INTEGRATED AGRICULTURAL SYSTEMS
Tomato Crop Response to Short-Duration Legume Green Manures in Tropical Vegetable Systems
Carmen Thönnissena, David J. Midmorea, Jagdish K. Ladhab, Robert J. Holmerc and Urs Schmidhalterd
a The Asian Vegetable Res. & Dev. Ctr., P.O. Box 42, Shanhua Tainan, Taiwan People’s Republic of China
b IRRI, P.O. Box 933, Manila 1099, Philippines
c Bukidnon Resources Co., Inc. (BRCI), Diklum, Manola Fortich, Bukidnon 8703, Philippines
d Dep. of Plant Nutrition, Technische Universität München, Freising-Weihenstephan, D-85350 Germany
The potential of legume green manure (GM) as an alternativeto mineral N fertilizer in tropical horticulture has receivedscant attention. The feasibility of meeting N needs of tomato(Lycopersicon esculentum Mill.) with GM was studied in six fieldexperiments at three locations in major vegetable growing areasof Taiwan and the Philippines between 1993 and 1995. Legumebiomass, N2 fixation and N accumulation, and tomato yield andN uptake were quantified within a 6-mo experiment cropping pattern.Yields of GM-amended tomato crops were compared with those amendedwith fertilizer N (0–150 kg N ha-1). The residual effectof the fertilizing method of a second crop (maize; Zea maysL.) was estimated at AVRDC by measures of biomass and N uptake30 d after sowing. Legume N recovery in tomato crops was tracedwith 15N at Mariano Marcos State University (MMSU). Soybean[Glycine max (L.) Merr.] harvested at 60 to 74 d accumulateda minimum of 2.8 Mg ha-1 biomass and 100 kg ha-1 N in all locationsand seasons. A maximum of 6 Mg biomass ha-1 and 140 kg N ha-1was reached in the wet season (WS) at AVRDC. Indigofera (Indigoferatinctoria L.) and mungbean [Vigna radiata (L.) Wilcz.] biomassyields were more variable and always inferior than soybean yields.Tomato yields across locations ranged from 3 to 70 Mg fruitha-1. Tomato yields responded to GM N in the WS in Taiwan andin the northern Philippines, comparing favorably with fertilizerat 38 to 120 kg N ha-1. No response to GM N was found in thedry season (DS) at AVRDC or at Bukidnon Resources Company, Inc.(BRCI). The 15N experiments showed that only a small fractionof legume N (9–15%) was recovered by the tomato crop atMMSU. Maize biomass and N uptake, following the tomato crop,was increased with soybean GM compared with the control in theAVRDC WS and DS. Tomato yield response to GM N is high on infertilesoils and tomato N requirement can be substituted fully or partiallyby GM, depending on soil N mineralization.
Abbreviations: AVRDC, Asian Vegetable Research and Development Center • BRCI, Bukidnon Resources Company, Inc. • DS, dry season • GM, [legume] green manure • IRRI, International Rice Research Institute • MMSU, Mariano Marcos State University • WS, wet season
Agronomy Journal 92:245-253 (2000). © 2000 American Society of Agronomy.