Technical Regulations for Under-forest Cultivation of Paris polyphylla Smith in Hunan Province

Rong SONG, Wenwen JIANG, Bei YAN, Hengbo JIANG

1. Institute of Agricultural Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha 410125, China; 2. College of Horticulture, Hunan Agricultural University, Changsha 410128, China; 3. College of Plant Protection, Hunan Agricultural University, Changsha 410128, China; 4. Xintian County Hospital of Traditional Chinese Medicine, Yongzhou 425799, China; 5. Xintian County People’s Hospital, Yongzhou 425799, China

Abstract In this paper, the seedling raising, cultivation, field management, pest and disease control, harvesting and processing of Paris polyphylla Smith under the forest in Hunan Province were scientifically standardized, to provide technical support for standardized cultivation and sustainable development of Paris polyphylla Smith industry in Hunan Province.

Key words Paris polyphylla Smith, Paridis Rhizoma, Standardized cultivation, Hunan province

1 Introduction

ParispolyphyllaSmith, also known as Zaoxiu, Tiedengtai, Ziheche, Caoheche,etc.[1], is a perennial plant ofParisL. in the Liliaceae family, and its rhizome is used as medicine[2]. It is slightly cold in nature, bitter in taste, slightly toxic, attributive to heart and lung meridians, and has the effects of clearing away heat and toxic materials, relieving swelling and pain, cooling the liver and relieving convulsion. It is often used to treat furuncle, carbuncle, sore throat, snake bite and other diseases[3]. In the folk of western Hunan,P.polyphyllaSmith is one of the most widely used herbs to treat snake injuries, and the proverb "P.polyphyllaSmith can cure any pyogenic infections" is still spread today[4].

P.polyphyllaSmith is distributed in Hunan, Yunnan, Sichuan, Guizhou and other provinces[5], and often grows in damp shade under broad-leaved forests at an altitude of 700-3 000 m in Hunan. Huaihua and Zhangjiajie in southwest Hunan are natural distribution areas ofP.polyphyllaSmith[6], and they also grow in low altitude areas (about 300 m above sea level) in western Hunan[7]. Western Hunan is the main potential suitable area forP.polyphyllaSmith,P.polyphyllavar.chinensisandP.polyphyllavar.stenophyllain the present period and in the future[8].

In recent years, the wild resources ofP.polyphyllaSmith are decreasing and facing the dilemma of depletion[9].P.polyphyllaSmith is a typical shade plant with low natural germination rate and extremely slow growth and other characteristics[10-12]. According to the National Food and Drug Administration’sChineseHerbalMedicineProductionQualityManagementStandard(GAP) (forTrialImplementation), we worked out theTechnicalRegulationsforUnder-forestCultivationofP.polyphyllaSmithinHunanProvince(SOP), to scientifically standardize the seedling raising, cultivation, field management, pest control, harvesting and processing of under-forest cultivation ofP.polyphyllaSmith in Hunan Province on the basis of several years’ research and drawing lessons from traditional cultivation techniques.

2 Main contents and scope of application

2.1 Main contentsThis regulation specifies the terms and definitions, environmental and management requirements of under-forest cultivation ofP.polyphyllaSmith in Hunan Province, as well as seedling raising, cultivation, field management, pest control, harvesting and processing in the process of under-forest cultivation ofP.polyphyllaSmith in Hunan Province.

2.2 Scope of applicationThis standard is applicable to the whole process of under-forest planting ofP.polyphyllaSmith in Hunan Province.

3 Reference standard

GB3095-2012AmbientAirQualityStandard; GB5084-2005FarmlandIrrigationWaterQualityStandard; GB/T8321-2018GuidelinesforRationalUseofPesticides; GB15618-2008SoilEnvironmentalQualityStandard;PharmacopoeiaofthePeople’sRepublicofChina, 2020Edition(PartI).

4 Terms and definitions

4.1P.polyphyllaSmithIt refers toP.polyphyllaSmith var. chinensis (Franch.) Hara, a variety ofP.polyphyllaSmith in the Liliaceae family.

4.2 Canopy densityThe degree of contact and closure of crowns in forest stands, that is, the ratio of the vertical projection area of forest crown to the total area of forest land[13].

