Study

Spartina alterniflora response to fertilizer, planting dates, and elevation in Galveston Bay, Texas

  • Published source details Webb J.W. & Dodd J.D. (1989) Spartina alterniflora response to fertilizer, planting dates, and elevation in Galveston Bay, Texas. Wetlands, 9, 61-72

Actions

This study is summarised as evidence for the following.

Action Category

Add inorganic fertilizer before/after planting non-woody plants: brackish/saline wetlands

Action Link
Marsh and Swamp Conservation

Directly plant non-woody plants: brackish/saline wetlands

Action Link
Marsh and Swamp Conservation
  1. Add inorganic fertilizer before/after planting non-woody plants: brackish/saline wetlands

    A replicated, randomized, paired, controlled study in 1977 on intertidal sediment in Texas, USA (Webb & Dodd 1989) found that applying fertilizer had no significant effect on the survival, cover or height of planted smooth cordgrass Spartina alterniflora, and typically had no significant effect on its density. After two months and/or one growing season, fertilized and unfertilized plots supported similar cordgrass survival in two of two comparisons, had similar cordgrass cover in two of two comparisons, and contained cordgrass of similar height in four of four comparisons (data not reported). Fertilized and unfertilized plots had similar cordgrass densities in three of four comparisons (data not reported). In the other comparison, fertilized plots had higher cordgrass densities on average (17 stems/m2) than unfertilized plots (15 stems/m2). Neither fertilizer dose nor timing of application affected any result. Methods: In 1977, three hundred 15-m2 plots were established (in 30 sets of 10) at varying elevations on created intertidal land (sediment deposited and graded, protected by a breakwater and fenced). All plots were planted with field-collected cordgrass in February or May (60 plants/plot). Two hundred and forty plots (eight plots/set) were fertilized in one of four ways: high dose (244 kg/ha of N, P2O5 and K2O) or low dose (122 kg/ha of N, P2O5 and K2O), all before planting or split before and after planting. The other 60 plots (two plots/set) were not fertilized. After two months (April and July) and one growing season (November), the central 30 cordgrass plants in each plot were surveyed. This study used the same marsh as (2), but a different experimental set-up.

    (Summarised by: Nigel Taylor)

  2. Directly plant non-woody plants: brackish/saline wetlands

    A replicated study in 1977 on intertidal sediment in Texas, USA (Webb & Dodd 1989) reported that 20–91% of planted smooth cordgrass Spartina alterniflora survived for two months, with increases in cordgrass density and height over one growing season. Statistical significance was not assessed. After one growing season, planted plots contained 21–230 cordgrass stems/m2 (vs 4 stems/m2 when planted). Cordgrass plants were 54–157 cm tall (vs 48–59 cm when planted). Cordgrass cover was <10–50% (initial cover not reported). Amongst the plots, results depended on planting date, elevation and the combination of the two (see original paper for full details). For example, after one growing season, plots planted in February supported higher cordgrass densities than plots planted in May at the lowest elevation (February: 153; May: 2 stems/m2), but the opposite was true at highest elevation (February: 21; May: 56 stems/m2). Fertilizer typically had no significant effect on the results (see Action: Add inorganic fertilizer before/after planting). Methods: In 1977, four hundred and fifty 15-m2 plots were established, in three sets of 150, at varying elevations on created intertidal land (sediment deposited and graded, protected by a breakwater and fenced). All plots were planted with field-collected cordgrass (60 plants/plot): half in February and half in May. Most plots were also fertilized. After two months (April or July) and one growing season (November), the central 30 cordgrass plants in each plot were surveyed.

    (Summarised by: Nigel Taylor)

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