Effects of the second crop on maize yield and yield components in organic agriculture

The second crop use in organic agriculture is a known method of maintaining the soil tilth, soil protection against environmental deterioration, soil nutrients conservation and even the weed control. The nitrogen conservation from previous leguminose crop is even more important, especially in the organic agriculture where use of N-fertilizers is the strictly forbiden, and second crops can be used as a catch crops for nutrients in rotation prior to the crops with the high N requirement. The choice of the proper second crop has, however, been insufficiently investigated, especially for agri-environmental conditions of the Panonian agricultural area in Croatia. The second crop experiment was established in Valpovo, Croatia, in the eutric brown soil type, during the years 2005 and 2006. The aim of the experiment was to investigate the effects of different second crops and their combinations on maize (Zea mais L.) yield and yield components in organic agriculture after soybean (Glycine max L.) in crop rotation. The experimental design was set up as a CRBD in four repetitions, with soybean as a previous crop in crop rotation. The six second crop treatments were: O – Control, without second crop; WW – winter wheat (Triticum aestivum L.) second crop; RY – rye (Secale cereale L.) second crop; FP – fodder pea (Pisum arvense L.) second crop; WP – mixture of the WW and FP; and RP – mixture of RY and FP. The WW treatment had the highest second crop dry mass, whereas FP had the lowest dry mass. The highest plant density was recorded for FP, and it was higher than the RP plant density, which also had the lowest plant height. The achieved maize yields were the highest for RY, but they were not significanlty different from the O, RP, and WW treatments. However, the yield achieved by RY treatment was significantly higher than the yields recorded for WP and FP treatments. The absolute mass and hectolitre mass did not show any statistical differences among treatments

The economic sustainability of second crops implementation in organic maize production

Although organic crop production has numerous advantages, concerns about economic sustainability, both environmental and financial, make farmers reluctant to convert their conventional production into the organic production. Certain agricultural methods, such as second crop use, can alleviate some problems regarding soil tilth, erosion prevention, nutrients availability and weed control, thus contributing toward more sustainable crop production. Also, the added value crop growth, such as maize (Zea mais L.) hybrid's parental line production, with lower yields but higher prices, can contribute to sustainability of organic production. In order to test the hypothesis that the use of second crops can contribute toward the sustainability of organically grown maize after soybean (Glycine max L.) as a previous crop in the crop rotation, the experimental site was established in Valpovo, Croatia, in the eutric brown soil type, during the years 2005 and 2006. The experimental design was set up as a CRBD in four repetitions, with six second crop treatments: CT – Control, without second crop; WW – winter wheat (Triticum aestivum L.) second crop; RY – rye (Secale cereale L.) second crop; FP – fodder pea (Pisum arvense L.) second crop; WP – mixture of WW and FP; and RP – mixture of RY and FP. In order to assess the soil surface protection and evaluate the weed suppression, the second crop coverage had been recorded. Regarding the economic sustainability, the second crop use depending costs were analysed in relation to the extra produced maize yield. The RY treatment had the highest profitability, followed by WW, RP and O. The WP and FP revealed lower relative profitability than O, thus presenting the evidence of sustainability risk of these treatments

Comparison of two soil tillage treatments for winter barley-soybean growing based only on residual nitrogen after soybean

The winter barley crop growing has not been adequately researched regarding soil tillage systems, especially in crop rotation with the soybean, both crops gaining importance as food or fodder. Also, productivity of such crop rotation in low nitrogen environment is especially interesting for organic crop growing, where mineral nitrogen fertilization is not allowed. The research on two soil tillage systems, the conventional one, based on mouldboard ploughing (PLOW) and reduced soil tillage, based on discharrowing (DISC), with no other nitrogen source except symbiotic soybean bacterial fixation, was conducted at the experimental site Bokšić (Croatia), during the seasons 2004/05 and 2005/06. Results showed low but stable yields of winter barley, between 2.1 and 2.6 t ha-1, where PLOW treatment recorded lower yield than DISC in 2005, and usual soybean yields (between 2.8 and 3.4 t ha-1), with higher soybean grain yields for PLOW only in 2006. The absolute mass and hectolitre mass did not show any statistical differences among treatments either

Evaluation of genetic diversity: Which o f the v arieties can be named 'Rebula' (Vitis vinifera L.)?

The variety 'Rebula' is an indigenous but also ancient variety in the Slovenian and Italian world-renowned winegrowing district Collio dating back to the ages of the Roman Empire. The DNA analyses of the variety ‘Rebula’ and its potential related varieties were conducted to evaluate its biodiversity. The variety 'Rebula' showed a very low similarity (16 %) with other analysed varieties, also with 'Rebula briška' and 'Rebula-old'. The varieties called 'Prosecco', 'Števerjana', 'Beli teran' and 'Briška Glera' revealed identical genotypes in all 11 SSR microsatellites analysed, therefore are regarded as synonyms. The varieties 'Rebula' and 'Ribolla gialla' revealed the identical SSR profile at 8 out of 9 SSR loci. 'Vitovska Grganja' share with 'Vitouska' only 55 % of analysed alleles but show their first degree relationship. The DNA analysis still showed existing deviations in synonyms and homonyms linked to the variety 'Rebula' what impedes its standardisation and revitalization.

