Responses of forage nutrient quality to grazing in the alpine grassland of Northern Tibet

doi:10.11686/cyxb2021123

Abstract

Abstract:

In this study， we determined the responses of herbage nutrient quality to grazing in alpine grasslands in different seasons and different grassland types. Three fenced and free-grazing grassland sites in the alpine grassland in the Northern Tibetan Plateau were selected for this study. We found that winter grazing increased the nutritional quality of forbs by decreasing the acid detergent fiber content by 24.29% and the neutral detergent fiber content by 18.98%， and by increasing the crude ash content by 41.05%. However， winter grazing did not affect the nutritional quality of the plant community and high-quality forage in the alpine steppe meadow. Summer grazing increased the nutrient quality of the plant community by decreasing the acid detergent fiber content by 31.82% and the neutral detergent fiber content by 27.45%， and by increasing the crude ash content by 137.35% and the crude fat content by 24.73% in an alpine steppe meadow. Summer grazing increased the nutrient quality of high-quality forage by decreasing the acid detergent fiber by 22.04% and the neutral detergent fiber content by 22.50%， and by increasing the crude ash content by 202.19%. However， summer grazing did not change the nutrient quality of forbs in the alpine steppe meadow. Summer grazing increased the nutritional quality of forbs through decreasing the acid detergent fiber content by 37.18% and the neutral detergent fiber content by 25.10%， and tended to increase the nutritional quality of high-quality forage through increasing the crude protein content by 26.55%， but had no effect on the nutritional quality of plant community in an alpine meadow. The nutritional quality of the plant community was related to its α and β diversity. The nutritional quality of high-quality forage was mainly related to soil variables， and the nutritional quality of forbs was related to its α diversity and soil variables. Therefore， in alpine grasslands of Northern Tibet， the responses of forage nutrient quality to grazing differ depending on plant types and grazing seasons. Alpine grassland should be managed by different grazing patterns.

Key words: grassland type, grazing season, classified management, Tibetan Plateau

Gang FU, Jun-hao WANG, Shao-wei LI, Ping HE. Responses of forage nutrient quality to grazing in the alpine grassland of Northern Tibet[J]. Acta Prataculturae Sinica, 2021, 30(9): 38-50.

