Rock biofertilizer and earthworm compost on sugarcane performance and soil attributes in two consecutive years

ABSTRACT The deployment of soluble fertilizers has been one of the most commonly applied agricultural practices in the bid to increase crop yield. However, the production of soluble fertilizers has a considerable economic cost and consumes a substantial amount of energy. In general, soil organic matter provides the nutrients needed for plant growth in organic agriculture. However, these nutrients are not sufficient if the best yield is to be obtained. The aim of our field experiment was to evaluate the effectiveness of phosphate and potassic sources (rocks, bio-fertilizers and soluble fertilizers) based on several sugarcane characteristics and soil attributes. Our experiment was conducted over two consecutive years, and we assessed the effect of using sugarcane filter mud cake (SFMC). In addition, we mixed the phosphate and potassic sources with earthworm compost enriched in N by inoculation with diazotrophic bacteria (OM) and applied at 50, 100 and 150 % of the recommended dosage rate (RDR). The PK biofertilizer with OM enriched in N positively affected sugarcane height, yield, and industrial characteristics. The application of SFMC greatly increased available P and K in the soil and plant characteristics with residual effect in the two consecutive harvests. We conclude that the biofertilizer has the potential to increase sugarcane characteristics and may represent an alternative to soluble fertilizers

Hydraulic isothermal pressure reduction turbine: An efficient and low-cost electricity generation source

There is currently a large amount of energy being wasted on pressure reduction valves across the world. This paper argues that this energy could be harnessed with isothermal depressurization by applying a hydraulic isothermal pressure reduction turbine. The hydraulic isothermal pressure reduction turbine consists of two tanks filled with water or an organic liquid. The pressurized gas enters the tank, displacing the liquid, which flows through a turbine, generating electricity. The proposed system has efficiencies surrounding 90%, which is higher than usual pressure reduction turbines. The estimated cost for the proposed technology is 1300 USD/kW. The proposed technology could be feasible to harness the potential for electricity generation wasted in pressure reduction valves. The need for this technology will increase significantly in a future hydrogen-based economy, given the low volumetric density of hydrogen and the significant energy losses when compressing and decompressing hydrogen

Soil cover plants on water erosion control in the South of Minas Gerais

Water erosion is responsible for soil, water, carbon and nutrient losses, turning into the most important type of degradation of Brazilian soils. This study aimed to evaluate the influence of three cover plants under two tillage systems on water erosion control in an Argisol at south of Minas Gerais state, Brazil. The cover plants utilized in the study were pigeon pea, jack bean and millet, under contour seeding and downslope tillage. Experimental plots of 4 x 12 m, with 9% slope, under natural rainfall were used for the quantification of losses of soil, water, nutrients, and organic matter. One experimental plot was kept without plant cover (reference). Higher erosivity was observed in December and January, although a great quantity of erosive rainfall was detected during the whole raining period. Contour seeding provided a greater reduction of water erosion than downslope tillage, as expected. The jack bean under contour seeding revealed the lowest values of soil, water, nutrients and organic matter losses