Tag Archives: organic matter

73-85 A. Karlsons and A. Osvalde
Effect of zeolite, clay and peat on salt stress tolerance of lettuce (Lactuca sativa L.)
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Effect of zeolite, clay and peat on salt stress tolerance of lettuce (Lactuca sativa L.)

A. Karlsons* and A. Osvalde

Institute of Biology, Faculty of Medicine and Life Sciences, University of Latvia, 4, O. Vaciesa Street, Riga, LV−1004, Latvia
*Correspondence: andis.karlsons@lu.lv

Abstract:

The present study aimed to investigate the effects of natural zeolite, clay and peat amendments on the growth and NaCl absorptions of lettuce (Lactuca sativa L.) under gradually increasing salinity. Four different growing media based on quartz sands with 10% additions of zeolite, clay and peat were tested. The worst effect of NaCl on plant biomass was evident at the highest salinity levels for zeolite applications. While adverse salinity impact on leaf and root biomass was least pronounced in treatments with peat additives. As expected, the lowest Na concentrations in plant tissues were found in the growing media supplemented with zeolite. In the case of Cl, however, it was the opposite – lettuce leaves accumulated significantly higher chloride concentrations in the zeolite variants in salinity treatments above 20 mM NaCl. In the control, clay and peat treatments, as the substrate salinity increased, the Cl level in the plant increased similarly. Adverse changes in leaf chlorophyll concentration (SPAD) and photosynthetic rate (µmol m^-2 s^-1) parameter appeared under salinity concentrations above 20 mM and were more pronounced in zeolite and sand substrate. According to the obtained results, peat additives can effectively mitigate the harmful effects of excessive salts by binding and immobilizing them as well as improving the water-holding capacity and nutrient availability. The study also concluded that natural zeolite successfully immobilizes cationic sodium, but the harmful effect of chlorine significantly reduced plant growth and photosynthetic performance. Clay additives to the growth medium showed the potential to reduce the adverse effects of salinity on lettuce, however, under the experimental conditions implemented, the effect was small.

Key words:

organic matter, photosynthesis, plant biomass, pot experiment, sodium chloride

637-655 R.P. Ria, K. Kartika, B. Lakitan, F. Sulaiman and M. Meihana
The impact of straw application on growth dynamics and proline accumulation in drought-stressed rice
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The impact of straw application on growth dynamics and proline accumulation in drought-stressed rice

R.P. Ria¹, K. Kartika²*, B. Lakitan¹³, F. Sulaiman¹ and M. Meihana⁴

¹University of Sriwijaya, Faculty of Agriculture, Department of Agronomy,
Jl. Raya Palembang-Prabumulih Km 32 Indralaya, Ogan Ilir 30662, Indonesia
²Research Center for Horticulture, Research Organization for Agriculture and Food, National Research and Innovation Agency (BRIN), Cibinong 19611, Indonesia
³Research Centre for Sub-optimal Lands, Universitas Sriwijaya. Jl. Padang Selasa No. 524, Bukit Besar, Palembang 30139, South Sumatra, Indonesia
⁴STIPER Sriwigama, Faculty of Agriculture, Department of Agronomy, Palembang 30137, South Sumatra, Indonesia
*Correspondence: kart011@brin.go.id

Abstract:

The frequent occurrence of unpredictable extreme droughts necessitates investigating measures to mitigate their impacts, as drought may occur at any growth phase of rice. This study evaluated the efficiency of straw applications to conserve soil moisture and mitigate the negative effect of drought stress on rice in tropical riparian wetlands. Rice straw was applied as organic matter (S1) and as mulch (S2) and then subjected to drought stress during early vegetative (D1), late vegetative (D2), and generative (D3) phases. The result of this study showed that the utilization of straw slowed down the water loss through evaporation as indicated by soil moisture. However, both rice straw applications, organic matter and mulch, were inefficient in maintaining the optimum plant growth when the soil moisture declined to < 10%. Drought stress at the early vegetative phase reduced the number of leaves by 63.68%, the number of tillers by 50.58%, and the total leaf area by 72.36%. Drought stress at the early vegetative phase also delayed flowering time for 11 days. Meanwhile, drought stress during the generative phase reduced the number of filled spikelets by 45.18% and increased sterile spikelets to 247.05%, which significantly reduced the yield. Plants that experienced drought stress during the vegetative and generative phases eventually increased the proline content by about 10 times (18.47 mmol g^-1) compared to unstressed plants (1.62 mmol g^-1). Straw mulching is recommended for mild to moderate droughts, but additional methods are needed to maintain soil moisture below 10%.

