Organic Cropping Systems do not Increase Weed Seed Numbers but do Increase Weed Diversity

The influence of different cropping systems on the soil weed seed bank after the first crop rotation within a five-field crop rotation (barley undersown with red clover, red clover, winter wheat, pea, potato) in three organic (Org) and in two conventional (Conv) cropping systems was investigated. In organic systems Org I and Org II cover crops were incorporated as a source of nutrient inputs to the soil and in Org II composted cattle manure was also applied. The Org 0 acted as the organic control system without cover crops and manure. The two conventional cropping systems were treated with herbicides and fungicides and differed in fertilizer application (i.e. Conv I no fertilizer use (as control) and Conv II mineral fertilizer use). In general, the lowest number of annual weed seeds was found in system Conv I, the highest in Conv II. In organic systems with cover crops (Org I, II) there was a strong tendency for decreased weed seed numbers and increased biodiversity. The highest values of the Shannon-Wiener diversity index and Margalef richness index were in Org II system. In all systems the most abundant species in weed seed banks were Chenopodium album L. and Viola arvensis Murr

Pestitsiidid suruvad alla mulla mikroobide hüdrolüütilist aktiivsust

Mulla kvaliteet on mulla võime toetada bioloogilist aktiivsust, säilitada keskkonna kvaliteeti ning soodustada mullaelustikku

Winter cover crops impact on plant nutrients in an organic crop rotation

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

THE EFFECT OF FARMING SYSTEM ON SOIL MICROBIAL HYDROLYTICAL ACTIVITY

The aim of this study was to investigate the influence of conventional and organic farming on soil hydrolytic activity (FDA). The experiment consisted of five-field crop rotation with three organic systems: Org 0 without winter cover crops (as control), Org I with winter cover crops and Org II with winter cover crops plus composted manure; and two conventional farming systems: Conv I as control (no fertiliser use) and Conv II (with mineral N). The results show increase of FDA in all systems in 2013. Within the average of 2012-2014 the FDA is the lowest in Conv. I and the highest in Org II system

Impact of winter cover crops on soil quality and weeds in organic cropping systems

Winter cover crops and their combination with composted cattle manure have shown significant influence on soil quality and weeds in five-field crop rotation (barley undersown with red clover – red clover – winter wheat – pea – potato) of three organic cropping systems

Soil weed seed bank and factors influencing the number of weeds at the end of conversion period to organic production

In 2008 an experiment was set up on the field in Eerika experimental station (Estonian University of Life Sciences) as a 5-field crop rotation: red clover, winter wheat, pea, potato and barley undersown with red clover. The objective of the study was to measure the content of weed seeds in the soil and to evaluate the diversity of the species at the end of the period of converting to organic production. In conventional farming systems without fertilizer (Conv I) and conventional farming with mineral fertilizer (Conv II) herbicides were used for weed control. All the crops in Conv II system received P 25 kg ha-1 and K 95 kg ha-1, but the application rates of mineral nitrogen fertilizer differed. In organic systems (Org I – organic farming based on winter cover crop and Org II - organic farming based on winter cover crop and manure), the winter cover crops (ryegrass after winter wheat, winter oilseed rape after pea, winter rye after potato) were sown after the harvest and were ploughed into the soil as green manure in spring. The content of annual weed seeds was the lowest in red clover that had 17.7% less weed seeds in the soil of Org II system compared to control (Conv I). In winter wheat the content of winter annual weed seeds was 50–76% higher compared to other crops. By the end of 2009 the content of organic carbon (Corg %) in the soil had increased significantly in both organic systems which results in higher activity of organisms that decrease the viability of weed seeds

Winter cover crops improve soil properties in organic cropping systems.

An introduction of winter cover crops (wcc) into the crop rotation had a positive impact on soil quality in organic cropping systems. Wcc alone and in combination with composted manure enriched soil with organic matter, activated soil life (increased number of earthworms and higher soil microbial activity - FDA), increased soil pH value, and supported nutrient cycling and soil formation