Effect of crop rotation on soil nutrient balance and weediness in soddy podzolic organic farming fields

The nutrient balance in different crop rotations under organic cropping system has been investigated in Latvia at the Institute of Agricultural Resources and Economics since 2006. Latvia is located in a humid and moderate climatic region where the rainfall exceeds evaporation (soil moisture coefficient > 1) and the soil moisture regime is characteristic with percolation. The average annual precipitation is 670-850 mm. The average temperature varies from -6.7 ◦ C in January to 16.5 ◦ C in July. The growing season is 175 - 185 days. The most widespread are podzolic soils and mainly they are present in agricultural fields in all regions of Latvia. In a wider sense the goal of the soil management in organic farming is a creation of the biologically active flora and fauna in the soil by maintaining a high level of soil organic matter which is good for crops nutrient balance. Crop rotation is a central component of organic farming systems and has many benefits, including growth of soil microbial activity, which may increase nutrient availability. The aim of the present study was to calculate nutrient balance for each crop in the rotations and average in each rotation. Taking into account that crop rotations can limit build-up of weeds, additionally within the ERA-net CORE Organic Plus transnational programs supported project PRODIVA the information required for a better utilization of crop diversification for weed management in North European organic arable cropping systems was summarized. It was found that the nutrient balance was influenced by nutrients uptake by biomass of growing crops in crop rotation. The number of weeds in the organic farming fields with crop rotation is dependent on the cultivated crops and the succession of crops in the crop rotation

The most success action to manage weeds – proper crop sequence plus harrowing in the right time.

The best practices for weed control on the farm KELMENI (lATVIA) are summarized

Efektīvākās nezāļu ierobežošanas metodes – gudri plānota augu maiņa plus ecēšana pareizajā laikā

Since Kelmeni farm is a good example in field crop management for other organic farms, it was invited to participate in the Core Organic Plus project, named PRODIVA, in which weeds were surveyed in more than 200 fields across regions in Finland, Sweden, Germany, Denmark, Poland and Latvia; all bordering the Baltic Sea (http://projects.au.dk/coreorganicplus/research-projects/prodiva/). In context of weed control farmer using all possible crop diversity experiences– undersowing, crop mixtures, diverse rotation, winter cover

VIRSAUGĀ SĒTU VASARĀJU LABĪBU EFEKTS NEZĀĻU IEROBEŽOŠANĀ: PROJEKTA PRODIVA MONITORINGA REZULTĀTI BIOLOĢISKAJĀS SAIMNIECĪBĀS

Viens no projektā PRODIVA (Augu daudzveidība un nezāles) plānotajiem uzdevumiem ir, bāzējoties uz monitoringos iegūtiem, rezultātiem apkopot informāciju par virsaugā sētu vasarāju labību efektu nezāļu ierobežošanā (http://coreorganicplus.org/research-projects/prodiva/). Izvirzītā hipotēze- vasarāju labību lauku ar pasēju nezāļainības līmeni un nezāļu sugu sastāvu ietekmē virsauga suga

UNDER-SOWING EFFICIENCY FOR WEED MANAGEMENT IN SPRING CEREALS

The data on weediness from the ongoing crop rotation experiment at the State Priekuli Plant Breeding institute were analysed on the basis of hypothesis that under-sowing in spring cereals can improve weed management. Grass/clover mixture (Trifolium pratense L. and Phleum pratense L.) as under- sowing in spring barley (Hordeum vulgare L.) was grown for one and two seasons in six field crop rotation. Numbers of weed plants in spring (BBCH 20 – 29) were recorded using 0.1 m2 big frame in 10 places; plant biomass of under-sown crops and weeds were sampled within 1.0 x 1.0 m squares after the first cut in the following year after harvesting of main crop (barley). The total of 28 weed species were registered. The most common species were Chenopodium album L.; Tripleurospermum inodorum L., Raphanus raphanistrum L., Centaurea cyanus L., and Spergula arvensis L. were also amongst the five common species. In addition, to examine the efficiency of under-sowing in weed management in the fields, the data obtained from the monitoring under the project PRODIVA were used. Weediness data from twenty fields in Vidzeme and Latgale regions were summarized and compared with the results from the long term experimental field. The aim of this study was to investigate the effect of under-sowing spring cereal fields with grass/clover mixture on weediness

Spring cereal variety mixtures and their relevance for weed suppression in agroecological conditions of Latvia

The aim of the present study was to evaluate spring cereal(barley and oat)variety mixtures for their weed suppression ability in agroecological conditions of Latvia. It was concluded that in two-years tudy,investigated spring cereal variety mixtures did not show better ability to suppress weeds if compared to their pure components.Additional studies would be necessary to evaluate root development and allelopathic activity of crop and weed plants

Genotype and environment interaction on field pea cultivars in organic cropping system

Like other grain legumes, also field pea globally is important sources of plant protein and their growing have also positive effect on soil fertility. But, there are some constraints in their production, such pests and diseases and unstable yield. A high biodiversity and the selection of appropriate cultivars are important factors for the stability of agricultural systems especially in organic farming. Corresponding genotype choice for pea growing in mixtures with cereals can be one of the possibilities which enhances stable yield through field environment changes based on species diversity

Efficiency of different type of vermicompost in potato/DAŽĀDU VERMIKOMPOSTU VEIDU EFEKTIVITĀTE KARTUPEĻU STĀDĪJUMOS

There were two types of vermicompost (VK1-green manure sward, VK2- sheep manure)compared in Latvia at State Priekuli Plant Breeding Institute compared in potato starting 2013

CEREAL SPECIES EFFECT ON PROTEIN CONTENT IN PEA GRAINS IN LEGUME CEREAL MIXTURES DEPENDING CROPPING SYSTEM

Within the European Union’s Seventh Framework Programme project “Enhancing of legumes growing in Europe through sustainable cropping for protein supply for food and feed” (EUROLEGUME) producing of the knowledge required for the implementation of legume supported cropping system in sustainable agriculture was done. The main objective of this study was to investigate spring cereal species effect on protein content in pea grains depending cropping system (organic and conventional). The research involved two field pea (Pisum sativum var.arvense L.) cultivars – ‘Kirke’ and ‘Bruno’, and two spring cereal species: spring wheat (Triticum aestivum L.) and oat (Avena sativa L.) grown in mixtures. The results demonstrated that in pea-cereal mixtures cereal species can affect the protein content of grains of pea. Depending cultivar the effect was different. In grains of cv ‘Bruno’ crude protein content was highest; the higher the protein of grains fixed in yield from organic field

Crop diversity - a crucial remedy for weed management in organic cropping

A wide variety of crop species in crop rotations has turned out an essential means to obtain diversification in organic cropping systems. Moreover, the potential of cover crops to assist the main crop in weed suppression has been studied in Denmark, Finland and Latvia. Long-term field experiments in Denmark and Latvia demonstrated that crops with different life cycles and life spans in crop sequence resulted in a relatively low and manageable pressure of annual weeds. The study was part of the PRODIVA project (Core Organic Plus) in which crop diversification for better weed management has been studied and presented in the 18th EWRS Symposium