Search

Viie katseaasta (2012–2016) keskmised tulemused näitavad, et võrreldes tavasüsteemidega on maheviljelussüsteemidel eelised kestlikuks taimekasvatuseks. Viljelussüsteemi mitmekesistamine vahekultuuride ja lisaks veel kompostitud veisesõnnikuga, võimaldab oluliselt parandada mulla omadusi. Tõusis mulla mikroobide aktiivsus, mulla orgaanilise süsiniku ja üldlämmastiku sisaldus. Mulla mikroobide aktiivsuse ja üldlämmastiku sisalduse vahelised seosed aga vajavad jätkuvaid uuringuid.

Kartul on üheks armastatumaiks kultuuriks nii meil kui maailmas. Teda on läbi aegade peetud teiseks "leivaks" ning tänapäeval ei kujutaks meist keegi ette toidulauda, kust puuduks kartul (Eremeev jt., 2012). Mahepõllumajanduslikult kasvatatav kartulipind on Eestis pidevalt suurenenud. Samas ei ole seni veel piisavalt andmeid selle kohta, kas põhiliselt vaid mulla toitainevarudel ja haljasväetistaimedel baseeruv majandamine on piisavalt jätkusuutlik. Kas ilma sõnnikuta külvikordades – paljudes mahetaludes ju loomakasvatus puudub – võib toimuda mulla väljakurnamine (Järvan jt., 2014)? Käesoleva töö eesmärgiks oli uurida kuidas erinevate maheviljelusviisidega kartuli kasvatamine mõjutab mulla toitainete sisaldust.

In crop rotations winter cover crops (WCC) can play a certain role in organic matter and plant nutrient formation. Under Nordic conditions the selection of crops for winter cover crops is quite limited. The aim of the present research was to explain the biomass and nutrients (N, P and K) formation by certain winter cover crops in an organic crop rotation. The effects of WCC on the following main crop yields were monitored.

A Thesis for applying for the degree of Doctor of Philosophy in Agriculture The world’s population is estimated to exceed over 9 billion people by 2050 (FAO, 2013), thus the demand for high yielding, good quality crops as well as the “challenges for the sustainability of the ecosystems” increases (Somers and Savard, 2015). Proper crop management is a key element in achieving high yields of good quality. Crop rotation, animal manures, and winter cover crops as catch crops (CC) play important roles in sustainable plant production systems because they provide nutrients for the system (Stark and Porter, 2005). CC and animal manures are mainly used by organic producers, because these are the main nutrient-rich sources for organic crop production. Animal manures are used by conventional producers only if, in addition to crop production, they have also livestock. Conventional producers, who grow only crops, largely depend on mineral fertilizers and different synthetic agrochemicals. According to Luik et al. (2008) conventional systems might not be sustainable in the long term, because they tend to be oversimplifi ed and maximally intensifi ed. But Edwards-Jones and Howells (2001) claimed that neither conventional nor organic farming systems (FS) are sustainable because both of them require inputs from non-renewable resources and, one way or another, they both impact on the environment. For organic producers there are also two main challenges, such as managing diseases and nutrients since nutrient availability is limited and there are only a few effective pesticides available that are allowed for use (Finckh et al., 2006). Also, Nelson et al. (2009) confi rm that in organic systems nutrient transformations almost exclusively relyon soil. In conventional systems, if there are problems with diseases or pest and with plant malnutrition, synthetic agrochemicals and mineral fertilizers can be provided throughout almost the entire growing season. Despite some limitations in organic farming, organic agriculture is based on its own self-regulating production system, and the concept of a farm is as an agro-ecosystem (Lammerts van Bueren et al., 2002). But organic agriculture alone does not provide a suffi cient amount of food for the growing population (Oliver and Gregory, 2015). In contrast, conventional agriculture depends mainly on external inputs, which makes it somewhat more vulnerable. To consider farming systems to be sustainable they must be “productive and maintain their contribution to society in the long term” (Gadanakis et al., 2015). In general, the demand for agricultural practices and food security that are more environmentfriendly is increasing rapidly, which favours the development of new 10 integrated farming systems (Duc et al., 2015). Such farming systems that use integrated management practices, such as crop rotations and organic (green manure crops, leguminous crops, CC) and inorganic fertilizers, will maintain soil as well as human health (Marsh, 2000; Oliver and Gregory, 2015). Future agriculture must also evolve towards climate-smart agriculture technologies, which are more adaptive to climate change by improving