New Researches in Biotechnology - Facultatea de Biotehnologii ...

Proceeding of the 4 rd International Symposium“NEW RESEARCH IN BIOTECHNOLOGY” USAMV Bucharest, Romania, 2011The implementation of the adopted soil tillage system met serious difficulties fromthe very beginning. During the autumn of 2002 because of poor content of moisture in thesoil and the big compacting of area / 1.75 – 1.90 g/сm 3 / as a result of meliorative worksand embankment of substrates, the necessary depth of tillage could not be reached andtherefore, neither could the homogeneous mixing of the components. With its meliorativerole, the winter forage pea showed extremely high technological qualities and adaptabaility,given the relative unfavorable soil conditions. Other than the not-so-good pre-sowingpreparation of the soil and the low content of organic matter, another limitary factor was thehigh density of the sowing layer, because of which the roots of the pea were placed mainlyin the 0-20 сm layer, and under that depth only separate roots. The total quantity of thereceived by the soil absolutely dry biomass /Table 2/ is significant, especially in option 3,where it reaches 5650 kg/ha. The bio productivity of peas, grown as a separate culture isbest expressed in option 3 with component humus soil material and ash. Its analog, option2, in which there is no ash, has 16% less bio mass. Despite of the found lodging of the crop,the plant debris were very well minced and distributed across the test area, using the rotorsilage harvester – KIR – 1.5.Table 2. BIOMAS CONTRIBUTION TO THE SOILS(aboveground residues + root residues abs. dray mass kg/ha)TreatmentsYears Crops 1 2 3 42003 Peas 3190 4770 5650 3310Sudan grass 15400 10740 10910 83102004 Peas barley mix 2790 5510 7670 4540Sudan grass 6930 8030 7070 4070Total 28310 29050 31300 20230Peas F=14.34 F crit=4.06 Sudan grass F=44.94 Fcrit=4.06p=0.001p=0.00002For the growing of the winter peas + barley mix, a quality pre-sowing preparationof the soil and even sowing were carried out. The climate conditions were very suitable andan optimum density and height of 80cm were reached in the options with addition of humussoil to the substrates. The received quantity of biomass is highly dependable on the type ofsoil substrate. It is almost three times lower in option 1 compared to option 3. Theimproved soil conditions – drainage and aeration in option 3 have given the winter peas andbarley the opportunity to show their full productive potential.The results from two years of growing Sudan grass show that it is a veryappropriate crop as a source of humus formation, given the xerophytic properties of thearea. During the first year the main limiting factor for productivity was the prolongeddrought period. As a result the crop was under-trimmed, the yield being a function only ofthe number of plants - R 2 =+0.86. This shows that wherever the crop was trimmed enough,the reserve of spring moisture in the soil was used and therefore the yield is highest Option1(Table 2). During the second year of growing Sudan grass, a significantly lower yield ofbiomass was received, because of poor soil preparation due to worsened weatherconditions. Unlike the peas, the Sudan grass adapts better to substrates not containing ash,which could be explained by the clay soils’ ability to hold the scarce soil moisture during35