Haljasväetiste mõju ulatusest teise järelmõju aastasse ning kultuuride valikuvõimalused vastavalt agronoomilistele ja majanduslikele eesmärkidele

A field experiment was conducted on organic land at the Centre of Estonian Rural Knowledge in Jõgeva to evaluate the after-effects of five leguminous species used as green manure during two years following incorporation of the green biomass. In the first follow-up year, winter rye, winter and spring wheat, barley and oats (two varieties of each) were grown; in the second follow-up year, barley and oats plots were grown after these crops. The fertilizing value of green manure species was assessed by comparing changes in grain yield and quality of the follow-up crop with the control treatment. The results showed that the yield-increasing effects of all green manure species extended into the second follow-up year. For biennial and perennial species, yield increase of approximately 20% were statistically plausible, whereas yield increases of 8-9% of annual species remained within the experimental error. The after-effect of green manure increased grain protein content in both barley and oat. Among the preceding crops, winter rye and winter wheat proved most suitable for both barley and oats. Economic calculations indicated that through appropriate crop and variety selection, the market value of grain yield per hectare over the two subsequent years can be increased by up to 1,000 euros under organic conditions when using green manure.