By Mahdi Al-Kaisi, Department of Agronomy
Conservation planning can play a significant role in sustaining soil quality as climate change imposes additional stress on natural resources, including soil. Most of Iowa's landscape is "working land" used for agricultural activities such as row crops, pasture and forestry. Conservation practices will increase the resilience of agriculture production systems and ultimately sustain soil productivity and environmental quality. Iowa has the largest percentage of working land in the nation coupled with intense management; each of which raise concerns about the resulting impact on soil and water quality.
Many producers have voluntarily adopted conservation practices that lessen the negative effects of agricultural activities on the environment. The outcome has been significant over the past two decades, when benefits in crop productivity, efficient use of time and equipment and reduction in soil erosion were observed.
But conservation planning is becoming necessary for every producer, especially with the current weather challenges we are experiencing. The current thinking of removing Conservation Reserve Program (CRP) land back to agriculture production raises a lot of concerns and can be a significant setback to the soil and environmental benefits that were gained. Land in CRP is generally enrolled for production and environmental reasons, where the row crop production can be very damaging to both soil and water quality. These lands are enrolled in CRP to prevent highly erodible land with marginal productivity from further deterioration.
Develop practical, site-specific plans
Developing and implementing a conservation plan is in the producer's best interest against potential environmental regulations and legal action intended to protect natural resources. Producers should consider adopting conservation plans that are practical, site specific, achieve the intended objectives and are easily integrated within an overall production system.
Conservation plans can include, but are not limited to, practices that can be implemented based on site-specific characteristics, whether land is rented or owned by the producer:
- conservation tillage, strip-till, or no-till
- cover crop as a soil and water quality improvement measure
- residue cover and relationship of residue cover to each successive tillage system
- terraces to control soil erosion on slopes of 4 or 5 percent or steeper
- proper manure applications and management practices
- installation and maintenance of buffers, waterways and terraces
- proper calibration and maintaining combine equipment for optimal and uniform residue distribution
- pasture erosion control through proper vegetation establishment and rotational grazing plans
- enroll highly erodible land or marginal land in the Conservation Reserve Program
- tile inlet and outlet maintenance of a drainage system
- systematic soil testing on a regular schedule and adoption of split nitrogen (N) application
Strip Cropping
The use of the above practices is among many other measures for implementing a conservation plan. In Iowa, row crops planted in fields with slopes of greater than 18 percent will experience erosion rates greater than "T," regardless of soil type and type of tillage system. One of the practices to reduce the degree and length of the slope effect in accelerating soil erosion is to consider removing row crops from these areas and establish permanent vegetation or what is called strip cropping system with small grain or hay on steep slopes to minimize soil erosion. Strip-cropping is defined as "growing crops in a systematic arrangement of strips on the contour to reduce erosion." Thus, the crops are arranged so that a strip of grass or cover crop is alternated with a strip of row-crop.
Summary
Conservation planning and implementation of practices such as those listed above need to be considered carefully as solutions to reducing potential row cropping system effects on soil and water quality. Consideration of site specific and objectives of implementing conservation practices should be included in the planning process.
Mahdi Al-Kaisi is an associate professor in agronomy with research and extension responsibilities in soil management and environmental soil science. He can be reached at malkaisi@iastate.edu or (515) 294-8304.
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