Green Manure Amendment Research Articles

Comparison of Soil Physical Properties between a Permanent Fallow and a Long-Term Rice–Wheat Cropping with Inorganic and Organic Inputs in the Humid Subtropics of Eastern India

A comparison was made between a long-term rice–wheat cultivation with fertilizer nitrogen–phosphorus–potassium (NPK) or added organics [farmyard manure (FYM), paddy straw (PS), green manure (GM)] and a permanent fallow on bulk density (BD), saturated hydraulic conductivity (Ksat), available water capacity (AWC), maximum water-holding capacity (MWHC), aggregation, and soil organic carbon (SOC) dynamics on an Inceptisol of humid subtropics of eastern India. Continuous cropping caused a net decrease in SOC content. Undisturbed fallow was comparable to soils with FYM, PS, and GM amendments in structural and hydrophysical properties. Maximum WHC and AWC values were in the order of FYM followed by PS, GM, fallow, NPK, and control. The relative efficacy of the organics for physical buildup was FYM > PS > GM, which increased structural indices. This study represents further steps toward understanding the ecological importance of fallow management and integrated use of balanced fertilizer and organics.

Field evaluation of effective microorganisms (EM) application for growth, nodulation, and nutrition of mung bean

Effective microorganisms (EM) is a commercial biofertilizer that contains a mixture of co-existing beneficial microorganisms collected from natural environments. Predominantly it consists of species of photosynthetic and lactic acid bacteria, yeast, and actinomycetes. The present study was conducted to evaluate the effect of EM application on growth, nodulation, yield, and nutrient uptake in mung bean [Vigna radiata (L.) Wilczek] var. NIAB Mung 98 under field conditions. Field soil was amended with farmyard manure at 20 t ha^{-1}, Trifolium alexandrinum green manure at 20 t ha^{-1}, and recommended (NPK) and half (½ NPK) doses of chemical fertilizers. EM was applied in the form of a dilute solution in water (1:1000) at fortnight intervals throughout the experiment. EM application significantly enhanced shoot biomass in farmyard manure, ½ NPK and NPK amendments. Similarly, EM significantly increased grain yield by 24% and 46% in farmyard manure and NPK fertilizers amendments, respectively. By contrast, in green manure amendment, EM application resulted in a significant decline of 23% in grain yield. In ½ NPK amendment, the effect of EM application on grain yield was insignificant. Nodulation in terms of number and biomass of nodules was significantly suppressed by EM application in farmyard manure and green manure amendments. In NPK amendment, a significant increase in nodule biomass was recorded due to EM application. EM significantly enhanced nitrogen, phosphorus and potassium nutrition of the test plant in farmyard manure amendment both at flowering stage and maturity. However, in NPK amended soil, EM application markedly enhanced plant nutrition at later growth stage only.

Effect of Chinese milk vetch ( Astragalus sinicus L.) as a green manure on rice productivity and methane emission in paddy soil

This field study was undertaken to investigate the optimum recycling rate of the above ground biomass of Chinese milk vetch ( Astragalus sinicus L. hereafter, vetch) to improve rice productivity and decrease seasonal methane (CH 4) flux in mono-rice cultivation system. The above ground part of vetch was applied in paddy field at rates 0, 10, 20 and 40 Mg ha −1 on fresh weight basis to investigate its effect on rice ( Oryza sativa) productivity and CH 4 emission flux and was compared with the typical standard NPK chemical fertilization (N–P 2O 5–K 2O = 90–45–58 kg ha −1). Rice productivity increased significantly with increasing vetch application, and more interestingly, similar grain yield was obtained between vetch application at 10 Mg ha −1 as green manure and NPK fertilization. Methane emission rates, which were measured by closed-chamber method, increased significantly ( p < 0.05) with increasing application levels of vetch, and seasonal CH 4 fluxes exceeded to that in NPK fertilization at over 10 Mg ha −1 vetch application. Our findings revealed that 10 Mg ha −1 vetch application as green manure amendment can be an effective application level of sustaining rice productivity without increasing CH 4 emission compared to NPK fertilization in Korean mono-rice cultivation systems.

