Corn has been a pillar of American agriculture for decades and continues to receive much attention from the scientific community for its potential to meet the food, feed and fuel needs of a growing human population in a changing climate. By midcentury, global temperature increase is expected to exceed 2°C where local effects on heat, cold and precipitation extremes will vary. The Northeast United States is a major dairy producer, corn consumer, and is cited as the fastest warming region in the contiguous U.S. It is important to understand how key agronomic climate variables affect corn growth and development so that adaptation strategies can be tailored to local climate changes. We analyzed potential local effects of climate change on corn growth and development at three major dairy locations in the Northeast (Syracuse, New York; State College, Pennsylvania and Landisville, Pennsylvania) using downscaled projected climate data (2000–2100) from nine Global Climate Models under two emission pathways (Representative Concentration Pathways (RCP) 4.5 and 8.5). Our analysis indicates that corn near the end of the 21^st century will experience fewer spring and fall freezes, faster rate of growing degree day accumulation with a reduction in time required to reach maturity, greater frequencies of daily high temperature ≥35°C during key growth stages such as silking-anthesis and greater water deficit during reproductive (R1-R6) stages. These agronomic anomalies differ between the three locations, illustrating varying impacts of climate change in the more northern regions vs. the southern regions of the Northeast. Management strategies such as shifting the planting dates based on last spring freeze and irrigation during the greatest water deficit stages (R1-R6) will partially offset the projected increase in heat and drought stress. Future research should focus on understanding the effects of global warming at local levels and determining adaptation strategies that meet local needs.

With rising global demand of poultry products, a surge in poultry production would warrant safe disposal of waste byproducts such as poultry litter (PL). A dilemma exists over environmental phosphorus (P) loss risk and agronomic utilization of PL in highly weathered soils with high P fixation capacity. The objective of this study was to determine P forms and their distribution in highly weathered Piedmont soils located in high density poultry operation (HDPO) areas and evaluate environmental P loss risk using soil P storage capacity (SPSC) approach. Soil samples from agricultural fields with 10 ± 2 years PL application history were collected from surface (0-15 cm) and subsurface (15-30 cm) depths. Approximately 64 ± 11% of total P was in non-reactive P (NRP) form, 35 ± 19% in moderately reactive P (MRP) forms, and < 1% in highly reactive P (HRP) form. Phosphorus sorption index (PSI) was higher in subsurface (316 L kg^-1) compared to surface soils (150 L kg^-1). The SPSC calculated based on a distinct soil threshold P saturation ratio (PSR; ratio of P/[Al + Fe], all elements expressed in moles) was higher in subsurface (17 mg kg^-1) than surface (-150 mg kg^-1) soils. Repeated application of PL resulted in P saturation of surface soils (SPSC<0) and represents a source of P to the environment. The NRP form decreased, and MRP forms increased when a) soil test P (STP) rating transitioned from low to extremely high, and b) SPSC changed from positive to negative. Results indicate that P release in soil solution is predominantly controlled by buffering action of MRP forms since HRP was minimal and NRP is mostly unavailable in highly weathered soils. A holistic approach that includes STP for maintaining agronomic productivity along with SPSC to minimize environmental P loss risk will be desirable for sustainable management of PL in HDPO.

