Addition Of Organic Amendments Research Articles

Ameliorative influence of organic matter on biological activity of salt‐affected soils

Salt‐affected soils have low biological activity both because of osmotic and ionic effects of salts and owing to ¡imitation of carbonaceous substrates. Alkali soils and artificially salinized soils were incubated at 28°C for 3 months with or without organic (1% Sesbania cannabina green manure) amendment, at 60% water‐holding capacity. CO2 evolution was measured by absorption in alkali, microbial biomass by chloroform fumigation‐incubation, dehydrogenase activity by tetrazolium reduction, and urease activity by measuring ammonia release titrimetrically. CO2 evolution and microbial biomass were reduced at pH 8.7 in unamended alkali soils by 18% and 35%, respectively; at pH 10.3 the reduction was by 83% and 35%, respectively. Organic matter (OM) amendment stimulated CO2 evolution, and the biological activity in soils up to pH 10.0 was restored to that of amended normal soil (pH 8.1). The activity of pH 10.3 soil was 78% of normal. Extent of added carbon decomposed was ∼38% throughout the pH range studied. CO2 evolution and microbial biomass were reduced at ECe 16 in unamended saline soils by 33% and 40%, respectively; at ECe 97 it was reduced by 62% and 63%, respectively. OM amendment improved activity only at salinities ECe ≤ 26. Dehydrogenase activity (DHA) showed a similar trend; OM stimulated activity in alkali soils up to pH 10.0, whereas in saline soils it could not fully restore the activity even at ECe 16.0. In saline soils there was an immediate reduction in DHA on salt addition followed by a further reduction on incubation. DHA increased immediately on salt removal by leaching. There was a reduction in pH and ESP values and increases in soil C and N contents of alkali soils, and an increase in urease activity of saline and alkali soils following the addition of organic amendment. Results supported our hypothesis that microbial growth is depressed in alkali soils owing, at least in part, to carbon stress and in saline soils owing to salt stress. Results reinforce the need to apply organic amendments during alkali soil reclamation, whereas in saline soils, organic amendments must follow leaching.

EFFECT OF ALACHLOR CONCENTRATION AND AN ORGANIC AMENDMENT ON SOIL DEHYDROGENASE ACTIVITY AND PESTICIDE DEGRADATION RATE

Past studies have shown that extremely high concentrations of alachlor in soil can depress microbial biomass and bioactivity; consequently, degradation of alachlor is also inhibited. Studies were undertaken to further characterize the relationship among alachlor concentration in soil, dehydrogenase activity (as an indicator of microbial activity), and degradation rate. Alachlor initially inhibited soil dehydrogenase in soil at concentrations as low as 250 mg/kg with prolonged inhibition through at least 21 d occurring at concentrations ≥750 mg/kg. The inhibition of soil dehydrogenase was associated with a prolonged persistence of alachlor beyond the previously reported ranges of half-life observed at normal field rates of application. Amendment of soil with cornmeal caused degradation of 10 to 250 mg/kg alachlor at rates substantially faster than previously reported for laboratory incubations. At alachlor concentrations ≥750 mg/kg, dehydrogenase activities in amended soils surpassed levels in corresponding no-pesticide controls after 21 d; coincidentally, >50% of the initially added alachlor had degraded during the same period. These results suggested that stimulation of microbial bioactivity by addition of organic amendments may enhance co-metabolism of high concentrations of pesticides in soil.

Effect of alachlor concentration and an organic amendment on soil dehydrogenase activity and pesticide degradation rate

