Considerable amounts of N can be lost from manure through NH$ sb3$ volatilization. Four laboratory studies were conducted to evaluate the effects of organic amendments on reducing NH$ sb3$ loss from liquid hog manure (LHM). The organic amendments used in these studies were sugar, sawdust and paper products including filter paper (FP), paper bag (PB), newsprint (NP) and pulp sludge (PS). Generally, organic amendments had significant effects on reducing NH$ sb3$ loss from LHM and their effectiveness increased with increasing addition rates. Sugar addition of 3% or higher could eliminate the NH$ sb3$ loss, depending on LHM properties and incubation conditions. The effectiveness of sugar, especially lower rates, decrease with time. The unrecovered NH$ sb4$ loss increased and manure pH decreased with the increase in sugar rates, indicating that the reduction in NH$ sb3$ loss due to sugar addition may have been caused by N immobilization and pH reduction. Sawdust addition reduced the NH$ sb3$ loss by as much as 20% compared to the control. The mixture of 5.5% sugar and 5% sawdust was more effective in reducing NH$ sb3$ loss than 5.5% sugar alone but, lower sugar rates were not similarly affected by sawdust addition. Addition of 5% FP, PB, NP and PS resulted in the decrease in NH$ sb3$ loss by as much as 40, 47, 37 and 29% in comparison to the non-amended manure. The unrecovered NH$ sb4 sp+$ loss and the loss of added C increased with increasing C addition, indicating that N immobilization may be the cause of the decrease in NH$ sb3$ due to paper product additions. (Abstract shortened by UMI.)

Ammonia (NH$ sb3$) volatilization from manure can represent a major process through which nitrogen (N) is lost from the soil-plant-animal system. Reductions in NH$ sb3$ volatilization have significance both in economic and ecological aspects. Calcium lignosulphonate (CaLS), an acidic, water-soluble organic waste product of the pulp and paper industry, is expected to reduce NH$ sb3$ volatilization from liquid hog (Sus scrofa dometicus) manure (LHM) and consequently increase fertilizer value of LHM. Reduction of NH$ sb3$ loss from LHM was studied using added CaLS at 0, 6% 12% and 18% CaLS (based on fresh LHM weight) during 21 d incubation. Cumulative losses of NH$ sb3$-N ranged between 0 to 46% of initial total N. Compared to untreated LHM, the 6% CaLS treatment control N loss for 7 d and promoted N loss thereafter, while 12% and 18% CaLS treatments effectively reduced N losses throughout the 21 d incubation period. The N availability and the effect of CaLS-LHM mixtures on ryegrass (Lolium multiform Lamb.) growth were assessed on two soils mapped as St. Amable (sandy loam) and Ste. Rosalie (clay loam) from eastern Canada. Calcium lignosulphonate showed adverse effect on ryegrass plant growth, while as an amendment it did not reduce the effectiveness of LHM-N for ryegrass dry matter yield (DMY) and chemical composition at application rate up to 12% of LHM for the sandy loam soil and 18% of LHM for the clay loam soil. These findings suggested that CaLS may be used as an amendment for controlling N losses from animal manures.

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The aim of this work was to assay the effects of previous history of organic amendment to soils in the field on the ability of those soils to mineralise mustard, a non-legume green manure. Soil and 15N labelled mustard mineralisation was followed in laboratory microcosms. Volatilised N was assayed by direct acid trapping of N in glass fibre disks, followed by direct combustion isotope ratio mass spectrometry. Animal manures, green manures and straw added to the soil in the field in the previous season, same season and for 7 years continuously did not significantly affect these soils' ability to mineralise mustard in microcosms. Nitrification and mineralisation were the dominant processes during the first 12 days of incubation. Volatilisation rates were 1000-fold lower than mineralisation or nitrification rates. Mustard N accounted for between 1-3% of the soil mineral N, whereas only a maximum of 0.01% of mustard N was volatilised over 24 days. Soils sampled at different times in the season decomposed mustard at similar rates at stimulated low spring temperatures. Nitrification rate was reduced 5-fold more than the mineralisation rate at 8oC. Straw incorporation for seven years did not affect the subsequent recovery of 15N enriched fertiliser or of 15N from labelled straw, by oil seed rape. 15N labelled fertiliser contributed up to 63% of the winter barley N. The labelled barley straw subsequently contributed 16% of the oil seed rape N in the absence of any applied fertiliser. Ploughing in straw in the autumn, in the absence of applied fertiliser had no yield penalty or effect on crop uptake, and may retain more mineral N in the upper soil layers, lessening the risk of leaching over the winter period. The results obtained here emphasise the importance of additions of organic materials to soil in supplying plant nutrients and minimising nutrient losses.

The study evaluates the potential of pine litter for use as a substrate in the propagation of vegetable transplants in trays. Sub-optimum pH and electrical conductivity of pine litter were addressed by incorporating 10 % feedlot manure by volume. The water holding capacities of pine litter and the pine litter-feedlot manure mixture were higher than the minimum required, but their air filled porosities were below optimum. The pine litter-feedlot manure mixture reduced the germination percentages of cabbage seedlings by 17 % and lettuce seedlings by 13 % relative to composted pine bark, but the germination percentage of tomato seedlings was similar in both substrates. There were no significant differences in the growth of vegetable transplants between the two substrates. In both substrates increasing nutrient availability by adding controlled-release fertilizer had similar positive effects on the growth transplants. Substrate-nutrient availability interactions were only observed in dry shoot mass of lettuce seedlings and dry root mass of tomato seedlings. Composting the pine-litter animal manure mixture could possibly improve the observed low germination percentage of vegetable transplants in pine litter.

A laboratory incubation study was conducted to determine the effects of liming on microbial activity and N mineralization in two Bizana soils amended with broiler manure. The experimental layout was a 4 x 3 complete factorial experiment with three replicates, arranged in a randomized design. Soil pH, CO2 evolution, and mineral N concentration were measured. After 56 days the soil pH ranged from 4.50 to 5.74 and 4.99 to 5.94, in the Magusheni and Nikwe soils, respectively. The effect of liming on microbial activity and N mineralization differed between the soils. In the Nikwe soil (acid saturation 4.0%), microbial activity and N mineralization increased as the rate of broiler manure application was raised, but liming had no effect. In the Magusheni soil (acid saturation 25%), microbial activity increased as both lime and chicken manure application rates increased, but liming reduced N mineralization, suggesting N immobilization was being driven by an active microbial population in the limed soils. The rates of lime and/or chicken manure application, percentage Ca2+ and soil acid saturation were important factors influencing microbial activity and N mineralization, but the effect of soil pH on N mineralization was not evident in either of the soils.