Paulo H. Pagliari

Investigation of the inorganic and organic phosphorus forms in animal manure.

The most viable way to beneficially use animal manure on most farms is land application. Over the past few decades, repeated manure application has shown adverse effects on environmental quality due to phosphorus (P) runoff with rainwater, leading to eutrophication of aquatic ecosystems. Improved understanding of manure P chemistry may reduce this risk. In this research, 42 manure samples from seven animal species (beef and dairy cattle, swine, chicken, turkey, dairy goat, horse, and sheep) were sequentially fractionated with water, NaHCO₃, NaOH, and HCl. Inorganic (P(i)), organic (P(o)), enzymatic hydrolyzable (P(e); monoester-, DNA-, and phytate-like P), and nonhydrolyzable P were measured in each fraction. Total dry ash P (P(t)) was measured in all manures. Total fractionated P (P(ft)) and total P(i) (P(it)) showed a strong linear relationship with P(t). However, the ratios between P(ft)/P(t) and P(it)/P(t) varied from 59 to 117% and from 28 to 96%, respectively. Water and NaHCO₃ extracted most of the P(i) in manure from ruminant+horse, whereas in nonruminant species a large fraction of manure P was extracted in the HCl fraction. Manure P(e) summed over all fractions (P(et)) accounted for 41 to 69% of total P(0) and 4 to 29% of P(t). The hydrolyzable pool in the majority of the manures was dominated by phytate- and DNA-like P in water, monoester- and DNA-like P in NaHCO₃, and monoester- and phytate-like P in NaOH and HCl fractions. In conclusion, if one assumes that the P(et) and P(it) from the fractionation can become bioavailable, then from 34 to 100% of P(t) in animal manure would be bioavailable. This suggests the need for frequent monitoring of manure P for better manure management practices.

Phosphorus runoff from turfgrass as affected by phosphorus fertilization and clipping management.

Phosphorus enrichment of surface water is a concern in many urban watersheds. A 3-yr study on a silt loam soil with 5% slope and high soil test P (27 mg kg(-1) Bray P1) was conducted to evaluate P fertilization and clipping management effects on P runoff from turfgrass (Poa pratensis L.) under frozen and nonfrozen conditions. Four fertilizer treatments were compared: (i) no fertilizer, (ii) nitrogen (N)+potassium (K)+0xP, (iii) N+K+1xP, and (iv) N+K+3xP. Phosphorus rates were 21.3 and 63.9 kg ha(-1) yr(-1) the first year and 7.1 and 21.3 kg ha(-1) yr(-1) the following 2 yr. Each fertilizer treatment was evaluated with clippings removed or clippings recycled back to the turf. In the first year, P runoff increased with increasing P rate and P losses were greater in runoff from frozen than nonfrozen soil. In year 2, total P runoff from the no fertilizer treatment was greater than from treatments receiving fertilizer. This was because reduced turf quality resulted in greater runoff depth from the no fertilizer treatment. In year 3, total P runoff from frozen soil and cumulative total P runoff increased with increasing P rate. Clipping management was not an important factor in any year, indicating that returning clippings does not significantly increase P runoff from turf. In the presence of N and K, P fertilization did not improve turf growth or quality in any year. Phosphorus runoff can be reduced by not applying P to high testing soils and avoiding fall applications when P is needed.

Phosphorus availability and early corn growth response in soil amended with turkey manure ash.

Incinerating turkey manure is a new option in the USA to generate renewable energy and to eliminate environmental problems associated with manure stockpiling. Incineration produces turkey manure ash (TMA) with a nutrient content of 43 g phosphorus (P) kg−1 and 100 g potassium (K) kg−1. We conducted a greenhouse pot study using a low P (6 mg kg−1) and high K (121 mg kg−1) soil/sand mixture with a 7.0 pH to evaluate early growth response of corn (Zea mays L.) to TMA. A control and five rates based on P (5.6, 10.9, 16.5, 21.9, and 27.2 mg kg−1) and respective K contents in TMA were compared with triple-superphosphate and potassium chloride fertilizer. Plant height and stalk thickness at 24 and 31 days after emergence (DAE) were greatest with the fertilizer, but no differences were detected at the final sampling (52 DAE). Regardless of nutrient source, plant biomass increased with P rate. Because of faster initial plant development, corn dry matter 52 DAE was 15 to 20% greater with fertilizer than with TMA. Corn tissue P concentration was greater with TMA than with fertilizer, but P uptake was similar. Tissue micronutrient concentrations were greatest for the control. Bray 1 P appeared to extract excessive amounts of P in TMA-amended soil, whereas soil P levels with the Olsen extractant provided an estimate of plant-available P that was consistent with plant response. Based on this first approximation, we conclude that TMA is a potential source of P for field crops. Field studies are required to determine recommended application rates.