AbstractPast studies have shown that extremely high concentrations of alachlor in soil can depress microbial biomass and bioactivity; consequently, degradation of alachlor is also inhibited. Studies were undertaken to further characterize the relationship among alachlor concentration in soil, dehydrogenase activity (as an indicator of microbial activity), and degradation rate. Alachlor initially inhibited soil dehydrogenase in soil at concentrations as low as 250 mg/kg with prolonged inhibition through at least 21 d occurring at concentrations ≥750 mg/kg. The inhibition of soil dehydrogenase was associated with a prolonged persistence of alachlor beyond the previously reported ranges of half‐life observed at normal field rates of application. Amendment of soil with cornmeal caused degradation of 10 to 250 mg/kg alachlor at rates substantially faster than previously reported for laboratory incubations. At alachlor concentrations ≥750 mg/kg, dehydrogenase activities in amended soils surpassed levels in corresponding no‐pesticide controls after 21 d; coincidentally, >50% of the initially added alachlor had degraded during the same period. These results suggested that stimulation of microbial bioactivity by addition of organic amendments may enhance co‐metabolism of high concentrations of pesticides in soil.

Carbon and nitrogen in arable soils as affected by supply of N fertilizers and organic manures

Results from a long-term, small plot field experiment, started in 1956, comparing different mineral N fertilizers and organic amendments are presented. Continuous bare fallow was included in the plan. The treatments resulted in large differences in soil organic carbon. No steady state was established. In spite of large additions of fresh organic matter with varying nitrogen content, the C/N ratio remained as a rule around 10. The only exception was peat. This is comparatively resistant against microbial decomposition. Therefore the C/N ratio was influenced by undecomposed peat, poor in nitrogen. Nitrogen balances covering the whole experimental period are presented. Crop residues poor in nitrogen and nitrogen uptake by the crop were found to decrease nitrogen losses. Where no organic amendment was added, there was a decrease in total nitrogen in soil. Addition of organic amendments resulted in the opposite situation. Farmyard manure caused a greater increase of total nitrogen in soil than green manure, demonstrating the importance of the quality of raw material for the yield of humus material.The sizes of soil organic matter fractions were estimated. The “old” humus fraction was estimated to 23.6 t ha−1 C. The “active” and “young” humus fractions accounted for 20–61% of the soil organic carbon depending on the level of fertilization and the supply of fresh organic matter. It was stated that those fractions are of great importance for the capacity of the soil to mineralize nitrogen.

Effects of organic amendments and irrigation waters on the physical and chemical properties of two calcareous soils in Bahrain

The present investigation studies the effects of cow and chicken manure and sewage sludge at different rates of addition and with two irrigation waters of different salinities on two major calcareous soils in Bahrain. The aim was to quantify potential improvements in soil quality, the accumulation of trace metals, and quality of leachates.From the pot experiments it was found that soil waterholding capacity did not change significantly after addition of organic amendments, except in the case of sewage sludge. Total organic carbon and total Kjeldhal nitrogen content increased in the 0-5 cm layer. Low salinity water and sewage applications improved aggregate stability. Extractable phosphorus was enhanced by the chicken manure treatment more than others. Addition of different organic amendments did not affect exchangeable cations. pH values did not show appreciable changes and soils were neutral. Trace metals studied were present at non-toxic levels in the 0-5 cm layer. Zinc and copper were the only metal showing a tendency to leach to the lower soil layer. In all cases metal levels in the surface layer were proportional to the quantities added in the amendments and their levels in the leachate were very low.

Seasonal variation in methane flux from rice paddies associated with methane concentration in soil water, rice biomass and temperature, and its modelling

To attempt to develop physicochemical and physiological modelling for methane transport from the rhizosphere to the atmosphere through rice plants, methane flux, methane concentration in the soil water, and the biomass of rice were measured in lysimeter rice paddies (2.5 × 4 m, depth 2.0 m) once per week throughout the entire growing season in 1992 at Tsukuba, Japan. The addition of exogenous organic matter (rice straw) or soil amendments with the presence or absence of vegetation were also examined for their influence on methane emissions. The total methane emission over the growing season varied from 3.2 g CH4 m-2 y-1 without the addition of rice straw to 49.7 g CH4 m-2 y-1 with rice straw and microbiological amendment. In the unvegetated plot with the addition of rice straw, there was much ebullition of gas bubbles, particularly in the summer. The annual methane emission due to the ebullition of gas bubbles,from the unvegetated plot with the addition of rice straw was estimated to be almost the same as that from the vegetated site with the addition of rice straw. In the early growth stage, the methane flux can be analyzed by the diffusion model (Flux=Methane concentration × Conductance of rice body) using parameters for methane concentration in the soil water as a difference in concentration between the atmosphere and the rhizosphere, and for the biomass of rice as a conductance of rice body. On the other hand, although the diffusion model was inapplicable to a large extent from the middle to late growth stage, methane flux could be estimated by air temperature and concentration in the soil water. Thus, methane transport from the rhizosphere to the atmosphere through rice plants consisted of two phases: one was an explainable small part by diffusion in rice body; the other was a large part strongly, governed by air temperature. The existence of gas bubbles in the soil may be related to the transition between the two phases

