Research & Extension
Rice
Fertilization represents the largest single-cost category for rice produced on loamy soils. Soil analysis is the best available means for estimating the types and amounts of fertilizer nutrients needed to prevent and/or diagnose nutrient deficiencies that may limit rice growth and yield. Developing soil-test-based nutrient management recommendations is a continual process and seeking more accurate methods of predicting soils that require fertilization is needed. The overall goal of the Arkansas Soil Fertility program is to have sufficient research databases to support current recommendations and/or develop new recommendations regarding soil and fertilizer management practices that facilitate efficient nutrient uptake, the production of high rice yields, and maximize profits. Our research and extension program also focuses on novel approaches to assess in-season nutrient deficiencies in rice and provide producers with a means to address these issues in a timely manner.
Active projects
- Arkansas Rice Research and Promotion Board: Rice Fertilization – Developing novel methods to assess nutrient availability to Arkansas rice
- Arkansas Rice Research and Promotion Board: Nitrogen management tools for Arkansas rice producers
Soybean
Soybean is the crop with largest acreage in Arkansas and fertilization costs represent about one-fifth of the total operating expenses for full-season soybeans grown on silt loam soils. Accurate identification of yield-limiting nutrients will enable recommendations to be refined so that the correct fertilizer sources and rates are applied in a timely manner to maximize yield and sustain soil productivity. Long-term fertilization trials are invaluable for verifying that recommended phosphorus (P) and potassium (K) fertilizer rates are sufficient for sustainable production and for developing tissue-based interpretations to verify sufficient crop nutrition. Likewise, an improved understanding of how nutrient deficiencies influence individual yield components will positively impact soybean production economics. The Arkansas Soil Fertility program is developing tools that will allow producers to identify potential nutrient deficiencies before they can be detected through deficiency symptomology to ensure that nutrients such as P and K are no longer yield-limiting factors in Arkansas soybean production systems.
Active projects
- Arkansas Soybean Promotion Board: Fertilization of soybean
- Mid-South Soybean Board: Soybean yield components and seed nutrient concentration responses among nodes to phosphorus fertility
Corn
Corn continues to be an important rotational crop in Arkansas production systems, with a trend of increasing acreage in recent years. One of the largest input costs for corn production is fertilization and potassium (K) can account for a significant portion of the input costs, specifically on silt loam soils. Corn is highly responsive to fertilizer-K applications and significant yield increases can be realized when responsive sites are identified, and the proper rate of K fertilizer is applied. Likewise, the ability to predict the need for in-season K applications with tissue testing is important to correct K deficiencies and rescue yield potential. The Arkansas Soil Fertility program is developing multiple corn K response trials to increase the database of corn grain yield response to K fertilization on a range of soil test K concentrations, assess the ability to use leaf-K concentration as a predictor of corn grain yield and K nutritional status and define the window of opportunity to correct K deficiency with in-season fertilization.
Active projects
- Arkansas Corn and Grain Sorghum Board: Fine-tuning potassium recommendations and investigating intensive tissue analysis for sustainable corn production
- Arkansas Corn and Grain Sorghum Board: Cover crops in corn rotations – what works and what doesn’t?
Cotton
To develop and implement sound, science-based fertilizer rate recommendations that provide yield and profit-maximizing nutrient application rates, it is paramount to identify those agronomic and economical yields and develop tools that increase our predictive ability to determine when and where fertilizer nutrients are needed to achieve these goals. The yield of modern cotton cultivars is steadily increasing with the introduction of new plant protection technologies, alternative management practices, improved irrigation strategies, and genetic yield gains. And so has the nutrient demand for high-yielding modern cotton cultivars. The Arkansas Soil Fertility program is developing multiple cotton nitrogen and potassium response trials to facilitate the correlation and calibration of fertilizer rates and establishing critical tissue nutrient concentrations to ensure the proper nutrient management techniques are being implemented for furrow-irrigated cotton in Arkansas.
Active projects
- Cotton Incorporated / Arkansas State Cotton Support Group: Cotton yield and tissue-K responses to potassium fertilization
- Arkansas Soil Test Review Board: Potassium loss by runoff in different cotton production systems
- Arkansas Soil Test Review Board: Cotton response to nitrogen and potassium fertilization
Forage
In Arkansas, there are 1.2 million acres of hayland production, with an additional 4.5 million acres of pasture. However, the majority of southern pastures and haylands are not regularly soil tested; and of the tested acres, many are deficient in essential plant nutrients. Further, hayland acres are frequently not fertilized annually. With the large amount of tissue removed from haylands and pastures, nutrient deficiencies can quickly develop and compromise forage yield and quality if nutrients are not applied in adequate amounts. The Arkansas Soil Fertility program is investigating the cumulative effects of various fertilizer phosphorus and potassium rates on soil-test values, and forage yield performance, nutrient uptake, and nutrient deficiencies to demonstrate the importance of adequate nutrient management for optimum hay production.
Active projects
- Arkansas Soil Test Review Board: Assessment of bermudagrass forage yield and nutrient uptake in response to phosphorus and potassium fertilization
Soil Health
The ability to objectively evaluate the impact of short- and long-term agronomic practices on soil health is fundamental for sustainable and profitable agriculture. Agricultural practitioners have increased interest in crop and soil management systems that build soil organic matter and enhance soil health, but limited research has been conducted in Mid-South US poorly drained soils to identify crop management practices that improve soil quality and increase crop yield. The Arkansas Soil Fertility program is investigating how soil conservation practices, such as no-tillage, reduced tillage and cover crops, and nutrient management practices affect soil health indices, carbon sequestration, and crop yield in Mid-South US irrigated production systems to assist crop producers in defining crop management practices to increase soil resilience, farm profitability, and environmental sustainability.
Active projects
- USDA-NIFA-AFRI: Soil health assessment in irrigated, row-crop production systems in the Midsouthern US
- Arkansas Soybean Promotion Board: Economics of soil health practices for soybeans in Arkansas
Soil Testing
Long-term monitoring of crop response to phosphorus (P) and potassium (K) fertilization is needed to ensure that fertilization recommendations aimed at maintaining or building soil-test P and K values are accurate. The Arkansas Soil Fertility team is examining the effects of long-term fertilizer-P and -K rates and cover crops on corn, cotton, and soybean yield and how cover crop biomass and nutrient uptake influence soil-test results across time (compared to conventional management).
Active projects
- Arkansas Soil Test Review Board: Long-term P and K cover crop fertilization trial