Decomposition, nitrogen and phosphorus mineralization from winter-grown cover crop residues and suitability for a smallholder farming system in South Africa
Decomposition, nitrogen and phosphorus mineralization from winter-grown cover crop residues and suitability for a smallholder farming system in South Africa
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冬季生长的覆盖作物残留物的分解、氮和磷矿化以及南非小农耕作系统的适用性
DOI：
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发表时间：
2010
影响因子：
3.1
通讯作者：
P. Mnkeni
中科院分区：
文献类型：
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作者：
F. S. Murungu;C. Chiduza;P. Muchaonyerwa;P. Mnkeni
日益严重的土地退化引起了人们对保护性农业的兴趣，其中包括种植覆盖作物。除了提供土壤覆盖外，腐烂的覆盖作物还可能释放大量的养分。对冬季覆盖作物[野豌豆(Vicia Darsycarpa)、饲用豌豆(Pisum Sativum)和燕麦(Avena Sativa)]的分解、N和P释放进行了评估，以确定其在南非小农灌溉部门的种植制度中的适宜性。还估算了覆盖作物残体对玉米生长的氮、磷贡献。覆盖作物残留物质量下降幅度最大的是放牧豌豆(124天后残留量为7%)，其次是饲用豌豆(16%)，最后是燕麦(40%)。最大净矿化N、P含量牧草(84.8 mg·N/kg；P=3.6 mg/kg)高于饲用豌豆(66.3 mg·N/kg；2.7 mg P/ha)和燕麦(13.7 mg·N/kg；2.8 mg P/kg)。放牧野豌豆和饲用豌豆残留物对玉米秸秆的氮素贡献高于燕麦残留物。农户可利用野豌豆改良土壤矿质氮，燕麦分解慢，可提高土壤有机质，减少土地退化。在夏季作物种植前一个月终止豆类覆盖作物，使冬季种植的豆类覆盖作物释放的养分与夏季作物吸收的养分同步。
Increasing land degradation has prompted interest in conservation agriculture which includes growing cover crops. Besides providing soil cover, decaying cover crops may release substantial amounts of nutrients. Decomposition, N and P release from winter cover crops [grazing vetch (Vicia darsycarpa), forage peas (Pisum sativum) and oats (Avena sativa)] were assessed for suitability in a cropping system found in the smallholder irrigation sector of South Africa. Nitrogen and P contribution to maize growth by cover crop residues was also estimated. Decrease in mass of cover crop residues was highest in grazing vetch (7% remaining mass after 124 days) followed by forage peas (16%) and lastly oats (40%). Maximum net mineralized N and P were higher for grazing vetch (84.8 mg N/kg; 3.6 mg P/kg) than for forage peas (66.3 mg N/kg; 2.7 mg P/ha) and oats (13.7 mg N/kg; 2.8 mg P/kg). Grazing vetch and forage pea residues resulted in higher N contribution to maize stover than oat residues. Farmers may use grazing vetch for improvement of soil mineral N while oats may result in enhancement of soil organic matter and reduction land degradation because of their slow decomposition. Terminating legume cover crops a month before planting summer crops synchronizes nutrient release from winter-grown legume cover crops and uptake by summer crops.