Combining Legumes and Compost: A Viable Alternative for Farmers in Conversion to Organic Agriculture

Soil nitrogen (N) availability and crop performance of broccoli (Brassica oleracea var. orion) were observed in a field plot study under different organic amendments addition and chemical fertilizer. The treatments consisted on no amendment; poultry manure based compost, woollypod vetch (Vicia dasycarpa var. lana), a combination of compost with Lana vetch and ammonium sulphate. For almost all sampling dates, the soils treated with vetch (3.6 Mg/ha) combined with compost (9.0 Mg/ha) showed a good performance in replenishing the inorganic N taken up by plants and soil microbes. High yields were achieved with the combination of vetch and compost and moderately high yields were achieved with vetch only and compost only. Yields appeared to be related to quality and N levels in the amendments, and size of existing soil nitrogen pools susceptible to the priming effect.

Suppression of Sclerotinia soft rot of lettuce with organic soil amendments

The incidence of sclerotinia soft rot of lettuce and survival rate of sclerotia of Sclerotinia sclerotiorum were reduced by the addition of organic amendments to field plots at the Frankston Research Station, Seaford, Vic. Of the 6 materials tested, stable manure, fowl manure, and lucerne hay were the best, and all except brown coal significantly reduced disease compared with control. Composting of the already mature materials (as supplied) made no difference to their effectiveness. Incorporating the amendments into soil increased the number (to 229% of the control) and fresh weight (to 202% of the control) of marketable lettuce. Stable manure provided the greatest number of marketable heads (270% of the control), while fowl manure gave the greatest increase in head weight per plot (268% of the control). These benefits were less evident following the first applications of amendments (experiment 1) than the second to the same soil plots (experiment 2).

Improving the productivity of a degraded ultisol in Nigeria using organic and inorganic amendments. Part 2: Changes in physical properties

Abstract The effects of addition of organic amendments on the physical properties of a degraded Ultisol were compared with those of high rates of inorganic fertilizer. The treatments were: control (C), F 1 (N, P, K and Mg at 120, 30, 120 and 20 kg/ha, respectively), F 2 (N, P, K and Mg at 180, 45, 180 and 30 kg/ha, respectively), RS (rice shavings at 50 Mg/ha), RS + F 1 (rice shavings at 50 Mg/ha plus N, P, K and Mg at 120, 330, 120 and 20 kg/ha, respectively) and PM (poultry manure at 50 Mg/ha). All amendments were applied in 1986 and their effects monitored three months and three years later. When compared with the control, applications of rice shavings or poultry manure significantly ( P =0·05) decreased bulk density and increased total and macroporosity, volumetric water retention and available water capacity, saturated hydraulic conductivity, infiltration capacity, cumulative infiltration and time to reach infiltration capacity, more than did inorganic fertilizer amendments. Their effects were more pronounced three months than three years after application. Improvements in these properties were directly related to the residual concentrations of soil organic matter left by the amendments. Organic-matter concentrations accounted for between 52 and 77% of variability in bulk density, 35 and 88% variability in water retention and available water capacity, and between 56 and 98% variability in water transmission characteristics of this Ultisol. Considering the immediate and residual effects of these treatments the order of improvements in the measured physical properties was RS > RS + F 1 > PM > F 1 ⩾ F 2 > C .