resource use effi ciency and ensuring food security (Zhang et al., 2015). Achieving food security does not only mean an adequate food supply but it also means that the food must be nutritious, of good quality (Wei et al., 2015). The potato is one of the most important crops worldwide, ranking fourth in annual production (Fernie and Willmitzer, 2001). The potato can be grown in harsher climates, and it is able to give, relatively quickly, high nutritious yields compared to any of the other major food crops (Lutaladio and Castaldi, 2009). However, to be productive, the potato needs signifi cant nutrient inputs to maintain its productiveness and quality. Crop management is the main factor that infl uences crop production and disease resistance (Larkin and Halloran, 2014; Olanya et al., 2014). Previous research has shown that FS affect tuber quality characteristics such as tuber nutrients (Järvan and Edesi, 2009) as well as starch and dry matter (DM) contents (Roinila et al., 2003). Plant nutrition is an important factor that infl uences natural disease resistance. If there is a defi ciency of essential elements susceptibility to potato diseases increases (Czajkowski et al., 2011), because the plant’s natural ability to fi ght them is lowered (Mulder and Turkensteen, 2005). Nutrients affect the plant physiology and thus potential for infection with pathogens (Dordas, 2008). At the European Association for Potato Research (EAPR, 2014) conference last year it was concluded that the agronomy side of potato production has gained too little attention over the past years and needs to regain its importance, because the agronomic side of potato production determines the potato performance parameters. Potato is a crop that has been studied in Estonia extensively because of its importance in Estonians everyday diet. The fi rst true Estonian potato scientist was Julius Aamisepp who promoted the cultivation of potato and its research. The fi rst fertilization experiments were conducted by Arnold Piho in 1960–1980 which also included the potato crop. The latest potato fertilization research has been made by Kuldkepp et al. 11 (1999), by Astover and Roostalu (2003), by Järvan and Edesi (2009), by Toomsoo and Leedu (2002), by Toomsoo et al. (2009; 2012). However, such complex potato fertilization research (under different organic and conventional farming systems) presented in current thesis has not been made before in Estonia. Earlier potato research has had mainly domestic importance. In the past, besides potato fertilization, the effect of different potato pre-planting thermal treatments on the tuber yield formation has been studied by Viacheslav Eremeev. Also there has been some potato disease related research by Mati Koppel who studied the potato soft rot (Erwinia/Pectobacterium spp.) disease and by Eve Runno-Paurson who investigated the potato late blight (Phytophthora infestans). The potato meristem multiplication has been studied by Viive Rosenberg and Marje Särekanno. Potato research related to plant breeding has been conducted by Aide Tsahkna and Mati Koppel. There are many other great potato researchers in Estonia who are a true experts in their fi eld of study. Crop rotations are important tools that affect potato productivity (Carter et al., 2003) and diseases (Peters et al., 2004). Catch crops are essential to avoid nutrient losses (Stark and Porter, 2005). Brassica crops used as CC have, furthermore, been found to have a disease suppressing effect (Cohen et al., 2005). Since the potato is a high nutrient demanding crop, additional mineral or organic fertilizers must be provided. Despite nitrogen (N) being a basic potato nutrient, the selection of its appropriate application rate for the potato is quite diffi cult, due to signifi cant variation (Zebarth et al., 2009). The appropriate N demand can vary among many factors such as climatic conditions during the growth period, crop management practices the previous crops cultivated. Addressing all the aforementioned factors should ensure high potato yields of good quality. Currently, these are the following gaps in our knowledge: (i) how the yield increase through different agronomic practices affects the potato tuber mineral elements concentrations (which are considered tuber nutrients) (White et al., 2009) and overall crop quality (Wang et al., 2008), (ii) how crop rotations infl uence tuber quality parameters (Mohr et al., 2011), and (iii) how the plant nutrition and crop rotations together affect the occurrence of tuber diseases (VanderZaag, 2010). The focus of much research tends to be on organic or conventional management systems separately, it is important to investigate their infl uence together comparatively (Bernard et al., 2014). Thus, the overall aim of this thesis is to 12 investigate