一年生草木樨营养的积累与矿化的研究

于1979年和1982—1983年,对一年生草本樨进行了田间试验。在生殖生长期内,分四期测定肥田养分及饲料营养等共7个项目。结果表明,养分积累速度最快的为盛花期。但进入结荚期养分仍在持续增长,故肥田改土或饲喂均以结荚期为宜。而盛花期繁茂、柔嫩多汁是可溶性糖积累高峰期,因此饲喂泌乳期家畜,以盛花期为佳。草木樨埋入土壤一年内,分7次取样测定有机质及氮的转化,结果说明,我省翻压草木樨一年后、增加了土壤有机质。矿化速度当年最快,而碱解氮积累高峰在第一年。

STUDY ON ACCUMULATION AND MINERALIZATION OF THE NUTRIENTS OF ANNUAL MELILOTUS

1.The experiment indicated that for annual sweetclover(Melilotus sp.)plowed into soil as green manure or for feeding animal,the optimum harvesttime should be at podding stage.The peak of nutrient accumulation observedwas at full bloom stage,but biomass continued to increase even after the peak;therefore hervest at pod stage can get higher herbage yield than at the fullbloom stage.2.At full blooming,the vegetation was succulent,tender and comparative-ly high yielding.After this stage,soluble sugars tended to decrease,so theoptimum harvest time for milking cows should be at the full bloom stage.3.One year after plowing the annual sweetclover into soil,organicmatter mineralized.Amounted to 55.5% of that turned into soil,slightlyhigher than the unchanged residue(44.5%),indicating that green manuringcan increase soil organic matter content.4.The rate of alkaline hydrolyzable nitrogen accumulation was quick atthe first year,but maximum accumulation occurred at the second year.Thus,green manure can provide available nutrients for following crops.