Effect of K and micronutrient application on medical herbs in Hunan

Hunan province is rich in natural resources of Chinese medicinal herbs, of which have 63 kinds of artificial planting medicinal herbs covered 6500 hectares in the province. The largest herbs are lily and rhizome which played an important role in developing local economy. Lily and rhizome mainly planted in hilly region. In past, people only pay attention to applying nitrogen fertilizer and don't use potassium and micronutrient fertilizers. It result in the yields and quality of medicine herbs been reduced year by year. In order to understand the effect of nutrient on herbs growth and yield, quality and nutrient uptake of the lily and rhizome, Hunan SFI conducted field experiments at Pingjiang and Longhui counties for 3 years.
The soil at Pingjiang and Longhui counties are alluvial sandy loam soil derived from alluvial deposite and grey clayey soil derived from limestone. Treatments included: 1) NP, 2) NPK, 3) NPKB, 4) NPKZn, 5) NPKBZn. Fertilizers were applied as N 150 kg /ha, P2O5 120 kg/ha, K2O 150 kg/ha, borax 22.5 kg/ha and ZnSO4 22.5 kg/ha. Each plot received 750 kg/ha rapeseed cake. Fertilizer sources were urea, superphosphate, potassium chlorine, borax and ZnSO4.7H2O. In the lily experiments, 50% of N in each treatment be used for basal dressing, 50% for topdressing. In experiment of rhizome, 40% of N in each treatment be used for basal dressing, 60% for topdressing. All superphosphate, potassium chloride, borax, ZnSO4.7H2O and rapeseed cake were applied for basal dressing.
Results in 2002~2004 showed that potassium application increased yield on lily by 33.5% compared with no potassium (buld yield 4,375 kg/ha), net income raised by US$2,817/ha in alluvial sandy soil. On the basis of applied potassium, boron, zinc and boron + zinc, yield increased on lily by 63.3%, 55.4% and 66.1% compared with no potassium (buld yield 4,375 kg/ha), net incomes were raised by US$5,341, 4,671 and 5,573/ha. On grey clayey soil, potassium application increased yield of lily by 12.6% compared with no potassium (buld yield 8,597 kg/ha), net income was raised by US$2,061/ha. On the basis of applied potassium, boron, zinc and boron + zinc, yield increased on lily by 15.0%, 19.4% and 20.9% compared with no potassium (buld yield 8,597kg/ha), net income were raised by US$2,463, 3,195 and 3,439/ha. On grey clayey soil, potassium application increased yield of rhizome by 34.6% compared with no potassium (rhizome yield 5,880 kg/ha), net income was raised by US$2,439/ha. On the basis of applied potassium, boron, zinc and boron + zinc, rhizome yield increased by 46.9%, 42.4% and 48.1% compared with no potassium (rhizome yield 5,880 kg/ha), net incomes were raised by US$3,305, 2,976 and 3,378/ha, respectively.
There are 1,430 hectares of lily and 1,050 hectares of rhizome planted in Hunan province. If recommend fertilization on the rate of N 150-P2O5 120-K2O 150-borax 22.5-zinc sulfate 22.5 kg/ha, it is estimated that the net income from lily and rhizome in Hunan province would be reach about US$ 10 million per year.