机播深度、播种量和施肥量对苦荞倒伏及产量的影响

为探明小型机械在丘陵山区播种苦荞的农机农技配套技术，以酉荞5号（中抗倒伏苦荞品种）为试验材料，于2016和2017年秋季，利用播种深度2（A₁）、3（A₂）和4 cm（A₃），播种量16.8（B₁）、33.6（B₂）和50.4 kg·hm^-2（B₃），施肥量150（C₁）、300（C₂）和450 kg·hm^-2（C₃）三因素三水平设计L₉3⁴正交试验，研究9个处理水平对苦荞倒伏和产量的影响。结果表明：对苦荞倒伏影响表现为播种深度>播种量>施肥量，随播种深度的增加，倒伏时期后移，3 cm播种深度苦荞倒伏级别和倒伏率最小；随播种量、施肥量的增加倒伏级别和倒伏率都增大。茎秆基部第二节间长度、茎粗、鲜重和抗折力从盛花期到成熟期逐渐增加，对茎秆基部第二节间茎粗、鲜重和抗折力的影响表现为播种量>播种深度>施肥量，随播种量的增加，第二节间茎粗、鲜重和抗折力逐渐减小，第二节间长度先减后增；播深对茎秆第二节间长度影响大于播量和施肥量，随播深的增加，第二节间茎粗、鲜重和抗折力先增后减，第二节间长度先减后增；随施肥量的增加，第二节间长度、直径、鲜重和抗折力逐渐增加。从盛花期到成熟期茎秆基部第二节间4-香豆酸辅酶A连接酶（4-coumarate：CoA ligase， 4CL）、苯丙氨酸解氨酶（phenylalanine ammonia-lyase，PAL）、肉桂醇脱氢酶（cinnamyl alcohol dehydrogenase，CAD）活性先升后降，木质素含量逐渐增加，对木质素含量、4CL、PAL、CAD酶活性的影响表现为播种量>播种深度>施肥量。对产量、单株粒数和总株数的影响表现为播种量>播种深度>施肥量，对千粒重的影响表现为播种量>施肥量>播种深度。随播种量的增加，总株数增加，单株粒数和千粒重减少，产量先增后减；随播种深度的增加，产量、单株粒数和总株数先升后降，千粒重先减后增；随施肥量的增加，总株数和产量差异不显著，单株粒数和千粒重显著增加。本试验条件下，丘陵山区苦荞小型机械播种A₂B₂C₃处理（3 cm播种深度、33.6 kg·hm^-2播种量和450 kg·hm^-2施肥量）最佳。

Effects of machine sowing depth and amounts of seeds and fertilizer on lodging and yield of Tartary buckwheat

Tartary buckwheat （Fagopyrum tataricum） belongs to the Polygonaceae， and originated in the southwest of China， northern India， Bhutan， and Nepal. Most Tartary buckwheat is grown in hilly and mountainous areas， where mechanized farming is still underdeveloped. Lodging is a serious problem in Tartary buckwheat grown in hilly and mountainous areas， and this greatly restricts the development of the Tartary buckwheat industry. Because the appropriate use of agricultural machinery can increase agricultural productivity， we conducted a field study to identify the optimal method for mechanical sowing and fertilization of Tartary buckwheat in hilly and mountainous areas. The field study consisted of an L₉3⁴ orthogonal experiment with three factors and three levels conducted in 2016 and 2017. Seeds of Youqiao 5， a moderately lodging-resistant Tartary buckwheat cultivar， were sown at a depth of 2 （A₁）， 3 （A₂）， or 4 cm （A₃）， at a rate of 16.8 （B₁）， 33.6 （B₂）， or 50.4 kg seeds·ha^-1 （B₃）， with fertilizer applied at 150 （C₁）， 300 （C₂）， or 450 kg·ha^-1 （C₃）. The lodging and yield of Tartary buckwheat were determined at different growth stages. Of the three factors， sowing depth had the strongest effect on lodging rate， followed by the amount of seeds and then the amount of fertilizer. As the sowing depth increased， the lodging period was delayed， and the lodging level and the lodging rate decreased and then increased. The lodging level and lodging rate increased as the amount of seeds and fertilizer increased. The length， diameter， fresh weight， and bending resistance of the second internode of the stem base gradually increased from flowering to maturity. Compared with sowing depth and amount of fertilizer， the amount of seeds had a greater effect on the diameter， fresh weight， and breaking force of the second internode of the stem， but not on the length of second internode. With increasing sowing depth， the diameter， fresh weight， and bending force of the second internode initially increased and then decreased， and the length of the second internode initially decreased and then increased. With increasing amounts of seeds sown， the diameter， fresh weight， and bending strength of the second internode decreased gradually， and the length of the second internode first decreased and then increased. With increasing amounts of fertilizer， the length， diameter， fresh weight， and bending resistance of the second internode increased gradually. The activity of 4-coumarate：CoA ligase （4CL）， phenylalanine ammonia-lyase （PAL）， and cinnamyl alcohol dehydrogenase （CAD） increased and then decreased from flowering to maturity， and the lignin content gradually increased. The lignin content and the activities of 4CL， PAL， and CAD in the second internode of the stem were most strongly affected by the amount of seeds sown， followed by sowing depth and then fertilizer amount. The lignin content and the activities of 4CL， PAL， and CAD first increased and then decreased with increasing sowing depth； gradually decreased with increasing amounts of seeds sown； and increased with increasing amounts of fertilizer. Yield， grain number per plant， and number of plants （but not 1000-grain weight） were most strongly affected by the amount of seeds sown， followed by sowing depth and then fertilizer amount. As the amount of seeds sown increased， the yield and number of plants increased， and the number of individual plant grains and 1000-grain weight decreased. As the amount of fertilizer increased， the yield and number of plants were not significantly affected， but the individual grain number and 1000-grain weight gradually increased. Overall， the combination of A₂B₂C₃ （sowing depth of 3 cm， seed sowing rate of 33.6 kg·ha^-1， fertilizer amount 450 kg·ha^-1） was found to be beneficial for growing Tartary buckwheat with a high yield and strong lodging resistance in hilly and mountainous areas.