播期对北方农牧区青贮玉米产量和品质的影响

Effects of different sowing dates on yield and quality of silage maize in northern agricultural and pastoral areas

为了明确播期对北方农牧区青贮玉米产量和品质的影响,2017-2018年在张家口农业科学院试验基地以青贮玉米品种大京九26为材料,采用分期播种方法,考查了2007-2018年青贮玉米生育期内有效积温、日均气温、气温日较差和降水量等气候因子,测定分析了5个不同播期[S1(4月15日)、S2(4月30日)、S3(5月20日)、S4(6月10日)、S5(6月30日)]下青贮玉米的生育期、产量[鲜重(叶、茎、雌穗和鲜草产量)、干重(叶、茎、雌穗和干草产量)]和品质(指标包括酸性洗涤纤维、中性洗涤纤维、粗蛋白、粗脂肪、每吨干物质产奶量、干物质消化率)等性状表现,并分析气候因子的变化及其与产量和品质等性状的相关性。结果表明:2017-2018年较过去十年(2007-2016年)的气候明显变暖,特别是4月份有效积温、日均气温、气温日较差和降水量均有不同程度增高。青贮玉米大京九26最长生育期在S1播期,2017年全生育期为160 d,2018年全生育期为153 d;随着播期推迟,苗期日均气温逐渐升高,粒期日均气温逐渐降低,大京九26生育进程明显加快;S1~S4生育期内的有效积温均能满足大京九26积温需求。随着播期推迟,青贮玉米鲜重和干重以及叶重、茎重和雌穂重呈明显下降趋势。2017,2018年,S1播期青贮玉米干重产量均最高,分别为35.253 t/hm^2和33.462 t/hm^2;S5播期最低,分别为18.564 t/hm^2和16.094 t/hm^2,干重产量由高到低分别为S1>S2>S4>S3>S5和S1>S2>S3>S4>S5。随播期推迟,青贮玉米的品质呈下降趋势,青贮玉米大京九26 S1播期的酸性洗涤纤维和中性洗涤纤维含量均最低,分别为7.561%和13.232%;粗蛋白含量达3.313%,高于S3、S4和S5,比S2的3.354%略低;每吨干物质产奶量最高为1 550.000 kg;干物质体外消化率最高,达81.000%。全生育期有效积温和降水量、粒期有效积温、日均气温和降水量与青贮玉米干重产量呈极显著正相关(P<0.01);有效积温和降水量与酸性洗涤纤维、中性洗涤纤维含量呈极显著或显著负相关(P<0.01或P<0.05);有效积温与粗蛋白含量和每吨干物质产奶量呈正相关(P<0.05),降水量与粗脂肪含量呈显著正相关(P<0.05)。说明北方农牧区青贮玉米可提早到4月中旬播种,全生育期有效积温与降水量增加,青贮玉米较其他播期产量高、品质优,在6月30日以后播种大京九26,可能达不到青贮玉米收获要求。

In order to clarify the impact of sowing date on the yield and quality of silage maize in northern agricultural and pastoral areas, the silage maize variety "Dajingjiu 26" in the experiment base of Zhangjiakou Academy of Agricultural Sciences was used as the material and planted by stages to examine the climatic factors such as effective accumulated temperature, daily average temperature, daily temperature difference, and precipitation during the growth period of silage corn from 2007 to 2018.The growth period, yield(fresh and dry weight of leaves, stems spikelets and forages) and quality of silage maize(indicators include acid detergent fiber, neutral detergent fiber, crude protein, crade fat, milk yield per ton of dry matter, dry matter digestibility) under 5 different sowing dates [S1(April 15), S2(April 30), S3(May 20), S4(June 10), S5(June 30)] were measured and analyzed, and the changes in climate factors and their correlation with traits such as yield and quality were analyzed. The results showed that the climate in 2017-2018 is significantly warmer than that in the past ten years(2007-2016), especially the effective accumulated temperature, daily average temperature, daily temperature range and precipitation in April were all increased to varying degrees. The longest growth period of silage maize Dajingjiu 26 was S1 sowing date, and the whole growth period was 160 d in 2017 and was 153 d in 2018. With the delay of the sowing date, the average daily temperature in the seedling stage gradually increased, and the average daily temperaturein grain period gradually decreased, which indicated that the growth process of Dajingjiu 26 was significantly accelerated. The effective accumulated temperature during S1 ~ S4 growth period could meet the accumulated temperature demand of Dajingjiu 26. With the postponement of the sowing date, the fresh weight, dry weight, leaf weight, stem weight and female stalk weight of silage corn showed a significant decline trend. In 2017 and 2018,the dry weight yield of silage corn in S1 sowing dates, which was 35.253 t/hm^2 and 33.462 t/hm^2, respectively;the dry weight yield of silage corn in S5 sowing dates were the lowest, which was 18.564 t/hm^2 and 16.094 t/hm^2, respectively, and the dry weight yield was S1>S2>S4>S3>S5 and S1>S2>S3>S4>S5, respectively. With the postponed sowing date, the quality of silage corn decreased. The content of acid detergent fiber and neutral detergent fiber of silage corn Dajingjiu 26 in S1 sowing date were the lowest, which was 7.561% and 13.232%, respectively;crude protein content of silage corn Dajingjiu 26 in S1 sowing date reached 3.31%, which was higher than those in S3, S4 and S5 sowing date, but slightly lower than that in S2 sowing date(3.354%);the highest milk yield per ton of dry matter was 1 550.000 kg;the highest in vitro digestibility of dry matter was 81.000%. The effective accumulated temperature and precipitation during the whole growth period and the effective accumulated temperature and average daily temperature during the grain period, were extremely significantly positively correlated with the yield of silage corn(P<0.01). The effective accumulated temperature and precipitation were significantly negatively correlated with the content of acid detergent fiber and neutral detergent fiber(P<0.01 or P<0.05);effective accumulated temperature was positively correlated with crude protein content and milk yield per ton of dry matter(P<0.05);and precipitation was significantly positively correlated with fat content(P<0.05). The results indicated that silage corn could be sown as early as mid-April in northern agricultural and pastoral areas, the effective accumulated temperature and precipitation during the whole growth period increased, and the yield and quality of silage corn were higher than those in other sowing periods. If Dajingjiu 26 are sown after June 30, the silage corn may not be harvested.