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Declining rate of productivity and environmental sustainability is forcing growers to use organic manures as a source of nutrient supplement in maize farming. However, weed is a major constraint to maize production. A field study was carried out over two seasons to evaluate various integrated nutrient and weed management practices in hybrid maize. The treatment combinations comprised of supplementation of inorganic fertilizer (25% nitrogen) through bulky (Farmyard manure and vermicompost) and concentrated (Brassicaceous seed meal (BSM) and neem cake (NC)) organic manures and different mode of weed management practices like chemical (atrazine 1000 g ha−1) and integrated approach (atrazine 1000 g ha−1 followed by mechanical weeding). Repeated supplementation of nitrogen through concentrated organic manures reduced the density and biomass accumulation of most dominant weed species, Anagalis arvensis by releasing allelochemicals into the soil. But organic manures had no significant impact on restricting the growth of bold seeded weeds like Vicia hirsuta and weed propagated through tubers i.e., Cyperus rotundus in maize. By restricting the weed growth and nutrient removal by most dominating weeds, application of BSM enhanced the growth and yield of maize crop. Repeated addition of organic manures (BSM) enhanced the maize grain yield by 19% over sole chemical fertilizer in the second year of study. Application of atrazine as pre-emergence (PRE) herbicide significantly reduced the density of A. arvensis, whereas integration of mechanical weeding following herbicide controlled those weeds which were not usually controlled with the application of atrazine. As a result, atrazine at PRE followed by mechanical weeding produced the highest maize grain yield 6.81 and 7.10 t/ha in the first year and second year of study, respectively. [ABSTRACT FROM AUTHOR]

Sodic-alkalinity is a more seriously limiting factor in agricultural productivity than salinity. Oat (Avena nuda) is a salt-tolerant crop species and is therefore useful in studying the physiological responses of cereals to alkalinity. We evaluated the differential effects of sodic-alkalinity on two naked oat lines, Caoyou1 and Yanke1. Seedlings of the two lines were exposed to 50 mM alkaline salt mixture of NaHCO3 and Na2CO3 (18:1 molar ratio; pH 8.5) for 2 weeks in a soil environment. Sodic-alkalinity exposure led the assimilation of abundant Na+ at similar concentrations in the organs of both lines. However, Caoyou1 showed much stronger growth than Yanke1, exhibiting a higher dry weight, total leaf area, and shoot height under sodic-alkalinity. Further analysis showed that Caoyou1 was more sodic-alkalinity tolerance than Yanke1. This was firstly because of differences in the oxidative stress defense mechanisms in leaves of the two lines. Antioxidant enzyme activities were either slightly elevated (catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GP), glutathione reductase (GR)) or unaltered (superoxide dismutase (SOD)) in Caoyou1 leaves, but some enzyme (SOD, GPOX, GR) activities were significantly reduced in Yanke1. AnAPX1 transcript levels significantly increased in Caoyou1 under sodic-alkalinity conditions compared with Yanke1, indicating its better antioxidant capacity. Secondly, the related parameters of Mg2+ concentration, phosphoenolpyruvate carboxylase (PEPC) activity, and AnPEPC transcript levels in the leaves showed significantly higher values in Caoyou1 compared with Yanke1. This demonstrated the effective utilization by Caoyou1 of accumulated HCO3− in the irreversible reaction from phosphoenolpyruvate to oxaloacetate to produce inorganic phosphorus, which was elevated in Caoyou1 leaves under alkalinity stress. Overall, the results demonstrated that the greater sodic-alkalinity tolerance of Caoyou1 is the result of: (1) maintained antioxidant enzyme activities; and (2) a higher capacity for the phosphoenolpyruvate to oxaloacetate reactions, as shown by the higher PEPC activity, Mg2+ concentration, and total phosphorus concentration in its leaves, despite the lower soil pH. [ABSTRACT FROM AUTHOR]

In the coastal zone of the Ganges Delta, water shortages due to soil salinity limit the yield of dry season crops. To alleviate water shortage as a consequence of salinity stress in the coastal saline ecosystem, the effect of different water-saving (WS) and water-conserving options was assessed on growth, yield and water use of tomato; two field experiments were carried out at Gosaba, West Bengal, India in consecutive seasons during the winter of 2016–17 and 2017–18. The experiment was laid out in a randomized block design with five treatments viz., surface irrigation, surface irrigation + straw mulching, drip irrigation at 100% reference evapotranspiration (ET0), drip irrigation at 80% ET0, drip irrigation at 80% ET0 + straw mulching. Application of drip irrigation at 80% ET0 + straw mulching brought about significantly the highest fruit as well as the marketable yield of tomato (Solanum lycopersicum L.). The soil reaction (pH), post-harvest organic carbon, nitrogen, phosphorus and potassium (N, P and K) status and soil microbial population along with the biochemical quality parameters of tomato (juice pH, ascorbic acid, total soluble solids and sugar content of fruits) were significantly influenced by combined application of drip irrigation and straw mulching. Surface irrigation significantly increased the salinity level in surface and sub-surface soil layers while the least salinity development was observed in surface mulched plots receiving irrigation water through drip irrigation. The highest water productivity was also improved from drip irrigation at 80% ET0 + straw mulched plots irrespective of the year of experimentation. Such intervention also helped in reducing salinity stress for the tomato crop. Thus, straw mulching along with drip irrigation at 80% ET0 can be recommended as the most suitable irrigation option for tomato crop in the study area as well as coastal saline regions of South Asia. Finally, it can be concluded that the judicious application of irrigation water not only increased growth, yield and quality tomatoes but also minimized the negative impact of soil salinity on tomatoes grown in the coastal saline ecosystem of Ganges Delta. [ABSTRACT FROM AUTHOR]

