Legume-Based Mobile Green Manure Can Increase Soil Nitrogen Availability and Yield of Organic Greenhouse Tomatoes

Information about the availability of soil mineral nitrogen (N) in organic greenhouse tomatoes after the application of mobile green manure (MGM), and its impact on plant nutrient status and yield is scarce. Considering this knowledge gap, the effects of legume biomass from faba beans that are cultivated outdoors (FAB), or from feed-grade alfalfa pellets at two different doses (AAL = 330 g m−2; AAH = 660 g m−2) that were applied as MGM on the nutrition and yield of an organic greenhouse crop of tomatoes were evaluated. All of the MGM treatments increased the mineral N concentrations in the soil throughout the cropping period, and the total N concentration in tomato leaves when compared to the untreated control. FAB and AAH treatments had a stronger impact than AAL in all of the measured parameters. In addition, AAL, AAH, and FAB treatments increased the yield compared to the control by 19%, 33%, and 36%, respectively. The application of MGM, either as faba bean fresh biomass or as alfalfa dry pellets, in organic greenhouse tomatoes significantly increased the plant available soil N, improved N nutrition, and enhanced the fruit yield. However, the N mineralization rates after the MGM application were excessive during the initial cropping stages, followed by a marked decrease thereafter. This may impose an N deficiency during the late cropping period.

Ameliorative Effects of Nitrogen Application on Vegetative Growth and Productivity in Genotypes of Ragi (Eleusine coracana Gaertn.) under Saline Conditions

Background: Salinity and low soil nitrogen availability are important growth limiting factors for most crops. The proper use of N fertilizer is not only important for growth but it may also alter the salinity tolerance of plants depending on the level of salinity. Methods: The present study was undertaken to determine the interactive effects of N nutrition and saline irrigations (3, 6, 7.2, 10, 12 and 14 dSm-1) on growth and grain productivity in two varieties of finger millet viz. VL-315 and Local Hills. Different growth and productivity parameters (like plant height, dry weight of shoot, root and leaves, dry weight of panicle/plant, no. of grains, grain yield/plant etc.) adversely affected by saline irrigations, however, nitrogen nutrition minimized at different levels of salinity. Result: The positive response of nitrogen was comparatively higher at lower salinity levels (3-7.2 dSm-1) as well as at control than higher salinity (10-14 dSm-1). The effect of salinity was lower in cv. VL- 315 than Local Hills, but the interactive effects of N nutrition and salinity also enhanced the dry weight of shoot, root, leaves, dry weight of panicles and grains/plant. It is probable that N nutrition had enhanced assimilation of NO3-1-N, through the activity of NRA which further increased total nitrogen and protein content in leaves, hence, enhanced growth, biological and grain yield in both cultivars.