Phosphorus Concentrations in Sequentially Fractionated Soil Samples as Affected by Digestion Methods.

Sequential fractionation has helped improving our understanding of the lability and bioavailability of P in soil. Nevertheless, there have been no reports on how manipulation of the different fractions prior to analyses affects the total P (TP) concentrations measured. This study investigated the effects of sample digestion, filtration, and acidification on the TP concentrations determined by ICP-OES in 20 soil samples. Total P in extracts were either determined without digestion by ICP-OES, or ICP-OES following block digestion, or autoclave digestion. The effects of sample filtration, and acidification on undigested alkaline extracts prior to ICP-OES were also evaluated. Results showed that, TP concentrations were greatest in the block-digested extracts, though the variability introduced by the block-digestion was the highest. Acidification of NaHCO3 extracts resulted in lower TP concentrations, while acidification of NaOH randomly increased or decreased TP concentrations. The precision observed with ICP-OES of undigested extracts suggests this should be the preferred method for TP determination in sequentially extracted samples. Thus, observations reported in this work would be helpful in appropriate sample handling for P determination, thereby improving the precision of P determination. The results are also useful for literature data comparison and discussion when there are differences in sample treatments.

Turkey Manure Ash Effects on Alfalfa Yield, Tissue Elemental Composition, and Chemical Soil Properties

A power plant that utilizes turkey manure as fuel to produce energy was built in Benson, Minnesota, and started full energy production in 2007. The plant was built to meet legislative requirements governing the use of renewable sources to generate energy in Minnesota. Although the use of turkey manure as biofuel generates energy, it also results in turkey manure ash (TMA) as a by‐product that contains phosphorus (P), potassium (K), sulfur (S), and zinc (Z) as well as other essential and nonessential elements. A 2‐year study was conducted to compare TMA with triple‐superphosphate and potassium chloride fertilizers as a source of nutrients for alfalfa (Medicago sativa) at three locations: Lamberton, Morris, and Appleton, Minnesota. The soils at Lamberton and Appleton were acidic with P and K concentrations ranging from medium‐high to very high, whereas the soil at Morris was alkaline with high concentrations of P and K. The experiment consisted of a control (0 P and 0 K) and annual and split applications of TMA and fertilizer. Annual TMA and fertilizer rates were 84 kg P2O5 ha−1, 118 kg K2O ha−1, and 34 kg S ha−1. Split rates were 42/42 kg P2O5 ha−1, 59/59 kg K2O ha−1, and 17/17 kg S ha−1. However, because of an overestimation of citrate‐soluble P in 2005 for the TMA, the total amount of available P applied with the TMA for the 2‐year study was 168 kg P2O5 ha−1 compared with 286 kg P2O5 ha−1 for the fertilizer. In the first year, fertilizer resulted in greater alfalfa biomass yield than TMA and the control, whereas in the second year, alfalfa yields with TMA and fertilizer were similar and both more than the control. In 2005, TMA resulted in more copper (Cu) and S tissue concentrations than the fertilizer. In 2006, application of both sources increased tissue P and S concentrations compared with the control. The TMA increased tissue Cu concentration and Zn plant uptake compared with fertilizer. Bray P1–extractable soil P concentrations were less with TMA and control treatments than with the fertilizer treatments. Ammonium acetate–extractable soil sodium (Na) concentrations were greater with TMA than with fertilizer and the control. By the second year, both ash and fertilizer treatments resulted in more K uptake than the untreated control with no difference in K uptake between the two sources or time of application. Both sources were effective in increasing P uptake compared with the untreated control. TMA was shown to be an effective source of nutrients for alfalfa production.

Efeito de subdoses de 2,4-D na produtividade do algodão e suscetibilidade da cultura em função de seu estádio de desenvolvimento

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Variety and solubility of phosphorus forms in animal manure and their effects on soil test phosphorus

Animal manure has been recognized as one of the best sources of nutrients for crop production for centuries. However, only over the last few decades have we started to fully understand and recognize the negative environmental impacts of agricultural use of manure. Although all essential nutrients required for plant growth can be found in a manure sample, there are primarily two that are well known to negatively impact the environment the most, nitrogen (N) and phosphorus (P). Both of these nutrients have considerably high mobility while within the manure matrix; however, their mobility significantly decreases once manure is incorporated into the soil. Phosphorus is found in two forms in animal manure, inorganic (Pi) and organic (Po). The Po can be further categorized as enzymatically hydrolysable or non-hydrolysable Po. The Pi and Po can be found dissolved in solution and also precipitated as minerals or complexed with organic compounds and metals in the manure matrix. The relative amount of each P form is highly variable and depends among other factors on the animal species, animal age, growth stage, animal diet, and manure storage conditions. When manure is applied to soils, most often there is an increase in soil test phosphorus (STP) levels. However, the magnitude of the increase in STP will depend on soil and manure properties. Understanding how manure and soil properties interact is key to minimize the negative impact of manure on the environment. This chapter will discuss the variety and solubility of manure P and also how the different forms of Pi and Po can affect the increase in STP.

