Eco-compost a winner
Compost made from green waste collected in Timaru kerbside bins has received a glowing report following a five-year study.
The just-released Plant and Food Research report says using the compost could pay big dividends to commercial farmers and green-thumbed gardeners.
The science company tested compost from Transpacific Industries' Timaru and Christchurch sites and Living Earth's Christchurch site. It found that a single application of compost could enhance crop production for at least two years.
About 14,000 tonnes of vegetative and food waste per year is received and processed into "eco-compost" at the Timaru site.
Regular applications of around eight to 12 tonnes per hectare of compost every two years reduced a farmer's nitrogen fertiliser use by about one third.
This rate was also the most financially viable scenario for a compost application.
The compost's quality was consistent and the resulting crop yields from the trials made it a cost saving option for farmers.
"It won't necessarily suit all farmers, but they are not going to be losing money and there are benefits to be had.
"It can fit in with a lot of farmers' [crop] rotations," Miss Horrocks said.
The compost worked best when used in conjunction with chemical fertiliser, rather than switching entirely. The yield and profit results were not the same when the compost was used on its own.
The compost was trialled on a forage and pastoral plot at Karina Downs near Cave, on an arable crop near Lincoln and on a vegetable trial near Christchurch.
Using compost also led to increased levels of carbon in the soil, elevated levels of nutrients including potassium and phosphorus and improvements in soil structure in the long term.
It was also beneficial for urban gardeners.
"In a home garden situation where the applications are being made every year, over time you're going to see really high organic mass levels and really high water holding capacity," Miss Horrocks said.
Transpacific Industries Group managing director Tom Nickels said inquiry for the compost was increasing.
"There has been strong demand from the local community for compost for residential vegetable garden and general landscaping use, as well as for rural and horticulture application."
The Timaru Herald