Annual Meeting, Winnipeg, Manitoba, 2009

Annual Meeting, Winnipeg, Manitoba, 2009

Suppressing Potato Cyst Nematode, Globodera rostochiensis, with Extracts of Brassicacea Plants

The golden potato cyst nematode, Globodera rostochiensis (Woll) is responsible for large yield losses in potato crops in northern Portugal. Fumigation with synthetic chemicals controls this soil pest with possible negative impact on the environment. Thus, it is desirable to find environmentally friendly alternative measures to control this nematode species. Amending plant parts of Brassicaceae have been recognized as potential biofumigation practices. Active volatiles compounds released after enzymatic hydrolysis are responsible for the efficacy of biofumigants. The glucosinolate-myrosinase-isothiocyanates system appears to be controlling several soilborne pests and pathogens. The biological role of Brassicacea green manure amendments on potato cyst nematodes populations has not been reported in Portugal. In this study we evaluated the effects of two concentrations (0.2 and 0.05 µmoles 100 g−1 dry weight) of total glucosinolates of six plants extracts (broccoli, cauliflower, collards of Brassica rapa, collards of kale, Portuguese cabbage and watercress) on potato cyst nematodes population. The results were expressed as number of new cysts formed on bioassay Desiree potato roots. ANOVA analysis showed a highly significant effect (P < 0.001) of the plant extracts and concentrations tested on the suppression of potato cysts nematodes. The LSD test showed that the number of newly formed cyst on root system of bioassay plant was also related (P<0.05) to type and concentrations of glucosinolates extracts. The lowest numbers of cysts were recovered from potato roots that received extracts of watercress, cauliflower and B. Rapa, respectively. The cyst reduction appeared to be associated with high levels of 2-Phenthyl and 2-propenyl glucosinolates in these plants.

Effects of Green Manure Type and Amendment Rate on Verticillium Wilt Severity and Yield of Russet Burbank Potato.

Increasing restriction of agrochemicals is motivating development of ecology-based cropping systems, including green manures, to manage soilborne diseases. Green manures have shown promise in suppressing Verticillium dahliae, but information about effect of different green manures and optimal application rates remains limited. Therefore, we conducted two single-year field experiments comparing effects of Austrian winter pea (Pisum sativum 'Melrose'), broccoli (Brassica oleracea var. botrytis 'Excelsior'), and Sudan grass (Sorghum vulgare var. sudanense 'Monarch'), amended at 6, 12, or 24 Mg ha-1, on soil populations and root infection by V. dahliae, wilt severity, and yield of Russet Burbank potato. Inoculum density was reduced relative to the nonamended, infested control by all broccoli treatments, Austrian winter pea applied at 12 and 24 Mg ha-1, and Sudan grass applied at 12 Mg ha-1. Root infection was not reduced by any green manure treatment. Median wilt severity was reduced approximately 70% by all green manures applied at 24 Mg ha-1 and 74% by Austrian winter pea applied at 12 Mg ha-1. Tuber yield was reduced approximately 20% in nonamended, V. dahliae-infested controls relative to the noninfested controls. No green manure treatment improved yield relative to the nonamended, infested control.

Influence of various forms of green manure amendment on soil microbial community composition, enzyme activity and nutrient levels in leek