how different organic and conventional management practices under the same crop rotation infl uence tuber quality characteristics as well as yield. Käesoleva doktoritöö raames uuritakse, kuidas erinevad viljelussüsteemid (neli tavaviljeluse süsteemi koos suureneva mineraalse lämmastiku normiga vs kaks mahesüsteemi koos vahekultuuride ja sõnnikuga), mis järgivad sama külvikorda (punane ristik, talinisu, hernes, kartul, oder punase ristiku allakülviga) mõjutavad kartuli kogu ja kaubanduslikke saake, mugulate toiteainete (N, P, K, Ca, Mg), nitraatide (NO3–), tärklise ja kuivaine sisaldust kui ka mugulahaiguste nagu harilik kärn (Streptomyces spp.), hõbekärn (Helminthosporium solani), kuivmädanik (Fusarium spp.) ja märgmädanik (Pectobacterium spp.) esinemist, mida määratletakse ka kui mugulate kvaliteedinäitajaid. Antud töö peamine hüpotees on, et kartuli saagikus ning mugulate toitainete, nitraatide, kuivaine ja tärklise sisaldus kui ka mugulahaiguste esinemine sõltuvad kõik viljelussüsteemist, külvikorrakultuuridest ning kliimatingimustest. Tulenevalt töö hüpoteesist oli uurimustöö eesmärkideks täpsemalt (i) hinnata viljelussüsteemi mõju kartuli saagierinevustele, (ii) uurida, kuidas erinevad viljelussüsteemid mõjutavad mugulate makrotoitainete kontsentratsiooni kui ka kuivaine ja tärklisesisaldust (iii) ning mugulahaiguste esinemist. Uurimistööst ilmnes, et uuritavate aastate keskmisena oli viljelussüsteemidel usutav mõju kartuli saagikusele, mugulate N, NO3–, P ja Mg sisaldustele kui ka mugulahaiguste nagu kuivmädanik, hõbekärn ja harilik kärn (madala nakkustasemega) esinemisele. Seega viljelussüsteemide toitainetega varustatus kui ka nende allikas võivad suuresti mõjutada mõningaid mugulate kvaliteedinäitajaid. Mugulate K, Ca, tärklise ja kuivaine sisaldused kui ka märgmädaniku esinemine vastupidiselt ei olnud mõjutatud erinevatest viljelussüsteemidest ning nende toitainetega varustatusest, kui välistatakse kasvuaasta ilmastikutingimuste mõju. See, kuidas konkreetne süsteem mõjutab mugulate kvaliteediomadusi, on otseselt mõjutatud ka kasvuperioodi keskkonnatingimustest. Publication of this thesis is supported by the Estonian University of Life Sciences

The TILMAN-project aims to develop robust and sustainable arable crop production systems via the introduction of reduced tillage techniques combined with a strategic use of green manures in organic crop rotations, while maintaining and improving soil quality and crop productivity parameters. The adoption of reduced tillage and/or green manures strongly affects nitrogen quantity and availability during the vegetative period and throughout the crop rotation. Specifically, changing soil and water conditions may affect the availability pattern of nitrogen, notably in spring. We present aggregated data of several long- and medium-term European experimental field studies in which green manures including cut-and-carry-fertilizers, and reduced tillage techniques are used in organic cropping systems. By presenting and analyzing field level nitrogen budgets, insight is gained in the nitrogen dynamics of such systems and possible bottlenecks. Moreover, results of model simulations of these trials by the decision support tool Ndicea are shown and analyzed.

The dynamics of soil organic carbon (SOC) content and crop productivity were studied on three still continuing field experiments situated at the experimental station of the Estonian University of Life Sciences in Tartu, Estonia. The first trial was established in 1964. The effect of mineral fertilizers and farmyard manure applied to barley and sward with different species composition on soil organic carbon content was studied. The second trial with 3-crop rotation (potato - spring wheat - spring barley) was established in 1989. Experimental factors were organic (without amendment, solid cattle manure and alternative organic fertilisers) and mineral fertilisers (0, 40, 80, 120 and 160 kg N ha-1). The third field experiment with 5-crop rotation experiment was established in 2008. Five different crops were following each other – barley undersown with red clover, red clover, winter wheat, pea and potato. Experimental factors were organic (catch crops as green manures, catch crops as green manures combined with composted cattle manure) and conventional farming systems. The conventional farming systems differed in the amounts of mineral fertilizers used: 0, 50, 100 and 150 kg N ha-1. The first goal of this research was to quantify plant C inputs to the soil in Estonian arable lands and the net primary production using crop-specific allometric relationships. Secondly, the impact of the different management scenarios on the changes in soil C stock was evaluated using plant C input data. The preliminary results of these data analysis will be presented.

