No abstract

Hydroponic corn cultivation is an efficient, fast, and feasible alternative for periods of food scarcity; however, there is still little information on the qualitative and quantitative parameters of the produced biomass, especially with regard to substrates. This study aimed to evaluate the productive and qualitative aspects of hydroponic feed corn grown on different substrates with a cultivation period of 15 days. Four substrates were evaluated: 1) fermented whole açaí seeds, 2) crushed açaí seeds, 3) sugarcane bagasse, and 4) ground Tifton hay, with five replications under a randomized block design. Substrate temperature was monitored during the production period. After harvesting on day 15, roots length (RL), shoot length (SL), biomass dry matter content (BDM), dry biomass yield, forage dry mass productivity, crude protein (CP), and ash content were assessed. There was no correlation of growth period and substrate temperature. RL was not affected by substrates, BDM was lower in treatment 3, CP was not influenced, and ash content was higher in treatment 1. In general, the best development was observed in treatment 1 because of the absence of distinction regarding qualitative parameters (CP and ash) and higher granulometry of whole açaí seeds which affects mass density and substrate aeration, thus allowing higher dry biomass yield.

Chamaecrista rotundifolia is a legume of high yield and nutritional value for livestock; however, it presents high seed dormancy. The aim of this study was to evaluate dormancy-breaking methods and the influence of soil texture on seedling emergence and initial development of C. rotundifolia. The experiment was performed in a greenhouse in a split-plot design with five replications. There were three treatments including dormancy-breaking techniques with immersion of the seeds in (1) hot water at 80°C for 30 s followed by 12 h in water at room temperature (25 °C; HW); (2) water at room temperature (25 °C) for 24 h (EW); and (3) hydrochloric acid (0.05 mol L-1) for 15 min (HA) (4) and a control group with no seed intervention, disposed in the main plots in randomized blocks. Seeds were cropped in two types of soil as subplots. Seedling emergence was evaluated daily to calculate the percentage emergence and emergence speed index. Plant performance was evaluated (21 days after sowing) through measurements of mass and length of components. Chamaecrista rotundifolia showed a high degree of dormancy in the seeds, and the treatment using HW had greater efficiency in seedling emergence (p < 0.01) and emergence speed index (p < 0.05). Total dry mass was superior in sandy soil (p < 0.05). Soil texture and dormancy treatments influenced the initial performance of plants, which performed better in sandy soil.

No abstract

Chamaecrista rotundifolia is a forage legume little used with Brazilian livestock; however, it has been studied for this purpose for over 40 years in Australia. The aim of this study was to characterize the influence of plant densities of approximately 444,400, 111,100 and 27,800 plants/ha (equivalent to spacings of 0.15 × 0.15; 0.30 × 0.30 and 0.60 × 0.60 m) on quantitative and qualitative parameters of C. rotundifolia grown in pure stands as forage under exclusive cropping for hay. While leaf dry matter yields in the first 93 days after planting ranged from 1.48 to 9.32 t DM/ha, declining to 0.71–4.92 t DM/ha in the subsequent 83 days, crude protein concentration of the material was only 7–8%. Since this species tends to lose leaf during periods of stress, larger paddock studies are needed to determine how well leaf material is retained under conventional hay-making conditions. Optimal stubble height following harvesting should be investigated in an endeavor to increase DM yields at second harvest along with improved survival of plants.