This article is part of the Woodleaf Farm Organic Systems Description.
Table 1. Woodleaf Farm Soil Management System
Strategies and tools | Implementation details |
| I. Soil organic matter building1 | See also Living Mulch and Organic Residues. |
| Optimize quantity of soil organic matter (SOM) | SOM increased from an average of 2.2% in the 1980s to an average of 5.1% in 2014 (Fig. 1). |
| Optimize quality of soil organic matter | Diverse organic residues are added regularly. Materials typically are high in carbon and low in nitrogen. |
| Maintain soil cover* | Since the 1990s, a perennial grass/legume/weed living mulch has been grown between and beneath tree and vegetable crop rows. |
| Use winter cover crops | Winter cover is maintained by the year-round perennial living mulch between crop rows. Total acreage in winter cover crops ranges from 30 to 50%. |
| Use summer cover crops | Summer cover is maintained by the year-round perennial living mulch between crop rows. Total acreage in summer cover crops ranges from 30 to 50%. |
| Apply organic soil amendments and residues | Residues include mowed living mulch, chipped branch wood, and yard waste compost. Materials are surface applied annually. |
| Apply chipped branch wood | Trees are pruned twice per year. Branches are chipped with a mower, and chipped wood is left in row middles and blown beneath trees. |
| Apply manure-based compost | Manure-based compost was applied through 1991. Woodleaf no longer uses manure-based materials. |
| Apply plant-based compost | Woodleaf applies yard waste compost one to three times per year at a rate of 2 tons/acre. |
| Apply a mix of carbon:nitrogen ratio organic amendments | Organic residues with different C:N ratios are added spring, summer, and fall. |
| Reduce tillage | Woodleaf has practiced no-till/reduced tillage since the 1990s. |
| Diversify soil biota with crop and noncrop diversity* | Woodleaf grows both perennial and annual crops. The living mulch contains diverse annual and perennial species with different rooting types and depths. |
| Grow a living root in the soil year-round* | The perennial living mulch maintains year-round presence of grass, legume, and weed roots. |
| Mow weeds to enhance nutrient cycling | Weeds are a major component of the perennial living mulch, which is mowed two to six times per year. |
| Till weeds to enhance nutrient cycling | Since the 1990s, Woodleaf has used no-till and reduced-tillage methods. Weeds are no longer incorporated. |
| Apply organic nonliving mulches such as straw | Alfalfa hay is used over the winter in no-till trellis vegetable crop rows. |
| Maintain animals/livestock as part of the cropping system | Chickens were part of the system in the early 1990s, but have not been present since 1994. |
| II. Soil fertility building | Table 2 shows Woodleaf's soil health trends, targets, and amendments. |
| Match nitrogen supply to crop need | The diverse mix of organic residues and amendments supplies N gradually from the soil reservoir. On average, total soil N levels are high (3,204 ppm) (Fig. 4). Nitrate-N decreased from an average of 23 to 9 ppm between 1982 and 2014 (Fig. 3). |
| Optimize soil potassium levels | Between 1982 and 2014, average soil K increased from 127 to 173 ppm (Fig. 16). |
| Optimize soil phosphorus levels | Between 1982 and 2014, average soil P increased from 46 to 95 ppm (Fig. 17). |
| Optimize soil calcium levels | Between 1982 and 2014, average soil Ca increased from 1,202 to 1,524 ppm (Fig. 13). |
| Optimize soil magnesium levels | Between 1982 and 2014, soil Mg increased from an average of 229 to 240 ppm (Fig. 18). |
| Optimize soil micronutrient levels | Between 1982 and 2014, soil zinc and copper increased (Fig. 5 and Fig. 6). Boron, sulfur, and manganese decreased (Fig. 7, Fig. 8, and Fig. 9). |
| Optimize soil Cation Exchange Capacity (CEC) | Between 1982 and 2014, average CEC increased from 9.5 to 11.7 meq/100g (Fig. 2). |
| Optimize soil cation balance | Woodleaf's target is 68-70% Ca, 15% Mg, and 3–7% K. The current average across fields is 67% Ca, 18% Mg, and 5% K (Fig. 14, Fig. 15, and Fig. 19). |
| Optimize soil pH | Between 1982 and 2014, soil pH decreased from an average of 6.7 to 6.4 (Fig. 20). |
| Apply off-farm soil amendments and fertilizers | Minerals, gypsum, and yard waste compost are applied annually. Gypsum is applied each spring at 250 lb/acre. Boron is applied annually at 10 lb/acre. |
| Apply foliar minerals and fertilizers | Kelp, sulfur, boron, and other minerals are sprayed in a foliar mineral mix one to three times at bloom, depending on precipitation during bloom. |
| Apply foliar compost teas | Carl Rosato experimented with compost teas in the early 1990s, but stopped using them in the mid-1990s based on on-farm testing (Disease Fig.1 and Disease Fig. 2) |
| Rotate crops | Rotation is weak. Peaches are more than 50% of total acreage and often are replanted in the same field. No replant disease has been observed, so Carl sees no need to change rotation practices. |
| Use soil tests to measure soil trends | Carl usually samples soil for analysis every 1 to 5 years in each of seven fields. |
| Optimize irrigation to minimize evapotranspiration (ET) loss** | Woodleaf uses microsprinklers. Tree tops receive 2 to 2.5 inches of water per week, while vegetables receive 1 inch/week. |
| 1*Strategy listed in the NRCS Soil Quality Initiative **ET can be determined with the use of CIMIS data, in-field soil moisture measurement, or both. | |
This article is part of the Woodleaf Farm Organic Systems Description.
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