Compost use nets 10 percent gain in yield on farm

A California almond farm reported a yield improvement of 20 percent – half of which was attributed to the use of compost. Okuye Farms, of Merced County, Calif., was featured this month in a case study from the USDA Natural Resources Conservation Service (NRCS) and the American Farmland Trust that highlights the economic benefits of implementing soil health management practices.

Of the four case studies published, Okuya Farms was the only one that cited the land application of compost as a factor in increased production.

By using compost and other nutrient management practices, Okuye Farms improved its bottom line by $657 per acre, and $76,155 over 116 acres last year, the case study reported.

The farm is operated by Ralf Sauter and his family, which grows almonds on 116 acres of flat, sandy loam soil. The land has been in the family for more than 100 years and is protected from development by a conservation easement.

Fourteen years ago, Sauter took over the operations from his mother-in-law, Jean Okuye, when he and his wife moved their family from Germany to the San Joaquin Valley. Jean Okuye, the president of the East Merced Resource Conservation District, pioneered the use of cover crops, compost and micro-sprinkler irrigation at Okuye Farms, as well as owl boxes, hedgerows and solar energy.

Since taking over in 2005, Sauter has grown the farm from 80 to 116 acres and extended these efforts throughout the orchard. Sauter credits increased adoption of soil health practices to the inspiration he gained from attending grower workshops. He learned about the dual opportunity to cut cost and increase yield by implementing nutrient management, conservation cover, mulching and compost application.

Sauter has realized multiple financial benefits from soil health, including higher yield and lower cost.

His approach to nutrient management (leaf sampling and fertigation) resulted in greater fertilizer use efficiency. He observed an increase in beneficial insects from conservation cover, which led to fewer miticide applications. Sauter decreased his pruning cost and believes he increased soil organic matter by transitioning from burning to chipping prunings within the orchard alleyway.

Finally, Sauter credits part of the increase in yield to compost application, which he believes improves microbial activity and water holding capacity.

In the 14 years since Sauter took over the orchard, he said experienced a 20 percent increase in yield, which he attributes to a combination of nutrient management and improved soil health from the use of compost as a nutrient source.

Sauter’s nitrogen management plan, a requirement of the state’s Irrigated Lands Regulatory Program, includes an annual nitrogen budget. Sauter uses leaf sampling (about $3 per acre) to determine tree nutrient status. He then estimates his compost rate and supplements with synthetic fertilizer through his irrigation fertigation system.

Sauter applies compost at a rate of 5 tons per acre.

Placing compost in the tree row adds organic matter to feed soil microbes and provides essential nutrients for tree uptake.

Sauter attributes half of his yield increase to compost use, but these benefits come at a cost. Delivered compost costs $21 per ton and an additional $5 per ton to spread. At five tons per acre, compost costs Sauter $130 per acre. Fertigation facilitates delivery of the right fertilizer rate in the right location at the right time. Increased yield from fertigation as a nutrient management strategy more than offsets the cost of the micro-irrigation system and the added $60 cost per acre of switching potassium forms from granular to liquid.

Sauter allows native vegetation to grow as conservation cover over winter and mows the orchard floor in spring and summer. The cover also provides habitat for beneficial insects. Since adopting this practice, Sauter has reduced miticide sprays from four times to one time every five years, saving him $30 per acre per year.

Sauter also hires a brush shredder to chop and mulch the orchard prunings.

This practice replaced burning that required a tractor to push prunings to the end of the orchard row where they were piled and burned, costing $75 per acre. The brush shredder costs $13.50 per acre, saving him $48 per acre.

Sauter believes that mulching has led to increased soil organic matter, greater microbial activity and improved water holding capacity.

To estimate the water quality and climate benefits experienced on one of Sauter’s 11-acre fields, USDA’s Nutrient Tracking Tool was used, which found that Sauter’s use of nutrient management, conservation cover, mulching and compost application reduced nitrogen losses by 98 percent.

On the same 11-acre field, USDA’s COMET-Farm Tool estimates that Sauter’s soil health practices resulted in a 16 percent reduction in total greenhouse gas emissions, which corresponds to taking 3/4 of a car off the road.

Partial budgeting analysis was used to estimate the benefits and costs of adopting nutrient management, conservation cover, mulching and compost application for the Okuye farm. The study limited its focus to variables affected by the adoption of these soil health practices.

Sauter improved his bottom line by $657 per acre and by $76,155 on all 116 of his orchard acres by adopting the soil health practices.

Those numbers include $455.40 per acre from improved yield due to compost application and the same amount of increased net income from improved yield due to nitrogen management. Costs dropped by $78 per acre due to pasticide savings and the switch from burning orchard prunings to mulching.

Increased income and decreased costs, calculated before the costs of implementing the practices, showed an improvement of $989 per acre.

That gain was reduced by such costs as applying compost ($130.42 per acre), an annualized cost of an irrigation system ($130 per acre) and an increased nutrient cost due to nutrient management ($60 per acre).

Sauter’s experience in agriculture for 14 years has centered on implementing soil health practices in collaboration Okuye. Sauter’s early adoption and expansion of soil health practices, including nutrient management, conservation cover, mulching of prunings and use of compost resulted in reduced cost and higher yield. He firmly believes that these practices have made his trees and soils healthier, all the while protecting groundwater from nitrate pollution. Though many soil health practices are more expensive to implement than conventional practices, Sauter has found the increase in yield and other benefits far outweigh these costs.

For more information, or to read the other three case studies, visit

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