Phenology, growth, and yield of field-grown soybean and bush bean as a function of varying modes of N nutrition

Abstract

Summary-In field trials conducted at four sites in Hawaii, soybean (Glycine max) and bush bean (Phaseolus vulgaris) were either inoculated with homologous rhizobia, fertilized at high rates with urea, or left unamended. Crop phenology was assessed every few days. Rates of biomass and N accumulation and components of yield were measured five times during each crop cycle to assess the extent to which: (i) crops relying on soil, symbiotic, or fertilizer N differed in their growth characteristics; (ii) mode of N nutrition affected the timing of developmental stages; and (iii) effects of N nutrition on crop growth and development were related to final yield. While all measured variables differed significantly between sites, the effect of changing N source on these variables, in N limited environments, was consistent across sites. Rate and extent of node production, crop growth and yield were increased in symbiotic and N-fertilized crops as compared to unamended, non-fixing crops, while reproductive development was protracted. Extended time required to reach reproductive maturity was attributable to an increase in seed fill duration as time to flowering was not affected. Development and yield of N2-fixing crops were similar but not equivalent to those of N-fertilized crops. To produce reliable yield estimates, legume growth simulation models must be able to accurately simulate crop growth and phenology. The present data indicate that information relating to source and supply of N must be incorporated before such models can be used to generate reliable yield estimations. Results of these trials also provide a valuable dataset for calibrating model subroutines for inorganic nitrogen uptake and nitrogen fixation in soybean and bush bean growth under field conditions and adjusting model coefficients for tropical environments.

Tolerant pearl millet (Pennisetum glaucum (L.) R. Br.) varieties to low soil P have higher transpiration efficiency and lower flowering delay than sensitive ones

“…Irrigation was suspended in ws treatments at 56 DAS and restarted at 74 DAS during grain filling at the end of the rains and of grain filling occuring solely under residual moisture. That is why it is generally accepted that annual plants flower and mature earlier to avoid late-season water stress (Thies et al 1995;Dorn et al 2000;Gungula et al 2003). In contrast to previous findings, the data from our first trial show that genotypes sensitive to low P had a larger delay in flowering under LP.…”

Nitrogen uptake, fixation and response to fertilizer N in soybeans: A review

“…Still, most of the 11 data points that defined the responsive high-yielding sites in Figure 5 came from experiments in which N was applied after R3, indicating a tendency for extra N during grain filling under high-yield conditions. This analysis included only a few studies conducted at high yield levels (Parker and Harris, 1977, Ray et al, 2005, Thies et al, 1995, Wesley et al, 1998. Published data for soybean yields >5 Mg ha −1 are scarce and there are no reported measurements of N uptake and N 2 fixation from field studies in which soybean yields approach the yield potential.…”

“…Because some studies on N fertilization did not concurrently quantify N 2 fixation and other studies did not evaluate response to N fertilizer when quantifying N 2 fixation, data analyses were performed for two data sub-sets: Data set A was used to examine relationships between N uptake, N 2 fixation and grain yield; Data set B was used to evaluate yield response to fertilizer-N. Data set A comprised 61 studies in which N 2 fixation was quantified. Several different techniques were used: (1) the N difference method (Dashti et al, 1998, Israel and Burton, 1997, Israel and Mikkelsen, 2001, Saxena and Chandel, 1997, Thies et al, 1995, Wagner and Zapata, 1982, Weber, 1966; (2) Ureides determination in the xylem sap (Gan et al, 2002, Guafa et al, 1993, Herridge, 1982, Herridge et al, 1990, Hughes and Herridge, 1989, Hungria et al, 2003, Peoples et al, 1995a, Reis et al, 2002, Takahashi et al, 1992, Yinbo et al, 1997, Ying et al, 1992, Zotarelli, 2000; (3) 15 N dilution and abundance techniques (Afza et al, 1987, Alvarez et al, 1995, Alves et al, 2006, Amarger et al, 1979, Bergersen et al, 1989, Bergersen et al, 1992, Boddey et al, 1990, Chapman and Myers, 1987, Coale et al, 1985, Eaglesham et al, 1982a, Eaglesham et al, 1982b, George and Singleton, 1992, Guffy et al, 1989, Hardarson et al, 1984, Hardarson et al, 1989, Kucey et al, 1988a...…”

“…Studies of nodulated soybeans showed significant yield response to frequent N additions when the N 2 fixation apparatus could not meet N demand (Thies et al, 1995). However, yield response of soybean to fertilizer N has been inconsistent at economically acceptable levels (Barker and Sawyer, 2005, Gan et al, 2003, Schmitt et al, 2001).…”

To Meet Future Food Demands We Need to Change from Annual Grain Legumes to Multipurpose Semi-Perennial Legumes

“…Furthermore, models have been developed for leguminous grain crops like soyabean (Lim et al, 1990;Thies et al, 1995), faba bean (Stützel, 1995) (Hammer et al 1995). Nevertheless, none of these approaches take N 2 -fixation into account in a mechanistic manner in spite of its importance for nitrogen dynamics of legume-based cropping systems in the short as well as in the longer term.…”