青海省贵南县天然草地等级面积统计数据（1988，2012）

该数据集记录了1988年，2012年度青海省贵南县天然草地等级面积统计数据，数据按照天然草地等级代号分类统计，草地等的划分以草地型为基本单元，划分为优、良、中、低、劣五个等别。各等的划分标准如下：
Ⅰ等（优等）草地：优类牧草重量占60%以上；
Ⅱ等（良等）草地：良类以上牧草重量占60%以上，其他类占40%；
Ⅲ等（中等）草地：中类以上牧草重量占60%以上，其他类占40%；
Ⅳ等（低等）草地：低类以上牧草重量占60%以上，其他类占40%；
Ⅴ等（劣等）草地：劣类牧草重量占40%以上｡
草地级的划分以草地型为基本单元，按鲜草产量将全省草地划分为8级。各级标准如下：
1级草地：每公顷草地产鲜草12000k g 以上；2级草地：每公顷草地产鲜草9000kg ~ 12000kg；
3级草地：每公顷草地产鲜草6000kg~ 9000kg；4级草地：每公顷草地产鲜草4500kg ~ 6000kg；
5级草地：每公顷草地产鲜草30001kg~ 4500kg；6级草地：每公顷草地产鲜草1500kg~ 3000kg；
7级草地：毎公顷草地产鲜草750kg~ 1500kg；8级草地：每公顷草地产鲜草750kg以下。数据整理自青海省草原总站与1988年和2012年发布的《青海省草地资源统计册》。数据集包含2个数据表，分别为：贵南县天然草地等级面积统计数据（2012），贵南县天然草地等级统计数据 （1988）。数据表结构相似。例如贵南县天然草地等级面积统计数据（2012）表共有9个字段：
字段1：合计
字段2：1级
字段3：2级
字段4：3级
字段5：4级
字段6：5级
字段7：6级
字段8：7级
字段9：8级

This dataset records the statistical data of natural grassland grades and their corresponding areas in Guinan County, Qinghai Province, for the years 1988 and 2012. The data is classified and counted according to the codes of natural grassland grades.

The grassland quality gradation takes grassland types as the basic unit, and is divided into five quality grades: excellent, good, medium, low, and inferior. The division criteria for each grade are as follows:
1. Grade Ⅰ (Excellent) grassland: excellent-type forage accounts for more than 60% of the total fresh weight;
2. Grade Ⅱ (Good) grassland: good-type and above forage accounts for more than 60% of the total fresh weight, with other forage types accounting for 40%;
3. Grade Ⅲ (Medium) grassland: medium-type and above forage accounts for more than 60% of the total fresh weight, with other forage types accounting for 40%;
4. Grade Ⅳ (Low) grassland: low-type and above forage accounts for more than 60% of the total fresh weight, with other forage types accounting for 40%;
5. Grade Ⅴ (Inferior) grassland: inferior-type forage accounts for more than 40% of the total fresh weight.

The grassland yield classification also takes grassland types as the basic unit, and divides all grasslands in Qinghai Province into 8 grades based on fresh forage yield. The criteria for each yield grade are as follows:
1. Grade 1 grassland: fresh forage yield of more than 12000 kg per hectare;
2. Grade 2 grassland: 9000 kg to 12000 kg of fresh forage per hectare;
3. Grade 3 grassland: 6000 kg to 9000 kg of fresh forage per hectare;
4. Grade 4 grassland: 4500 kg to 6000 kg of fresh forage per hectare;
5. Grade 5 grassland: 3000 kg to 4500 kg of fresh forage per hectare;
6. Grade 6 grassland: 1500 kg to 3000 kg of fresh forage per hectare;
7. Grade 7 grassland: 750 kg to 1500 kg of fresh forage per hectare;
8. Grade 8 grassland: fresh forage yield of less than 750 kg per hectare.

The data is compiled from the *Statistical Book of Qinghai Grassland Resources* published by the Qinghai Grassland Station in 1988 and 2012. This dataset contains two data tables, namely: Statistical Data of Natural Grassland Grade and Area in Guinan County (2012), and Statistical Data of Natural Grassland Grade in Guinan County (1988). The structures of the two tables are similar. For example, the *Statistical Data of Natural Grassland Grade and Area in Guinan County (2012)* table has a total of 9 fields:
1. Field 1: Total
2. Field 2: Grade 1
3. Field 3: Grade 2
4. Field 4: Grade 3
5. Field 5: Grade 4
6. Field 6: Grade 5
7. Field 7: Grade 6
8. Field 8: Grade 7
9. Field 9: Grade 8