Productivity of natural phytocenoses of the Namsky agrolandscape in Yakutia under organic and mineral nutrition regimes

The results of the study of the productivity potential of natural phytocenoses of different species composition in the Namsky agrolandscape of the middle taiga subzone of the Republic of Sakha (Yakutia) are presented. The research was conducted in 2009-2016. The soils of the experimental plot are permafrost soils with a thin humus layer. The effect of mineral and organic fertilizers on the productivity of steppe meadows was studied. On herb-grass, wheatgrass, steppificated phytocenoses the following practices of organo-mineral nutrition of plants were used: control (no fertilizer); humus 20 t/ha; humus 20 t/ha once every 4 years + N60P60K60 annually; N30P30K30 annually; humus 20 t/ha annually. The optimum rates of organic and mineral nutrients to improve the productivity potential of natural steppe meadows have been established. The highest productivity potential in the Namsky agrolandscape was obtained with the combined application of organic and mineral fertilizers (humus 20 t/ha once every 4 years + N60P60K60 annually). On herb-grass and wheatgrass phytocenoses hay yield reached 23.0-24.1 c/ha. Yield per 1 ha of metabolizable energy was 27.0-22.4 GJ, fodder units 1472-1663, crude protein 336-371 kg. The content of digestible protein in 1 fodder unit in herb-grass was 92 g, in wheatgrass - 102 g. The annual application of mineral fertilizers at a dose of 60 kg/ha of the active substance provided a 2-fold increase in the productivity of natural phytocenoses, depending on agroclimatic conditions of the growing season. The influence of mineral fertilizers and their joint application with organic fertilizers on the yield of natural phytocenoses is statistically reliable, which indicates the possibility of regulating the productivity of steppificated phytocenoses.

Root deformation affects mineral nutrition but not leaf gas exchange and growth of Genipa americana seedlings during the recovery phase after soil flooding

Root deformation (RD) caused by errors in the pricking out process are irreversible and very difficult to detect in container-grown seedlings at the time of planting in the field. The objective of this study was to evaluate the effects of RD on leaf gas exchange, growth, biomass allocation and mineral nutrition of G. americana seedlings during the recovery phase after soil flooding. Four-months-old seedlings, with and without RD, were flooded for 42 days and their recovery was evaluated 28 days after soil drainage. There were no significant interactions between RD and soil flooding for all leaf gas exchange, growth and mineral nutrition after soil drainage, with the exception of leaf P concentrations. In plants with no RD, the P concentration in leaves of non-flooded plants was significantly higher than that of plants with RD. Soil flooding and RD did not influence leaf or root N concentrations or whole-plant N content. RD increased the K concentration in the roots, but not in the leaves. Changes in the nutrient concentrations in leaves and roots indicate that RD may affect physiological performance of seedlings after planting in the field.

Influence of Nitrogen Sources Applied by Fertigation to an Enriched Soil with Organic Compost on Growth, Mineral Nutrition, and Phytochemicals Content of Coriander (Coriandrum sativum L.) in Two Successive Harvests

The aim of the present study was to evaluate the effects of nitrogen source applied by fertigation to an enriched soil with organic compost on plant growth, mineral nutrition, and phytochemical contents in two successive harvests in coriander. The treatments were as follows: unfertilized soil, soil enriched with organic compost, and soil enriched with organic compost to which 60 kg N ha−1 as ammonium nitrate and as ammonium sulfate applied by fertigation were added. Ammonium nitrate addition allowed to obtain a high total fresh yield (3.6 kg m−2) with a low inorganic nitrogen input. Ammonium nitrate increased plant shoot dry weight; fresh yield; and shoot N, K, and Ca uptake in the first harvest. Ammonium nitrate relative to organic compost and to ammonium sulfate increased fresh yield by approximately 57 and 25%, respectively. However, ammonium sulfate in the first harvest greatly increased shoot total phenols, from 137 mgGAE/100 g FW in ammonium nitrate to 280.4 mgGAE/100 g FW. Coriander’s fresh yield, in the second harvest, was unaffected by nitrogen addition. However, ammonium nitrate increased shoot total phenols and FRAP activity. Overall, the shoot phytochemical accumulation in the second harvest was lower than in the first. The combined application of ammonium nitrate and organic compost is a strategy to reduce inorganic nitrogen application.

Cultural treatments in pineapple crop. Management for high yield – Review

Several factors influence in the vegetative development, yield and quality of pineapple fruits, among which the cultural treatments adopted throughout the production cycle stand out, mainly weed control, mineral nutrition, irrigation and induction artificial flowering. The purpose of this review was to present the main advances in research on cultural treatments in the cultivation of pineapple (Ananas comosus L. Merril) and their effects on yield and fruit quality. Current research shows that interventions for weed management, through chemical control with herbicides or the adoption of organic or inorganic soil cover are strategies that can be adopted by producers who seek to reduce labor costs and provide good conditions for plant development. The use of mulching is a promising and effective practice, given the cost reduction with polluting herbicide applications and improvement of the physicochemical quality of the soil. Regarding mineral nutrition, pineapple is a rustic plant, tolerant to soils with moderate acidity and low levels of nutrients in the soil, however, liming and fertilization are essential for crops where high yields are sought. In the same way, it is verified that the pineapple, even being a CAM metabolism plant, tolerant to situations of water stress, is highly responsive to irrigation, which provides improvements in the vegetative and reproductive development of the plant. Another essential management practice in pineapple crops is artificial floral induction, a practice that aims to synchronize the flowering period, facilitate harvesting and ensure a consumer market in times when the supply of fruit is scarce