Figures/Tables 14

References 29

1	Yao X X， Wu J P， Gong X Y， et al. Effects of long term fencing on biomass， coverage， density， biodiversity and nutritional values of vegetation community in an alpine meadow of the Qinghai-Tibet Plateau. Ecological Engineering， 2019， 130： 80-93.
2	Cui G X， Yuan F， Degen A A， et al. Composition of the milk of yaks raised at different altitudes on the Qinghai-Tibetan Plateau. International Dairy Journal， 2016， 59： 29-35.
3	Sun W， Li S， Zhang Y， et al. Effect of long-term experimental warming on the nutritional quality of alpine meadows in the Northern Tibet. Journal of Resources and Ecology， 2020， 11（5）： 516-524.
4	Waterman R C， Grings E E， Geary T W， et al. Influence of seasonal forage quality on glucose kinetics of young beef cows. Journal of Animal Science， 2007， 85（10）： 2582-2595.
5	Zhang Y P， Jiang Y， Liu Q R， et al. Impacts of grazing on herbage quality of the alpine and subalpine meadows within Wutai Mountain. Acta Ecologica Sinica， 2011， 31（13）： 3659-3667.
	章异平，江源，刘全儒，等. 放牧对五台山高山、亚高山草甸牧草品质的影响. 生态学报， 2011， 31（13）： 3659-3667.
6	Zhang C Y， Niu Z， Wang Y Q， et al. Effects of grazing intensity on the aboveground present biomass and dynamic changes of nutrient components in Deyeuxia angustifolia meadow. Chinese Journal of Grassland， 2014， 36（4）： 18-23.
	张丞宇，牛壮，王彦庆，等. 放牧强度对小叶章草场地上现存量和营养成分动态变化的影响. 中国草地学报， 2014， 36（4）： 18-23.
7	Zhang H， Fu G. Responses of plant， soil bacterial and fungal communities to grazing vary with pasture seasons and grassland types， northern Tibet. Land Degradation & Development， 2021， 32（4）： 1821-1832.
8	Wu J S， Fu G. Modelling aboveground biomass using MODIS FPAR/LAI data in alpine grasslands of the Northern Tibetan Plateau. Remote Sensing Letters， 2018， 9（2）： 150-159.
9	Fu G， Shen Z X， Zhang X Z， et al. Response of microbial biomass to grazing in an alpine meadow along an elevation gradient on the Tibetan Plateau. European Journal of Soil Biology， 2012， 52： 27-29.
10	Tahmasebi P， Manafian N， Ebrahimi A， et al. Managing grazing intensity linked to forage quantity and quality trade-off in semiarid rangelands. Rangeland Ecology & Management， 2020， 73（1）： 53-60.
11	Ergon A， Kirwan L， Fystro G， et al. Species interactions in a grassland mixture under low nitrogen fertilization and two cutting frequencies. II. Nutritional quality. Grass and Forage Science， 2017， 72（2）： 333-342.
12	Van Soest P J， Robertson J B， Lewis B A. Methods for dietary fiber， neutral detergent fiber， and nonstarch polysaccharides in relation to animal nutrition. Journal of Dairy Science， 1991， 74（10）： 3583-3597.
13	Yemm E W， Willis A J. The estimation of carbohydrates in plant extracts by anthrone. Biochemical Journal， 1954， 57（3）： 508-514.
14	Lithourgidis A S， Vasilakoglou I B， Dhima K V， et al. Forage yield and quality of common vetch mixtures with oat and triticale in two seeding ratios. Field Crops Research， 2006， 99（2/3）： 106-113.
15	Fu G， Shen Z X. Grazing alters soil microbial community in alpine grasslands of Northern Tibet. Acta Prataculturae Sinica， 2017， 26（10）： 170-178.
	付刚，沈振西. 放牧改变了藏北高原高寒草甸土壤微生物群落. 草业学报， 2017， 26（10）： 170-178.
16	Fu G， Shen Z X. Response of alpine plants to nitrogen addition on the Tibetan Plateau： A meta-analysis. Journal of Plant Growth Regulation， 2016， 35（4）： 974-979.
17	Xu W， Zhu M Y， Zhang Z H， et al. Experimentally simulating warmer and wetter climate additively improves rangeland quality on the Tibetan Plateau. Journal of Applied Ecology， 2018， 55（3）： 1486-1497.
18	Sun T， Shang Z H， Liu Z Y， et al. Nutrient composition of four species of grasshoppers from alpine grasslands in the Qilian Mountain of the Tibetan Plateau， China. Philippine Agricultural Scientist， 2010， 93（1）： 97-103.
19	Shen S T， Zhang S J， Fan M， et al. Classification of plant functional types based on the nutrition traits： A case study on alpine meadow community in the Zoige Plateau. Journal of Mountain Science， 2017， 14（10）： 2003-2012.
20	Roukos C， Papanikolaou K， Karalazos A， et al. Changes in nutritional quality of herbage botanical components on a mountain side grassland in North-West Greece. Animal Feed Science and Technology， 2011， 169（1/2）： 24-34.
21	Thorvaldsson G， Tremblay G F， Kunelius H T. The effects of growth temperature on digestibility and fibre concentration of seven temperate grass species. Acta Agriculturae Scandinavica Section B-Soil and Plant Science， 2007， 57（4）： 322-328.
22	Shi C G， Silva L C R， Zhang H X， et al. Climate warming alters nitrogen dynamics and total non-structural carbohydrate accumulations of perennial herbs of distinctive functional groups during the plant senescence in autumn in an alpine meadow of the Tibetan Plateau， China. Agricultural and Forest Meteorology， 2015， 200： 21-29.
23	Scocco P， Piermarteri K， Malfatti A， et al. Increase of drought stress negatively affects the sustainability of extensive sheep farming in sub-Mediterranean climate. Journal of Arid Environments， 2016， 128： 50-58.
24	SchÖnbach P， Wan H， Schiborra A， et al. Short-term management and stocking rate effects of grazing sheep on herbage quality and productivity of Inner Mongolia steppe. Crop & Pasture Science， 2009， 60（10）： 963-974.
25	Miao F H， Guo Z G， Xue R， et al. Effects of grazing and precipitation on herbage biomass， herbage nutritive value， and yak performance in an alpine meadow on the Qinghai-Tibetan Plateau. PLoS ONE， 2015， 10（6）： e0127275.
26	Yao X X， Wu J P， Gong X Y. Precipitation and seasonality affect grazing impacts on herbage nutritive values in alpine meadows on the Qinghai-Tibet Plateau. Journal of Plant Ecology， 2019， 12（6）： 993-1008.
27	SchÖnbach P， Wan H， Gierus M， et al. Effects of grazing and precipitation on herbage production， herbage nutritive value and performance of sheep in continental steppe. Grass and Forage Science， 2012， 67（4）： 535-545.
28	Dong S K， Long R J， Hu Z Z， et al. Productivity and nutritive value of some cultivated perennial grasses and mixtures in the alpine region of the Tibetan Plateau. Grass and Forage Science， 2003， 58（3）： 302-308.
29	Yu C Q， Han F S， Fu G. Effects of 7 years experimental warming on soil bacterial and fungal community structure in the Northern Tibet alpine meadow at three elevations. Science of the Total Environment， 2019， 655： 814-822.