Kartulikasvatus on Eestis järjest hääbuv majandusharu, kuna kartulikasvatuses on palju käsitööd ning probleeme esineb ka turustamisega. Kartulikavatamise tasuvust on vaja uurida, et anda ettevõtjatele infot, kas antud tegevus on tasuv ja milliseid võtteid peaks kasutama et tasuvust suurendada. Töö eesmärgiks oli uurida, milliseks kujuneb kartuli kasvatamise tasuvus erinevate viljelusviiside korral 2013. ja 2015. aastal. Erinevate viljelusviiside saagiandmed on saadud Eesti Maaülikooli Eerika katsepõllul toimund külvikorrakatsest, kus kartulit kasvatati 7. erinevas variandis – N0, N50, N100 ja N150, kus number tähistab antud mineraalse lämmastiku kogust ning M0, M1 ja M2, millest esimene on kontrollvariant, teise puhul on kasutatud vahekultuuri ning kolmas on vahekultuuri ning sõnnikuga. Tööst selgus, et kartuli kasvatamine on tasuv ka ilma makstavate toetusteta, kui vaadati tasuvust erinevatel aegadel. Kui 2013. aastal saadi suurim kasum 70. kasvupäeval turustades, siis 2015. aastal aga 100. kasvupäeval turustades. Suurimad kasumid teenisid mahevariandid kuna mahekartuli hind oli Eesti Konjuktuuriinstituudi andmetel kordades kõrgem kui tavakartulil. Potato growing is a fading economical branch in Estonia. Potato growing needs a lot of manual labor and has many problems with distribution. Profitability of potato growing needs further research, in order to give entrepreneurs information whether their actions are profitable and what kind of measures to take in order to increase profitability. The goal of this research paper was to examine profitability of different cultivation techniques in 2013 and 2015. Yields of different cultivation techniques were obtained from a long term field experiment taking place in Eerika test site managed by Estonian University of Life Sciences. Potatoes were grown in seven different variations. Conventional farming plots N0, N50, N100 & N150, where the number indicates the amount of nitrogen given to each plot. Organic farming plots M0, M1 & M2 – M0 being control variant, M1 used cover crops and M2 used manure and cover crops combined. The results shoved, that potato cultivation was profitable even without European subsidies, if profitability was compared over different years. In 2013, greatest profit was obtained by selling potatoes harvested on 70th growth day but in 2015, greatest profit was obtained by selling potatoes harvested on the 100th growth day. Highest profit was made by organically grown potato which was, according to the Estonian Institute of Economic Research, many times more expensive than conventionally grown potato.

Viimaste aastatega on tõusnud taimekasvatusele tehtavad kulutused tekitades olukorra, kus tuleb ökonoomsemalt majandada. Väiketootjad on läinud üle maheviljelusele. Seevastu suurtootjad on läinud rohkem intensiivse tootmise poole. Suurte ja laiade põllutööriistadega saavutatakse ökonoomsem tootmine. Uurimustöö eesmärgiks on selgitada välja kumba viljelusviisi juures on põldhernest kasulikum kasvatada. Põldherne katsed teostati Eesti Maaülikooli põllumajandus- ja keskkonnainstituudi, Rõhu katsejaama Eerika katsepõllul 2012. ja 2013. aastal. Uurimustöös käsitletakse mahe- ja tava herne võrdluskatset. Katse rajati neljas korduses ning variandid paiknesid süstematiseeritult. Katsetes kasutati põldherne sorti „Tudor“. Katselappide suuruseks oli 60 m2 ning katselappe oli kokku 28. Katsesüsteemideks olid maheviljeluses Mahe 0, Mahe I ja Mahe II. Tavaviljelusvariantideks olid väetamata süsteem N0P0K0 ja väetatud süsteemid N20P25K95 (1), -(2), ja –(3) variandid, mille eelviljad said lämmastikku vastavalt 50 kg/ha, 100 kg/ha ja 150 kg/ha. 2012. aasta herne saagikused olid madalamad tavaviljelusest. 2013. Aastal tõusid maheviljeluses saagikused tavaviljelussüsteemidega samale tasemele. Eelvilja enamväetamisega langesid herne saagikused. 