Influence of Various Composted Organic Amendments and Their Rates of Application on Nitrogen Mineralization and Soil Productivity Using Chinese Cabbage (Brassica rapa. L. var. Chinensis) as an Indicator Crop

There is a diversity of locally available nitrogen (N)-rich organic materials in Samoa. However, none them was evaluated for their N supplying capacity after composting Samoan Inceptisols vegetable cultivation. Thus, N-releasing five composted amendments (OAs) namely macuna, gliricidia, erythrina, lawn grass and giant taro, two application rates (10 20 t ha−1) were assessed through laboratory incubation crop response study using Chinese cabbage as test crop. Among the OAs, mucuna characterized by higher total (2.91%), C (63.6%) NO3−N content (341 mg kg−1). A significant difference mineralization observed among OAs well rates. The highest recorded followed grass, taro. also showed similar trend. Mucuna treatment had biomass yield uptake Leguminous @ ha−1 performed substantially better all plant growth parameters, compared to 10 that not case non-leguminous OAs. should be applied at ha−1. All leguminous promising results while best both Therefore, can promoted supply cultivation Samoa, other Pacific Islands tropical countries where fertilizer costly easily available.