样地 Sample plot	β bray距离 β bray distance （βBray）			β 系统发育距离 β mean nearest taxon distance （βMNTD）
样地 Sample plot	群落Community	优势牧草Dominant forage	杂草Forbs	群落Community	优势牧草Dominant forage	杂草Forbs
A	7.08*	0.66	9.24*	59.51*	10.64	58.30*
B	1.87	0.80	1.21	-0.37	-2.78	0.65
C	3.57*	4.63	2.86+	12.12*	9.00	4.33

样地 Sample plot	β bray距离 β bray distance （βBray）			β 系统发育距离 β mean nearest taxon distance （βMNTD）
样地 Sample plot	群落Community	优势牧草Dominant forage	杂草Forbs	群落Community	优势牧草Dominant forage	杂草Forbs
A	7.08*	0.66	9.24*	59.51*	10.64	58.30*
B	1.87	0.80	1.21	-0.37	-2.78	0.65
C	3.57*	4.63	2.86+	12.12*	9.00	4.33

样地 Sample plot	群落 Community		Dominant forage优势牧草		Forbs杂草
样地 Sample plot	F	P	F	P	F	P
A	0.46	0.567	3.38	0.107	12.56*	0.026
B	20.75*	0.028	15.17*	0.028	1.05	0.398
C	2.01	0.142	5.02+	0.059	4.47*	0.032

样地 Sample plot	群落 Community		Dominant forage优势牧草		Forbs杂草
样地 Sample plot	F	P	F	P	F	P
A	0.46	0.567	3.38	0.107	12.56*	0.026
B	20.75*	0.028	15.17*	0.028	1.05	0.398
C	2.01	0.142	5.02+	0.059	4.47*	0.032

分组 Group	变量 Variables	SOC	TN	TP	NH₄⁺-N	NO₃^--N	AP	pH	C∶N	C∶P	N∶P	N∶P	NH₄⁺-N∶NO₃^--N
群落 Community	CP	0.66***	0.71***	0.14	0.41*	0.00	0.25	-0.64**	0.60**	0.63**	0.66***	0.12	0.46*
	ADF	0.10	0.07	-0.03	0.25	0.12	-0.04	-0.02	0.10	0.12	0.09	0.37+	-0.11
	NDF	0.07	0.08	0.06	0.15	0.09	-0.12	0.00	0.04	0.06	0.06	0.38+	-0.05
	EE	-0.12	-0.13	-0.19	-0.19	-0.16	-0.13	-0.02	-0.11	-0.09	-0.07	-0.20	-0.04
	Ash	-0.31	-0.33	-0.21	-0.24	0.05	-0.07	0.23	-0.27	-0.28	-0.28	-0.16	-0.22
	WSC	0.79***	0.82***	0.06	0.44*	-0.50*	0.40+	-0.68***	0.73***	0.78***	0.79***	-0.24	0.72***
	营养品质 Nutrition quality	-0.02	0.01	-0.06	-0.12	-0.04	-0.08	-0.07	-0.07	-0.04	-0.05	-0.06	-0.09
优势牧草 Dominant forage	CP	-0.22	-0.17	-0.05	-0.40+	-0.35+	-0.23	-0.02	-0.26	-0.23	-0.17	-0.35+	-0.13
	ADF	0.34	0.31	0.09	0.10	-0.55**	0.40+	-0.21	0.34	0.33	0.29	-0.47*	0.17
	NDF	0.12	0.13	-0.07	-0.07	-0.67***	0.20	-0.07	0.09	0.14	0.15	-0.52**	0.17
	EE	0.25	0.25	0.28	0.38+	0.30	0.30	-0.09	0.23	0.20	0.18	0.27	0.23
	Ash）	-0.22	-0.26	0.09	0.03	0.72***	-0.11	0.29	-0.18	-0.23	-0.28	0.43*	-0.27
	WSC	0.15	0.20	-0.01	-0.17	-0.11	-0.20	-0.44*	0.14	0.14	0.19	-0.13	0.07
	营养品质 Nutrition quality	-0.04	0.00	-0.13	-0.06	0.31*	0.05	0.16+	-0.08	-0.02	0.03	0.15	-0.05
杂草 Forbs	CP	0.23	0.26	-0.04	0.11	-0.05	-0.09	-0.38+	0.20	0.24	0.27	0.05	0.23
	ADF	0.16	0.23	0.05	-0.04	-0.13	-0.05	-0.22	0.08	0.13	0.20	-0.05	0.23
	NDF	0.45*	0.46*	0.19	0.26	-0.03	0.09	-0.48*	0.44*	0.42*	0.41*	0.09	0.35+
	EE	-0.43*	-0.45*	-0.19	-0.33	-0.07	-0.37+	0.42*	-0.37+	-0.42*	-0.42*	0.03	-0.13
	Ash	-0.45*	-0.47*	-0.06	-0.31	0.16	-0.04	0.61**	-0.43*	-0.42*	-0.44*	-0.05	-0.32
	WSC	0.34	0.40+	0.02	0.14	-0.18	-0.01	-0.47*	0.29	0.30	0.36+	-0.07	0.28
	营养品质 Nutrition quality	0.15*	0.15*	-0.07	-0.04	-0.02	-0.03	0.20*	0.14*	0.14*	0.13+	-0.11	0.05