Key words:

morpho-physiological adaptations, mulch, organic matter, soil moisture, wetland

1241-1253 O. Nikipelova, N.Pyliak, V. Yarochevsky, A. Rucins and V. Bulgakov
Study of the influence of different organic fertilizers on soil agrochemical parameters in hazelnut plantations in Ukrainian Southern Steppe
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Study of the influence of different organic fertilizers on soil agrochemical parameters in hazelnut plantations in Ukrainian Southern Steppe

O. Nikipelova¹, N.Pyliak¹, V. Yarochevsky¹, A. Rucins²* and V. Bulgakov³

¹Engineering and Technological Institute ‘Biotekhnika’ of the National Academy of Agrarian Sciences of Ukraine, 26 Mayatska doroha Str., Khlibodarske, UA67666 Odesa District, Ukraine
²Latvia University of Life Sciences and Technologies, Ulbroka Research Center, 1 Instituta Str., LV-2130 Ulbroka, Latvia
³National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony Str., UA 03041 Kyiv, Ukraine
*Correspondence: adolfs.rucins@lbtu.lv

Abstract:

The effect of different origin organic fertilizers on agrochemical indicators of typical medium-humic chernozem in hazelnut plantings in the conditions of Ukrainian Southern Steppe was studied. There were used cattle manure, chicken droppings, Biofertilizer No. 1 (the combination of sewage sludge, winter wheat straw, phosphate-mobilizing bacteria Microbacterium barkeri), Biofertilizer No. 2 (the combination of sewage sludge, sunflower seed husks, phosphate-mobilizing bacteria Microbacterium barkeri), and native sewage sludge in the study. It was found that different origin organic fertilizers effected on the main agrochemical soil indicators increasing. The content of easy hydrolyzable nitrogen in soil increased from 84.0 mg kg^-1 in control up to 98.0 mg kg^-1 in the tests, mobile phosphorus – consequently from 138.75 mg kg^-1 in control to 306.30 mg kg^-1 in the tests, and potassium from 108.40 mg kg^-1 in control to 166.90 mg kg^-1. In addition, the organic matter content increasing from 3.76% (control) to 4.18% (tests) in the soil was detected. The express biosensor analysis of the fertilized soil showed a variation of the average ecotoxicity indicator from 0.92 to 1.41 which could be classified as a “low” common pollution level. It also detected an elevated zinc content in soil samples fertilized by Biofertilizer No. 1 and native sewage sludge. It proves that organic fertilizers based on sewage sludge applying can allow for overcoming the zinc deficit in Ukrainian soils. The advantages of Biofertilizers No. 1 and No. 2 were identified in respect to other studied organic fertilizers. New biofertilizers using allows soil nutrient content increasing, soil biological activity enhancement, which resulting in improvement in crop yield, and environmental enhancement.

Key words:

biofertilizers, cattle manure, easy hydrolysable nitrogen, organic matter, soil

1082-1092 V. Denisova, K. Kokina, K. Gruskevica and L. Mezule
Simultaneous nutrient and organic matter removal from wastewater by aerobic granular sludge process
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Simultaneous nutrient and organic matter removal from wastewater by aerobic granular sludge process

V. Denisova*, K. Kokina, K. Gruskevica and L. Mezule

Riga Technical University, Faculty of Civil Engineering, Water Research and Environmental Biotechnology Laboratory, Kipsalas 6a, LV-1048, Riga, Latvia
*Correspondence: viktorija.denisova@rtu.lv

Abstract:

Aerobic granular sludge (AGS) technology offers several benefits, such as simultaneous removal of nutrients and organic matter from wastewater, stronger granule structure, excellent settleability, and high resistance to toxicity. However, the formation of granules can take a long time and needs to be dense and stable.

In this study, the formation of aerobic granules in sequencing batch reactors (SBRs) using a granular activated carbon (GAC) and aluminium sulphate coagulant were evaluated for the simultaneous removal of nutrient (phosphorus (TP) and nitrogen (TN)) and organic matter (chemical oxygen demand (COD)) from wastewater. The reactors were continuously operated for 107 days and were fed with synthetic media and real domestic sewage. However, adaptation process with the synthetic wastewater led to relatively slow granulation process (sedimentation rate of sludge flocks was 3 m h^-1). During the experiments, there was no visible formation of granules in SBRs based on the analysis of the sludge samples, only the formation of aggregate structures similar to flocks. However, the results showed that total phosphorus (TP) removal efficiency was over 90% in SBR operated with aluminium sulphate. However, COD and total nitrogen (TN) removals were higher in GAC SBR, 75% and 10%, respectively. Thus, even if granules are not developed yet, the system is working efficiently. The results of this study could be useful in the development of AGS technology for full-scale wastewater treatment plant.

