Effects of drip irrigation frequency, fertilizer sources and their interaction on the dry matter and yield components of sweet corn

Irrigation frequency is one of the most important factors in the management of water in the agriculture sector to sustain crop productivity, especially in arid and semi-arid regions of the world. Additionally, fertilizers have to be adequately applied. An experiment was carried out under a rain shelter from July to December 2012 in Malaysia to determine the effects of irrigation frequency and fertilizer sources on the growth and yield of sweet corn planted on a limed sandy clay, Ultisol, using a drip-irrigation system. This experiment was conducted using a split-plot design with four drip-irrigation frequencies (daily, once every 2 days, once every 3 days and once every 4 days) and four sources of fertilizers (NPK, goat manure, poultry manure and control). The drip irrigation was the main plot, while fertilizers were the subplot factors. The results of the study indicated that total dry matter and yield components increased with the increase in drip-irrigation frequency with values of 44% and 32% respectively. The highest growth parameters and shoot dry weight were recorded from daily irrigation intervals with goat manure, while the highest yield components were obtained from daily irrigation frequency with NPK fertilizer and poultry manure. In the light of these results, therefore, for optimum biomass of corn, high irrigation frequency with goat and poultry manure is the most viable option while yield was greatly favoured by a high irrigation frequency with NPK

Using plant species for phytoremediation of highly weathered soils contaminated with zinc and copper with application of sewage sludge

The ability of woody plant species to remediate heavy metals contaminated soils was investigated with the addition of sewage sludge. Jatropha curcas, Hibiscus cannabinus, Acacia mangium, and Syzygium cumini growth was monitored on an Oxisol-and an Ultisol-treated soil with sewage sludge at a level of 0% w/w, 5% w/w, or 10% w/w. The sewage sludge was found to enhance soil fertility, as shown by an increase in soil pH, cation exchange capacity, exchangeable bases (potassium, calcium, and magnesium), available phosphorous, total carbon, and total nitrogen. However, zinc and copper accumulated in soils at toxic levels; thus, they had to be removed before being used for crop production. The concentration of the two heavy metals in Jatropha curcas and Hibiscus cannabinus at harvest were higher than those of Acacia mangium and Syzygium cumini. The high uptake of zinc and copper by the first two plant species was the result of their high translocation factor, although the bio-concentration factor was low. Thus, Jatropha curcas and Hibiscus cannabinus were considered tolerant to zinc and copper toxicity and able to remove the metals efficiently from the contaminated soils

Synergistic Use of Remote Sensing and Modeling for Estimating Net Primary Productivity in the Red Sea With VGPM, Eppley-VGPM, and CbPM Models Intercomparison

Primary productivity (PP) has been recently investigated using remote sensing-based models over quite limited geographical areas of the Red Sea. This work sheds light on how phytoplankton and primary production would react to the effects of global warming in the extreme environment of the Red Sea and, hence, illuminates how similar regions may behave in the context of climate variability. study focuses on using satellite observations to conduct an intercomparison of three net primary production (NPP) models--the vertically generalized production model (VGPM), the Eppley-VGPM, and the carbon-based production model (CbPM)--produced over the Red Sea domain for the 1998-2018 time period. A detailed investigation is conducted using multilinear regression analysis, multivariate visualization, and moving averages correlative analysis to uncover the models\u27 responses to various climate factors. Here, we use the models\u27 eight-day composite and monthly averages compared with satellite-based variables, including chlorophyll-a (Chla), mixed layer depth (MLD), and sea-surface temperature (SST). Seasonal anomalies of NPP are analyzed against different climate indices, namely, the North Pacific Gyre Oscillation (NPGO), the multivariate ENSO Index (MEI), the Pacific Decadal Oscillation (PDO), the North Atlantic Oscillation (NAO), and the Dipole Mode Index (DMI). In our study, only the CbPM showed significant correlations with NPGO, MEI, and PDO, with disagreements relative to the other two NPP models. This can be attributed to the models\u27 connection to oceanographic and atmospheric parameters, as well as the trends in the southern Red Sea, thus calling for further validation efforts

Multidecadal Analysis of Beach Loss at the Major Offshore Sea Turtle Nesting Islands in the Northern Arabian Gulf

Undocumented historical losses of sea turtle nesting beaches worldwide could overestimate the successes of conservation measures and misrepresent the actual status of the sea turtle population. In addition, the suitability of many sea turtle nesting sites continues to decline even without in-depth scientific studies of the extent of losses and impacts to the population. In this study, multidecadal changes in the outlines and area of Jana and Karan islands, major sea turtle nesting sites in the Arabian Gulf, were compared using available Kodak aerographic images, USGS EROS Declassified satellite imagery, and ESRI satellite images. A decrease of 5.1% and 1.7% of the area of Jana and Karan islands, respectively, were observed between 1965 and 2017. This translated to 14,146 m2 of beach loss at Jana Is. and 16,376 m2 of beach loss at Karan Is. There was an increase of island extent for Karan Is. from 1965 to 1968 by 9098 m2 but comparing 2017 with 1968, Karan Is. lost as much as 25,474 m2 or 2.6% of the island extent in 1968. The decrease in island aerial extent was attributed to loss of beach sand. The southern tips of the island lost the most significant amount of sand. There was also thinning of beach sand along the middle and northern sections that exposed the rock outcrops underneath the beach. The process of beach changes of both islands was tracked by the satellite imagery from Landsat 1,3,5,7 and Sentinel-2 during 1972 to 2020. Other factors including the distribution of beach slope, sea level changes, as well as wind & current from both northward and eastward components were analyzed to show its impact on the beach changes. The loss of beach sand could potentially impact the quality and availability of nesting beach for sea turtles utilizing the islands as main nesting grounds. Drivers of beach loss at the offshore islands are discussed in the context of sea level rise, dust storms, extreme wave heights and island desertification

Influence of NPK fertilizer rates and irrigation frequencies on the biomass and yield components of sweet corn (Zea mays L.)

