Issue link: https://read.dmtmag.com/i/473131
46 MARCH 15, 2015 GOOD FRUIT GROWER www.goodfruit.com KERIAN MACHINES, INC. 1709 Hwy 81 South, P.O. Box 311 Grafton, ND 58237 701-352-0480 • Fax 701-352-3776 sales@kerian.com • www.kerian.com GENTLE: Separates without damaging peaches, apples, mushrooms and fresh tomatoes ACCURATE: Precisely grades grape tomatoes, cherries, nuts, and small berries, maintaining that accuracy for larger products including cantaloupes and pineapple FAST: Thirteen standard models custom- designed to meet your needs sort from 1,000 lb/hr to 100,000 lb/hr SIMPLE: Effective but simple design provides a rugged, low-cost, low-maintenance machine at a high value to our customers. It can even be used in the field! VERSATILE: Specialized rollers allow for the accurate sizing of round products (potatoes, onions, and citrus), long products (carrots, russets, and cucumbers), and irregular products (bell peppers, jalapeños, and garlic) FRUIT AND VEGETABLE KERIAN SIZER molecules and release other organic compounds, which other biota can use to build into new organic molecules or store in their own bodies. At the same time, the biota release carbon dioxide, energy, water, and inorganic materials, such as nitrogen, phosphorus, and sulfur, and micronutrients that plants and biota can use. There is generally a high turnover of biota in soil, which continues to add organic matter. Fine roots and hyphae do not live long in soil, but are fairly quickly replaced by new roots and microorganisms. Amount of organic matter The amount of organic matter in soil depends on: —amount and quality of the organic residues returned to soil —soil texture, depth, and density —soil pH —temperature, water content, and aeration of soil —microbial population Sometimes a soil test shows organic matter as organic carbon. To calculate the percentage of organic matter, multiply the percentage of organic carbon by 1.6. Organic residues of high quality, i.e., with a low ratio of carbon to nitrogen (less than 18:1), are decomposed quickly as there is enough nitrogen to stimulate microbial activity; organic residues with a high carbon- to-nitrogen ratio of more than 60:1 are decomposed very slowly. Simple sugars, simple proteins, and starch are easily decomposed, whereas hemicellulose, cellulose, fats, waxes, and resins are slowly decomposed. Lignin comes from cell walls of plants and some algae, and is decomposed very slowly. Charcoal is inert so is not further decomposed. Eventually, the complex organic matter, humus, is produced and darkens the soil. For each soil, there is a limit to the amount of organic matter that can be stored. Organic matter is more quickly decomposed in sandy soils, so they contain less organic matter than do clay soils. The deeper the soil, the more organic matter it can hold. Soils that are less dense are usually better aerated and drained and are warmer, so that plants grow better, releasing more organic residues into soil and supporting more biological activity. Soils in wetter and cooler climates generally contain more organic matter than do soils in drier and warmer climates. This is because plants grow better with high rainfall and a long growing season, adding more organic residues; yet, bacteria are less active and decompose the organic residues slowly. Very wet soils, such as swamps, contain little air and biological activity, so decomposition is slow, and the percentage of organic matter is high. Soil pH also affects the supply and decomposition of organic materials in soil. It is best to aim for a pH of about 5.8 to 6.5 so that the plants grow well and add plenty of organic residues to soil. Organic matter and nutrient supply There is a significant correlation between the percent- age of organic matter in soil and soil fertility. In Australian conditions, most well-managed soils should have 2 to 4 percent organic matter, depending on the texture of the soil. Less than 1.5 percent is usually low and can lead to waterlogged or dehydrated soil and imbalanced nutri- ents. On the other hand, in soils with more than 5 percent organic matter, herbicides often become attached to the organic matter and are inactivated, so the grower needs to apply more herbicide. Nutrients come not only from the original plant res- idues, but some nutrients become attached to humus (highly degraded organic matter in soil) and are slowly released for plants and other soil biota. The humus pro- vides both negative and positive charges that can hold and exchange nutrients. Nutrients with positive charges, such as potassium, calcium, and magnesium, adhere to the negative charges on the humus, whereas nutrients with negative charges, such as phosphate and sulphate, adhere to positive charges. In both cases, the nutrients remain available to plants and are not leached down beyond the root zone.