Evaluation Of Nutritional Composition Of Straw And Alfalfa Hay By Using NIRS Technology

The purpose of this study was to use near infrared spectroscopy to establish near infrared prediction models of corn stalks,wheat straws and alfalfa hay,respectively,and compare the effects of different treatment methods of alfalfa hay on the prediction accuracy of the established near infrared prediction models.This paper includes the following three experiments:Experiment 1: The experiment aimed to establish a near-infrared prediction model for corn straw and wheat straw by using near-infrared spectroscopy(NIRS).A total of 155 samples of corn straw and 135 samples of wheat straw were collected from three provinces of Gansu,Xinjiang and Henan.A total of 124 corn stalks were selected as the calibration set,and 31 were used as the verification set.108 wheat straws were selected as the calibration set and 27 were used as the verification set.The near-infrared prediction models of DM,CP,NDF,ADF and ADL of corn straw and wheat straw were established by near-infrared spectroscopy combined with modified partial least squares(MPLS)and other stoichiometry methods.The results showed that 1)the average contents of DM,CP,NDF,ADF and ADL in corn straw were 94.60%,5.16%,63.88%,36.33% and 3.32%,respectively.The average contents of DM,CP,NDF,ADF and ADL in wheat straw were 95.35%,3.42%,77.31%,46.59% and 6.84%,respectively.2)The prediction model of the CP content of corn and wheat straw is interactive verification coefficient(1-VR)>0.90,and the external verification determination coefficient(RSQ)is >0.84.The constructed model can be used for actual prediction.3)The 1-VR value of the calibration model for corn stalks DM,NDF,ADF and wheat straw DM is over 0.80,which can roughly predict the nutrient content.The prediction results of other indicators are not ideal,and the model needs further optimization.In summary,the study provides a theoretical basis for the rapid prediction of nutrient content of corn and wheat straw in production practice,and established its near-infrared prediction model through NIRS.Experiment 2: The experiment aimed to establish a near-infrared prediction model for six nutrients of alfalfa hay by using near-infrared reflectance spectroscopy(NIRS).200 samples of alfalfa hay were collected from five provinces of Gansu,Ningxia,Hebei,Jiangsu and Shanxi to analyze DM?Ash?CP,neutral detergent fiber.(NDF),acid detergent fiber(ADF)and ether extract(EE).The calibration sets and verification sets included 160 samples and 40 samples,respectively.The NIRS is combined with Modified partial least squares(MPLS)to construct and verify the prediction model which is accurate and inaccurate.The results show that the coefficient of determination for validation(RSQ)and ratio of performance to deviation for validation(RPD)of the DM and NDF prediction models of alfalfa hay were 0.87 and 2.67,0.90 and 3.16,respectively.It was constructed that the model can be used for prediction in actual production.The prediction model RSQ and RPD of the CP and ADF content were 0.83 and 2.41,0.82 and 2.28,respectively.The constructed prediction model can not completely replace the wet chemical analysis,but can be used for the screening analysis of a large number of samples.The ash content Zprediction model RSQ and RPD were 0.59 And 1.51.The constructed prediction model can only be used for rough analysis.the RSQ and RPD of the EE content prediction model are 0.45 and 1.32,and the constructed prediction model is poorly correlated and needs further optimization.Experiment 3: The purpose of this experiment was to use NIRS to establish the near infrared prediction models of DM,Ash,CP,NDF,ADF and EE for chopped and crushed alfalfa hay.The least square method was used to establish the prediction model of each index,and the prediction deviation of each near infrared prediction model of cut and crushed alfalfa hay was analyzed.The results show that the prediction deviations of the prediction models of DM and Ash are P > 0.05,and the difference is not significant.The short-cut and crushed CP,NDF,ADF and EE prediction models had a prediction deviation P < 0.01,the difference was very significant.The near infrared prediction model of 6 nutrient components of cut alfalfa hay has poor prediction effect.In summary,It was established the corn straw,wheat straw and alfalfa hay prediction models by NIRS.It was aimed to analyze their nutritional value.Provide convenient,efficient and rational use of these three coarse feed resources to provide theoretical basis.