Soil: A Precious Resource

by Patrick Kirchhofer, Peoria County Farm Bureau

Last year, we had an ideal planting season, with record warm temperatures and plenty of sunshine. Ideal soil conditions at spring planting in 2012 set the framework for a good growing season the rest of the summer. Even with record temperatures in July—eight 100-degree days, and 26 of the 31 days reaching 90 degrees—most Peoria County farmers harvested a surprisingly good crop.

Setting the stage for a great crop-growing year begins with soil conditions at the first tillage pass through the field in the spring. Soil conditions must be correct for maximum yields to be harvested in the fall. Too much moisture combined with heavy farm equipment will compact the soil, making it difficult for plant roots to grow through and denying them access to moisture, air and nutrients. Conversely, too little moisture at planting and the farmer risks the seed being unable to germinate. A corn or soybean seed lying idle in dry soil is also vulnerable to seedling diseases, as well as the critters that love to eat them.

So just what are the components of a slice of soil? About half is made up of “pores” full of air and water. Roots need oxygen from the air, and they need water, as plants are composed mostly of water. The other half of soil consists of minerals and organic matter, or humus. The minerals or organic matter in the soil come in three textures and sizes: sand, silt and clay.

Of the three, sand is the largest, and we do have some sandy soil in our area, especially around Chillicothe and south of Pekin. Several farmers in these areas have invested in irrigation systems. Because sand is coarse, water filters through it rapidly and is not held in the soil profile for plants to utilize it, hence the need to irrigate these fields during dry periods. Silt is the medium-sized soil particle, and many of our ideal soil types are referenced as silt loams. They are excellent soils in which to grow plants, as they have great water-holding capacity and can store nutrients for the plant’s roots to uptake. The smallest soil particle, clay, is very fine, sticky when wet, and hard as a brick when dry. Clay soil can grow bountiful crops, but like sandy soils, requires moisture throughout the growing season in order for farmers to harvest respectable yields in the fall. To put the sizes of these three soil particles into perspective, visualize them as a basketball (sand), baseball (silt) and marble (clay).

The Farm Bureau’s Ag Literacy program brings agriculture into the classroom, and one of the recent topics Peoria County third through sixth graders learned about was soil and composting. The following illustration was given, which really hit home the value of good soil:

Cut an apple into four equal parts. Three of these parts represent the oceans of the world; the fourth represents the land area. Cut the land section in half lengthwise. Now, you have two 1/8 pieces. One of these sections represents land such as deserts, swamps, the Antarctic, Arctic, and mountain regions. Slice the other 1/8 section crosswise into four equal parts. Three of these 1/32 sections represent areas of the world that are too rocky, too wet, too hot, or too poor to grow food or where humans have built cities and roads. Now peel the last 1/32 section. The peel on this tiny piece represents the amount of soil on which we have to grow food.

In the Midwest, we are blessed with some of the best soil in the world. Though we often take it for granted, it’s a precious natural resource to our economy and our daily living. iBi

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