Effects of Diversification of Rainfed Cropping Systems to Enhance Sustained Yields for Semi-Arid Tropical Agroecosystems: Effects of 11–Years of Farmers’ Practice

Semi-arid tropical (SAT) soils cover approximately 11 million hectares (Mha) globally. Soils in SAT regions are prone to degradation if poorly managed, and approximately 38% of the developing countries’ poor who depend on these soils for their livelihood are at risk of malnutrition. Agronomic practices that can improve soil quality, and can sustain or improve crop productivity are critical for SAT agroecosystems. The objective of this study was to investigate the 11-year effects of farmer-imposed agronomic practices (cropping system and fertilization) on soil organic carbon (SOC), nitrogen (N), phosphorus (P), sulphur (S), and micronutrients [zinc (Zn) and boron (B)], and crop productivity in the Kothapally watershed, Andhra Pradesh, India. Rainfed diversified cropping systems with legumes in rotation or intercropping systems were compared with rainfed monoculture cotton systems. Soil samples were collected from each field of the participating twenty-three farmers in June 2010 and were compared with soil data collected in June 1999 from the same farmer’s fields. All soil samples were analyzed (with 10% replication) in the laboratory for physical and chemical characteristics using analysis of variance, where we tested the effects of crop (independent variable) on the dependent variables, e.g. SOC stocks, at p £ 0.05. Differences in the means were compared with a Tukey test. Relationships between SOC stocks and yield were evaluated with Pearson correlation analysis, and the sample size and correlation coefficients were reported when p £ 0.05. Increased SOC stocks were observed in rainfed diversified cropping systems with legumes in rotation or intercropping systems compared to rainfed monoculture cotton cropping system (p = 0.0283), and SOC stocks (in 2010) were correlated with 2010 crop yields (r = 0.384, n = 23, p £ 0.05). Overall, the 11-year study showed sustained crop productivity in rainfed diversified cropping systems compared to rainfed cotton cropping systems

Can airborne ultrasound monitor bubble size in chocolate?

Aerated chocolate products consist of solid chocolate with the inclusion of bubbles and are a popular consumer product in many countries. The volume fraction and size distribution of the bubbles has an effect on their sensory properties and manufacturing cost. For these reasons it is important to have an online real time process monitoring system capable of measuring their bubble size distribution. As these products are eaten by consumers it is desirable that the monitoring system is non contact to avoid food contaminations. In this work we assess the feasibility of using an airborne ultrasound system to monitor the bubble size distribution in aerated chocolate bars. The experimental results from the airborne acoustic experiments were compared with theoretical results for known bubble size distributions using COMSOL Multiphysics. This combined experimental and theoretical approach is used to develop a greater understanding of how ultrasound propagates through aerated chocolate and to assess the feasibility of using airborne ultrasound to monitor bubble size distribution in these systems. The results indicated that a smaller bubble size distribution would result in an increase in attenuation through the product

Identifying irrigation and nitrogen best management practices foraerobic rice–maize cropping system for semi-arid tropics using CERES-rice and maize models

Research based development of best management options for aerobic rice–maize cropping systems must be developed to improve water and nitrogen use efficiency. The main objective of this study was to identify water saving rice production technology for rice grown in sandy loam soils in semi-arid conditions using the calibrated CERES-Rice and Maize models of the Decision Support System for Agro Technology Transfer (DSSAT). A two-year experiment with two different crop establishment methods viz., aerobic rice and flooded rice with four nitrogen rates followed by maize under zero tilled conditions was used to calibrate and evaluate DSSAT CERES-Rice and CERES-Maize models. The calibrated models were used to develop best management options for an aerobic rice–maize sequence which can produce similar yields with water savings relative to that of traditional flooded rice–maize system. The results showed that application of 180 kg N ha−1 in four splits and automatic irrigation with 40 mm, when soil available water (ASW) in top 30 cm fell below to 60% was the best management combination for aerobic rice, saving 41% of water while producing 96% of the yield attainable under flooded conditions. Similarly for maize, application of 120 kg N ha−1 and irrigation with 30 mm of water at 40% ASW in the top 30 cm soil was the most dominant management option. Further, application of 180 kg N ha−1 with rice followed by 120 kg N ha−1 in maize provided stable yield for both aerobic and flooded rice systems over time as simulated by the model. The results illustrate that DSSAT model is a useful tool for evaluating alternative management options aimed at maintaining yields and saving water in rice–maize systems in semi-arid regions

Uptake efficiency of 15 N-urea in flooded and aerobic rice fields under semi-arid conditions

The sustainability of traditional rice (Oryza sativa L.) cultivation in many Asian countries is being questioned due to severe water shortage conditions, envisaging the need for development of water-saving rice production technologies. A 2-year-field study on a typic Haplustalf soil was conducted to compare traditional transplanted rice–maize system with water-saving aerobic rice–maize system, with an overall objective of investigating the fate of fertilizer nitrogen (N) using 15N-labeled urea. Results from the field experiments showed that the rice plants positively responded to N fertilizer application. The average fertilizer N recovery by rice crop over the 2 years in aerobic rice was 26 kg per 100 kg of applied fertilizer N in the main field and 21 kg per 100 kg of applied N in the microplot, while the recoveries were 41 and 32 kg ha−1 per 100 kg of applied N in traditionally cultivated rice under flooded conditions. The fraction of 15N that was found in soil after the harvest of rice crop ranged from 11.4 to 47.1 kg ha−1 in aerobic rice and 14.2–51.4 kg ha−1 in flooded rice. Average recovery of 15N fertilizer in maize after the first growing season was 3.3 %, and the corresponding recovery in soil was 19 %. An additional 1.3 % of the fertilizer was recovered by crops during the two subsequent seasons. This study indicates the need to develop management practices that improve N use efficiency in aerobic rice by reducing losses to improve yields and reduce N export to the environment