The influence of different forms of green manure amendment on selected soil microbial characteristics and crop productivity was investigated in a leek cropping system. Mulching with fresh red clover, and incorporation of red clover-derived biogas slurry and compost were tested as alternatives to direct incorporation of a red clover crop. The specific aim of this study was to investigate how these different green manure forms, fresh and processed, influenced soil microbial biomass, microbial community composition and soil enzyme activity. An initial increase in abundance of bacteria and fungi was observed after direct incorporation and amendment with red clover-derived slurry and compost, but amendment with fresh red clover sustained a higher bacterial and fungal biomass until the end of the cropping season. Mulching stimulated arbuscular mycorrhizal (AM) fungi at the end of the cropping season. The treatments with fresh red clover, direct incorporation and mulch, tended to differ in their microbial community composition from the treatments with processed red clover. The protease, acid phosphatase and arylsulphatase activities were highest in the direct incorporation treatment, whereas enzyme activity in treatments with processed red clover was never higher than in the control treatments. There were no differences in leek harvest yield, but the nitrogen (N), phosphorus (P) and sulphur (S) concentrations in the leek crop at harvest increased in response to higher amounts of slurry and compost amendment. Arylsulphatase activity was negatively correlated with leek S concentration at harvest, indicating that the activity was regulated by the nutrient status of the cropping system. We concluded that direct incorporation of a red clover crop was most effective for enhancing and sustaining a high microbial biomass and high rates of enzyme activity in soil.

Soil enzyme activities, microbial community composition and function after 47 years of continuous green manuring

Green manuring practices can influence soil microbial community composition and function and there is a need to investigate the influence compared with other types of organic amendment. This study reports long-term effects of green manure amendments on soil microbial properties, based on a field experiment started in 1956. In the experiment, various organic amendments, including green manure, have been applied at a rate of 4 t C ha −1 every second year. Phospholipid fatty acid analysis (PLFA) indicated that the biomass of bacteria, fungi and total microbial biomass, but not arbuscular mycorrhizal (AM) fungi, generally increased due to green manuring compared with soils receiving no organic amendments. Some differences in abundance of different microbial groups were also found compared with other organic amendments (farmyard manure and sawdust) such as a higher fungal biomass and consequently a higher fungal/bacterial ratio compared with amendment with farmyard manure. The microbial community composition (PLFA profile) in the green manure treatment differed from the other treatments, but there was no effect on microbial substrate-utilization potential, determined using the Biolog EcoPlate. Protease and arylsulphatase activities in the green manure treatment were comparable to a mineral fertilized treatment receiving no additional C, whereas acid phosphatase activity increased. It can be concluded that green manuring had a beneficial impact on soil microbial properties, but differed in some aspects to other organic amendments which might be attributed to differences in quality of the amendments.

Foliar application of effective microorganisms on pea as an alternative fertilizer

Effective microorganisms are cultures of coexisting beneficial microorganisms predominantly consisting of species of photosynthetic and lactic acid bacteria, yeast and actinomycetes, that could be used for alternative crop production. I studied the effect of soil and foliar application of these microorganisms on crop growth, yield and nodulation in pea (Pisum sativum L.), in soils amended with Trifolium alexandrinum L. green manure, farmyard manure and NPK fertilizers. The results show that foliar application of effective microorganisms enhanced nodulation, using NPK amendment, reaching a 217% increase for nodule number and a 167% increase for nodule biomass. Similarly, a grain yield increase of 126% for NPK amendment and of 145% for green manure amendment was found after foliar application of effective microorganisms. These findings show that foliar application of effective microorganisms in combination with proper soil amendment can improve nodulation and yield in pea.

Response of different forms of propagules of Rhizoctonia solani AG2‐1 (ZG5) exposed to the volatiles produced in soil amended with green manures