5 Natural conditions of producing area

5.1 Site and climatic conditionsThe altitude is 500-900 m, the average annual temperature is 10-13 ℃, and the frost-free period is over 240 d. The annual rainfall is 850-1 200 mm, the air relative humidity is above 75%, the irrigation is convenient and the drainage is good. The concept of "authentic medicinal materials" and the concept of "origin" of medicinal materials should be reflected as much as possible[5,14].

The selected planting land types are forest land, sparse woodland, shrub land and open space in the forest. Plots away from residential areas, roads and other pollution sources are selected. The soil is loose and fertile sandy black loam or red loam rich in humus and organic matter, and the soil pH is 5.5-7.0, which is weakly acidic or neutral. The content of heavy metals in soil should meet the requirements of GB15618SoilEnvironmentalQualityStandard. The terrain is required to be flat, the slope should be below 15°, and the aspect of slope should be shady slope and semi-shady slope[15-16].

5.2 Regional scopeIt is located in the western part of Hunan Province where the surface is covered with broad-leaved forest or coniferous and broad-leaved mixed forest.

6 Seedling raising techniques

There are two seedling raising methods forP.polyphyllaSmith, one is to use seeds for seedling raising, and the other is to use rhizome cutting to propagate[5].

6.1 Seed collection and processing5-6 year strong plants of high qualityP.polyphyllaSmith were selected and the diseased and weak fruits were removed. Seed was collected from late September to early October, and it was harvested in time when capsule cracked and bright red berry appeared. After harvesting, seed coat was removed with plant ash, and rinsed with clear water and dried. It was soaked in 1% copper sulfate aqueous solution for 5 min, then taken out, rinsed with clear water and dried. The treated seeds were packed in kraft paper bags and put into the refrigerator for 90 d, and the temperature was kept at 5-6 ℃. The treated seeds were put into a nursery box and placed indoors to accelerate germination, and the temperature was kept at 18-20 ℃. After treatment for 90-100 d, direct seeding was performed when the radicle germinated[5-6,17].

6.2 Rhizome processingAfter lodging of overground stems ofP.polyphyllaSmith, the robust, pest-free and intact rhizomes were cut at the node length of 2-3 cm with terminal buds perpendicular to the main axis of rhizomes, or cut into small sections according to the characteristics of bud residual stems and bud scars of rhizomes, and each section was guaranteed to have one bud scar. Rhizomes with uniform size and weight of 5-10 g were selected, and then soaked in 200 mg/L No. 7 ABT for 2 h, dipped in plant ash and quicklime for disinfection. After treatment, seedlings with and without terminal buds should be raised separately. It was carried out from October to November every year[5].

6.3 Land selectionThe broad-leaved secondary forest or coniferous and broad-leaved mixed forest with suitable canopy density of 0.5-0.7 or vegetable garden was selected[5,18]; seedlings were raised in the open field, and shade shed was set up in time after emergence. It required flat terrain and good drainage, and the best soil was dark brown fertile soil.

6.3.1Land preparation. Shrubs and weeds were cut off, and stones and impurities were removed. It was dug 30 cm deep in the ground, the clods were broken, 15 000 kg/ha decomposed organic fertilizer was applied to the soil, and it was mixed evenly, raked flat, fined, disinfected with Bordeaux mixture before bedding[19].

6.3.2Bedding. Bedding was made along the hillside or slightly inclined with the hillside to prevent rain from scouring. The width of the furrow was 1.2 m, the height was 20 cm, and the length of the furrow was determined according to the topography. Generally, the length of the furrow was 10-30 m, the width of the furrow was 30 cm, and the depth of the furrow was 20 cm. Moreover, the furrow should be unblocked to facilitate drainage[5,14,18].

6.4 Seedling raising (seeds)From March to April every year, seeds were sown and seedlings were raised after radicle germination. The seeding method was drilling, and trenches were dug on the seedbed according to the row spacing of 15 cm, and the trench depth was 10 cm. The treated seeds were evenly sown into the trench, then it was covered with humus soil and plant ash (a ratio of 1∶1) with a thickness of 1.5 cm. After watering, it was covered with plastic film to keep it moist. Shading, weeding and proper fertilization should be paid attention to at seedling stage[5].

6.5 Seedling raising (rhizomes)The seeding method was drilling, and trenches were dug on the seedbed according to the row spacing of 15 cm, and the trench depth was 10 cm. The treated rhizomes were evenly put into the trench, then it was covered with humus soil and plant ash (a ratio of 1∶1) with a thickness of 1.5 cm. After watering, it was covered with plastic film and it can be transplanted in the following winter[16].

