Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8970804 | Agriculture, Ecosystems & Environment | 2005 | 17 Pages |
Abstract
Wheat (Triticum aestivum L.) and corn (Zea mays L.) rotation system is important for food security in the Loess Plateau of China. Grain yield and water-use efficiency (WUE: grain yield per unit of water consumed) trends, and changes in soil properties during a 24-year fertilization experiment in Pingliang, Gansu, China, were recorded. Mean yields of wheat for the 16 years started in 1981 ranged from 1.29 t haâ1 for the unfertilized plots (CK) to 4.71 t haâ1 for the plots that received manure (M) annually with inorganic nitrogen (N) and phosphorus (P) fertilizers (MNP). Corn yields for the 6 years started in 1979 averaged 2.29 and 5.61 t haâ1 in the same treatments. Yields and WUEs declined significantly with lapse of time except CK and MNP for wheat. Wheat yields with the N and M declined at rate of 77 and 81 kg haâ1 yearâ1, but the decline of 57 kg haâ1 yearâ1 for NP was similar to that of 61 haâ1 yearâ1 for straw with N annually and P every second year (SNP). Likewise, the corn yields and WUEs declined from 160 to 250 kg haâ1 yearâ1 and from 0.01 to 0.03 kg mâ3 yearâ1 among treatments, respectively. These declines were likely to loss of soil fertility and gradual dry weather. Yields were significantly correlated with seasonal evapotranspiration with slopes ranging from 0.5 to 1.27 kg mâ3 for wheat and from 1.15 to 2.03 kg mâ3 for corn. Soil organic carbon (SOC), total N (TN), and total P (TP) gradually built up with time except the CK, in which TN and TP remained unchanged but SOC and available P (AP) decreased. Soil AP decreased in the N. Soil available K declined rapidly without straw or manure. Balanced fertilization should be encouraged to ensure sustainable productivity in this intensive cropping system. The greatest SOC increases of about 160 mg haâ1 yearâ1 occurred in the SNP and MNP, suggesting that long-term additions of organic materials to soil could increase soil water-holding capacity which, in return, improves water availability to plants and arrests yield declines, and decrease CO2 emission from agricultural soils and sustain land productivity.
Keywords
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Agronomy and Crop Science
Authors
Tinglu Fan, B.A. Stewart, Wang Yong, Luo Junjie, Zhou Guangye,