沙土地有机肥替代化肥与灌溉优化在苜蓿上的耦合效应研究

The coupling effect on alfalfa from integrated improvement of replacing chemical with organic fertilization and optimized irrigation on sandy soil

在沙土为主的牧区,为适应粮改饲的发展需求,在苜蓿种植中有机肥替代化肥并协同优化灌溉是可持续发展的重要途径。本研究在典型牧区-河北滦南县的沙土地,设置了有机肥氮替代0%、50%和100%化肥3个替代率,设常规灌溉和优化灌溉两个灌溉水平,以不施氮且常规灌溉为对照,共计7个处理。在2013～2015年通过大田试验测定苜蓿生物性状、土壤无机矿化氮和0～180 cm土层水分含量等,探索了水肥耦合效应。有机肥氮替代50%和100%的土壤无机氮供应与化肥氮相比差异不显著,相同替代条件下优化灌溉能提高12%～25%的苜蓿产量。有机肥100%替代化肥氮(180 kg/hm^2)以及优化灌溉(262 mm)的苜蓿产量比其他处理提高4. 4%～53. 3%,同时降低了硝酸盐的淋洗风险。该方案既解决畜禽粪便污染的难题又减少化肥和灌溉水投入,是值得推广的种养结合新模式。

In Chinese pasturing areas with sandy soil,organic manure nitrogen (MN)substitution with optimized irrigation in affalfa planting for feeding need was key way to agricultural sustainable development.In 2years'experiments in a typical pasturing area of Luannan county,7different treatments were designed,including CK (non-N fertilization),0%MR [chemical fertilizer N (CFN)with regular irrigation],0%MO (CFN with optimized irrigation),50%MR (50%CFN and 50%MN with regular irrigation),50%MO (50%CFN and 50%MN with optimized irrigation),100%MR (MN with regular irrigation),100%MO (MN with optimized irrigation).The alfalfa biological properties,soil mineral N and 0-180cm soil mois- ture were tested to research the effects of the coupling of water and the organic N.The results showed that 50%and 100%of manure nitrogen substitution provided the same nitrogen supply with chemical N,while optimized irrigation improved 12%- 25%alfalfa yield.100%MR (N 180kg/hm^2 and 262mm irrigation)not ordy improved 4.4%-53.3%grass yield bat also decreased nitrate leaching,which could provide valuable reference for the nutrient and water management.Organic manure substitution could decreased chemical fertilizer and irrigation input to mitigate the pollution,and a new management pattern with manure and irrigation in pasturing regions was built.