6.6 Seedling management

6.6.1Coverage. After sowing until the emergence of seedlings in the next spring, the furrow surface should be covered with pine needles or straw (1-3 cm thick), and the covering should be placed evenly without exposing soil on the furrow surface. From early April to mid-April of the following year, 2/3 or 1/2 of the furrow covering was removed before emergence. From late September to early October, the seedlings were covered with pine needles or straw (1-3 cm thick) after withering[14].

6.6.2Water management. It should be watered in time during drought and drained in the rainy season.

6.6.3Weeding and fertilization. It should be weeded in time. Before the soil freezing, the furrow surface was covered with 1-2 cm thick rotten farm manure.

7 Cultivation techniques and management under the forest

7.1 Direct seeding and direct planting

7.1.1Land selection. The broad-leaved forest or mixed coniferous and broad-leaved forest with canopy density of 0.5-0.7, and shady slope or semi-shady slope with slope gradient below 15° were selected. The soil should be sandy black loam or red loam with rich humus and good drainage performance.

7.1.2Land preparation. After selecting the planting land, shrubs, weeds, impurities and residues on the ground were removed. After 30 cm deep digging, 1 500 kg/ha decomposed and fermented cake manure or 3 500 kg/ha farm manure were evenly spread on the ground. After digging, finely crushing and leveling, it was disinfected by spraying Bordeaux mixture. Then, bedding was performed according to the aspect and gradient of the slope. The surface was 120 cm wide and 20 cm high, the furrow was 30 cm wide and 20 cm deep, and the furrow mud was broken and spread on the furrow surface when planting.

7.1.3Digging holes. The hole was dug according to the planned planting specifications. Generally, 20 cm×30 cm or 30 cm×30 cm was used for planting under the forest, and the hole depth is 5-6 cm.

7.1.4Direct seeding. From March to April every year, the seeds after radicle germination were put into holes, with bud tips upward and radicle downward. For each hole, 250 g of decomposed fermented bran shell plus livestock manure or 500 g of farm manure was applied, then it was watered thoroughly to keep the soil moist, and the furrow surface was covered with pine needles, straw or sawdust until no soil was exposed.

7.1.5Direct planting of rhizomes. From October to November every year, the treated rhizomes with bud tips upward were put into holes. For each hole, 250 g of decomposed fermented bran shell plus livestock manure or 500 g of farm manure was applied, then it was watered thoroughly to keep the soil moist, and the furrow surface was covered with pine needles, straw or sawdust until no soil was exposed.

7.2 TransplantingSeedlings (seeds or rhizomes) cultivated for 1-2 years can be transplanted before sprouting in winter or early spring. When transplanting, the bud tip was upward and the radicle was downward, so that the root system stretched. For each hole, 250 g of decomposed fermented bran shell plus livestock manure or 500 g of decomposed farm manure was applied, then it was watered thoroughly to keep the soil moist. The furrow surface was covered with pine needles, straw or sawdust until no soil was exposed. Seedlings should be planted when needed.

7.3 Field management

7.3.1Thinning and filling the gaps with seedlings. In the middle and late May, thinning was carried out after watering, and root was watered in time after filling the gaps with seedlings[20].

7.3.2Intertillage, weeding and earthing up. In the first year after transplanting and planting, if there are not many weeds, it is not necessary to remove them, but weeds should be removed after the second year, once in the first half of the year (June) and once in the second half of the year (October), respectively; or three times a year, in May, July and October, respectively. The weeds around the plant were first pulled out, and the small hoe was then used to remove other weeds before intertillage. It should not be ploughed too deep, so as not to damage the underground roots and seedlings. Based on intertillage and weeding, earthing up was carried out[5].

7.3.3Pruning in woodland. According to the years after transplantation, the excess branches in the high places were gradually trimmed, and in principle, the canopy density was 0.7 after two years, and the canopy density was 0.4-0.6 after three years[5,16].

7.3.4Fertilization and topdressing. The base fertilizer was mainly applied, accounting for 70%-80% of the total fertilizer application, supplemented by topdressing, accounting for 20%-30% of the total fertilizer application. It was applied once a year before emergence from February to March and during the peak period of vegetative growth from May to June. Each plant was applied with 50 g of decomposed bran shell plus livestock manure or 100 g of decomposed farm manure. From June to July, 0.5% urea and 0.2% potassium dihydrogen phosphate were used for foliar fertilization once every 15 d and sprayed three times continuously[5].

