Effect of soil type and sowing depth on the germination and early growth of two grain amaranth cultivars

Abstract Grain amaranth is a highly nutritious pseudo‐cereal with good adaptability to a range of environmental conditions and potential to be further cultivated in many areas of the world. Although the crop has good adaptability, soil type can influence crop establishment and production; thus, the objective of this study was to evaluate how cultivar, sowing depth, and soil type affect emergence and early growth of grain amaranth. A pot experiment was carried out in two runs under greenhouse conditions. The experiment was set in a randomized complete block design in a 3 × 5 × 2 factorial arrangement with three soil types (loam, clay loam, and clay) × five sowing depths (0, 5, 10, 15, and 20 mm) × two grain amaranth cultivars (Amaranthus cruentus BRS Alegria and Amaranthus caudatus Inca). Amaranthus caudatus had greater seedling height, stem diameter, number of leaves, root length, fresh weight, and dry weight compared to A. cruentus. Emergence was affected by cultivar and was 15% greater for A. cruentus. Seedling height was significantly greater at a 5 and 20 mm sowing depth. Root growth varied as a function of the interaction between soil types and sowing depths in which the longest roots were obtained when grain amaranth was sown in a loam soil at 10 mm depth. For better growth of grain amaranth, the recommended combination is A. caudatus in a loam soil at a depth between 5 and 20 mm

Nitrate: ammonium nutrition alleviates detrimental effects of salinity by enhancing photosystem II efficiency in sorghum plants

ABSTRACT This study was carried out to evaluate if replacement of nitrate (NO3-) by ammonium (NH4+) in the growth medium prevents the damage in the photosystem II (PSII) efficiency and degradation of photosynthetic pigments caused by saline stress in sorghum plants. Sorghum bicolor plants were cultivated in nutrient solutions containing different NO3-:NH4+ ratios (100:0, 75:25, 50:50, 25:75 and 0:100) at a final concentration of 5.0 mM. Salinity was imposed by adding NaCl at 75 mM in the growth medium; and the analysis were performed after ten days of salt stress. The most striking effects of nitrogen regime were observed in plants supplied with equal amounts of NO3-: NH4+ (50:50). Under salt stress, 50:50-grown plants displayed an increase in the photosystem II maximum efficiency (Fv/Fm), which was associated with a lower non-photochemical quenching (NPQ). The superior performance of salt-stressed plants grown in 50:50 ratio was indicated by a higher effective quantum yield of PSII (ΦPSII) and electron transport rate (ETR), as well as increased chlorophyll b and anthocyanins. In conclusion, nitrogen nutrition with same amounts of nitrate and ammonium avoids the degradation of photosynthetic pigments and allows higher PSII efficiency in salt-stressed sorghum plants

Staking system and planting spacing in the asparagus bean production

<p></p><p>ABSTRACT The optimization of plantation spacing, just like the use of staking plant systems, are cultural practices that have improved production efficiency of various kinds of vegetable. The aim of this study was to compare the asparagus bean cultivation conducted in different staking and spacing systems. The experiment was conducted in the design of randomized blocks in a factorial scheme (4x3) with four replicates. The first factor was constituted by four staking types [narrow ribbon vertical (FV), “V” normal (VN), inverted “V” (VI) and creeping (R)]. The second factor was constituted of three plant spacing (20, 40, and 60 cm), keeping constant the spacing of 1 m between crop rows. The evaluated characteristics were precocity (cultivation cycle); number of pods, mass of grains and pods per plant; length of pods; number of grains and mass of grains per pod; grain and pod yield. The gas exchange as well as the cost of deploying each of the treatments were also evaluated. The density of 50,000 plants/ha (spacing of 20 cm) provided the highest productivity in the FV and VI systems, with 9.10 and 6.72 t/ha, in addition to promoting higher net income to the producer, with averages of approximately 23 and 15 thousand R$ above R system. For the gas exchange variables, there was a reduction in net photosynthesis with density increase. The use of higher planting densities are indicated, combined with the use of FV and VI systems, in detriment to R system. The higher planting densities generate higher productivity and net income to the producer.</p><p></p