连续耕种和退耕造林对典型草原氮、磷养分的影响

doi:10.3864/j.issn.0578-1752.2026.19.007

Abstract

Abstract:

【Objective】This study aimed to investigate the effects of long-term cultivation and cropland afforestation on soil nitrogen and phosphorus nutrients in typical grasslands of Inner Mongolia, so as to provide the scientific basis for rational utilization and sustainable development of grassland.【Method】Soil samples were collected in 0 to 50 cm soil layers from natural grassland, cropland (continuously cultivated for 60 years) and shrubland (afforestation for 17-18 years) of typical grassland in XilinGol, Inner Mongolia in August 2020. The content of soil total nitrogen (TN), total phosphorus (TP), ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N) and available phosphorus (AP) were compared and analyzed under different land-use types.【Result】Grassland cultivation and the conversion of cropland to shrubland significantly affected soil nitrogen and phosphorus nutrients: (1) Reclamation and long-term cultivation of natural grassland significantly reduced the content of total nitrogen, total phosphorus, and ammonium nitrogen in the 0-10 cm soil layer, while significantly increasing the available phosphorus content in the 0-30 cm soil layer. (2) Following shrubland establishment through cropland conversion, no significant changes were observed in soil total nitrogen or ammonium nitrogen content; however, nitrate nitrogen content throughout the 0-50 cm profile, total phosphorus in the 20-50 cm soil layer, and available phosphorus in the 0-30 cm soil layer all decreased significantly. (3) In response to land-use change, soil nitrate nitrogen and available phosphorus-representing readily available nutrient pools-exhibited more pronounced changes compared to total nitrogen and total phosphorus.【Conclusion】Grassland cultivation significantly decreased the content of soil total nitrogen and total phosphorus, however, the current management model of planting leguminous shrubs combined with understory herb harvesting struggled to achieve effective soil nutrient recovery in the short term and might even exacerbate phosphorus deficiency.

Key words: grassland cultivation, conversion of cropland to shrubland, soil nitrogen, soil phosphorus, typical steppe

BAO YuFan, ZHU Na, ZHANG JingMin, ZHAO Man, LIU JiaHui, LUO YuHong, LI Le, XU Nuo, YAN YuChun. Effects of Continuous Cultivation and Cropland Afforestation on Nitrogen and Phosphorus Nutrients in Typical Steppe[J].Scientia Agricultura Sinica, 2026, 59(19): 4277-4288.

Figures/Tables 8

Table 1

Basic characteristics of study sites"

		样地1 Site1
草地 Grassland	优势种 Dominant species	糙隐子草、羊草、苔草、克氏针茅 Cleistogenes squarrosa, Leymus chinensis, Carex duriuscula, Stipa krylovii
草地 Grassland	管理方式 Management	放牧 Grazing	放牧 Grazing	刈割 Mowing	刈割 Mowing	刈割 Mowing
耕地 Cropland	开垦年限 Cultivation duration (a)	60	60	60	60	60
	作物类型 Crop type	向日葵 Helianthus annuus	小麦 Triticum aestivum	小麦 Triticum aestivum	小麦 Triticum aestivum	苜蓿 Medicago sativa
	管理方式 Management	1960-2013：小麦-燕麦轮作 2013-2020：小麦-燕麦-向日葵轮作灌溉施肥 Triticum aestivum-Avena sativa rotation from1960 to 2013, Triticum aestivum-Avena sativa and Helianthus annuus rotation after 2013 Irrigation Fertilization	1960-2020：小麦-燕麦轮作施肥 Triticum aestivum-Avena sativa rotation from1960 to 2020 Fertilization	1960-2020：小麦-燕麦轮作施肥 Triticum aestivum-Avena sativa rotation from1960 to 2020 Fertilization	1960-2020：小麦-燕麦轮作施肥 Triticum aestivum-Avena sativa rotation from1960 to 2020 Fertilization	1960-2017：小麦 2017-2020：苜蓿灌溉施肥 Triticum aestivum planting from 1960 to 2017, Medicago sativa planting after 2017 Irrigation Fertilization
灌木林地 Shrubland	土地利用历史 Land use history	开垦43年后退耕造林17年 Afforestation for 17 years following a 43-year cultivation	开垦43年后退耕造林17年 Afforestation for 17 years following a 43-year cultivation	开垦43年后退耕造林17年 Afforestation for 17 years following a 43-year cultivation	开垦43年后退耕造林17年 Afforestation for 17 years following a 43-year cultivation	开垦42年后退耕造林18年 Afforestation for 18 years following a 42-year cultivation
	林下草地优势种 Understory dominant species	黄蒿Artemisia scoparia 披碱草Elymus dahuricus 糙隐子草Cleistogenes squarrosa	大籽蒿Artemisia sieversiana 黄蒿Artemisia scoparia	糙隐子草Cleistogenes squarrosa 黄蒿Artemisia scoparia 无芒雀麦Bromus inermis	羊草Leymus chinensis 黄蒿Artemisia scoparia	羊草Leymus chinensis 阿尔泰狗娃花Heteropappus altaicus
	管理方式 Management	刈割 Mowing	刈割 Mowing	放牧 Grazing	刈割 Mowing	放牧 Grazing

Table 1

Table 2

Fig. 1

Fig. 2

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Fig. 6

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变量 Variable	全氮 Total nitrogen, TN		全磷 Total phosphorus, TP		铵态氮 Ammonium nitrogen		硝态氮 Nitrate nitrogen		速效磷 Available phosphorus		铵态氮/全氮 Ammonium nitrogen/TN		硝态氮/全氮 Nitrate nitrogen/TN		速效磷/全磷 Available phosphorus/TP
变量 Variable	F	Sig.	F	Sig.	F	Sig.	F	Sig.	F	Sig.	F	Sig.	F	Sig.	F	Sig.
用地类型 Land-use type	53.512	***	48.436	***	10.335	***	71.255	***	71.747	***	11.716	***	58.027	***	53.167	***
土层Soil layer	125.073	***	24.866	***	7.442	***	16.498	***	30.032	***	31.246	***	2.522	*	8.489	***
样点Site	104.697	***	28.8	***	9.841	***	0.537	NS	25.589	***	47.637	***	14.011	***	17.217	***
用地类型×土层 Land-use type× Soil layer	6.012	***	1.006	NS	1.694	0.07	2.433	***	9.551	***	5.014	***	0.671	NS	8.007	***
用地类型×样点 Land-use type×Site	2.048	*	4.1	***	15.657	***	2.479	***	6.983	***	18.487	***	6.343	***	7.098	***
土层×样点 Soil layer×Site	3.923	***	1.993	*	1.174	0.292	1.322	NS	2.156	**	3.999	***	1.248	NS	1.062	NS
用地类型×土层×样点 Land-use type× Soil layer×Site	1.414	*	0.709	NS	0.989	0.501	1.618	*	1.072	NS	2.197	***	1.966	**	0.968	NS

Effects of Continuous Cultivation and Cropland Afforestation on Nitrogen and Phosphorus Nutrients in Typical Steppe

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