Soil Fertility and Management

Soil fertility is essential for plant growth and to optimize agronomic crop yield. Use Penn State Extension’s extensive resources on soil fertility and management of agronomic crops, including quality assessment and conditions such as crusting, compaction, and rill erosion. You’ll also find tips on levels of nitrogen, potassium and phosphorus, crop rotation, and no-till yields.

Soil Health and Conservation Practices

Healthy soil is the foundation for profitable, productive, and environmentally sound agronomic production. There are many ways to optimize the health of the soil, but you first need to understand the soil's physical, chemical, and biological components if you want to manage them successfully.

There are lots of different things that can affect soil quality. Wet conditions in fall and spring, for example, can lead to problems with severe soil compaction during harvest or manure spreading. Soil compaction can drastically affect the growth of crops when their roots hit the compacted layer. It can also lead to issues with compaction infiltration.

Popular ways of improving soil health include using a no-till system and cover crops. Both bring many advantages, such as reduced soil erosion, improved soil physical properties and soil quality, and improved water quality. It requires careful management, in particular for livestock farms as continuous applications of manure can lead to high concentrations of phosphorus. Soil tests can measure these levels as well as levels of different nutrients.

Soil Fertility and Nutrient Management for Agronomic Crops

Nutrients are essential for maintaining soil health and soil fertility. Soil fertility can be improved by incorporating the 4Rs. These are:

• Right fertilizer source: matching fertilizer type to crop needs
• Right rate: matches the amount of fertilizer each crop needs
• Right time: allowing nutrients to be available when they are needed
• Right place: providing nutrients where crops can use them

Different crops take up nutrients in unique ways which means careful nutrient management is imperative. Much research is being done to discover how to optimize carbon, nitrogen, and phosphorus management, because of the vital role these nutrients play. Potassium also has a critical role to play in crop production.

Nitrogen is present in the air that we breathe, but it can only be used by plants after it’s fixed, or taken from the air. A process called the nitrogen cycle controls levels in the soil. Two processes make up the cycle: immobilization and mineralization.

How much nitrogen is in the soil changes almost daily, making it difficult for producers to predict and manage levels. Two methods for testing nitrate levels are currently being researched: Pre-sidedress Soil Nitrate Test (PSNT) and the leaf chlorophyll meter test. Both allow producers to determine when to top-dress nitrogen or apply a nitrate fertilizer. Several other tools are available for in-season nitrogen management decision making, for example, the Late Season Stalk Nitrate Test for Corn.

The Managing and Predicting Soil Carbon and Nitrogen in Agronomic Cropping Systems workshop helps you understand the importance of managing soil carbon and nitrogen, in regard to maintaining soil health, improving crop yields, and protecting the environment.