Corrigendum

Evaluation of genetic diversity: Which of the varieties can be named ,Rebula' (Vitis vinifera L.)?Vitis 49 (4), 129-136 (2010

Soil compaction alleviation as a solution in the climate stress mitigation

Tillage-induced soil compaction has often occurred in the Pannonian region. This form of compaction occurs on arable lands both in Hungary (1.82 million ha) and in Croatia (0.97 million ha) having negative impacts on crop production. In this study the tillage-induced compaction is discussed as an indicator of climate stress on arable fields. The research is based on soil condition monitoring and measuring that was started 32 years ago and on short and long-term experiments assessing the compaction impacts on the crops. The survey comprised 1870 monitoring places and 38 experimental plots. The following points were chosen for monitoring: 1. Root zone state (to a depth of 0-50 cm). 2. Occurrence of compacted layer (indicating the risk). 3. Extension of the compacted layer (indicating the degree of damage). 4. Long term effects of tillage (deterioration or improvement). 5. Tillage-induced drought and water-logging damage impacts on yield loss. The formation and location of compaction provided information concerning the depth, the method and the type of tillage applied, along with the expected risk for crop production under extreme climate conditions. The main objectives of the study are: 1. Occurrence and the extent of tillage-pan compaction in soils. 2. Consequences on water management in each of the years covered by the experiments. 3. Soil quality consequences. 4. Alleviation of pan-compaction by mechanical and biological methods. Long-term assessing has convincingly proven a correlation between tillage-pan compaction and the degree of climate stress. In view of the findings trends in soil tillage can be grouped into the following categories: climate damage mitigating and climate-stress increasing ones

EFFECTS OF DIFFERENT SOIL TILLAGE SYSTEMS ON NODULATION AND YIELD OF SOYBEAN

U našoj zemlji obrada tla za ratarske kulture temelji se uglavnom na konvencionalnoj tehnologiji koja predstavlja najskuplju stavku u proizvodnji tih kultura. Negativne posljedice koje se javljaju zbog velikog broja prohoda oruđima i strojevima (kvarenje strukture tla, zbijanje tla, smanjena biogenost i plodnost tla), kao i ekonomski i energetski troškovi, mogli bi se smanjiti i izbjeći uvođenjem reducirane obrade tla ili izravnom sjetvom bez obrade tla (no-tillage). Stoga je cilj ovih istraživanja bila procjena utjecaja konvencionalne i reducirane obrade tla na komponente prinosa i nodulacijsku sposobnost fiksatora dušika u usjevu soje. Istraživanja su provedena na pedosistematskoj jedinici černozem sjeverne Baranje, u vidu monofaktorijalnog pokusa u četiri repeticije po shemi slučajnog bloknog rasporeda. Varijante obrade tla bile su sljedeće: CT – standardna obrada (osnovna obrada oranje na 25-30 cm), DH – tanjuranje na 10-15 cm, kao osnovna obrada, te NT – izostavljena obrada. Rezultati istraživanja pokazali su značajno niže vrijednosti sklopa, mase 1000 zrna i prinosa zrna na varijantama s reduciranom obradom tla u obje ispitivane godine. Međutim, reducirana obrada pokazala je pozitivan trend na nodulacijsku sposobnost fiksatora dušika, jer su na tim varijantama dobivene najviše vrijednosti broja i mase kvržica po biljci, iako razlike nisu statistički značajne. Navedena istraživanja provedena su 2002. i 2003. godine, od kojih je druga godina bila ekstremno sušna, stoga bi se ta istraživanja trebala nastaviti.The primary soil tillage for different crops in Croatia is generally based on mouldboard ploughing which is the most expensive for crops production. Negative effects due to frequent passes by equipment and machines (deterioration of soil structure, soil compaction, lower biogenity and soil tilth), together with negative economical and energetical costs, can be lowered and avoided by introduction of reduced soil tillage or direct drilling (No-tillage). Accordingly, the main goal of this research was to determine effects of conventional and reduced soil tillage systems on yield components and nodulation ability of nitrogen fixing bacteria in soybean crop. The research was established at chernozem soil type of northern Baranja as monofactorial completely randomized block design in four repetitions. The soil tillage variants were as follows: CT) Conventional Tillage (primary soil tillage by moldboard ploughing at 25-30 cm depth), DH) Multiple Diskharrowing at 10-15 cm as primary tillage, and NT) No-tillage system. Results show significantly lower plant density, mass of 1000 grains and grain yield at variants with reduced soil tillage in both investigation years. However, reduced tillage systems had positive trend on nitrogen-fixing bacteria nodulation, since the highest values of number and mass of nodules per plant were recorded. This research was run during the years 2002 and 2003, the last one extremely droughty, thus it requires continuation