PRODUCTION AND PERSISTENCE OF SOIL ENZYMES WITH REPEATED ADDITION OF ORGANIC RESIDUES

Soil enzymes mediate biochemical transformations involving organic residue decomposition and nutrient cycling in soil. A field study was conducted to determine the activity and persistence of soil enzymes with repeated additions of different organic residues. The activities of 10 soil enzymes involved in carbon, nitrogen, phosphorus, and sulfur cycling were assayed in an Arlington coarse-loamy soil which had received 100 Mg ha-1 of either poultry manure, sewage sludge, barley straw, (Hordeum vulgare) or fresh alfalfa (Medicago sativa) over a 31-month time period (25 Mg ha-1 × 4 additions). The enzyme activity assayed in the amended soil was increased by an average of 2− to 4-fold by incorporation of the four organic amendments when compared with the unamended soil (tillage alone) during the 31-month study. In general, the addition of organic amendments greatly increased the enzyme activity during the first year of the experiment, but subsequent additions failed to sustain high enzyme activity in the amended soil. The straw amendment was the most effective amendment enhancing the soil enzyme activity for all the enzymes assayed except for urease. In contrast to other reported studies, soil enzyme activities were not inhibited by sewage sludge addition in this investigation. The increased level of enzyme activity in the organic-amended soil may be a reflection of the increased protective sites within the soil as a result of enhanced humus content.

Effect of intercropping and organic soil amendments on native VA mycorrhizal fungi in an oxisol

Abstract The effect of monocropping and intercropping of soybean and maize together with rice straw, maize straw, and pongamia leaf soil amendments on native vesicular‐arbuscular (VA) mycorrhizal fungi was studied. Intercropping stimulated proliferation of VA mycorrhizal fungi compared to monocropping with maize or soybean. In the soil cultivated with soybean there were more mycorrhizal propagules as compared to maize. Addition of organic amendments to soil increased the proliferation of VA mycorrhizal fungi. Of the three organic amendments studied, addition of pongamia leaf showed the highest increase of native mycorrhizal presence, followed by maize straw. Addition of rice straw to soil had the least stimulatory effect. Increase in the number of VA mycorrhizal propagules in soil was correlated with improved plant P uptake.

Influence of temperature and organic amendments on the mobilization of selenium in sediments

Toxic amounts of selenium have been found in sediments and water at Kesterson Reservoir (Merced County, Calif.). A sediment column study was established for determination of Se 0 (Se volatilization potential) and k (Se voltalization rate coefficient) derived from a first-order kinetics model. Increasing the temperature from 15 to 35°C promoted volatilization of Se ( Q 10 = 1.96). The amount of Se leached out of the sediments was independent of the initial total Se inventory. Volatilization of Se followed a first-order reaction and was highly dependent on the initial Se concentration. The Se 0 ranged from 0.18 to 3.63 mg Se kg −1 sediment with k values ranging from 0.003 to 0.053 day −1. The addition of organic amendments promoted volatilization with Se being less available for leaching. The application of gluten, a wheat storage protein, was found to enhance voltilization of Se (1.7 to 3.2-fold over the control) more strongly than other treatments (e.g. casein, orange peel and cattle manure). Volatilization may be an important dissipation mechanism for detoxification of seleniferous sediments.

Converting stewardship values into policy: The mission of the 1990 Farm Bill

AbstractFarmers committed to the overall goal of sustainability in agriculture have banded together to support legislative action favorable to that goal. Specific objectives relate to addition of organic amendments to soils to improve fertility, avoidance of excessive use of pesticides and synthetic fertilizers, crop rotation, species diversity among crops, protection of wildlife habitats, and support of family-operated farms. Currently applicable legislation is believed to be unfavorable to some of these objectives and needs modification.