2012. aastal oli herne kokkuostuhind 380 €/t, kuid 2013. aastal langes 348 €/t peale. Tavaviljeluses kasvatatud herne kokkuostuhind oli 2012. aastal 250 €/t ja 2013. Aastal langes see 190 €/t peale. Maheviljelussüsteemides kasvatatud hernes jäi mõlemal aastal kasumisse kuid tavahernes oma madalate kokkuostuhindade tõttu jäi kahjumisse 2013 aastal. Tavaviljeluses on mõistlik kasvatada hernest ainult lisaväetist andmata, seda kõrgete mineraalsete väetiste hindade tõttu, mis tõstavad kulud väga suureks. During the last years crop growth has gone more expensive. Mineraal fertilizers and chemical protection costs are rising. For that reaseon it is important to grow plants more economical way. Little farms grows plants mostly organical way. Big farms grows crop conventional. There are bigger field machines which makes plant crowth more economical. The research is based on experiments where pea was growed in both organic and conventional agriculture. The experiments took place in 2012 and 2013 on a test field in Eerika which belongs to the institute of agriculture and environment of the Estonian University of Life Sciences. A five-field crop rotation was used with red clover, winter wheat, pea, potato, barley with an undersow of red clover. That was the crop rotation. Pea growing was disserted in the research. The experiment was made in four repetitions. There were 3 variations of organic farming and 4 variations of conventional farming. The organic variations were Mahe 0, in which there was no alternate culture; Mahe I, where in the period during autumn and winter there was cover crop and Mahe II where the pre-crop got about 10 tonnes/hectar of manure and cover crop was also used. The variations in conventional agriculture were experiments with and without fertilizingThe fertilized variations got about 20 kilogrammes of nitrogen.Pre crop got four different nitrogen level norms, 50, 100 and 150 kg/ha. Each test field was measured to about 6x10 or perhaps 60 square meters. There were a total of 7x4 or perhaps 28 test fields.

Antud uurimustöö eesmärgiks oli uurida kuidas erinevad omavahel tava- ja maheviljeluse süsteemid. Vaadati nii taimede toitumist, tärklise- ja kuivaine sisaldust, kui ka haigustega nakatumist. Katse leidis aset Eesti Maaülikooli, Eerika põllul. Katses oli 4 tavasüsteemi ning 3 mahesüsteemi, neljas korduses. Kasvatatavaks kartulisordiks oli keskvarajane ’Maret’. Maheviljeluse süsteemid olid järgnevad: Mahe 0 – maheviljeluse kontrollsüsteem; Mahe VK – maheviljelusesüsteem, milles kasutati talviseid vahekultuure; Mahe VK+S – maheviljelusesüsteem, milles kasutati talviseid vahekultuure ning lisaks anti veisesõnnikut. Tavaviljeluse süsteemid erinesid üksteisest lämmastiku manustamise poolest: N0P0K0; N50P25K95; N100P25K95; N150P25K95. Kokkuvõtteks võib öelda, et nii maheviljeluses kui ka tavaviljeluses on omad head ja vead. Maheviljeluse plussiks on see, et mugulad ei sisalda taimekaitsevahendite jääke ning nitraate, samas on saagikus oluliselt väiksem võrrelduna tavaviljelusega. Maheviljeluses antakse orgaanilist väetist, mis ei pruugi laguneda piisavalt kiiresti ning taimed ei saa vajalikke toitaineid kätte. Tavaviljeluse eeliseks on suurem saak ning mineraalse väetise manustamine, mis on taimedele kohe kättesaadavas vormis. Õige viljavaheldus on eriti vajalik maheviljeluses, kui ka tavaviljeluses, tõstes mulla viljakust ja suurendades saaki. Kvaliteedinäitajatest oli selgelt näha, et suurem tärklise ja kuivaine sisaldus oli mahesüsteemides. Mugulate keemilise koostise vahel toimus antagonism ehk ühe elemendi liig pärssis teise elemendi omastamist. Antud töös pärssis magneesiumi liig kaaliumi ja kaltsiumi omastamist mugulates. Haigustest esines harilikku kärna, mida viljelusviis ei mõjuta, hõbekärna, mida oli rohkem tavasüsteemis ning kuivmädanikku, mida leidus väetamata süsteemides. Märgmädanikku antud aastal ei esinenud. The goal of this research was to investigate organic and conventional farming systems. Research examined plant nutrition, starch and dry matter content, as well as tuber diseases. Research took place in Estonian University of Life Science, Eerika field. The experiment was performed with three organic and four conventional farming systems. Potato variety was ’Maret’. Three organic farming systems were as follows: Organic 0 – Organic control system; Organic CC – were used winter catch crops; Organic CC+M – were used catch crops and also cattle manure was added as a fertilizer. Four conventional farming systems were differed from each other in the amounts of fertilizers which used as follows: N0P0K0; N50P25K95; N100P25K95; N150P25K95. In conclusion, we can say that both organic and conventional farming systems has its pros and cons. Organic farming advantage is that the tubers do not contain residues of crop protection products and nitrates, while the yield is significantly lower as compared to conventional farming. In organic farming is given organic fertilizer which does not mineralize fast enough, and the plants do not get necessary nutrients which they need. Conventional farming has the