氮钾肥配合施用对桑叶产量品质及蚕茧质量的影响

Effect of nitrogen and potassium combined application on mulberry (Morus atropurpurea Roxb.) leaf yield and quality,and silk cocoon quality

通过连续4年田间施肥试验和一季养蚕试验,研究了氮肥和钾肥配合施用对桑叶产量、品质及相应桑叶喂饲家蚕对蚕生长及蚕茧品质的影响。结果表明,桑园施用氮钾肥显著提高桑叶产量,在氮钾肥各养分配比中,以高氮高钾处理(N450K300)的产量最高,比N0K0处理年均增产35.2%,与其他各处理产量差异显著。桑叶品质分析结果表明,桑叶中必需氨基酸、氨基酸总量、粗蛋白、油脂含量随氮肥用量增加而提高,但单施氮肥会对蛋氨酸和油脂含量产生负面影响;施钾导致糖分含量下降,其他品质参数值随钾肥施用而提高,氮钾肥配合施用具有提高桑叶品质的作用。养蚕结果表明,桑园增施氮钾肥生产出的桑叶,有助于降低蚕茧的死笼率、具有提高全茧量和茧层率及提高蚕茧产量的作用。蚕茧上茧率、茧丝长、解舒率和茧丝净度随着钾肥用量的增加而提高,在施钾基础上增加氮肥用量有提高蚕茧品质的作用,但不施钾只施氮肥对上茧率有负面影响,说明氮钾肥配合施用能促进蚕茧质量的提高。

A four-year field trial was carried out to determine effect of nitrogen （N） and potassium （K） combined application on mulberry （ Morus atropurpurea Roxb. ） during 1999-2002 and a silk worm （ Bombyx mori Linne） experiment was conducted to determine their consequential effect on silk cocoon yield and quality in summer of 2001. The results showed that N and K fertilization significantly increased mulberry leaf yield, but the effect of only N without K treatment was very limited and high rate K with low rate N hindered the improvement of leaf yield. In comparison with leaf yield in other treatments, high rate N and K treatment IN 450 and K20 300 kg/ （ha·a）] received the highest yield, which increased by 35.2% over NoKo treatment. Essential amino acids, total amino acid, protein and fat content in leaves were increased by N and K application, indicated that N and K combined fertilization improved mulberry leaf quality. The treatments of only N without K decreased amminoacido metionina and fat content in leaves, while K application decreased sugar content. Silk worms fed results showed the death rate of worms was lower with the N and K fertilization leaves and cocoon weight, cocoon shell percentage and shell yield were increased. The silk cocoon quality test showed that silk worms fed with mulberry leaves from K treatments produced better quality cocoons in terms of silk worm weight, cocoon weight, reelable cocoon rate, filament length, reelability and silk neatness. N application improved cocoon quality combined with K, but had negative effect on quality without K application. The results revealed appropriate N and K management for mulberry orchards had important role on mulberry leaf product and silk cocoon yield and quality.