Phosphorus (P) runoff from agricultural lands receiving poultry litter (PL) poses a major environmental challenge. Application of flue-gas-desulfurization (FGD)-gypsum produced from coal power plants in agricultural lands has shown promise to reduce P losses. However, no information is available about the effectiveness of FGD-gypsum addition in reducing P solubility when applied as an in-house amendment. Hence, the objectives of this study were to understand a) effectiveness of FGD-gypsum as a litter amendment in reducing P loss risk; and b) how FGD-gypsum amendment in PL alters the distribution of P forms. Broiler chickens were raised for five flocks in seven individual litter treatments replicated four times in a randomized complete block design. Based on the FGD-gypsum addition, the PL treatments were broadly classified as FGD-gypsum treated and untreated. Toxic metal concentrations were analyzed in FGD-gypsum as well as the treatments. Sequential water extractions were performed to understand P solubility. Litter P fractionation was performed to identify bioavailable P (Water-P), labile P (NaHCO3-P), aluminum/iron chemisorbed P (NaOH-P), and mineral occluded P (HCl-P). Results indicated significantly higher soluble P in all untreated than in all FGD-gypsum treated litters in the initial water extraction. The FGD-gypsum treated litters reduced soluble P by 58 to 67% in the 1st water extraction compared to untreated litters. Fractionation study revealed lower proportion of Water-P and higher proportion of NaHCO3-P and HCl-P in all FGD-gypsum treated than in untreated litters. This study suggests reuse of FGD-gypsum in broiler houses can help reduce P mobility without any toxic metals concerns.

Several amendments have been used to reduce ammonia (NH₃) emissions from broiler litter (BL); however, a comparative study between amendments and their application rates has not been fully explored. This study evaluated the potential of biochar (B), zeolite (Z), Flue Gas Desulphurization-Gypsum (FGD-G), and sodium bisulfate (S) at four application rates in reducing NH₃ emissions from BL. The treatments comprised of amendment types (4) and their application rates (4), and a control with no amendment for a total of 17 treatments replicated twice and arranged in a completely randomized design. The treatments were incubated at 30 °C for 40 days at a moisture content of 40% (w/w), and NH₃ emissions were measured every day for the first 10 days and 3 days intervals afterward for 40 days. Results showed that the application of 13 and 17% B (w/w) reduced cumulative NH₃ emissions by 41 and 46%, respectively, compared to control over a 40-day period. Zeolite application at 8 and 11% reduced NH₃ by 20 and 33%, respectively. There was no significant difference between the different rates of FGD-G, and they were generally less effective; however, a 15% FGD-G rate reduced NH₃ by 9.1%. Application of S at rates of 2, 4, 6, and 7% significantly reduced NH₃ emissions by 91, 99, 100, and 100 %, respectively. The effectiveness of amendments to reduce ammonia emissions followed the order: S > B > Z > FGD-G. These findings contribute to an ongoing effort to identify non-acidic amendments to minimize NH₃ emissions in broiler houses.

Individual states in the United States have adopted different soil test P (STP) methods for agronomic and environmental purposes. Working between soil regions and state borderlines can be complicated by using multiple STP methods. For example, Alabama uses Mehlich 1 (M1) for noncalcareous soils (Appalachian Plateau [AP], Coastal Plain [CP], Limestone Valley [LV], Piedmont Plateau [PP]) and Lancaster (La) for calcareous soils (Blackland Prairie [BP]). Mehlich 3 (M3) has been proposed as an efficient and possibly a generic extractant for a broader range of soils. The objective of this study was to evaluate whether M3 can be used as a common or generic extractant for environmental P loss risk assessment for both calcareous and noncalcareous soils. More than 769 soil samples were collected from 68 agricultural fields representing noncalcareous and calcareous soils, and their extraction efficiencies for M1, M3, and La were compared. Mehlich 1 extracted 13.8, 13.1, 6.3, and 6.2% of total P; whereas M3 extracted 29.8, 35.4, 10.5, and 14.8% of total P from AP, CP, LV, and PP, respectively. There was no significant difference between La and M3 extractable P for both acidic and alkaline soils of BP. The conversion factor of 1.42 (95% confidence interval [CI_95%] = 1.36–1.47) was found suitable to convert M1‐P to M3‐P values for noncalcareous soils, and 0.92 (CI_95% = 0.87–0.98) was suitable to convert La‐P to M3‐P values for calcareous soils. The linear relationship between water‐soluble P (WSP) and extractable P was stronger for M3 than for M1 and La for all soil regions, as indicated by a greater correlation coefficient. Results suggest that M3 can be adopted as a generic extractant for environmental P loss risk assessment for calcareous and noncalcareous soils.