Alternative, non-animal based nutrient sources, for organic plant raising OF0308

Summary

Organic plant raising has been investigated under two previous government funded projects (OF0109 & OF0144) (1, 2) and it was shown in this research that organic ‘transplants’ could be produced for a range of crop species (3, 4, 6, 7). However, some species were easier to produce than others and one of the limiting factors was the availability of suitable nutrient sources, especially for supplementary feeding. The use of animal based nutrient sources in organic plant raising has always been considered far from ideal and there are now moves within the EU to ban all animal bi-products in organic plant raising. This work aimed to identify suitable non-animal based nutrient sources to be used as base nutrients for growing media and as supplementary feeds.
The objectives of the project are;
1. To identify suitable alternative, non-animal based nutrient sources for organic plant raising.
2. To assess these non-animal based nutrient sources under UK organic plant raising conditions.
To identify suitable alternative, non-animal based nutrient sources for organic plant raising.
A UK, European and international search (literature, web, phone/personal contacts) was undertaken in early 2002 to establish what suitable, non-animal based, nutrient sources were available. Information on the products was sourced from the producer, supplier or manufacture and collated. Products that were obviously not suitable for organic production were excluded. This search identified a wide range of different types of non-animal based nutrient sources. A range of these products were used in the assessments in objective 2.
To assess these non-animal based nutrient sources under UK organic plant raising conditions.
Media trials
Three commercially available growing media which utilise a non-animal based nutrient source were identified; Sinclair, Vapogro and Melcourt and a fourth was made for the purposes of these trials in consultation with the manufacturer; Vapogro with double the added base nutrients. Two species with contrasting requirements (leek and cabbage) were used to assess the efficacy of these media.
Cabbage
• The Sinclair, Vapogro and Melcourt media all produced cabbage transplants considered to be of an acceptable quality, when supplied with supplementary feed.
• The Vapogro media with double the normal strength of base feed was able to produce cabbage transplants of acceptable quality without the need for supplementary nutrients.
• The Vapogro media with double the normal strength of base feed was able to produce cabbage transplants that were as large as those produced in the Sinclair and Melcourt growing media with supplementary feed. Though they were at an earlier growth stage.
• When supplied with supplementary feed, the Vapogro medium with double the normal strength of base feed produced significantly larger cabbage transplants than the other three media, though they were not more advanced in terms of growth stage.
• The Sinclair, Vapogro and Melcourt media, when supplied with supplementary feed, produced cabbage transplants that were not significantly different from one another in most respects.
• Adding supplementary feed to all the media resulted in more severe aphid infestation.
Leek
• All of the growing media used were only able to produce leek transplants of acceptable quality when supplementary nutrients were added.
• The largest most vigorous leek transplants were produced in the Melcourt media, this is particularly significant as this is a peat free medium.
• The Vapogro media with double the added base nutrients was able to produce acceptable leek transplants, but they were severely attacked by sciarid fly, which caused large numbers to die.
Supplementary feed trials
Four commercially available non-animal derived, organic supplementary feeds were identified (AmegA BIOFEED 5.0-0-2.5; Westland Organic Tomato and Vegetable liquid feed (WTV); Bioplasma NATURAL GROW and Gem Fruit ‘n’ Veg Fertilizer). These were tested against a standard animal derived organic feed and conventional mineral fertiliser feed. Two species with contrasting requirements (leek and cabbage) were used to assess the efficacy of these feeds in a single growing media (Vapogro).
• Two of the feeds, WTV and AmegaA (with added phosphorus) produced cabbage and leek transplants of acceptable quality, broadly equivalent to those fed Nu-Gro, the standard organic supplementary feed.
• AmegaA without added phosphorus produced lower quality transplants.
• Bioplasma NATURAL GROW and Gem Fruit ‘n’ Veg Fertilizer produced poor quality transplants, not significantly different from zero feed in most respects.
• The exception to this was the degree of rooting, which was lower in the feeds with largest shoots, AmegaA with added phosphorus, and WTV and highest with the Bioplasma NATURAL GROW feed.
• Leeks grown with AmegaA with added phosphorus suffered severe sciarid fly attack
• The use of AmegaA and WTV merit further investigation, particularly regards their field performance.
Conclusion.
This study has shown that there area range of non-animal based organic base and supplementary feeds available to the UK organic plant raiser. Although only a limited range of feeds were trialled on a limited number of species (cabbage and leeks) it is likely that the products available will produce suitable quality organic transplants.