Interaction of maize and living mulch. Crop weediness and productivity.

Abstract

In 2009–2010, a field experiment was carried out at the Experimental Station of the Lithuanian University of Agriculture (LUA) (54o52′ N, 23o49′ E) on a silty loam, Calc(ar)i-Epihypogleyic Luvisol, LVg-p-w-cc(sc) in the conditions of transitional maritime-continental climate. The study was aimed to establish the interaction between maize and living mulch and its influence on maize crop weediness and productivity. Maize crop inter-rows were sown with spring oilseed rape (Brassica napus L.), white mustard (Sinapis alba L.), spring barley (Hordeum vulgare L.), Italian ryegrass (Lolium multiflorum Lamk.), black medic (Medicago lupulina L.), Persian clover (Trifolium resupinatum L.) and red clover (Trifolium pratense L.) plants as living mulch. Experimental data showed a strong negative linear relationship between living mulch (x, %) and weed coverage (Y, %) (r2009 = −0.90**, r2010 = −0.98**), coverage of living mulch (x, %) and irradiance (Y, %) (r2009 = −0.899**, r2010 = −0.860*), total air-dry mass of living mulch plants (x, g m 2) and air-dry mass of annual, perennial and total (Y, g m2) weeds: r2009 = −0.93** and r2010 = −0.615, r2009 = −0.639 and r2010 = −0.666, r(2009) = −0.93** and r2010 = −0.753). Living mulches competed with the maize crop and decreased its yield and other growth parameters. Living mulch exerted the highest negative significant influence on the height (r2009 = −0.795*, r2010 = −0.844*) and dry biomass of stems and leaves (r2009 = −0.74, r2010 = −0.689) of maize. Italian ryegrass mostly decreased maize shoot dry biomass due to rapid re-growth after each cutting. Because of their long vegetation and high biomass production rates, legumes (black medic, Persian and red clover) decreased maize productivity. Spring oilseed rape, white mustard and spring barley living mulches effectively suppressed weeds at first stages of development and had the least negative impact on maize productivity, therefore they might be suggested to be sown in maize crop inter-rows.