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Interpretive Summaries:
2005 - Soil Nutrient Management and Balanced Fertilization in Ningxia
2004 - Studies on Soil Nutrient Management Technology in Ningxia
2003 - Soil Nutrient Management and Fertilizer Use Strategies in Ningxia
2002 - Soil Nutrient Management and Fertilizer Use Strategies in Ningxia
Studies on Soil Nutrient Management Technology in Ningxia, 2004
The Ningxia Hui Autonomous Region, located in northwest China, has 400,000 hectares (ha) of cultivated land with access to irrigation from the Yellow River. Although this area accounts for only one-quarter of the total land cultivated in Ningxia, it produces three-quarters of the region's total crop production. Main crops include wheat, rice, maize, potato, grape, watermelon, and wolfberry.
Initial soil testing on a seed farm in Huinong County indicated that soils were low in available nitrogen (N) and potassium (K), while available phosphorus (P) was considered moderate. Two rice field trials, arranged at the Lingwu Monitoring Village, found 51%, 12%, and 14% yield reductions when N, P, and K were omitted. The highest yield and economic benefit was obtained with 225-150-150 kg N-P2O5-K2O/ha. Compared to the optimum treatment (OPT), omission of N, P, and K decreased tomato yield by 12%, 12%, and 29%, respectively; celery yield was lowered by 20%, 14%, and 18%. Potassium increased tomato yield by 5 to 11% (3,455 to 6,980 kg/ha) and improved net returns by US$35 to US$48/ha; celery yield was increased by 14 to 27% (16,720 to 31,670 kg/ha) and net returns were increased by US$258/ha to US$461/ha.
Field demonstrations were arranged in order to verify the past 3 years’ results. In 67 ha of rice demonstration in Linwu Village, K application increased yield by 10% (1,050 kg/ha) and enhanced gross income by US$203/ha. In Huinong Village, the 67 ha of field demonstrations included several crops wherein K increased yield of celery, sunflower, tomato, pimento, wheat, and maize by 17%, 4%, 9%, 7%, 4%, and 5%, respectively.
A long-term K fertilizer experiment (11 years) was continued in 2004 to monitor K cycling in the crop-soil system, study the effect of straw application on the soil K balance, and study the effect of K fertilizer application on crop yield. Application of 150 kg K2O/ha increased wheat and corn yields by 4% and 7%, respectively. The combination of recycled wheat straw plus potassium chloride (KCl) increased wheat yield by 7%. Soil analysis after harvesting indicated that available soil K and slow-release K were higher after K fertilizer and/or straw application than if fertilizer or straw were omitted. Application of K fertilizer and straw significantly increased crop uptake of N, P, and K. Ningxia-NMS02
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