"As farmers continue to adopt new and better technologies, soil testing more frequently is a good idea because the soil sampling and testing costs have decreased sharply compared with crop, fertilizer and land prices," says Mallarino. While it won't answer all the questions raised at the conference, it will verify current practices or suggest change. While his research has shown little decrease in pH until year four after appropriate liming in most fields, he agrees that more frequent sampling for pH and nutrients in general makes sense. Mallarino endorses the idea of more frequent sampling, especially in a corn and soybean rotation. With continuous corn and yearly anhydrous ammonia or manure applications, it is possible to get an acidic layer of pH 5.3 to 5.5 created at the 4- to 6-inch depth. Lime's resistance to movement within the soil is the main reason that sampling at the 2- to 3-inch depth for pH is commonly recommended. Depending on the cropping system, multi-layer testing may be recommended. He adds that additional research is needed to verify equations on how much lime is needed to raise pH to the desirable level.Įven soil sampling is up for discussion. A five-year, statewide on-farm project begun that year, largely confirmed existing recommendations for corn and soybeans. He points out that in Iowa, extensive research was done in the 1960s and 70s, only isolated research had been done from then until 2007. Mallarino agrees that particle size and source deserve more study however, he places an even greater emphasis on simply understanding the optimum pH for different crops. "What impact do particle size and purity of the limestone have on what happens in the soil versus the lab?" "Hydrochloric acid may digest large chunks of limestone in the lab, but that doesn't tell us what happens when the organic acids and root exudates hit it," says Andrew Hoiberg, director of research and development, Calcium Products, Gilmore City, Ia. The CCE is used to calculate the ECCE (effective calcium carbonate equivalent), which determines how much of a particular lime product is needed to raise pH to the recommended level. It uses hydrochloric acid to identify the percentage of lime’s calcium carbonate equivalent (CCE). One issue may be the basic test used to evaluate lime sources for their ability to affect pH change. Even if they were accurate when written, much has changed in cropping systems and inputs, such as anhydrous ammonia and tillage, since most lime-related research was conducted 50 to 60 years ago. Without data, it is hard to explain why 39 states have different grading systems and 19 offer different definitions of agricultural lime. "We assume the early Iowa researchers had a basis for them, but we don't have the data to look into it." "We have at least 50 particle-size efficiency factors built into the lab process to evaluate limestone in Iowa, but we don't have the research data that were used to determine those factors," says Antonio Mallarino, professor, soils, ISU. Particle size impact on reactivity in the soil is one example of current inconsistencies in liming practice.
The answers could impact input costs and yields as well as nutrient-management effectiveness. These were among the issues raised at a recent conference of lime-industry representatives and USDA-ARS and Iowa State University (ISU) soil researchers. While a low pH can reduce yields by 40% or more, there’s a surprising shortage of recent research about how lime is tested and graded and what impact it actually has on soil pH and crop yield. It does not store any personal data.For decades, applying lime to adjust pH has been accepted practice. The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. The cookie is used to store the user consent for the cookies in the category "Performance". This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other. The cookies is used to store the user consent for the cookies in the category "Necessary". The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". The cookie is used to store the user consent for the cookies in the category "Analytics". These cookies ensure basic functionalities and security features of the website, anonymously. Necessary cookies are absolutely essential for the website to function properly.
0 kommentar(er)
