NITROGEN CHANGES IN DRY MASS YIELD OF LUCERNE RELATED TO MINERAL AND ORGANIC FERTILIZATION UNDER WATER DEFICIENCY STRESS

摘要

A study of nitrogen changes in yield in total plant biomass of lucerne related to mineral and manure fertilization under water deficit conditions was carried out at the Institute of Forage Crops, Pleven, Bulgaria (1999-2000). The following design wasused: 1. Soil (Control 1) + N_0PK+ 75-80% FC; 2. Soil + mineral N_(70) + PK (MN_(70)PK) + 75-80% Field Capacity (FC); 3. Soil + organic N_(70) + PK (ON_(70)PK) + 75-80% FC; 4. Soil + mineral N_(210) + PK (MN_(210) PK) + 75-80% FC; 5. Soil + organic N_(210) + PK (ON_(210) PK) + 75-80% FC; 6. Soil (Control 2) + N_0PK + 37-40% FC; 7. Soil +mineral N_(70) + PK (MN_(70) PK) + 37-40% FC; 8. Soil + organic N_(70) + PK (ON_(70) PK) + 37-40% FC; 9. Soil + mineral N_(210) + PK (MN_(210) PK) + 37-40% FC; 10. Soil+ organic N_(210) + PK (ON_(210) PK) + 37-40% FC. Ammonium nitrate and well matured cattle manure as a source of mineral and organic nitrogen were usee The plants were grown for seeds production under optimum moistening (75-80% of the field capacity), and water deficiency (37-40% of the field capacity; It was found that nitrogen in the yield of dry aboveground mass under optimum water supply increased by 44 and 53% for mineral and manure fertilization, applied at the dose of 70 mg N/kg soil. Under waterdeficit conditions, manure fertilization at the dose of 70 and 210 mg N/kg soil increased nitrogen in the yield by 33 and 38%, respectively. The plants treated with manure made them less susceptible to the stress conditions of water deficiency. Other compounds then N in the manure supported plants to be more resistible to drought stress.