Analyses on nutrient requirements in current agriculture production in China

ObjectivesAnalyses of the nutrient requirements in current agricultural production and estimation of the chemical fertilizer demand in China will provide theoretical reference for the reliance of zero growth of chemical fertilizers by 2020, and also provide practical guide for rationally distribute, scientifically manage and apply nutrient resources under the situation of zero growth of chemical fertilizers.

MethodsBased on latest national statistical data, research data and literature review, this study made systematic estimation on N, P and K requirements by crops, forest, grassland and aquiculture under balance fertilization at a provincial level. The fertilizer gaps among fertilizer need and current consumption were also estimated considering recycle of available nutrients from organic sources.

ResultsThe current N, P₂O₅, K₂O requirements in China's agricultural production were 3746×10⁴ t for N, 2024×10⁴ t for P₂O₅ and 2640×10⁴ t for K₂O, respectively, with a total of 8410×10⁴ t. Grain crops, vegetables/melons, fruits/tea, oil crops, fiber crops, sugar crops, forage/grassland and aquiculture were accounted for 41.8%, 20.8%, 13.1%, 5.1%, 2.3%, 2.1%, 10.6% and 2.2% of total nutrient requirements, respectively. Northcentral (NC), Middle and Lower Reaches of Yangzi River (MLRY), Northwest (NW), Southwest (SW), Southeast (SE) and Northeast (NE) region were accounted for 20.3%, 23.2%, 18.8%, 16.8%, 11.1% and 9.8%, respectively, while nutrient requirements in Shandong, Henan and Sichuan were more than other provinces. Among the total nutrient consumption in China, chemical fertilizer was 6023×10⁴ t including 3001×10⁴ t N, 1943×10⁴ t P₂O₅ and 1079×10⁴t K₂O; the consumption distribution in NE, NC, MLRY, SE, SW and NW was accounted for 10.6%, 27.7%, 24.4%, 11.5%, 11.4% and 14.2%, respectively. The organic nutrient capacity was 3200×10⁴ t N, 1440×10⁴ t P₂O₅ and 3400×10⁴ t K₂O, but the available nutrient returned to cropland was estimated to be 484×10⁴ t N, 411×10⁴ t P₂O₅, 1273×10⁴ t K₂O. Organic nutrient return was mainly distributed in Hebei, Henan, Shandong, Sichuan and Hunan provinces, followed by Guangdong, Guangxi and Yunnan provinces, while relative small amount in NW, NE and SE regions. Gaps between fertilizer consumption and fertilizer demand indicated that N and K inputs were not enough as a whole in China, N and K₂O inputs were respectively in deficit of 261×10⁴ t and 288×10⁴ t, while P inputs were overused with 330×10⁴ t P₂O₅ surplus. Great difference existed in fertilizer gaps among provinces and regions. In some provinces of NE, NC, MLRY or SE regions such as Jilin, Hebei, Henan, Shandong, Anhui, Jiangsu, Hubei and Guangdong provinces, N, P and K fertilizers were all overused, but fertilizer inputs in most provinces of NW and SW regions were insufficient.

ConclusionsGrain crops were the main nutrient demander, followed by vegetables and fruit trees. Under the hypothesis of balanced fertilization achieved in all crops and areas, nitrogen and potassium fertilizer inputs were insufficient, and phosphate fertilizer inputs were excessive. Great variations existed among regions in nutrient requirement. The NE, NC, MLRY and SE coastal areas need to appropriately reduce fertilizer consumption and the NW and SW regions need to appropriately increase fertilizer inputs based on nutrient requirements.