Agroecosystem Optimization by Crop Rotation, Catch Crop and Manure in Organic Farming ; Agroekosistemų optimizavimas augalų kaita, tarpiniais pasėliais ir organinėmis trąšomis ekologinėje žemdirbystėje

Aistė

Sujets

• Agronomy
• Catch crop
• Agricultural productivity
• Crop rotation
• Organic farming
• WEED

Informations

• Publié par: lithuanian_university_of_agriculture
• Publié le: 01 janvier 2011
• Nombre de lectures: 43
• Langue: Lithuanian

Extrait

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LIETUVOS ŢEMĖS ŪKIO UNIVERSITETAS










Skirmantė Balnytė









AGROEKOSISTEMŲ OPTIMIZAVIMAS AUGALŲ KAITA,
TARPINIAIS PASĖLIAIS IR ORGANINĖMIS TRĄŠOMIS
EKOLOGINĖJE ŢEMDIRBYSTĖJE







Daktaro disertacijos santrauka
Biomedicinos mokslai, Agronomija (06B)











Kaunas, 2010
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Disertacija rengta 2004–2009 m. Lietuvos ţemės ūkio universitete.

Mokslinis vadovas:
Doc. dr. Vaclovas Boguţas (Lietuvos ţemės ūkio universitetas, biomedicinos mokslai,
agronomija – 06B).


Disertacija ginama Lietuvos ţemės ūkio universiteto Agronomijos mokslo krypties
taryboje:

Pirmininkas:
Prof. habil. dr. Rimantas Velička (Lietuvos ţemės ūkio universitetas, biomedicinos
mokslai, agronomija – 06B).

Nariai:
Habil. dr. Nijolė Anisimovienė (Gamtos tyrimų centro Botanikos institutas,
biomedicinos mokslai, botanika – 04B);
Prof. habil. dr. Vida Stravinskienė (Vytauto Didţiojo universitetas, biomedicinos
mokslai, ekologija ir aplinkotyra – 03B );
Dr. Ţydrė Kadţiulienė (Lietuvos agrarinių miškų mokslų centras, Ţemdirbystės
institutas, biomedicinos mokslai, agronomija – 06B);
Doc. dr. Darija Jodaugienė (Lietuvos ţemės ūkio universitetas, biomedicinos mokslai,
agronomija – 06B).


Oponentai:
Doc. dr. Irena Januškaitienė (Vytauto Didţiojo universitetas, biomedicinos mokslai,
biologija – 01B )
Doc. dr. Vytautas Liakas (Lietuvos ţemės ūkio universitetas, biomedicinos mokslai,
agronomija – 06B)



Disertacija bus ginama viešajame Agronomijos mokslo krypties tarybos posėdyje 2010 m.
gruodţio 21 d., 11.00 val. Lietuvos ţemės ūkio universiteto Centrinių rūmų 261
auditorijoje.
Adresas: Studentų g. 11, LT–53361 Akademija, Kauno r.; tel.: [phone], faks.: (8-37)
397 500.


Daktaro disertacijos santrauka išsiuntinėta 2010 m. lapkričio 21 d.
Disertaciją galima perţiūrėti Lietuvos ţemės ūkio universiteto ir Lietuvos agrarinių miškų
mokslų centro, Ţemdirbystės instituto bibliotekose.
3
INTRODUCTION
Relevance of the subject. Under intensification of agricultural production, the
point is reached at which environmental impact increases significantly and risk to human
health is observed. Negative effects caused by intensive agricultural development
encourage searching for greater harmony with nature maintaining the potential productivity
of plants, growing organic production and preserving healthy environment. With
appearance of negative effects caused by long-term application of intensive farming
systems, priorities of organic (natural, stable, sustainable) farming emerge.
The system of organic farming is based on complete exploitation of the natural
resources of agrocenosis and stabilisation of a closed cycle of biogenic elements. Organic
farming requires assuring the balance of nutrients, controlling the spread of weeds, diseases
and pests. To achieve rational functioning of an agroecosystem, agrocenoses shall preserve
sustainability of the main nutrition elements through combining in crop rotation the main
crops and catch crops of the plants featuring different biological properties: one plants are able
to fix nitrogen from atmosphere, whereas others are capable of taking nutrients from deeper
layers or assimilating the nutrition elements available in complex compounds. This fact is
especially relevant for growing great amounts of cereal in organic farms that are focused on
crop production as crop rotation stability and productivity decreases, supply of plants with the
required amount of nitrogen becomes more difficult, crop weediness increases.
Stable yield and competitive production may be grown only by maintaining the
potential soil fertility determined by a range of factors. More or less changes in one factor
lead to change in another one or even in another few factors. The effect made on the plants
and soil by one agricultural practice should be assessed by various aspects. Due to the
aforementioned reasons, complex evaluation of optimisation possibilities (maintenance of
the potential soil fertility, control of crop and soil weediness, yield stabilisation) of
agroecosystems is required in organic agriculture. Efficiency of individual agricultural
practices in organic farming has been investigated widely. However, what concerns the
complex influence on agroecosystems made by crop rotations with a different nitrogen-
fixing crop rate, catch crops and fertilisation with organic fertilisers, the lack of studies has
been observed thus far.

