Seed To Harvest: The Basics Of Row Crops In Pennsylvania

Introduction

Drive through just about any part of Pennsylvania, and at some point, you will see corn, soybeans, wheat, or barley growing or harvested. From spring through autumn fruits and vegetables are planted, cared for, and harvested. Some end up at roadside produce stands, while others are sent to processors for canning or freezing to be sold on grocery store shelves or in freezers. But have you ever wondered what happens to all the field corn, soybeans, and small grains? What does it take to grow these crops? Is it just a matter of putting the seed in the ground and hoping for the right amount of rain and sun? This series will supply the basics of what it takes to grow crops in Pennsylvania, and why farmers grow them.

Preparation

It all starts with soil, not dirt. Dirt can be considered part of the physical make up of soil. If you look at the soil pyramid, there are percentages of clay, sand, and silt, and depending on what those percentages are, the soil classification can be determined. Add to that dirt, the microbes, fungi, bacteria, decomposing plant matter, manure, and minerals, and now it becomes soil.

Plants require nutrients from the soil, water, and sunlight to grow. Knowing the amount of nutrients available in the soil is key to growing a good crop. Soil sampling is an important step prior to planting. Ideally, soil sampling should be done around the same time of year, most commonly in the fall, and at least once every three years. Taking samples around the same time each year allows for similar results that could otherwise vary due to weather conditions, seasonal management differences, etc. It is also beneficial to use the same laboratory for soil testing and one that is suited to the soil in your state so that the results are consistent and comparable from year to year. If there is a large area to be sampled, it is usually a good idea to zone the field into subsections, either by soil type or by cropping rotation. This allows for a more accurate representation of the nutrients required and more or less fertilizer can be added to certain areas rather than using a blanket application for an entire field.

When the soil tests have been analyzed and the data is collected, a plan can be written to decide how much fertilizer or manure should be added to the soil for whatever crop is going to be grown. The macro nutrients nitrogen, phosphorus, potassium, calcium, sulfur, and magnesium are essential for plant growth. Each type of crop grown requires differing amounts of macro nutrients. Nitrogen recommendations are based on years of research in understanding how much is required by the crop to grow. All other macronutrients will be recommended based on what is found in the soil. Micronutrients, such as boron, calcium, or magnesium, while also important for growth, are usually available in sufficient amounts in the soil, but can be supplemented if necessary. Fertilizer applications can also be split based on soil test recommendations. A portion of the nutrients can be applied to a cover crop in the fall and the remaining amount can be added when the new crop is actively growing in the late spring or early summer. Split applications of fertilizer can meet the nutrient demands of the crops at critical growth stages.  Not all these nutrients are plant-available in certain forms because they go through a process of nutrient cycling where they change between forms that are available and unavailable to the plant. This occurs due to nutrient interactions with the soil, soil microbes, and the atmosphere.

A soil test will also recommend how much lime needs to be added to the soil. A proper pH is necessary for nutrient uptake, based on the crop being grown. If the pH is too low or too high for the needs of the crop it can cause nutrient deficiencies or toxicities, even though the nutrients are plentiful in the soil. This recommendation will be based on the current soil pH and the pH needs of the crop that will be planted.  While fertilizer applications provide quick results and should be applied at the time of greatest crop need, liming needs to be done roughly six months in advance to allow for the calcium carbonate to remove some of the hydrogen from the soil and make it less acidic.

Time to Plant

Soil condition becomes an important consideration for all crops. If the soil is too cold, it will delay germination of the seed. If the soil is too wet, the seed can rot before germination and soil compaction can occur during planting. Every type of seed, whether it is a weed, vegetable or grain seed has an ideal germination temperature. Planting depth is also important. If the seeds are planted too deep it can prevent or delay emergence and weaken the plant, too shallow and there may not be enough seed-to-soil contact to allow for good germination. Proper soil temperature and moisture are also very important to allow the release of nutrients from the soil into the plant as it begins to grow. These factors often play a role in the decision-making process of implementing no-till versus conventional tillage and also the inclusion of cover crops and the timing and method of cover crop termination in the spring. Once the soil has been amended to match the needs of the crop being grown, the soil can be worked to move nutrients deeper into the soil for plant uptake later, or the field can be planted without tillage (no-till). Conservation or minimal tillage encompasses several practices, including no-till, but overall aims to leave at least thirty percent or more residue on the soil surface. Conventional tillage disturbs all of the soil surface and less than fifteen percent residue is left. There are pros and cons to all tillage practices. Higher soil residue - decaying plant tissue, corn stover, soybean stubble, wheat chaff - can add organic matter to the soil and reduce runoff potential in no-till systems. A no-till system can also improve soil health over time by improving soil organic matter, water infiltration, soil structure, etc. Conventional tillage typically involves the use of a moldboard plow which completely overturns the soil. This is followed by secondary and tertiary tillage passes with less aggressive equipment such as a chisel plow followed by a disk, that will level out the soil to provide a flat and firm seedbed that is ready for planting. Conventional tillage can be a means of reducing weed pressure which could reduce or eliminate the need for herbicides and aid in relieving soil compaction. There are other potential benefits, but results can be mixed and are best evaluated on a case-by-case basis.

What Happens Next?

The next few articles will discuss the needs of specific crops and their growth stages from emergence to harvest, and where they go after harvest. This series is by no means meant to cover everything that you would ever need to know, but to introduce the process that you can see from spring to winter throughout Pennsylvania, and beyond.