Synthetic gel structures in soils for sustainable potato farming

Abstract

Anti-pathogenic protection of potatoes remains one of the most pressing problems of sustainable agronomy and plant protection. For this purpose, we propose to use a new type of synthetic hydrogels filled with amphiphilic recipients (dispersed peat, humates) and modern plant protection products. We assumed that the introduction of swollen gel structures into the rhizosphere of potatoes will allow us: to optimize the water supply and productivity of potatoes; to protect the fertile layer and potato tubers from the main pathogens; to fix modern plant protection products in the rhizosphere, keeping them from leaching and entering the environment. Preliminary laboratory experiments tested the anti-microbial activity of gel structures, as well as their water retention, dispersity and hydraulic conductivity with subsequent computer modeling of the water exchange and root uptake in the system of “soil-gel-potato”. Field trials were carried out in humid (European Russia) and arid (Uzbekistan) conditions under the atmospheric precipitation and irrigation on different soils and potato varieties with instrumental monitoring of environment, potato growth and quality. All experimental results confirmed the high efficiency of water-accumulative and plant protective synthetic gel structures. Their usage sufficiently (up to 6–15 t/hct) increases the potato yield with 1.3–2 times water saving, complete retention of agrochemicals in the rizosphere, and its actually total protection against major potato pathogens, including late blight (Phytophthora infestans).

Water retention in sandy substrates modified by cross‐linked polymeric microgels and their complexes with a linear cationic polymer

“…Such a significant change in the structural organization of sand after treatment with microgels was also reflected in the pore size distribution (Figure 2(b)). The radii of the dominant pores of the obtained compositions shifted to the micropore region (about 1 μ), together with a strong expansion of the pore size distribution, which, according to, 25,41 reflects the aggregating effect of gels on the mineral substrate. At the same time, the obtained structure has a pore micro‐space of sufficient size for the free swelling of microgel particles, the dominant size (radius) of which in the swollen state does not exceed 200–250 nm (Table 2).…”

“…Being swollen in water, cross‐linked polymers (hydrogels) favor accumulation of moisture in eroded sandy and sandy loamy soils of arid regions, thus preventing gravity runoff and evaporation of water 18–19 . Additionally, cross‐linked polymers are able to increase the digestibility of mobile plant nutrients, 20,21 bind toxic compounds, including heavy metal ions, 22,23 and ensure a prolonged release of fungicides and pesticides 24,25 . The capacity of hydrogels to water, which 300–500 times exceeds the weight of polymer itself, is dependent on many factors, including the content of ionic groups in macromolecules, a degree of cross‐linking, composition of the absorbed solution, and a particle size of hydrogel 26–27 …”

Gel-Forming Soil Conditioners of Combined Action: Laboratory Tests for Functionality and Stability

“…Gel-forming polymeric materials can be considered as the most promising agents for soil conditioning [ 1 , 2 , 3 , 4 , 5 ], especially for widespread Arenosols [ 6 ]. The water absorption of some synthetic hydrogels, for example those based on an acrylic polymer matrix, reaches 500–1000 kg H 2 O per 1 kg of dry polymer and more [ 7 , 8 , 9 ].…”

“…The water absorption of some synthetic hydrogels, for example those based on an acrylic polymer matrix, reaches 500–1000 kg H 2 O per 1 kg of dry polymer and more [ 7 , 8 , 9 ]. This technological property of acrylic superabsorbents is effectively used in increasing the water-retention of Arenosols for saving water in arid irrigation farming and landscaping [ 3 , 4 , 5 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Small doses of gel conditioners (0.1–0.6% per mass) are sufficient to improve the water-retaining capacity of sands to the level of fertile loamy soils [ 13 , 15 , 17 ].…”

Effectiveness of slow‐release fungicide formulations for suppressing potato pathogens

“…55,56,62 The positive result of pre-emergence soil application of the embedded azoxystrobin was described in Smagin. 21 The fungicide was loaded into prolonged-action gel structures based on acrylates with silver ions. The use of this fungicide increased the yield of potatoes in some experiments from 6 to 15 t ha −1 while saving water for irrigation by 1.3-2.0 times.…”