Soil salinity has emerged as one of the most prominent threats to modern intensive farming systems, and it has necessitated the cultivation of halophytes to ensure food security and human nutrition. Peucedanum japonicum Thunb. is an edible wild plant with medicinal value that is widely distributed along the Pacific coast of western Japan. However, the adaptive mechanisms of this plant with respect to salt stress tolerance have not yet to be elucidated. The purpose of this study was to compare the physiological responses of P. japonicum to salt stress with those of barley (Hordeum vulgare), which is considered a salinity-tolerant plant. Seedlings of both species at the same height were exposed to different concentrations (0, 50, 75, and 150 mM) of NaCl for 16 days, after which the leaves were analyzed with respect to different physiological parameters. The results revealed a maintenance of leaf growth in P. japonicum compared with that in barley, the growth of which was severely impaired at low concentrations of NaCl (50 and 75 mM). In response to salt stress, a higher suppression of Na+ and Cl− assimilations was observed in P. japonicum than in barley under all NaCl treatments. Moreover, P. japonicum showed a greater ability to maintain leaf K+ and Ca2+ concentrations, whereas barley exhibited a significant reduction in the concentrations of these ions under saline conditions. Thus, the superior salinity tolerance of P. japonicum could be attributed to a more efficient maintenance of ionic balances. Taken together, our results indicate that P. japonicum may be classified as a halophyte, given its superior regulation of K+, Ca2+, SO4−, and sucrose concentrations and lower NO3− concentrations compared with those of barley. [ABSTRACT FROM AUTHOR]

Sodic-alkalinity is a serious limiting factor in agricultural productivity. This study was conducted to examine the contribution of acclimation to the adaptation of rye (Secale cereale) to sodic-alkalinity. Effects of acclimation were determined in two sets of experiments: One experiment for mineral accumulation, antioxidative capacity, and other physiological parameters; and a vivo experiment for root Evan's Blue and Na+ influx from medium to root. Being exposed to sodic-alkalinity, acclimation did not affect plant dry weight. However, acclimation significantly reduced Na+ concentration and maintained a lower Na+/K+ ratio in all the tissues, increased the Ca2+ and Mg2+ concentrations in the root tissues, and increased the water uptake ability in comparison to the non-acclimated plants. Acclimation increased the antioxidant capacity represented by the increased activities of the enzymes SOD, GR, CAT, and GPOX in the leaf tissues of acclimated plants in comparison to the non-acclimated plants. Moreover, acclimation increased the root cell viability inhibited the Na+ influx to the root tissues in comparison to the non-acclimated plants. Together, these results suggest that rye can acclimate to sodic-alkalinity by increasing root cell viability, and therefore limited Na+ influx to root tissues and increased water uptake and antioxidant capacities without any change in the plant growth. [ABSTRACT FROM AUTHOR]

Crop seed phosphorus (P) is primarily stored in the form of phytate, which is generally indigestible by monogastric animals. Low-phytate soybean lines have been developed to solve various problems related to seed phytate. There is little information available on the effects of P fertilization on productivity, physiological characteristics, and seed yield and quality in low-phytate soybeans. To address this knowledge gap, studies were conducted with a low-phytate line and two normal-phytate cultivars from western Japan when grown under high- and low-P fertilization. The whole plant dry weight, leaf photosynthesis, dinitrogen fixation, and nodule dry weight at the flowering stage were higher in the higher P application level, but were not different between the low-phytate line and normal-phytate cultivars. As expected, seed yield was higher in the higher level of P application for all lines. Notably, it was higher in the low-phytate line as compared with the normal-phytate cultivars at both levels of fertilizer P. The total P concentration in the seeds of the low-phytate line was the same as that of the normal-phytate cultivars, but the phytate P concentration in the low-phytate line was about 50% less than that of the normal-phytate cultivars. As a result the molar ratio of phytic acid to Zn, Fe, Mn, and Cu in seed were also significantly lower in the low-phytate line. From these results, it can be concluded that growth after germination, leaf photosynthesis, nitrogen fixation, yield and seed quality were not less in the low-phytate soybean line as compared with two unrelated normal-phytate cultivars currently grown in Japan, and that low-phytate soybeans may improve the bioavailability of microelements. [ABSTRACT FROM AUTHOR]