AbstractThe sensitivity of different forms of propagules of Rhizoctonia solani anastomosis group (AG)2‐1/zymogram group (ZG)5 to volatile compounds produced in soil amended with green manure will influence the efficacy of green manures used to manage the disease. In laboratory experiments, we determined the impact of volatiles arising from residues of five species of Brassicaceae, and Avena sativa (oat), a non‐Brassicaceae species, and volatiles of pure allyl isothiocyanate (AITC) or 2‐phenylethyl isothiocyanate (2‐PEITC) in either their soluble or vapour phase on the hyphal growth of R. solani arising from different propagules. The brassicaceous species were Brassica napus var. Karoo, B. napus B1, B. napus B2, B. nigra and Diplotaxis tenuifolia (a brassicaceous weed). Colony growth and hyphal density on water agar were measured up to 7 days. The amendment of a sandy soil with green manures at a high (100 g kg−1, 10%) concentration generally suppressed the growth of the pathogen, but at a low (10 g kg−1, 1%) concentration, the amendment had little effect on the radial fungal growth of the pathogen but increased the density of hyphae through more branching. The inhibition by volatiles from the residues of Brassicaceae species at 10% concentration was stronger (82–86%) than that by volatiles from oat (64%) amendment at the same rate. Hyphae arising from sclerotia and precolonised ryegrass seed were less sensitive than hyphae growing out of potato dextrose agar plugs. This indicates that thick‐pigmented cell walls may have protected the fungus from these unfavourable conditions. Pure AITC and 2‐PEITC in the range of 0.5–2.0 mM inhibited the growth of R. solani from all forms of propagules, but hyphae originating from agar plugs were the most vulnerable compared with the two others. Thus, hyphae arising from the medulla of the sclerotia may be relatively tolerant to volatile compounds emanating from decomposing Brassica green manure amendments in the field and in vitro inhibition of the vegetative growth of the pathogen may not reflect its response to the amendments in the field.

Effect of Green Manure Addition on Soil Organic Phosphorus Mineralisation

The mineralization of organic forms of phosphorus (P) in soil contributes significantly to plant P uptake, although quantification of organic P mineralisation has been impeded by methodological difficulties. An isotopic dilution method, based on tracer kinetic theory, was used to study the organic P flux rates for unamended and green manure amended soil in an incubation experiment carried out over 35 days. Firstly, the specific activity (SA) between two points of time as affected by dominant biological processes (under conditions of constant soil respiration rates) was determined in a series of successive labelling incubation experiments. Secondly, the instantaneous specific activity (instSA) between two points of time was also determined by shaking an unlabelled soil with 33P, i.e. soil samples that were not labelled with 33P, but kept under conditions identical to the labelled soil samples. This gives the net size of the exchangeable inorganic P pool in the labelling experiments at two points of time during incubation. The SA dilution in the labelling experiments at a constant exchangeable inorganic P pool between two times was attributed to the release of non-labelled inorganic P from the organic P pool by mineralisation. The daily gross organic P mineralisation rates for the 21 days of incubation were 0.06 and 0.27 mg P kg−1 day−1 for unamended and green manure amended soils, respectively. The study demonstrated that green manure amendment contributed to an overall increase in soil P availability through enhanced organic P mineralisation.

Improving phosphorus availability in two upland soils of Vietnam using Tithonia diversifolia H.

Phosphorus was added to two acidic upland soils (a Cambisol and a Ferralsol) at two rates (9 mg P kg−1 and 145 mg P kg−1) either in an inorganic P form (KH2PO4) or as a green manure (Tithonia diversifolia H. at 2.5 g kg−1 and 40 g kg−1). The effect of P source on the chemical availability of P was assessed in an incubation experiment by measuring resin extractable P, soluble molybdate reactive (DMR-P) and unreactive P (DMU-P). Soil pH and extractable Al were monitored during the incubation period of 49 days. Green manure addition caused an immediate and sustained increase in soil pH and an immediate and sustained decrease in extractable Al. Labile P (resin P + DMR-P + DMU-P) was increased more by P added as a green manure than when added in inorganic form in one soil (Ferralsol), while it decreased or did not differ in the other one (Cambisol). In both soils, the concentrations of soluble DMU-P were frequently higher where Tithonia had been added. The effects of green manure amendment on physical factors governing the phosphorus supply through diffusive transport were also investigated. Aggregate size distribution was substantially changed by green manure amendment due to a shift in the percentage of microaggregates (<250 μm in diameter) to larger sizes. Changes in soil aggregation as a consequence of green manure amendment led to a reduction in specific surface area (SSA) of the whole soil. Coupled with the large increase in effective cation exchange capacity caused by green manure amendment in both soils, and the decrease in SSA, there was an increase in the net negative surface charge density in both soils. In summary, at a large addition rate – and in addition to the well-known effect derived from the extra supply in P, green manure amendment may improve the chemical availability and diffusive supply of P through the following mechanisms: (i) an increase in soil pH increasing the solubility of phosphate sources; (ii) a decrease in extractable Al reducing the fixation of added P; (iii) increased macro-aggregation and reduced specific surface area and porosity leading to fewer sorption sites for P and hence enhanced diffusion rates; and (iv) increased negative charges and reduced positive charges at the soil surface resulting in a net increase in repulsive force for P. The induced changes in most measured soil properties were smaller in the Ferralsol than in the Cambisol.

