Preliminary results of nitrogen uptake with mown grass in an apple orchard under influence of mulch and irrigation
¹Latvia State Institute of Fruit–Growing, Graudu iela 1, Dobele, LV 3701; e–mail:Valentina.Surikova@lvai.lv
²Latvia University of Agriculture, Lielā iela 2, Jelgava, LV 3001; e–mail:Aldis.Karklins@llu.lv
Abstract:
Nitrogen leaching from intensive agriculture systems is one of the major contributors responsible for nitrate concentration increasing in groundwater. The aim of the study was to determine the content of total nitrogen in the orchard lawn and use this parameter as a correction factor for reduction of nitrogen fertilizers application and to include the nitrogen from mown grass into the N balance and turnover calculation. The investigation was conducted at the Latvia State Institute of Fruit–Growing, Dobele in 2009, on the basis of an existing field experiment planted in 1997 with cultivar `Melba` (rootstock B 9). The influence of soil moisture management treatments were compared near the alleyway: control, sawdust mulch and fertigation. The alleyway was covered by grass vegetation (Lolium perenne L. and Poa pratensis L,). Total nitrogen was determined using the Kjeldahl method. The preliminary results show that the mulch used in tree strips in an apple orchard had a significantly negative influence on the concentration of nitrogen in the dry matter of mown grass of the alleyway compared with control and fertigation. Near the mulching treatment the concentration of nitrogen in dry matter of mown grass in the alleyway was 2.23%, but near the control and fertigation treatments it was 8% higher. Nitrogen concentration in the grass of the alleyway was significantly influenced by the time of grass mowing. Nitrogen uptake with mown grass biomass in the alleyway near the control in tree strips was 33.36 kg ha-1, near the mulch treatment it was higher by 6%, but in fertigation treatment – by 20%.
Key words:
Malus domestica Mill., mineral nutrition, nutrient uptake