Applied and Environmental Chemistry of Animal Manure: A Review

Abstract Animal manure consists of predominantly urine and feces, but also may contain bedding materials, dropped feed, scurf, and other farming wastes. Manure is typically applied to soils as fertilizer for agricultural production. The estimated amount of manure produced in 12 major livestock-producing countries is 9 × 109 Mg of manure annually. Manure is rich in plant nutrients. However, manure is also considered as an environmental pollutant when it is over-applied to cropland or following runoff into surface water. Manure can also influence global climate change via emissions of methane (CH4) and nitrous oxide (N2O). Thus, increased and updated knowledge of applied and environmental chemistry of animal manure is needed to shed light on the research and development of animal manure utilization and minimization of its adverse environmental concerns. The advances in basic and applied studies of manure major components, organic matter, phosphorus, and nitrogen, primarily related to US livestock production are summarized in this review. Detailed focus was placed on three notable challenges for future manure research: 1) soil application of animal manure, 2) manure phytate phosphorus, and 3) manure nitrogen availability. This review may contribute to the global effort in sustainable and environmentally sound agriculture by stimulating new ideas and directions in animal manure research, and promoting application of knowledge and insight derived from manure research into improved manure management strategies.

Changes in Soil pH and Extractable Phosphorus Following Application of Turkey Manure Incinerator Ash and Triple Superphosphate

During the incineration of turkey manure, a wide variety and concentration of nutrients are conserved in the turkey manure ash (TMA). In particular, the high concentration of citrate-soluble phosphorus (P) (43 g kg−1) may make it a suitable P source for crop production. The ash is alkaline with a pH of 12.2. We conducted a soil incubation study using a low-P soil with a pH of 6.2 to evaluate the effects of TMA on soil pH and extractable P. Two TMA rates, based on citrate-soluble P (10.9 and 21.9 mg kg−1), were compared with equivalent rates of triple superphosphate (TSP). In addition, a 0-P control was included. At the rates tested, TMA slightly increased soil pH, but this increase would be of minor agronomic importance. At equivalent P rates, changes in water-soluble P (WSP) concentrations with TMA and TSP were similar. Changes in iron-oxide-strip–extractable P (FeO P) and Bray 1 P concentrations were greater with TMA than with TSP. In contrast, changes in Olsen P concentrations were greater with TSP than with TMA for up to 32 days. For TMA, the ability of the tests to extract P was ranked, from highest to lowest, as Bray 1 P > FeO P > Olsen P > WSP, and for TSP they were ranked Bray 1 P ≥ Olsen P ≥ FeO P > WSP. However, the Bray 1 P and FeO P tests tended to overestimate plant-available P because they measured more citrate-soluble P than that added with TMA. We conclude that TMA can be used as a P source for crop production and that the Olsen test may provide a better estimate of plant-available P in TMA-amended soil.

Manure-Induced Soil-Water Repellency

This laboratory study was conducted to evaluate the potential of nine manure samples from dairy (n = 7), beef (n = 1), and swine (n = 1) to cause water repellency (WR) in six soils; in addition, the duration of WR in two soils was assessed in an incubation study. Manures were applied to supply 40 mg phosphorus (P) kg−1 to each soil. Sand content in the soils ranged from 179 to 909 g kg−1. Water repellency was assessed with the water drop penetration time (WDPT) and the degree of repellency with the soil wetted area (SWA) methods. The potential for animal manure to induce WR measured with the WDPT method was dependent on the manure type and soil series. Swine manure did not increase the WDPT of any soil; beef manure increased WDPT in three of the six soils, whereas dairy manure had the greatest effect on WDPT. Results of the SWA method were similar to those with the WDPT; however, there were additional soil-water behavioral patterns identified by the SWA. For example, dairy manure 5 increased WDPT of a soil from 1 to 9 sec, whereas the SWA showed a decrease in the drop area from 120 mm2 in the control to 26 mm2 after manure addition. Incubating manure-treated soils for 1 and 2 weeks decreased the induced WR in the Antigo soil, but had little effect on the Rosholt. Field studies should be conducted to assess these phenomena under natural climatic conditions.