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Growing Ginger under a Natural Farming System: Use of Organic Amdendments and Cover Crops for Nematode Control and Nutrients

Grant Recipient:

Mokichi Okada Association
3510 Nuuanu Pali Drive
Honolulu, HI 96817
(MOA farm is in Waimanalo, HI)

Project Period:

August 1999 - June 2001

Principal Investigator:

Ivan Kawamoto

The project demonstrated the use of a natural farming method for ginger production in Hawaii. The MMokichi Okada Association (MOA)natural farming system uses crop rotation, cover crops and green manures to maintain soil fertility and manage pests and diseases. Ginger is an important crop for small farmers in Hawaii and has a ready local market. It has an eight-month growing cycle. Pesticides and fertilizers are heavily used during the growing season. The project tested two rotational cover crops, Crotalaria spectabilis and Crotalaria juncea, legumes that provide nitrogen to the soil and are known to control root-knot nematodes. The trial was located in field areas that had both reniform and root-knot nematodes. The Crotalaria plantings were allowed to grow for about three months and then were plowed into the soil and allowed to decompose for about two months. Following this fallow period, ginger was planted and later harvested.

Project goals and objectives
To demonstate the use of a natural farming method for ginger production in Hawaii and make use of cover crops and organic amendments in lieu of chemical fertilizers and nematicides:
1) to control root-knot (Meloidogyne spp.) and reniform (Rotylenchulus reniformis) nematodes in soil with non-host cover crops.
2) To provide sufficient nutrient to the ginger crop using leguminous green manure and organic compost.
3) To educate Hawaiian farmers on this system of ginger production

Crotalaria appeared to reduce the numbers of root-knot nematodes but the numbers were too low to be statistically significant. The reniform nematodes did not appear to be affected by the cover crop. Nonetheless, there was no visible damage to the ginger roots from either the root-knot nematodes nor the reniforms and a good crop was obtained. In addition, green onion were planted alongside the ginger roots. Green onions appear to reduce nematode numbers or prevent them from attacking nearby roots but were planted in all six treatment plots so their effect could not be measured. The ginger crops following Crotalaria had greater nutrient levels than those following fallow soil. The nitrogen supplied to the soil by Crotalaria also produced heavier ginger roots. The project cooperators now feel it is possible to grow ginger root in Hawaii in nematode-infested soil without the use of pesticides or chemical fertilizers.

Project Links
Data not required at time of project

American Farmland Trust