EFFECT OF CHISELING AND AMENDMENTS ON THE MANAGEMENT OF SOILS HAVING IMPERVIOUS LAYER AT SHALLOW DEPTHS

Occurence of hard pans at different depths of the cultivated soils is one of the serious soil physical problems encountered which are known to affect the crop growth and yield due to the restricted movement of air, water and nutrients and root penetration. Any attempt to break this barrier is bound to have notable benefits. The aim of this study was to investigate the effect of chiseling and the addition of organic amendments on the yield of sorghum grown in a soil having impervious layer at shallow depth. The " results of the experiment revealed that both chiseling at closer intervals and the addition of amendments like groundnut husk and rice husk had increased the yield of sorghum grain and starw over control. The physical properties of the soil viz,, bu k density, stabi- lity index and hydraulic conductivity examined at the post harvest stage were also found" to be improved considerably due to chiseling and addition of organic amendments.

Effects of pesticides, lime and other amendments on soil ethylene

The influence of a range of pesticides, lime and organic amendments on the level of soil ethylene was determined. Ethylene is important in soils because it can influence the growth of both plants and micro-organisms and thus influence soil fertility. The pesticides used, with the exception of fungicides, had a negligible influence on ethylene production. Fungicide treatment however, led to increased ethylene production. Similar, though more marked increases followed liming, and the addition of chitin, cellulose, urea and barley straw to soil. The results suggest that the action of fungicide in soils is due in part to the secondary production of ethylene following treatment. In the same way increased ethylene production following the addition of lime and organic amendments is likely to influence the activities of both saprophytic and plant pathogenic micro-organisms in the soil. re]19760726

Relation between Growth of Chrysanthemums and Aeration of Various Container Media1

Abstract Chrysanthemum morifolium cv. Brilliant Anne was grown in 13 different media under frequent irrigation such that all media were nominally at container capacity. Media were selected to represent a range in airfilled porosity (0–20%) at container capacity with a depth of 12 cm. Substantial addition of organic amendment (40–90% v/v) improved aeration in a poorly aggregated loam and in two sands. Peat plus vermiculite had the best aeration of all media. Thirty day top yields were related to aeration properties of the media measured at container capacity. A value of 10–15% air-filled porosity was generally related to best growth. Oxygen diffusion rate (ODR) for the medium profile provided a better correlation with plant growth than air-filled porosity. A profile ODR of 45g O2 × 10‒8 cm-2 min-1 and above gave best growth.

Effects of organic amendments on manganese toxicity in potatoes as measured by sand and soil culture studies

Soil and sand culture studies were carried out in the greenhouse to investigate the influence of organic amendments on the rate of mineralization of manganese and iron in different soil types of Quebec. Potatoes (Early Rose variety which is resistant to manganese toxicity) grown in culture solution containing 100 ppm of manganese produced flowers two weeks in advance of those grown in 0.5 ppm. The yields of tubers were increased two-fold by the combined treatment of humic compounds and high concentration of manganese. Due to microbial competition, the introduction of carbohydrates, alcohols, etc, decreased the yields of tubers. The yields recorded with the Keswick variety (susceptible to manganese toxicity) and different organic amendments on St. Andre soil (low pH and organic matter and high manganese) were in the following order: humate > compost > compost and peat > peat > control. A somewhat different order was recorded on De l'Anse (low pH and manganese and high organic matter): compost > humate > peat > compost and peat > control. The presence of sodium humate in the nutrient solution reduced the manganese content of potato leaves but increased that of stems. The addition of carbohydrates slightly depressed the content of manganese in potato leaves. Glycerine favored the accumulation of high amounts of manganese in potato stems. The Ca/Mn ratio should be around 360 in the leaves and 400 in the stems of normal plants. Plants showed manganese toxicity symptoms when the Ca/Mn ratio fell below 70, or when the Mn/Fe ratio was about 0.2 in the leaves and 0.6 in the stems of normal plants. The sum of Mn/Fe and Ca/Mn ratios remained the same in potato stems regardless of the organic amendments and the soil types. As the Mn/Fe ratio increased, the manganese toxicity symptoms became more severe and the Ca/Mn ratio narrower. The addition of organic amendments generally decreased the Mn/Fe ratio as well as toxicity symptoms. Various regression equations are formulated to establish the correlations between plant and soil data. The most interesting findings are as follows: 1 Organic matter, total nitrogen and C/N ratio in the soil were found to be negatively correlated with exchangeable manganese. 2 A positive correlation was found between the Mn/Fe ratio of soil and that of plants, and also between the manganese content of potatoes and the manganese toxicity indexes. 3 Manganese toxicity indexes were positively correlated with Mn/Fe ratios and negatively with the Ca/Mn ratios in plants. 4 There was a definite tendency for the yields of the Keswick variety (susceptible to manganese toxicity) to decrease as the manganese content of the soil increased. However, the yields of Early Rose variety (tolerant to manganese toxicity) were higher with 100 ppm of manganese than with 0.5 ppm in the culture solutions. Therefore, Early Rose appears to be a good variety for acid soils containing high levels of exchangeable manganese.

