Fishy Soil

Productive Soils Resulting in High Yields and Quality

Published in the February 2013 Issue Published online: Feb 19, 2013 Adrian L. Arp, Ph.D., Mir Seyedbadheri, Ph.D.
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FishPotato production has adopted many new practices to improve yield and quality. In the 1970s, foliar feeding was introduced, allowing in-season adjustments for plant nutrient needs with the use of tissue testing. Revised fertilizer guides, split application of fertilizer, variable-rate fertilization and fertilizer placement have made efficiency increase.

Soil conditioning began with the Native Americans using fish to fertilize and improve the soil environment for crop growth. The Pilgrims were introduced to this practice, which assisted in the settlement of America.

In the 1980s, humic acid was introduced as a means to improve the soil environment. Many soils have problems with alkalinity, compaction, low organic matter, crusting and poor water infiltration. Mir Seyedbagheri, University of Idaho Extension Educator, was a U.S. pioneer in humic acid research. In 1990, he reported average potato yield increases at three locations of 32-cwt-per-acre with the use of two gallons of humic acid.

Also, he found that humic acid increased the efficiency of fertilizer and water use. Now, many growers use humic acid yearly. Several growers apply humic acid along with other soil conditioners, like Penatron Soil Conditioner from Maz-Zee S.A. International, which was introduced in 1993. Penatron, with 30 interactive components, has proven to work synergistically with humic acid to further improve the soil environment leading to production increases.

Healthy crops that produce excellent yields and high quality come from soils where there is optimum oxygen, water and nutrients. The productivity of a soil depends on the quantity and quality of a wide range of micro-organisms and fungal mycorrhizae. These are limited under a low oxygen environment where there is a poor soil structure. Cap cells stop dividing when oxygen is lacking.

The mucilage (slime) from micro-organisms provides the cement that glues soil particles together, creating larger soil aggregates, which creates a better soil structure. This aids in water and nutrient uptake by roots and provide more oxygen for better plant growth. Plant roots secrete substances that are beneficial to mycorrhizae. Soil conditioning can stimulate more mycorrhizae, which helps plant roots utilize water and nutrients more efficiently. Because of improved oxygen in the root zone, there is less of a chance for diseases to infect plants, as most diseases like an anaerobic (without oxygen) environment to thrive and reproduce.

One of several benefits of using soil conditioners is to improve water infiltration. This can be achieved by using chemical wetting agents or natural desert plant extracts. The effect is to lower the surface tension of the water-make water wetter-and/or improve the soil structure to allow faster water infiltration. The result is that water gets into the soil profile easier, resulting in less runoff and erosion. The net result is higher water use efficiency.

Some soil conditioners, including Penatron, have growth substances that are beneficial to plant growth. There is a group of hormones that include cytokinins, auxins and gibberellins. Plant responses can occur with low concentrations of these substances. Norwegian sea kelp is one source that increases root growth by stimulating cell division. It also increases seed germination, lateral bud growth and chloroplast development.

One important observed effect of using soil conditioners is less hot/dry and cold/wet weather production stress. There has been less hollow heart and brown centers during cold, wet weather and fewer deformed tubers and wilting during excessive heat, which was evident in 2012. Penatron has greatly reduced clods and dirt at harvest when clods are formed during wet planting conditions and occur in heavy clay soils.

Some soil conditioners also contain small amounts of essential plant nutrients. Fish emulsion is added to some conditioners-the Pilgrims would be proud-providing additional direct nutritional benefits.

Yield and quality tests using Penatron Soil Conditioner have been conducted by the University of Idaho and several private consulting and fertilizer company agronomists. The yield increases have ranged from 36 to 60 cwt per acre, with a higher percentage of No. 1 potatoes with less hollow heart and brown centers. Yield and quality increases of barley, wheat, sugarbeets, alfalfa hay, corn and beans have also been measured in Idaho.

The bottom line is that potato growers throughout the country have not only seen increases in yield and quality of their potato crops, but have also been good stewards of the land because soil conditioning has improved the health of the soil. This creates an improved environment for rotation crops. Soil conditioning creates better soil physical properties, improved plant nutrition, better water management and reduced tillage and harvest costs. Soil conditioners have assisted not only Idaho, but also U.S. growers in producing premium potatoes for the processing and fresh potato markets.