Long-term fertilization effects on yield trends and soil properties under a winter wheat-summer maize cropping system

Yang, Xueyun
Yang, Yang
Sun, Benhua
Zhang, Shulan
African Journal of Agricultural Research
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This study examined yield trends and changes in soil chemical properties during a 26-year field experiment, involving a winter wheat - summer maize rotation on a loessial soil in China. Mean yields of wheat and maize increased significantly with increasing rates of manure (M) or inorganic nitrogen and phosphorus (NP) application. However, over time, the yield of both crops declined under the NP treatments, although the change was only significant for wheat. Positive yield responses for both crops were recorded under M+NP treatments. Soil organic matter and soil total N increased under all treatments. The Olsen P level dropped significantly in NP plots and increased markedly in manured plots. There was a reduction in soil exchangeable potassium under nearly all treatments, particularly on NP, where it dropped from an initial concentration of 245 mg kg-1 to ca. 110 mg kg-1. We conclude that annual inputs of NP fertilizers at rates of less than 240 kg ha-1 N and 52 kg ha-1 P were not sufficient to sustain crop production in the system investigated. The practice of applying organic manure as well as NP should be modified to facilitate continued crop production and to provide environmental protection.
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African Journal of Agricultural Research
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Document Type: 
Journal Issue/Article
Grassland Society of Southern Africa

The Grassland Society of Southern Africa (GSSA) is involved and concerned with the science and practice of range and pasture management. This broad field involves primarily the use and conservation of natural resources. It encompasses applied fields such as livestock production, wildlife management, nature conservation, water catchment management and range and mine-dump rehabilitation. The disciplines include, amongst others, ecology, botany zoology, range and pasture science, animal science, soil science and genetics. This collection includes journal articles from the African Journal of Range and Forage Science as well as related articles and reports from throughout the Southern African region.