AGRONOMIJAS VĒSTIS - Latvijas Lauksaimniecības universitāte

AGRONOMIJAS VĒSTIS (Latvian Journal of Agronomy), No.10, LLU, 2008Key wordsGalega orientalis, seed yield, harvesting time, seed storageIntroductionIn Lithuania the total area with perennial grasses was 1.33 million hectares in 2006. Themost important legumes are white clover, red clover and lucerne, which are commonly grown withgrasses. Farmers are looking for new legumes, characterised by longevity and a high adaptability togrowing conditions. Fodder galega (Galega orientalis Lam.) is one of the longest – persisting plantsin swards, which is capable of fixing atmospheric nitrogen and notable for a high productivity(Virkajarvi and Varis, 1991; Raig, 1994; Adamovich 2000). Attempts have been made to growfodder galega on extensively used or conserved soils, used up quarries and dug off peatbogs.Fodder galega cultivation protects the soil from erosion and prevents the spread of weeds. (Vavilovand Kondratjev,1975). Galega can be grown on various soils if they are not acid and waterlogged.(Raig and Nommsalu,2001) According to soil requirements, fodder galega is similar to lucerne andsaifoin, but can produce very high yield. Experimental data show that this long – lived plantsurvives in pure stand for 15-19 years (Drikis, 1995; Adamovich, 2000). Fodder galega has somedisadvantages, such as very slow development in the sowing year and in the first year of use andsensitivity to frequent cutting or grazing (Raig, 1994; Lillak and Laidna, 1999; Moller et al.,1997).Compared with other legumes (clover, lucerne) little research has been done on its cultivation.Research evidence on fodder galega cultivation for seed is even scarcer. During the recent years thedemand for galega seed has been on a steady increased, however, the amounts produced still cannotmeet the demand. As a result, it is very important to increase galega seed yield. The experimentalobjectives were as follows: 1) to identify fodder galega optimal seed harvesting time and method;2) to study changes in seed germination during storage.Materials and MethodsExperiments were carried out during 1996-2006. Four field experiments were carried outon a sod gleyic loam soil (Epicalcari – Endohypogleic Cambisol in the central part of Lithuania(55023' N, 230 51' E). The soil contained on average 2.63% of humus, 0.17N, 104mg kg-1of P,125mg kg-1 of K and pH 7.0. Fodder galega (cv. ‘Gale') was sown at a seed rate of 10 kg ha-1 andat row spacing of 23 cm with a cover crop of spring barley. The experiment was designed as arandomized complete block with 4 replications and a plot size of 2.5m × 14.0m. Seed harvestingwas investigated for four years in a fodder galega seed production crop of the first – fourth year ofuse. Fodder galega seed was harvested using swath and direct combine harvesting after 60±5%,80±5% and 90±5% of pods had matured and 14 days after the last term. The analysis of galegapods maturity was made twice a week starting with the fifth – sixth week from the beginning offlowering. For this purpose, 4-6 samples from each 0.25m2 plot were cut from representativeplaces of the stand. The pods picked from a stem were divided into 4 groups of maturity: green,yellowish – green, yellow – semibrown and dark brown. Seed harvesting time was determinedaccording to the number of brown and yellow – semibrown pods, expressed in per cent.Prior todirect harvesting fodder galega crops defoliated using 5 l ha-1 Reglon. The crop was thrashed by acombine Sampo 500 after 5-7 days. Fodder galega cut into thin swaths was dried on 20-30 cm highstubble for the same number of days. Then it was thrashed by a combine. The seed was dried,cleaned and seed quality was estimated. Seed yield data were corrected to 100% purity and 13%moisture content. In 1999 the seed was left for quality testing. The seed was stored for 5 years indifferent conditions in 1kg paper bags in two different places, in a winter-heated room andunheated wooden storage at a relative air humidity varying from 35% to 85%.Results and DiscussionFodder galega crop flowered for 24-48 days irrespective of the weather conditions. Due tothe lengthy flowering, seed ripening was uneven. Even when most of the pods had turned brown,part of pods were still green, underdeveloped, and part of the inflorescences were still flowering.Having marked individual inflorescences we determined seed quality in the groups of various171