advantage of higher yield and plants get mineral fertilizer which has already in the right form to plants. Crop rotation is very important for increasing crop yields and maintaining soil fertility for both organic and conventional farming. Quality indicators showed bigger starch and dry matter contents in organic farming systems. There was antagonism between tuber chemical compositions. In this study excessive magnesium inhibited potassium and calcium absorption in the tubers. There were three tuber diseases: common scab, which were not affected by farming system; silver scurf, which were more in the conventional farming system and dry rot, which were found in unfertilized systems. There was no soft rot in this year.

Antud uurimustöö eesmärgiks oli uurida kartuli saagikusi mahe- ja tavaviljelussüsteemides ning selgitada, milline on mõju väetamisviisidel ja agrotehnilistel töödel kartulisordi 'Maret' saagikusele ning kumb viljelusviisidest on tootjale majanduslikult kõige tasuvam. Katse korraldati Eesti Maaülikooli põllumajandus- ja keskkonnainstituudi katsepõllul Eerikal 2014. aastal, et uurida kuidas külvikord mõjutab erinevaid põllukultuure. Kartul oli üks külvikorra kultuuridest, kus punane ristik (Trifolium pratense L.), talinisu (Triticum aestivum L.), hernes (Pisum sativum L.), kartul ja oder (Hordeum vulgare L.) punase ristiku allakülviga olid kasvatatud üksteise järel. Katses kasutatud kartulisordiks oli 'Maret'. Maheviljeluses kasutati kolme erinevat viljelussüsteemi: 1) Mahe 0- kontrollsüsteem ilma vahekultuurita ja sõnnikuta, 2) Mahe VK- kasvatati talviseid vahekultuure 3) Mahe VK+Skasvatati talviseid vahekultuure ja kevadel lisati veisesõnnikut 20 t/ha. Tavaviljelussüsteemis oli neli erinevat süsteemi olenevalt lämmastiku kogustest: 1)N0P0K0(N0), 2) N50P25K95(N50), 3) N100P25K95(N100) ja 4) N150P25K95(N150). Kartuli kasvumääramised tehti 55, 69, 83 ja 96 kasvupäeval. Uurimustöö käigus selgus, et suurima kogusaagi andis tavaviljelussüsteemi variant N150, kus kasutati kõige suuremaid väetise koguseid. Antud süsteemi kogusaak 96. kasvupäeval oli 38,7 t/ha. Kõige tasuvamaks süsteemiks osutus tavaviljeluse süsteem N100, kus saadi kõige suuremat kasumit. Antud süsteemi kasum oli suurim 83. kasvupäeval kui koos toetustega saadi 5496,4 €/ha. Uurimustöö tulemustest selgub, et suurimad saagikused saavutati viljelussüsteemides kus kasutati mineraalseid väetisi ning taimekaitsevahendeid. Majandulikult kõige efektiivsemaks osutus tavaviljelussüsteem N100, kus teeniti kõige suuremat kasumit 83. kasvupäeval, mis näitab omakorda, et maksimaalse tulu sõltub mitte ainult saagikusest kuid ka antud kasvupäeval sõltuvast müügihinnast. The aim of this Bachelor's thesis was to study potato yields in organic and conventional farming systems and find out how fertilizers and agrotechnical works affect yields of the potato variety 'Maret' and which of the following farming systems is economically most profitable. The study was held in 2014 on the experimental field of the Institute of Agricultural and Environmental Sciences of the Estonian University of Life Sciences to find out how crop rotation affects different crops. Potato was one of the crops grown in the experiment in which red clover, winter wheat, pea, potato and barley undersown with red clover were grown after each other. The study involved three organic- and four conventional farming systems each in four duplication. Three different systems were used in the organic farming: 1) Mahe 0- without winter catch crop and manure, 2) Mahe VK- with winter catch crop and without manure and 3) Mahe VK+S- with winter catch crop and manure 20 t/ha added in spring. Conventional farming had four different systems depending on the nitrogen content: 1)N0P0K0(N0), 2) N50P25K95(N50), 3) N100P25K95(N100) and 4) N150P25K95(N150). The growth of potato was examined during four growing days 55, 69, 83 and 96. The research revealed that the biggest total yield was in conventional farming system N150, where biggest amounts of nitrate were used. Total yield of this system was 38,7 t/ha on 96th. N100 was discovered to be the most profitable system. It had the biggest profit of 5496,4 €/ha, including subsidies on the 83th growing day. The research results demonstrated that the biggest yields were achieved in the systems, where fertilizers and pesticides were used. Also results show that highest profit depends not only on the yield but also on the potato sale price on the given growing day.