7.3.5Water management. After transplanting, it should be watered once to keep the soil moisture at 30%-40%. After fixing seedlings, it was not advisable to water the stems on the ground before emergence, otherwise it was easy to rot roots. After emergence, the furrow surface and soil should be kept moist. Before the rainy season comes, the trench should be cleaned in time to keep the drainage unobstructed. In rainy season, waterlogging on the furrow surface should be avoided to prevent diseases. When the soil on the furrow surface is dry, it should be watered in time, and if there is no irrigation condition, the covering on the furrow surface should be thickened properly[5,21].

7.3.6Coverage. From early April to mid-April, the covering was removed before emergence; from the first ten days of October to the last ten days of November, it was covered with pine needles, straw or sawdust (1-3 cm thick) after the seedling withered.

7.3.7Fruit thinning. During the budding period, the flower buds were cut off in the production field and cleaned out of furrow surface; the diseased, weak fruits and small fruits were removed. In order to reduce nutrient consumption and supply nutrients to underground tubers for growth, when sepals appeared from May to July, ovaries of plants without reserved seed for planting should be removed in time, but sepals should be retained, which can improve photosynthesis and yield.

7.4 Integrated pest and disease control

7.4.1Root rot. It often occurred in the high temperature and damp season from June to July. Prevention and control methods: pull out the dead plants in time, spread quicklime in the holes, or spray carbendazim wettable powder mixed with 1∶250 liquid[22].

7.4.2Sclerotinia sclerotiorum. It occurred in the rainy and humid season in May, and the disease was harmful. Prevention and control methods: clear trenches and drain water in time to reduce the humidity of planting areas, find and remove diseased plants in time, and spread quicklime in the disease center. In severe cases, 50% thiophanate-methyl wettable powder can be mixed with 1∶1 000-2 000 liquid for spraying[23].

7.4.3Damping-off. The onset of the disease was caused by soil carrying bacteria or excessive accumulated water. Prevention and control methods: spray 50% carbendazim wettable powder mixed with 1∶500 liquid, pull out the diseased plants in time after the infection, and irrigate the disease area with 1∶500 copper sulfate solution.

7.4.4Sheath blight. It occurred in seedling stage, and it was serious in low temperature and heavy rain from April to May. At the early stage of the disease, yellow-brown water-stained disease spots appeared at the base of the stem of the seedlings, and expanded around the base, causing the seedlings to wither, and in severe cases, a lot of them died. It is necessary to strengthen field management, disinfect soil, pull out diseased seedlings after onset, disinfect seedbeds with drug, and spray zineb liquid medicine[9,24].

7.4.5Cutworm. To trap and kill cutworms, 50 g of 90% trichlorfon was mixed with 20 kg of fine fluvo-aquic soil, or 50 g of 90% trichlorfon was mixed with 5 kg of bait. The bait can also be made from 50 g of 50% phoxim emulsion mixed with 5 kg of fresh vegetables, and 5 kg of bait was sprinkled every 667 m2to trap and kill cutworms.

7.4.6Scarab. Adults harm leaves, while larvae bite roots. Prevention and control methods: trap and kill adults with torches at night, spray trichlorfon or dichlorvos on fresh vegetable leaves and put them on the soil to trap and kill larvae[9].

7.5 Harvest

7.5.1Harvest years. 4-5 years for propagation with seeds and 3-4 years for propagation with rhizome pieces[25-26].

7.5.2Digging time. October to March of the following year. After the overground stems withered, most of the nutrients were stored in the rhizomes at this time, and the drug component content was higher, the quality of the medicinal materials was better, and the yield was higher[27].

7.5.3Digging method. Sunny days were selected when digging. Stems and leaves were cut off first, and then clean hoes were used to dig out roots from the side. When digging, it is necessary to avoid damaging the rhizome and ensure that the rhizome is intact[27].

8 Primary processing

For the dug rhizomes, the stems and leaves were cleaned, and the parts with terminal buds were cut off for seedling. The rest was washed with clear water, and the fibrous roots were removed. The thick ones were cut into 2-4 pieces, dried in the air or at 30-65 ℃, and the water content was controlled at 10%-12%. The dried products were packed for storage or sale[5,19].