Impact of Aerobic Rice Cultivation on Growth, Yield, and Water Productivity of Rice–Maize Rotation in Semiarid Tropics

Limited water availability is a major constraint for cultivation of rice (Oryza sativa L.) in the traditional flooded systems, particularly in the semiarid regions of the world. Aerobic rice cultivation provides feasible alternative to traditional rice production in these regions, allowing significant water savings. Field experiments were conducted at the ANGR University Agricultural Research Station, India during 2009–2010 and 2010–2011 to compare crop growth, yield, and water savings under aerobic rice–maize (R–M) and flooded R–M rotation systems. The effect of aerobic rice on the succeeding maize crop was also studied. The total amount of water applied (including rainfall) in the aerobic plots was 967 and 645 mm compared to 1546 and 1181 mm in flooded rice system, during 2009 and 2010, respectively. This resulted in 37 to 45% water savings with the aerobic method. The soil moisture in aerobic treatment was maintained in the –30 to –40 kPa range throughout the crop growth. The aerobic rice system produced significantly lower grain yields in 2009 and 2010, where differences between flooded and aerobic rice were 39 and 15.4%, respectively. The yield differences were attributed to the differences in spikelet number per panicle and grain weight. Significant increase in yields was recorded in both systems with increased N rates up to 120 kg ha−1. Significantly higher yields were obtained in no-till maize grown subsequent to the aerobic rice than flooded rice, possibly due to residual soil N and improved soil physical conditions

Study of Spatial Water Requirement of Rice under Various Crop Establishment Methods Using GIS and Crop Models

Application of crop simulation models at larger spatial scales is very essential to develop best management practices in order to maximize yields and reduce environmental pollution. In the present study, spatial analysis of long- term simulations were carried out with DSSAT spatial analysis tool linked with GIS to estimate irrigation requirements and nitrate leaching under alternate rice establishment methods in the Wargal watershed, Andhra Pradesh, India. Rice yields were compared among three management scenarios: rainfed, aerobic and flooded systems. Grain yield, seasonal water balance components, nitrate leaching and water use efficiency were calculated, visualized and mapped with GIS. The rice productivity increased by 22% and 27% under aerobic and flooded management compared to rainfed rice. The adoption of new water efficient aerobic rice cultivation in the watershed resulted in 36% water saving with a relatively small yield reduction of 4%, thus increasing the water productivity to 0.77 g kg-1 in aerobic compared to 0.56 g kg-1 in flooded rice. The aerobic rice method reduced the overall water pumping hours to 88 h ha-1 during rice crop season compared to 299 h ha-1 with flooded rice cultivation, resulting in 71% energy savings

Soil Column Simulation of Natural Nutrient Flux after Short-term Inundation

Intact soil column studies have been widely used as laboratory simulations in determining the effects of long-term inundation on nutrient flux in soils, but preliminary studies on total Kjeldahl N (TKN) have shown that physical disturbance associated with current flooding techniques causes an overestimation of TKN flux after short-term inundation. Therefore, the objective of this study was to create a laboratory protocol that would minimize the effect of physical disturbance associated with current flooding procedures. To determine physical disturbance, total P concentrations were measured as a proxy for soil particles. Within 3 h of inundation, results found that total P concentrations in the water column were significantly reduced when using flat or cone-shaped filter paper on the soil surface compared with blanks. By adapting the Collins-filter barrier technique to short-term flooding simulations, we were able to more accurately predict TKN flux to represent a natural real-world response to short-term inundation

Dosimetry of Auger emitters: Physical and phenomenological approaches

Recent radiobiological studies have demonstrated that Auger cascades can cause severe biological damage contrary to expectations based on conventional dosimetry. Several determinants govern these effects, including the nature of the Auger electron spectrum; localized energy deposition; cellular geometry; chemical form of the carrier; cellular localization, concentration, and subcellular distribution of the radionuclide. Conventional dosimetry is inadequate in that these considerations are ignored. Our results provide the basis for biophysical approaches toward subcellular dosimetry of Auger emitters in vitro and in vivo. 12 refs., 7 figs., 2 tabs

Parametric Optimization of Abrasive Water Jet Cutting on AA 5083 through Multiobjective Teaching-Learning Method

The industrial sector is seeing an increase in the development of new technologies on a daily basis. Manufacturing advancements have resulted in low-intensity, inadequate outputs from cutting materials. The application of engineering materials requires cutting to produce the desired shapes and sizes. The material’s fundamental attributes are altered and utilised to improve machinability. Due to its significant benefits over traditional cutting processes, abrasive water jet cutting (AWJC) is now the most popular nonconventional machining for attaining the best cutting of any material. Because of its highly pressurised water power, the substance can quickly be separated from some properties by the use of a small pin with various kinds of abrasives. Due to the time-consuming process of cutting materials, determining optimal cutting conditions for the multiobjective criteria examined is a tough issue in techniques needing large resources. The operational parameters of the abrasive water jet cutting system must be changed in this article to achieve the lowest possible surface roughness while also attaining the maximum possible material removal rate. The abrasive water jet cutting method was utilised in this investigation to see how effectively the AA5083 aluminium alloy could be sliced. Water pressure, transverse speed, stand-off distance, and abrasive flow rate are some of the major cutting parameters that may be adjusted such that the output values such as material removal rate and surface roughness are at their optimal levels