Mônica B. Benke

Trace element changes in soil after long-term cattle manure applications.

Manure application supplies plant nutrients, but also leads to trace element accumulation in soil. This study investigated total and EDTA-extractable B, Cd, Co, Cu and Zn in soil after 25 annual manure applications. The residual effect of 14 annual manure applications followed by 11 yr with no applications was also investigated. Manure was applied at 0, 30, 60 and 90 Mg ha(-1) yr(-1) (wet weight) under rainfed (treatments Mr0, Mr30, Mr60, and Mr90) and at 0, 60, 120 and 180 Mg ha(-1) yr(-1) under irrigated conditions (Mi0, Mi60, Mi120, and Mi180). The manure applications had no significant effect on soil B, Cd and Co content under both rainfed and irrigated conditions, but significantly increased total Cu and Zn content under irrigated conditions with Zn in Mi120 and Mi180 reaching the lower maximum concentration (MAC) level set by the European Community. Manure application also significantly increased EDTA-extractable Cd and Zn content in soil. Up to 27% of the total Cd (0.156 mg kg(-1)) and 21% of total Zn (38 mg kg(-1)) are found in EDTA-extractable form (Mi180 at 0-15 cm). EDTA-extractable Cd and Zn content was also significantly elevated in the irrigated residual plots due to the higher manure rates used. Thus, the impacts of cattle manure application on trace elements in soil are long lasting. Elevated Cd and Zn are a concern as other studies have linked them with certain types of cancers and human illnesses.

Long-Term Manure Applications Impact on Irrigated Barley Forage Mineral Concentrations

Published in Agron. J. 105:1441–1450 (2013) doi:10.2134/agronj2012.0204 Available freely online through the author-supported open access option. Copyright

Retention and nitrification of injected anhydrous NH3 as affected by soil pH

Benke, M. B., Goh, T. B., Karamanos, R., Lupwayi, N. Z. and Hao, X. 2012. Retention and nitrification of injected anhydrous NH 3 as affected by soil pH. Can. J. Soil Sci. 92: 589-598. Anhydrous ammonia is an economical and extensively used fertilizer, yet loss after injection can reduce its agronomic efficiency. A laboratory experiment was conducted to examine how soil properties affect ammonia retention and nitrification following anhydrous NH3 injection using 10 different Canadian prairie soils. Soils were also injected with atmospheric air for comparison. Following injection, soils were incubated for up to 216 h at field capacity. Among the soil properties studied [pH (1:2 water), clay, total N, and organic C contents], only pH was negatively related (R 2=0.55, n=10, 24 h incubation) to percentage injected N retained by soil. The amount of N retained by soil 24 h following injection was 92±2% (mean±SEM) when pH <6, compared with 64±2% when pH>7.5. Rate of nitrification increased (P<0.001) about 48-96 h following injection and was greater in pH>7.5 than pH<6 soils. There was no difference (P>0.05) in bacterial diversity between ammonia- and air-injected soils. The slower nitrification rates suggest that potential leaching and denitrification losses in acid soils could be smaller than in alkaline soils.

Nutrient Uptake and Leaching from Soil Amended with Cattle Manure and Nitrapyrin

ABSTRACT We investigated whether nitrification inhibitor nitrapyrin can reduce nutrient leaching and increase nutrient uptake by corn (Zea mays L.) in cattle manure amended soil. Amendments included non-amended check (CK), urea (Urea), REG (manure from cattle fed barley grain), and DDGS (manure from cattle fed 60% dried distillers grains with solubles), co-applied with or without nitrapyrin and leached or unleached with water. Nitrapyrin reduced (P < 0.01) leaching of nitrate by 56, 32, and 24% from DDGS, REG, and Urea treatments, respectively, and also reduced (P < 0.05) leaching of phosphate (58%), potassium (39%), calcium (39%), and magnesium (39%) from DDGS treatment. While nitrapyrin reduces the rate of ammonium conversion to nitrate, higher magnesium and phosphate levels in DDGS-amended soil favor struvite formation and reduce their leaching. Corn biomass and nutrient uptake were higher (P < 0.01) in DDGS and Urea than CK and REG treatments, but remained unaffected by nitrapyrin. The benefits of nitrapyrin should be further investigated under field conditions. Abbreviations: DCD, dicyandiamide; DDGS, dried distillers grains with solubles; NI, nitrification inhibitor; TP, total P; TN, total N.

Yield and nutrient uptake of barley and camelina amended with manure from cattle fed barley, triticale dried distillers grains with solubles, and flaxseed diets

Abstract: Since animal diet affects manure properties, it is expected that manures from different diets may elicit differences in crop response. The objective of the study was to assess how application of manure from cattle fed with dried distillers grains with solubles (DDGS) and flaxseed (Linum usitatissimum L.) affected N and P availability, dry matter, and nutrient uptake in barley (Hordeum vulgare L.) and camelina [Camelina sativa (L.) Crantz] under controlled environment conditions. Treatments included manure from diets with barley grain (BARL), or barley grain replaced with triticale (× Triticosecale Wittmack) DDGS, flaxseed (FLAX), or both DDGS and flaxseed (DDGS/FLAX). Crops were grown for four consecutive phases (barley–camelina–barley–camelina). The DDGS/FLAX treatment had significantly higher barley dry matter weight (DMW) in phase 1 and camelina DMW in phase 2 than the other three manures (17 vs. 5–13 g kg-1 soil in phase 1 and 10 vs. 1–7 g kg-1 soil in phase 2). Barley N uptake in phase 1 and camelina N uptake in phase 2 were significantly higher for DDGS/FLAX than the other manures (222 vs. 82–191 mg kg-1 soil, phase 1; 146 vs. 20–102 mg kg-1 soil, phase 2). Our results indicate that cattle diet modifications have the capacity to tailor manure properties for optimum crop production.