Chemical Versus Microbial Decomposition of Amitrole in Soil

Degradation of 3-amino-l,2,4-triazole-5-C14 (amitrole-5-C14) in autoclaved, potassium azide, ethylene oxide, and dry-heat sterilized soil was compared with that observed in nonsterile soils by measuring evolved C14O2. Amitrole degradation occurred in azide and ethylene oxide-sterilized and nonsterile soils but not in autoclaved soils. Only slight degradation occurred in autoclaved soil re-inoculated with mixed cultures of soil microorganisms isolated from soil in which amitrole had been rapidly degraded. Addition of EDTA-Na to nonsterile and ethylene oxide sterilized soils reduced amitrole degradation. Addition of organic amendments to amitrole treated soil stimulated microbial activity but reduced amitrole degradation. Addition of specific metallic salts to certain soils increased the rate of amitrole degradation. Amitrole degradation occurred rapidly in several free radical generating chemical systems. These results and additional observations indicate that amitrole degradation, at least in three soils examined, was largely a chemical process, and that microbial involvement was only indirect.

Growth and survival of Histoplasma sapsulatum in soil.

Growth and survival of Histoplasma capsulatum, a fungus pathogen of man, in sterilized and non-sterile soil was determined. Growth in sterilized soil, as determined by plate counts, was favored by increasing moisture levels up to 85% of the water-holding capacity of the soil, and by the addition of several organic materials, including peptone, grass clippings, purified chitin, and chicken feces. The fungus survived for at least 8 weeks when introduced into non-sterile soil as conidia. Addition of organic amendments were not necessary for survival, and may, in fact, have been deleterious. Disappearance of the fungus from unsterile soil in some experiments suggests that it is sensitive to antagonistic biological effects. The fact that non-amended soils were as favorable for survival as were soils amended with chicken feces, or other organic materials, suggests that the search for natural habitats of this fungus should not be limited to bird roosting sites.

THE INFLUENCE OF NITROGEN ON THE DECOMPOSITION OF CROP RESIDUES IN THE SOIL

Additions of mineral nitrogen accelerated the initial decomposition rate of incorporated wheat straw, alfalfa hay and glucose when added to two soils differing widely in organic matter content. However, in the more advanced stages of decomposition the reverse was true, and over the total incubation period larger amounts of carbon were maintained in soils supplemented with nitrogen.In contrast to all other residues used, nitrogen additions to cellulose effected a continuous and substantial increase in residue decomposition. This was the only residue for which the mineralization of soil organic matter did not supply nitrogen adequate for its decomposition within 120 days.The very slow rate of decomposition of sphagnum peat could be attributed to its high lignin content, rather than to the nitrogen levels.Sulphacetolysis analysis, which measures the non-humified carbon, indicated the feasibility of separating non-humified crop residues from the more complex soil organic matter. Addition of organic amendments thus resulted in a drop in the soil humification quotient. Nitrogen resulted in the retention of a significantly higher percentage of the added residue, without a drop in the humification quotient for the high organic matter Melfort soil.Residue applications to soils produced a significant improvement of structural development, especially in the low organic matter soil (Arborfield).