Effects of red clover ( Trifolium pratense ) green manure and compost soil amendments on wild mustard ( Brassica kaber ) growth and incidence of disease

Using a soil bioassay technique, seedling growth and incidence of disease of wild mustard (Brassica kaber) and sweet corn (Zea mays) were assessed in soil from field plots that received either of two treatments: incorporated red clover (Trifolium pratense) residue plus application of compost (`amended soil'), or application of ammonium nitrate fertilizer (`unamended soil'). Soils were analyzed for percent moisture, dissolved organic carbon, conductivity, phenolics, and nutrient content. A trend toward greater incidence of Pythium spp. infection of wild mustard seedlings grown in amended soil was observed during the first 40 days after incorporation (DAI) of red clover and compost, with significant differences (α = 0.05) at two out of four sampling dates in 1997, and four out of four sampling dates in 1998. Incidence of Pythium infection was 10–70% greater in the amended soil treatment during that period. Asymptomatic wild mustard seedlings grown in amended soil were also on average 2.5 cm shorter (α = 0.05) at 5 DAI than those grown in unamended soil in one year out of two. Concentration of phenolic compounds in soil solution was weakly correlated with decreased shoot and root growth (r = 0.50, 0.28, respectively) and increased incidence of disease (r = 0.48) in wild mustard seedlings in one year out of two. Dissolved organic carbon concentration was weakly correlated with increased disease in wild mustard seedlings in both years (r = 0.51, 0.33, respectively). Growth of corn seedlings did not differ between the two soil treatments, suggesting that red clover green manure and compost may selectively reduce density and competitive ability of wild mustard in the field. Bioassay results corresponded well with emergence and shoot weight results from a related field study, indicating that this technique may be useful for screening potential soil treatments prior to field studies.

Effect of green manure amendment and flooding on methane emission from paddy fields

The effect of green manure amendment, flooding treatment and crop season on methane emission from paddy fields in Taiwan was investigated from August 1994 to July 1996. Sesbania amendment stimulated methane emission and the effect was more significant at the early growth stage of rice. Methane emission was higher in continuous flooding treatment than that in intermittent irrigation. Both redox potential and methane emission showed significant differences between these two irrigation systems. Methane concentration increased sharply with the depth of soil in the intermittent irrigation system due to oxidation; whereas it increased moderately in the continuous flooding treatment. The seasonal methane flux in the first crop season with chemical fertilizer was between 2.73 and 5.23 g m−2; while the value was between 10.54 and 10.56 g m−2 in the second crop season. In the case of Sesbania amendment in the second crop season, the seasonal methane flux in the first crop season was 6.35 g m−2; while the value was between 14.43 and 30.12 g m−2 in the second crop season. Total methane emission in the second crop season was about two to five-fold higher than that in the first crop season.

