Articles
LIVING AND SURFACE MULCHES AS NUTRIENT SOURCES IN ORGANIC VEGETABLE CROWING
Article number
571_12
Pages
109 – 117
Language
English
Abstract
A trial was performed in 1999 with red beet and white cabbage, to investigate the use of alsike clover (Trifolium hybridum) and white clover (Trifolium repens) as living mulches, with soil incorporation by rotary cultivation early in the growing season, and of chopped red clover (Trifolium pratensis) as surface mulch.
Surface mulch supplied the crops with large quantities of nutrients (210-470 kg N ha-1, 35-70 kg P ha-1, 240-490 kg K ha-1). The area required for growing mulch material, was 1.3-3.5 times the size of the mulched area itself.
Compared to the incorporation of clover mulch at planting, the presence of living mulch during early growth generally reduced yields, particularly when the mulch was not incorporated until six weeks after planting.
Yield reductions were much greater in red beet (Beta vulgaris), harvested in mid-August, (up to 45% lower yield), than in white cabbage (Brassica oleracea), harvested at the end of September, (up to 20% lower yield). A single surface mulch application, on the other hand, gave significant yield increases (up to 55% in red beet and 41% in white cabbage). Best results were obtained with early application.
Two applications gave a greater response in cabbage than in red beet.
Surface mulching led to significantly higher nutrient concentrations in both products and crop residues, and to large increases in total plant uptake.
The apparent N recoveries after a single mulch application were below 15% in red beet, and 22-27% in cabbage.
Corresponding figures for P were <8% and 14-31%. Two mulchings lowered the recovery percentages of these nutrients.
In the case of K, recoveries of up to 35% were found in both crops after a single mulching, whilst two mulchings increased recoveries somewhat.
Surface mulching led to significantly increased levels of mineral nitrogen in the soil after harvest.
The increases were much higher after red beet than after white cabbage, amounting to 45 kg N/ha in the former and only 15 kg N/ha in the latter after the use of two mulchings.
Surface mulch supplied the crops with large quantities of nutrients (210-470 kg N ha-1, 35-70 kg P ha-1, 240-490 kg K ha-1). The area required for growing mulch material, was 1.3-3.5 times the size of the mulched area itself.
Compared to the incorporation of clover mulch at planting, the presence of living mulch during early growth generally reduced yields, particularly when the mulch was not incorporated until six weeks after planting.
Yield reductions were much greater in red beet (Beta vulgaris), harvested in mid-August, (up to 45% lower yield), than in white cabbage (Brassica oleracea), harvested at the end of September, (up to 20% lower yield). A single surface mulch application, on the other hand, gave significant yield increases (up to 55% in red beet and 41% in white cabbage). Best results were obtained with early application.
Two applications gave a greater response in cabbage than in red beet.
Surface mulching led to significantly higher nutrient concentrations in both products and crop residues, and to large increases in total plant uptake.
The apparent N recoveries after a single mulch application were below 15% in red beet, and 22-27% in cabbage.
Corresponding figures for P were <8% and 14-31%. Two mulchings lowered the recovery percentages of these nutrients.
In the case of K, recoveries of up to 35% were found in both crops after a single mulching, whilst two mulchings increased recoveries somewhat.
Surface mulching led to significantly increased levels of mineral nitrogen in the soil after harvest.
The increases were much higher after red beet than after white cabbage, amounting to 45 kg N/ha in the former and only 15 kg N/ha in the latter after the use of two mulchings.
Authors
H. Riley, S. Dragland
Keywords
apparent recoveries, nutrient concentrations, red beet, soil mineral N, white cabbage, yield
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