Experimental hypothesis. Optimisation of agroecosystems in organic farming is
possible through application of a set of the following practices: by crop rotations with a
different ratio of nitrogen fixing crop, growing catch crops and fertilising with organic
fertilisers.

Experimental objective. To evaluate optimisation possibilities of agroecosystems
in organic farming by combining crop rotations with a different ratio of nitrogen fixing
crops, growing catch crops and fertilising with organic fertilisers.

Tasks. To analyse the influence of crop rotations with a different ratio of nitrogen-
fixing crops, catch crops and fertilisation with organic fertilisers on the following:
1. Soil enzyme activity;
2. Agrochemical properties of the soil and nitrogen balance;
3. Weed response;
4. Weed seed bank in the soil;
5. Crop yield and productivity.
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Novelty of the research. It was evaluated complex effect of crop rotations with a
different ratio of nitrogen fixing crops, catch crops and farmyard manure on
agroecosystems in organic agriculture. This new knowledge provided posibility to maintain
potential soil fertility, to control the spread of weeds, to grow stable grain yield in organic
agriculture. For the first time in Lithuania was evaluated the effect of crop rotations on
nitrogen turnover and changes in organic compounds of the soil, the influence of the first
year grass-clover on weed seed bank, efficiency of crop rotations with short crop links in
organic agriculture.
Practical value of the results obtained. Results of the research demonstrated that
the most purposeful way in organic farming is crop rotations with short links of row,
legume and especially grass crops, where the nitrogen-fixing crops ratio not less than 43 %.
The effect of farmyard manure used did not last more than two years. Catch crops for green
manure are recomended in order to reduce the negative nitrogen balance when weed control
is ensured by other practices.

Statements to be defended
In organic farming:
 soil enzymes activity, nitrogen turnover and changes in organic carbon processes
are more active when crop rotation with N –fixing crops are used;
 the potential of soil fertility maintained by the crop rotations with short crop links,
catch crops for green manure and fertilizing with farmyard manure;
 crop rotations with short crop links are effective for weed control;
 grass-clover after one year application effectively decreases the weed seed bank in
the soil;
 A stable cereal crop yield can be achieved in crop rotation with short links of row,
legume and grass crops and fertilizing with farmyard manure.

Approval and publication of the dissertation work. The main results of the
dissertation work were published in scientific journals: the Lithuanian Academy of
Science's scientific journal „Agricultural Sciences“ in 2008; the Lithuanian University of
agriculture's scientific journal „VAGOS“ (2009). Scientific conferences: „Žemdirbio vasara
2005“, „Žemdirbio vasara 2010“ (LŢŪU), scientific conference dedicated to commemorate
90 years anniversary of Professor Antanas Stancevičius, „Šiuolaikinių žemdirbystės sistemų
aktualijos“, (LŢŪU, 2010); international scientific conference dedicated to commemorate
100 years anniversary of Professor Petras Vasinauskas „Farming systems and environment
quality (LŢŪU, 2006); international scientific conference „Soil in Sustainable
Environment“ (LŢŪU, 2008); international scientific conference of PhD students „Youth
seeks progress“ (Akademija-Kaunas, 2009).
Volume of the work. The dissertation is written in Lithuanian. It consists of an
introduction, overview of the literature, experimental materials and methods, anglysis and
discussion of experimental data, conclusions, list of articles published in realation to the
dissertation research, list of referentes, summary in English. The dissertation inludes 106
pages, 27 tables, 11 figures, 253 Literature references have been used.

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EXPERIMENTAL MATERIALS AND METHODS
Experimental materials. Agroecosystem components (biodiversity) in organic
agriculture.
Experimental site and soil type. The field experiment was carried out in organic
certified field of the Experimental Station of the Lithuanian University of Agriculture
during the period of 2004-2009. The soil type – Calc(ar)i Epihypogleyic Luvisol (LVg-p-w-
cc). Soil texture: medium clay loam on heavy clay loam and clay. Arable layer (Ap 0-25