoysia sp. FIFA (2007) explains that planting method affected the turfgrass coverage, where sprigging method takes between eight to twenty weeks whereas sodding or grass rolls takes five to seven weeks for the soccer field to be ready use. In this study using stolon planting method P. vaginatum can coverage 100% at 8 weeks while Z. japonica and Z. matrella need 10 weeks after transplanting. According to Romero and Dukes (2009) Zoysia sp has slower growth than other warm-season turfgrass species. The recovery rate of Zoysiagrass can be increased by fertilizer application, although inorganic fertilizer shows faster recovery than organic fertilizer (Rahayu et al., 2014).

Table 3. Mean growth and quality of turfgrass species with variation root zone depth.

WAP: Weeks after planting.

Means with the same letters within the columns are not significantly difference at a P =0.05 level by the Duncan multiple range test.

Table 4. Growth and quality of Zoysia japonica , Zoysia matrella and Paspalum vaginatum on different root zone depth.

Root zone thickness gives a significant effect on grass height and clipping turfgrass weight. The thicker root zone gives relatively higher yields on grass height and clipping weight. Table 2 showed that the fresh weight of the P. vaginatum plant is higher than that of the fresh weight of Z. japonica and Z. matrella. In Z. japonica and Z. matrella thickness of 15 cm produces far less clipping than in thicknesses of 20 to 30 cm. The height of Z. matrella is the shortest than Z. japonica and P. vaginatum. The height of plants grown at the root zone 15 and 20 cm is shorter than the root zone depth of 25 and 30 cm for all three plants. The lower depth of the root zones brings about less water content or soil moisture, so it disrupts plant metabolism. Huang (2006) explains that when the supply of soil moisture is insufficient to replace what is lost from the bud, the stomata will be closed and metabolism in plants will stop. However plant height can be maintained by mowing. According to FNSW (2015) the average soccer field will be mowed at of 2.5-4 cm depending on the needs of the game. Whereas FIFA (2007) recommends cutting carried out at an altitude of 2.5-3.5 cm with cutting intervals twice per week. The higher the fresh weight value of the leaf shows the higher shoot density, while P. vaginatum has the highest shoot density. According to Huang (2006) turfgrass with denser shoot densities have lower water loss. Shoot density is related to the leaf texture. Table 5 showed that Z. matrella leaf's texture is significantly smaller than that of P. vaginatum and japonica age. The Z. japonica grown at root zone 25 and 30 cm deep has a rougher leaf texture than at 15 cm deep.

The thicker root zone gives a relatively long root length. Both fresh and dried root weights of Z. matrella were less than P. vaginatum and Z. japonica. At root zone 25 and 30 cm the root weight of the plants of the P. vaginatum and Z. japonica is higher than root zone 15 and 20 cm (Table 4). According to Gardner et al. (1991) one way for plants to get nutrients is by extending roots to ionic sources and deeper root zone. The thicker root zone gives relatively higher results in root volume (Table 3). The root length of plants in root zone 25 and 30 cm are the same in all three turfgrass species (Table 2). The root zone thickness of 15 cm showed the shorter root length than at the thickness of the root zone of 25 and 30 cm. The root volumes of Z. japonica and P. vaginatum on root zone 25 and 30 cm are not significantly different, but at root zone 15 and 20 cm the volume of the roots of the P. vaginatum is higher than that of Z. matrella and Z. japonica in the same root zone. Roots volume of Z. matrella and Z. japonica with rootzone15 and 20 cm were lower than in 25 and 30 cm root zone. Shallower root zone lowers moisture content and then affects lower root growth. Nio and Torey (2013) reported that a lack of water the plants will extend their roots to the soil layer which has sufficient water supply. Campbell et al. (2003) explain the roots found in the deeper soil layers are still surrounded by moist soil so that the roots can still grow. Schild (2013) explained that with deep root systems and stored soil moisture, turfgrass can survive the dry season. Species have no significant effect on root length, but significant effect on root volume of turfgrass. Z. matrella has the lowest root volume while P. vaginatum has the highest root volume. Harivandi et al. (2009) suggested that the characteristics of plants that contribute to the avoidance of drought are deep and long root systems and high root density. The thicker root zone indicates the more available water content, and the roots will grow in the soil layers that have water. According to Huang (2006) roots tend to expand in wet zones in soil profiles, where soils are kept wet constantly due to frequent irrigation or rain, plants tend to develop extensive and shallow root systems, and roots will extend with the soil left to dry periodically. Species have different fresh weights and dry weights of turfgrass roots. Z. japonica and Z. matrella gave similarly low yields on fresh root weights, while P. vaginatum gave the highest results. According to Romero and Dukes (2009) P. vaginatum produces a dense root system.

Authors Information


Sahrul Nugroho, Sebelas Maret University, Master student

Geunmo Yang, LCM Inc., CEO


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