Fate of 14C‐carbofuran in soils

AbstractThe degradation of14 C‐Carbofuran was studied in sterilized, unsterilized and green manure amended clay soil under moist and flooded conditions overa period of 30 days. The14 C mass balance showed that carbofuran did not undergo any degradation in sterilized moist soil. In sterilized flooded soil bound residues were formed to the extent of about 47% of the applied radioactivity at the end of 30 days. Carbofuran underwent considerable degradation in unsterilized moist and flooded soils. In moist soil about 48% of the applied14 C activity was recovered as bound activity while in flooded soil, about 23% of the activity was bound. Green manure amendment resulted in formation of more bound residues under moist conditions while it enhanced the degradation of carbofuran under flooded conditions. In flooded amended soil about 44% of the appliedl4 C‐activity was recovered as against about 54% in the unamended flooded soil. The notable degradation products formed under flooded soil conditions were 3‐keto carbofuran and 3‐hydroxy carbofuran.

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.

A DEMONSTRATION OF HORTICULTURAL CROP PRODUCTION ON A RECLAIMED SURFACE MINE SITE IN SOUTHERN WEST VIRGINIA

A 0.2-ha reclaimed minesoil site near Welch, W.Va., was amended with sewage sludge, hardwood bark, and a sorghum–sudan hybrid green manure crop to demonstrate production of horticultural crops. A selection of crops, including white birch, forsythia, zinnia, tomato, yarrow, red raspberry, and strawberry, was planted and grown. Plant growth and development, including flower and fruit production, tended to be enhanced by sludge-amended soils and reduced in green manure and hardwood bark–amended soils. Sludge increased pH, Ca, P, and Mg levels above that in the other treatments. Hardwood bark increased Mn but decreased P. The green manure amendment increased soil Fe content. In 1994 `Allstar' strawberry yield and berry weights were similar for all plots, but yield was about 10% of expected and was very close to the economic break-even point. Third-year yield of 1992 planted `Heritage' raspberries was about one-half the expected yield of 5000 lbs/acre, but still considered profitable. Zinnia flower production yielded a calculated 32% return on investment. Assuming that 50% forsythia plants were saleable in 2 years, return on investment was projected to be 30%. For white birch, assuming half were saleable in 4 years, a 16% return on investment was projected.

Methane emissions associated with a green manure amendment to flooded rice in California

The goals of sustainable food production and mitigation of greenhouse gas emissions may be in conflict when green manures are used in flooded rice systems. A field study was initiated in early spring 1992 near Sacramento, California to quantify the potential for enhanced methane emissions following a green manure amendment to rice. Replicate flux measurements were made twice a day every 3–4 days throughout the growing season in four treatment plots: burned rice straw, spring incorporated rice straw, burned straw plus purple vetch and spring incorporated straw plus vetch. Seasonal methane emissions ranged from 66–136 g CH4 m−2 and were 1.5 to 1.8 times higher from the straw plus vetch treatments relative to the straw only treatments. No significant differences in emissions were found between the two straw only treatments or the straw plus vetch treatments. Methane fluxes were exponentially related to soil temperature, but no effect of redox potential or floodwater depth were observed. The potential impact of these results on the global methane budget is discussed.

14C]-.gamma.-hexachlorocyclohexane in a flooded soil with green manuring

The fate of ({sup 14}C)-{gamma}-hexachlorocyclohexane ({gamma}-HCH) was studied in green manure amended and unamended flooded soils with a continuous-flow system permitting {sup 14}C mass balance. There was a greater loss of radioactivity in the form of organic volatiles and {sup 14}CO{sub 2} in green manure amended than unamended soil. The organic volatile compound formed was identified as benzene. Green manure amendment considerably decreased the levels of extractable residues from soil. Bound residue formation was also less in green manure amended than unamended soil.

Effects of organic amendments to soil on the rhizosphere microflora of antirrhinum infected withVerticillium dahliae Kleb.

Organic (e.g. chitin, green manure, cellulose) amendments to soil induced quantitative and qualitative changes in the rhizosphere microflora of antirrhinum plants infected withVerticillium dahliae Kleb. Whereas reduction in disease severity occurred with chitin and green manure amendments, an increase in disease severity was observed with the application of cellulose. The reduction of the disease severity with chitin and green manure may be correlated with the increased population of actinomycetes in the antirrhinum rhizosphere.