Key words:

aerobic granular sludge, nutrient removal, organic matter, sequencing batch reactor, wastewater treatment

99–110 L. Szajdak, P. Kuldkepp, E. Leedu, T. Teesalu, A. Toomsoo and R. Kõlli2
Some biochemical aspects of Fragi-Stagnic Albeluvisols’ organic matter
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Some biochemical aspects of Fragi-Stagnic Albeluvisols’ organic matter

L. Szajdak¹, P. Kuldkepp², E. Leedu², T. Teesalu², A. Toomsoo² and R. Kõlli2*

¹Research Centre for Agricultural and Forest Environment, Polish Academy of Sciences, ul. Bukowska 19, 60-809 Poznań, Poland; e-mail: szajlech@man.poznan.pl
²Institute of Agricultural and Environmental Sciences, Estonian Agricultural University, Kreutzwaldi 64, 54014 Tartu, Estonia; e-mail: raimo@eau.ee
*Author for correspondence

Abstract:

The concentrations of N-NH₄⁺, N-NO₃^–, N_total, total (TOC) and water extractable (DOC) organic carbon, P, K, Ca, Mg, S, the activity of nitrate reductase, the activity of urease activity as well as indole-3-acetic acid (IAA) were investigated in Fragi-Stagnic Albeluvisols’ organic matter under different organic and mineral fertiliser regimes from a long-term soil formation of a field experiment with three-field crop rotation (potato – spring wheat – spring barley) at Eerika near Tartu, Estonia, and also in the forest of Tiksoja. The concentrations of N_total, IAA, the activity of urease and also C/N ratios were generally highest in the forest soil of Tiksoja.
Consequently, characteristics, distributions and conversions in organic matter were found in the proportions of chemical and biochemical factors, particularly after mineral and organic fertilisers. The following kinds of fertilisers increased the activity of urease in the order: WOM/N-120 < FYM/N-120 < RS/N-120 (accordingly, WOM – without organic manure, FYM – farmyard manure, RS – recultivation substance), and increased the activity of nitrate reductase: WOM/N-120 > RS/N-120 > FYM/N-120. The highest increase of IAA was determined in the soil fertilised with RS/N-120.
The experiment was characterised by the highest activity of urease, and the highest increase of IAA and also TOC in soils fertilised with RS/N-120. The various fertiliser regimes were different both for their biochemical factors as well as the crop yields. WOM/N-120 as a mineral fertiliser and RS/N-120 as an organic one revealed the highest crop yield of potato, spring wheat, and spring barley.

Key words:

Albeluvisols, auxine, crop yields, long-term field experiment, organic and mineral fertilisation, organic matter, urease and nitrate reductase

63–67 E. Lauringson and L. Talgre
Problems of abandoned fields
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Problems of abandoned fields

E. Lauringson and L. Talgre

Department of Field Crop Husbandry, Estonian Agricultural University, Kreutzwaldi 64, 510014 Tartu, Estonia; e-mail: ennlaur@eau.ee

Abstract:

The study was based on data gathered in 1995–2002 in areas where plant cultivation was discontinued for various reasons and at various times. The objective of the study was to track changes in plant community, biomass production and soil weed seedbank in the abandoned fields.

The discontinuation of cultivation resulted in the emergence of plant communities, which were characterized for the first 1–2 years by a considerable proportion of annual species. The length of the period with annual species having a large representation in a community depended in many cases on the spread of Elytrigia repens in the abandoned fields. In land left idle for 5–6 years, perennial species supplanted annual species. Apart from E. repens, aggressive species turned out to be Cirsium arvense and Artemisia vulgaris (predominantly scattered all over the field). Weed seed density in the ploughed layer (30 cm) of abandoned fields amounted 157,000 to 666,000 seeds m-2, with the upper 10-cm layer accommodating up to 51% of the total seedbank. The biomass produced by plants depended on the texture of the soil and the age of the plant community, being 32.6 t ha-1 at the maximum. The accumulation of organic matter on and in the soil is a positive development in abandoned fields. Abundant residue contributes to an improvement of the physical and mechanical properties of the topsoil layer, reducing soil bulk density and decelerating soil compaction. The surface residue is a favorable environment for soil fauna.

Key words:

abandoned fields, organic matter, weed seedbank, weeds