Application of adequate fertilizers becomes one of the most important agronomic practices to sustain corn production on soils of the tropical regions, which are mostly acidic and poor in nutrients. An experiment under rain shelter was conducted at the Faculty of Agriculture, Universiti Putra Malaysia, Serdang to evaluate the influence of different NPK fertilizer rates on the biomass and yield components of sweet corn. The experiment was carried out using split plot design with four replications. Three drip irrigation frequencies as a main plot: [Once in 2 days (Ir1), once in 3 days (Ir2) and once in 4 days irrigations (Ir3)] and four NPK fertilizer rates as sub-plot [0:0:0 (0%), 60:30:45 (50%), 120:60:90 (100%) and 180:90:135 (150%), henceforth referred to as F1, F2, F3 and F4, respectively] were tested in this experiment. The results of the study showed that total dry matter significantly (P<0.05) increased with increase in the irrigation frequencies. For Ir1 treatments at F4 fertilizer rate, the shoot dry weight was higher compared to the other fertilizer rates due to better nutrient supply to the plant. Similarly, irrigation frequency and fertilizer levels significantly (P<0.05) influenced the yield components. Ear, cob and grain were found to have higher weight for once in 2 days irrigation frequency with fertilizer level of F4. When fertilizer rate was increased from 100% (F3) to 150% (F4), ear, cob and grain weight were increased by 25%, 39% and 23%, respectively

Zinc-lysine Supplementation Mitigates Oxidative Stress in Rapeseed (Brassica napus L.) by Preventing Phytotoxicity of Chromium, When Irrigated with Tannery Wastewater

Contamination of soil and water with metals and metalloids is one of the most serious problems worldwide due to a lack of a healthy diet and food scarcity. Moreover, the cultivation of oilseed crops such as rapeseed (Brassica napus L.) with tannery wastewater could contain a large amount of toxic heavy metals [e.g., chromium (Cr)], which ultimately reduce its yield and directly influence oilseed quality. To overcome Cr toxicity in B. napus, a pot experiment was conducted to enhance plant growth and biomass by using newly introduced role of micronutrient-amino chelates [Zinc-lysine (Zn-lys)], which was irrigated with different levels [0% (control), 33%, 66%, and 100%] of tannery wastewater. According to the results of present findings, very high content of Cr in the wastewater directly affected plant growth and composition as well as gas exchange parameters, while boosting up the production of reactive oxygen species (ROS) and induced oxidative damage in the roots and leaves of B. napus. However, activities of antioxidants initially increased (33% of wastewater), but further addition of tannery wastewater in the soil caused a decrease in antioxidant enzymes, which also manifested by Zn content, while the conscious addition of wastewater significantly increased Cr content in the roots and shoots of B. napus. To reduce Cr toxicity in B. napus plants, exogenous supplementation of Zn-lys (10 mg/L) plays an effective role in increasing morpho-physiological attributes of B. napus and also reduces the oxidative stress in the roots and leaves of the oilseed crop (B. napus). Enhancement in different growth attributes was directly linked with increased in antioxidative enzymes while decreased uptake and accumulation of Cr content in B. napus when cultivated in wastewater with the application of Zn-lys. Zn-lys, therefore, plays a protective role in reducing the Cr toxicity of B. napus through an increase in plant growth and lowering of Cr uptake in various plant organs. However, further studies at field levels are required to explore the mechanisms of Zn&ndash;lys mediated reduction of Cr and possibly other heavy metal toxicity in plants

Mycosubtilin Produced by <i>Bacillus subtilis</i> ATCC6633 Inhibits Growth and Mycotoxin Biosynthesis of <i>Fusarium graminearum</i> and <i>Fusarium verticillioides</i>

Fusarium graminearum and Fusarium verticillioides are fungal pathogens that cause diseases in cereal crops, such as Fusarium head blight (FHB), seedling blight, and stalk rot. They also produce a variety of mycotoxins that reduce crop yields and threaten human and animal health. Several strategies for controlling these diseases have been developed. However, due to a lack of resistant cultivars and the hazards of chemical fungicides, efforts are now focused on the biocontrol of plant diseases, which is a more sustainable and environmentally friendly approach. In the present study, the lipopeptide mycosubtilin purified from Bacillus subtilis ATCC6633 significantly suppressed the growth of F. graminearum PH-1 and F. verticillioides 7600 in vitro. Mycosubtilin caused the destruction and deformation of plasma membranes and cell walls in F. graminearum hyphae. Additionally, mycosubtilin inhibited conidial spore formation and germination of both fungi in a dose-dependent manner. In planta experiments demonstrated the ability of mycosubtilin to control the adverse effects caused by F. graminearum and F. verticillioides on wheat heads and maize kernels, respectively. Mycosubtilin significantly decreased the production of deoxynivalenol (DON) and B-series fumonisins (FB1, FB2 and FB3) in infected grains, with inhibition rates of 48.92, 48.48, 52.42, and 59.44%, respectively. The qRT-PCR analysis showed that mycosubtilin significantly downregulated genes involved in mycotoxin biosynthesis. In conclusion, mycosubtilin produced by B. subtilis ATCC6633 was shown to have potential as a biological agent to control plant diseases and Fusarium toxin contamination caused by F. graminearum and F. verticillioides.</i