	US 12,228,562 B2
	Method for assessing soil health of cultivated land
Gangcai Liu, Chengdu (CN); Kai Hu, Chengdu (CN); and Xuan Wang, Chengdu (CN)
Assigned to Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu (CN)
Filed by Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu (CN)
Filed on Nov. 18, 2021, as Appl. No. 17/530,324.
Claims priority of application No. 202110328796.3 (CN), filed on Mar. 27, 2021.
Prior Publication US 2022/0308036 A1, Sep. 29, 2022
Int. Cl. G01N 33/24 (2006.01)

CPC G01N 33/24 (2013.01) [G01N 33/243 (2024.05); G01N 33/245 (2024.05)]

10 Claims

1. A method for assessing a soil health of cultivated land, comprising the following steps:

a soil sample collection step comprising:

selecting 4-6 representative plots of soil to be sampled and investigated from plots with a highest yield in cultivated land to be subjected to health assessment as a control group;

collecting a first cultivated layer of the soil to be sampled from the control group comprising sampled soil in a 0-10 cm depth;

collecting a second cultivated layer of the soil to be sampled from the control group comprising sampled soil in a 11-20 cm depth, wherein the first cultivated layer and the second cultivated layer are separately collected; and,

collecting a non-cultivated layer of the soil to be sampled from the control group comprising sampled soil in a 21-40 cm depth or 21-60 cm depth; and,

selecting plots to be sampled and investigated from the cultivated land to be subjected to health assessment as an experimental group;

collecting a first cultivated layer of the soil to be sampled from the experimental group comprising sampled soil in a 0-10 cm depth;

collecting a second cultivated layer of the soil to be sampled from the experimental group comprising soil in 11-20 cm depth, wherein the first cultivated layer and the second cultivated layer are separately collected; and,

collecting a non-cultivated layer of the soil to be sampled from the experimental group comprising soil in 21-40 cm depth or 21-60 cm depth;

an index measurement step adapted to guide soil improvement comprising:

measuring indicators of the control group and the experimental group separately, wherein the indicators comprise a soil function index system, a soil nutrition index system, and a crop output index system; and an index value of the control group is an index health value E, and an index value of the experimental group is an index current value C;

wherein the soil function index system comprises a water and gas regulation indicator, a nutrition regulation indicator, and a comprehensive regulation indicator;

wherein the water and gas regulation indicator comprises soil bulk density, field moisture capacity, and wilting coefficient;

wherein the nutrition regulation indicator comprises cation exchange capacity (CEC), organic matter content, and soil carbon-nitrogen ratio (C/N); and,

wherein the comprehensive regulation indicator comprises a soil thickness, pH, microbial biomass, microbial main functional gene, microbial group, and a soil enzyme activity;

the soil nutrition index system comprising macroelements and trace elements;

the macro element comprising soil total nitrogen, total phosphorus, total potassium, available nitrogen, available phosphorus, available potassium, a nitrogen-phosphorus ratio (N/P), and a nitrogen-potassium ratio (N/K);

the trace element comprising available zinc, available boron, and available molybdenum;

the crop output index system comprising a macro-view indicator and a micro-view indicator;

wherein the macro-view indicator comprises output and income; and,

the micro-view indicator comprises a product quality; and,

performing a soil health assessment using a deviating degree of a ratio R comprising an index current value C/index health value E of a measured dual index; and,

performing a health level assessment using a deviating degree of the soil function index, the soil function index Ci/Ei=Ri, the soil nutrition index Cj/Ej=Rj and the crop output index Ck/Ek=Rk;

wherein an assessment relationship between deviating degree of the ratio R from 1 and the health level of the index, and the number of different health level indicators and the overall health level of the soil according to the following table:


The deviating degree of index ratio (R_i, R_j, and	Number of different health level indicators
R_k) from “1” and index health level grading	and overall soil health level grading

	Grading,		Health
Degree	health level	Number of indicators, q = m + n + p	level

0 ≤ \| R_ior R_jor R_{k −} 1 \|< 0.2	0, healthy	>or = 80% indicators meeting “0” level	Healthy
0.2 ≤ \| R_ior R_jor R_{k −} 1 \| < 0.4	1, sub-	> or = 20% indicators meeting “1” level	Sub-
	healthy		healthy
0.4 ≤ \| R_ior R_jor R_{k −} 1 \| < 0.6	2, weak	> or =20% indicators meeting “2” level	Weak
0.6 ≤ \| R_ior R_jor R_{k −} 1	3, disabled	> or =20% indicators meeting “3” level	Disabled

wherein i is 1, 2, 3 . . . m, j is 1, 2, 3 . . . n, and k is 1, 2, 3 . . . p.