Abstract: To investigate the factors affecting the content and composition of water-soluble carbohydrates (WSC) in feed grain amaranth (Amaranthus hypochondriacus L.) and to identify the optimal silage time for it,this study used ‘K472 grain amaranth’ as the material. Different factors were examined,including growth stages (bud stage,initial flowering stage,milk-ripe stage,and complete ripening stage),mowing times (8:00 AM,11:00 AM,2:00 PM,and 5:00 PM),wilting treatments (12-hour wilting),and fertilization conditions (nitrogen fertilizer at 150 kg·hm^-2 or 200 kg·hm^-2,potassium fertilizer at 150 kg·hm^-2 or 200 kg·hm^-2). Samples were analyzed for WSC,sucrose (S),glucose (G),and fructose (F) content. Results showed that WSC content was highest at the milk-ripe stage and lowest at the bud stage (P<0.05). Throughout the day,WSC content was lowest at 8:00 AM and highest at 5:00 PM (P<0.05). The WSC and sugar contents in the non-wilting group were higher than those in the wilting group (P<0.05). The highest contents of WSC,G,and F were observed with 150 kg·hm^-2 of both potassium and nitrogen fertilizers (P<0.05). Therefore,applying 150 kg·hm^-2 of both potassium and nitrogen fertilizers during the growth cycle and harvesting at 5:00 PM during the milk-ripe stage without wilting treatment can effectively increase the WSC content in forage grain amaranth.

Key words: Amaranth, Water-soluble carbohydrates, Sugar composition

摘要： 为探究饲用籽粒苋(Amaranthus hypochondriacus L.)的水溶性碳水化合物(Water Soluable Carbohydrate，WSC)含量及组成的影响因素，筛选出籽粒苋的最佳青贮时间，本研究以‘K472籽粒苋’为材料，选取不同的生育期(现蕾期、初花期、乳熟期和完熟期)、刈割时间(8:00，11:00，14:00和17:00)、萎蔫处理(萎蔫12 h)及施肥条件(氮肥150 kg·hm^-2，钾肥150 kg·hm^-2；氮肥200 kg·hm^-2，钾肥150 kg·hm^-2；氮肥150 kg·hm^-2，钾肥200 kg·hm^-2；氮肥200 kg·hm^-2，钾肥200 kg·hm^-2)进行取样，分析WSC、蔗糖(S)、葡萄糖(G)和果糖(F)的含量。结果显示，WSC含量在籽粒苋乳熟期时最高，现蕾期时最低(P<0.05)，且在一天中，8:00含量最低，17:00含量最高(P<0.05)。未萎蔫组的WSC及各类糖的含量均高于萎蔫组(P<0.05)；WSC，G和F含量均在钾肥和氮肥施用量为150 kg·hm^-2时最高(P<0.05)。因此，在籽粒苋生长周期内给予钾肥和氮肥施用量各150 kg·hm^-2，并在乳熟期17:00刈割，刈割后不进行萎蔫处理，可有效提高饲用籽粒苋中WSC含量。

关键词: 籽粒苋, 水溶性碳水化合物, 糖组成