The effect of conservation primary and zero tillage on soil bulk density, water content, sugar beet growth and weed infestation
¹Lithuanian University of Agriculture, Dept. of Soil Management, Studentu 11, LT-53067
Akademija, Kaunas r., Lithuania; e-mail:
email@example.com, firstname.lastname@example.org, email@example.com
²Lithuanian University of Agriculture, Dept. of Agricultural Machinery, Studentu 11, LT-53067
Akademija, Kaunas r., Lithuania; e-mail: firstname.lastname@example.org
The effect of different conservation primary soil tillage on sugar beet was investigated at the Experimental Station of the Lithuanian University of Agriculture in a silty loam Luvisol during the period of 2001 – 2006. The aim of the trial was to establish the influence of reduced soil tillage intensity on some soil physical properties, sugar beet yield and quality, and weed infestation. Treatments of the trial: 1. conventional (22–25 cm) ploughing with a mouldboard plough (CP); 2. shallow (12–15 cm) ploughing with a mouldboard plough (SP); 3.deep (25–30 cm) cultivation with a chisel cultivator (DC); 4. shallow (10–12 cm) loosening with a disc harrow (SL); 5. zero tillage (ZT). Reduction of primary soil tillage intensity increased the amount of moisture and level of soil bulk density in the soil upper layer (0-10 cm). According to the average data of 2001-2006, the highest amounts of moisture and soil bulk density were observed in no tilled soil (ZT) before pre-sowing soil tillage (25.8% and 1.40 Mg m-3) and after sowing until sugar beet germination (23.6% and 1.40 Mg m-3). Soil tillage intensity had no significant influence on soil moisture content and bulk density in a deeper (10-20 cm) layer. Sugar beet seed germination in shallow loosened soil (SL) was higher in comparison with control treatment (CP) fourfold per 6 years; this influence was significant in two experimental years. Average data showed that germination of directly sowed seeds was less by 37% in comparison with conventional ploughing (CP). Reducing of soil tillage intensity to zero tillage had no significant influence on sugar beet yield, ramification and sucrose content of root-crop. The reduction of soil tillage intensity and refusal to use full-scale herbicides had negative, but not significant influence on weed infestation in the sugar beet crop, except in the no-tillage pattern. The data of the beginning of the second rotation showed a significantly higher number of annual (32%) and all (29%) weeds in no-tilled (ZT) soil in comparison with conventional ploughing (CP). Generally, the number of weed species increased from 22 to 26. The number of Chenopodium album increased from 11.3 to 22.1, Poa annua – from 5.6 to 14.2, Taraxacum officinalis – from 0.66 to 6.1 plants per m2 . Elytrigia repens became a widespread weed.