Effect of Lime on No-Tillage Corn Yields

The rapidly growing popularity and adoption of no-tillage systems of corn production have required us to re-evaluate some of our long established soil fertility practices and recommendations. Recent work by researchers at Kentucky and adjacent states show that the soil surface becomes very acid after a few years of continuous no-tillage corn production. This rapid decrease in soil pH is primarily associated with surface application of nitrogen fertilizers. Most lime recommendations and related research information for row crop production are based on plow-down application. Therefore, the effectiveness of surface-applied and unincorporated lime under no-tillage systems becomes a question of concern. We conducted lime studies on no-tillage corn at Princeton and Lexington to study this situation

Profitability of Variable Rate Fertilization on a Kentucky Soil (a Theoretical Analysis)

Grid soil sampling and variable rate fertilizer applications are a part of the precision agriculture movement that has captured the interest of many farmers. Variable rate fertilization requires extra expense and effort plus the use of often unfamiliar technology. Global Positioning Systems (GPS) equipment and computer software are used to outline and grid the field into small manageable units or “cells” (usually 2.5 acres). Each grid cell is soil sampled and tested for pH and available nutrients. Fertilizer recommendations are made on each grid cell and the fertilizer is spread by each grid cell using a truck equipped with GPS and variable rate fertilizer spreaders

Zinc Fertilizer Rates and Mehlich III Soil Test Levels for Corn

Zinc (Zn) is the micronutrient most often deficient for corn in Kentucky. This problem occurs every year but is more commonly seen in years with a cool, wet spring. Although the environment, soil type and past erosion each have an effect, the most important factors controlling plant available Zn are the soil pH, extractable soil phosphorus (P) and extractable soil Zn. While the amount of Zn in the plant increases as the available soil Zn increases, increasing levels of soil P and pH are strongly associated with reduced levels of Zn in the plant

Contending with Soil Compaction

Most compaction results from use of machinery on soil which is too wet to work well, or from overworking soil and destroying natural structure. The resultant pressure from tires and tillage tools compresses more soil into a given volume. Regardless of reason, the proportion of solid soil material relative to total volume of soil increases. In the process, natural soil aggregates are broken down and large pores become smaller, generally resulting in soil more difficult for plant roots to penetrate

Urease Inhibitor Reduces Ammonia Loss from Surface-Applied Urea

Urea is the world\u27s leading N fertilizer, and its use continues to grow. In the USA, for example, the use of urea increased 50 fold from 1955 to 1986. During that same time, its use in Kentucky increased from 214 to more than 112,000 tons per year, which was 28% of the N used in Kentucky in 1986. The increasing popularity of urea is due to advantages over other N fertilizers in its manufacture and to its use in making most N solutions, another rapidly growing form of N fertilizer. Desirable qualities of urea include the highest N content of all solid N fertilizers (45-46%), excellent handling properties, and dissolves readily in water. There is, however, a serious agromonic management problem with urea

Maximum Net Returns from Fertilizers

Considerable interest in trends taking place in the consumption of commercial fertilizers in Kentucky has been evident during the last two or three years. Due both to the stressed agricultural economy and to government programs, total tonnage has dropped significantly. This has made a direct impact on the fertilizer industry serving Kentucky. Concern has been expressed that UK is telling farmers that they\u27re using too much fertilizer , suggesting that this is the cause of the reduced volume experienced by many dealers. We hope to address this concern in such a way that UK\u27s position regarding use of commercial fertilizers for crop production can be better understood

Comparisons of Nitrogen Fertilizer Sources under Kentucky Soil and Climatic Conditions

A summary of yield data comparing different nitrogen fertilizer sources in field experiments conducted by the Agronomy Department staff should provide information that will help answer some of the inquiries regarding the comparative value of some of the nitrogen fertilizers being marketed in Kentucky. Since the nitrogen rates per acre shown in all tables are ACTUAL NITROGEN the COST PER POUND OF NITROGEN in the different materials is an important consideration when evaluating the various products

Reductions of Wheat Yield and Yield Components and Nitrogen Loss Following Frozen Soil Nitrogen Applications

Most wheat producers in Kentucky apply nitrogen (N) as a split application. The first N increment is applied when wheat plants begin actively growing (green-up) in late winter, which is typically in mid- February between growth stages Feekes 2 to 3. The second N increment typically occurs in March when wheat is between Feekes 5 to 6. Many producers in Kentucky, especially Western Kentucky, have become accustomed to beginning first N applications in late January when the ground is frozen and the wheat is still dormant. This practice allows them to apply N to large acreages of wheat while avoiding rutting and/or compacting fields with large equipment. In most years, the soil will thaw within a few hours or days following N applications, which allows N to infiltrate the soil profile and reduce runoff potential. In 2014 Kentucky had below average temperatures for January and February (UK Ag Weather Center, 2013) resulting in frozen soil until mid-February throughout much of the state and delayed wheat development two to three weeks. In 2014, some producers made early N applications in January to dormant wheat grown on soil that was frozen to a depth of six to nine inches. This study was conducted to estimate grain yield response and N loss and to determine the yield components contributing to changes in grain yields when N was applied to frozen ground

Boron Fertilization of Corn in Kentucky

The need for use of boron (B) for alfalfa production has been recognized for many years in Kentucky and is presently recommended for general use as an annual topdressing on alfalfa fields. Use of B is also recommended in Kentucky for red clover fields which are to be harvested for seed. In recent years, there has been interest in use of fertilizer B for good corn production in Kentucky. Plant available B is greatly affected by soil pH and decreases with increasing soil pH. Because of this, some states recommend use of B on corn grown on soils with a pH of 6.1 or higher. Also, some commercial soil testing laboratories serving Kentucky routinely test for B, and often recommend its use for corn. This has resulted in many corn growers in Kentucky asking if they need to use B on corn