Käesoleva magistritöö eesmärgiks oli uurida, kuidas erinevad viljelusviisid mõjutavad kartulisordi ’Reet’ saaki ja kvaliteeti, mugulate nitraadi- ja tärklisesisaldust, põrutustele vastupanuvõimet, kartulimugulate tumenemist ning kartulikasvatuse majanduslikke näitajaid. Katses võrreldi neljas korduses olevat 6 erinevat kartulitootmise katsevarianti: 1. üleminek mahedale 2. üleminek mahedale + sõnnik 3. N0P0K0, 4. N50P25K95 5. N100P25K95 6. N150P25K95 Magistritöö on koostatud võrdluskatse ning kirjanduse allikate baasil. Katse korraldati Eesti Maaülikooli taimekasvatuse ja rohumaaviljeluse osakonna katsepõldudel Eerikal 2009 ja 2010 aastal. Uurimustöö tulemusena leiti, et erinevate väetisnormide mõju mugulasaagile oli märgatav. Samas mõjus lämmastikukoguse järjest suurenev suurus negatiivselt kartulimugulate kulinaarsetele omadustele. Näiteks tärklisesisaldus oli tavatootmise variantide mugulatel väiksem kui ülemineku järgus olevatel mahevariantidel. Nitraatide sisaldus oli tavavariantide puhul kõrgem kui üleminek mahevariantidel. Mugulate tumenemiskatsetest selgus, et väetamine võib suurel määral muuta mugulate kvaliteeti ning väljanägemist. Taimekaitsevahendite ja väetiste kasutamine taimekasvatuses aitavad kaasa suurema kaubandusliku saagi saamiseks. Majanduslikust tasuvusuuringust selgus, et tavavariantide puhul tõstab tulukust järjest kasvav saagikus ja üleminek mahevariantidel kõrgem toodangu realiseerimise hind. Põhjalikumate tulemuste saamiseks on vajalikud edasised uuringud. The main objective of this Master’s thesis was to evaluate the impact of conventional and organic production on the yield and quality of the potato variety ’Reet’ and to determine the nutrient concentrations of potato as well as the content of starch and nitrates (NO3 - ). The potato tuber darkening and resistance to damages were also examined. Another objective of the thesis was to assess the expenditure and revenue, and profitability with and without financial support. In the field experiment six different farming systems in four replications were studied. The used variety was ‘Reet’. The six farming systems were conversion to organic, conversion to organic + manure fertilizer, N0P0K0, N50P25K95, N100P25K95 and N150P25K95. Master thesis is based on the experiment and literarture. The field experiment was carried out in 2009 and 2010 at Eerika fields belonging to the Institute of Agricultural and Environmental Sciences of the Estonian University of Life Sciences. As a result, it was found that diferent rates of fertilizers increased noticeably tuber yields. On the other hand, increasing nitrogen content in tubers influenced negatively the culinary characteristics. Tuber nitrate contents (NO3 - ) were higher under conventional production in which mineral fertilizers were used compared to conversion to organic systems. The tuber darkening results shows that fertilization can greatly change the appearance and quality of the tubers. The use of pesticides during plant growth helps to increase marketable yield. On the one hand, high selling price increases the profitability of organic production. On the other hand, continuously increasing yield (t/ha) raises profitability in conventional production. Future investigations are necessary to give more precise results.