Influence of steam-treated grass clippings on grass growth, drainage water quality and soil microbial properties in a simulated golf course

Figures & data

Figure 1  Photo of grass clippings before and after steam treatment.

Figure 2  Schematic diagram of plant material, liguid residue and the golf course microcosms simulated using plastic containers. CF, chemical fertilizer.

Table 1 Amount of plant material, liquid residue and fertilizer applied per m−2 in the different treatments

Treatment	Plant material (kg)^†	Liquid residue (L)	Poultry manure (g)^†	Chemical fertilizer (g)^‡
				2004		2005^¶
Chemical fertilizer (CF)	–	–	20	25	25^§	10
Leaf litter (LL)	1	–	20	25	–	10
Grass steam–treated (GT)	1	–	20	25	–	10
Grass steam–treated + basalliquid (GT + BL)	1	6.0^††	20	25	–	10
Grass satem–treated + fertigation (GT + FL)	1	3.2^‡‡	20	25	–	10
Grass steam–treated (GT10)	10	–	20	25	–	10
^†Fresh material;
^‡NPK 8–8–8;
^§top dressing in 2004;
^¶top dressing on 33 days of the experiment 2005;
^††applied as basal fertilizer in a single application;
^‡‡diluted 10-fold and applied as fertigation (6 times, one per week).

Figure 3  (a) Sampling times and main management during the experiment until 1 October 2005 and (b) rainfall until 26 June 2005. CF chemical fertilizer; GT + FL, 3.2 L m−2 of liquid residue was diluted 10-fold and applied as fertigation six times, once per week, starting 1 month after transplanting in addition to 1 kg m−2 steam-treated grass clippings.

Table 2 Chemical properties of the soil

Sample	Total C	Total N	Total P	Total K	C/N ratio	Nitrate	Ammonium	pH
	(g kg^−1 dry soil)					(mg kg^−1 dry soil)
Surface	12.1	1.3	0.7	0.6	9.3	10.5	5.7	6.1
Subsurface	33.3	3.1	1.4	0.8	10.9	10.5	6.3	6.2
Surface, 0–10 cm (Andisol + sand); subsurface, 10–20 cm (Andisol). Andisol used was classified as Light-colored Andisol (Typic Hapduland) with a loam texture (Sakamoto and Hodono 2000).

Table 3 Chemical properties of the organic matter

Samples	Total C	Total N	C/N	Total P	Total K	Total Ca	Total Mg	Water content (%)
	(g kg^−1 dry matter)				(g kg^−1 dry matter)
GT	466.8	27.6	16.9	4.1	16.8	5.4	5 3	15
LL	321.7	12.1	26.5	1.2	1.9	13.2	6.6	54
PM	227.4	20.1	11.3	21.4	36.0	183.3	19.4	23
GT, grass treated; LL, leaf litter; PM, poultry manure.

Table 4 Chemical properties of the liquid residue

Liquid residue	DOC	DON	N-NO^− 3	N-NH^+ 4	pH	EC (dS m^−1)
	mg L^−1
	2232	214	n.d.	18.1	4.5	1.46
DOC, dissolved organic carbon; DON, dissolve organic nitrogen.

Figure 4  Dry matter of grass clippings in different treatments during two cuts in 2004 and two cuts in 2005. Statistical analyses of total dry matter: least significant difference (P < 0.05). The treatments GT + BL and GT + FL were only conducted at the first and second cuttings. CF, chemical fertilizer; LL, commercial leaf litter; GT, 1 kg m−2 steam-treated grass clippings; GT10, 10 kg m−2 steam-treated grass clippings; GT + BL, 6 L m−2 liquid residue was applied once as basal fertilizer in addition to 1 kg m−2 steam-treated grass clippings; GT + FL, 3.2 L m−2 of liquid residue was diluted 10-fold and applied as fertigation six times, once per week, starting 1 month after transplanting in addition to 1 kg m−2 steam-treated grass clippings.

Figure 5  Changes in drainage water (a) pH, (b) electrical conductivity (EC), (c) nitrate concentration and (d) ammonium concentration. Error bars in EC, pH and ammonium concentration are the standard deviation, and in nitrate concentration the error bars indicate the least significance difference values at P < 0.05. Leached samplings: 1∼9 in 2004 and 10∼16 in 2005.

Table 5 Total carbon and nitrogen, extractable carbon and pH in the surface layer (4–10 cm) sampled at the end of the growing season in 2005

Treatment	Total C	Total N	Extractable C^†	pH
	g kg^−1 dry soil		mg kg^−1 dry soil
CF	11.7	1.16	211.9	6.4
LL	15.2	1.33	236.1	6.6
GT	15.2	1.34	237.5	6.6
GT10	27.3	2.17	299.7	6.7
LSD (P = 0.05)	2.3	0.16	23.1
^†Extractable C in 0.5 mol L^−1 K2SO4 (unfumigated soil). CF, chemical fertilizer; LL, commercial leaf litter; GT, 1 kg m^−2 steam-treated grass clippings; GT10, 10 kg m^−2steam-treated grass clippings; LSD, least significant difference.

Figure 6  Soil biochemical and microbiological properties in the surface layer (4–10 cm): (a) microbial biomass carbon, (b) dehydrogenase activity, (c) protease activity, (d) phosphatase activity, (e) soil respiration and (f) microbial metabolic quotient. Values with the same letter are not significantly using least significance difference values at P < 0.05. Error bars indicate standard deviation. Note: Soil respiration refers to the cumulative carbon mineralized during the incubation period. CF, chemical fertilizer; LL, commercial leaf litter; GT, 1 kg m−2 steam-treated grass clippings; GT10, 10 kg m−2 steam-treated grass clippings.

Sakamoto , K and Hodono , N . 2000 . Turnover time of microbial biomass carbon in Japanese upland soils with different textures . Soil Sci. Plant Nutr , 46 : 483 – 490 .

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