Organic Fertilization Improves the Availability and Adsorptive Capacity of Phosphorus in Saline-Alkaline Soils

Abstract

Organic fertilizer could improve soil phosphorus (P) availability and retention capacity, and the intensive management of P nutrition in saline alkaline paddy soil is of great significance to the sustainable development of rice planting. The P fractions and adsorption-desorption characteristic in saline-alkaline soils were evaluated in a 5-year field experiment. Four treatments were designed: (1) NK (255 kg N ha −1 year −1 and 229 kg K ha −1 year −1), (2) NPK (128 kg P 2 O 5 ha −1 year −1 plus NK), (3) NPKC1 (450 kg C ha −1 year −1 plus NPK), and (4) NPKC2 (900 kg C ha −1 year −1 plus NPK). The results showed that, compared with NPK treatment, soil available P (AP) concentration was significantly increased in NPKC1 and NPKC2 treatments. Especially, soil NaHCO 3-P i concentration was increased by 112.4% and 94.6% in NPKC1 and NPKC2 treatments, respectively. And soil organic carbon (SOC) showed similar trend. However, soil pH and electrical conductivity (EC) were decreased in two organic fertilization treatments. The isothermal adsorption experiment showed that the X m values of all treatments were in the order of NPKC1 > NPKC2 > NK > NPK. Correlation analysis showed that X m was positively correlated with SOC and negatively correlated with soil pH. Under the same initial P concentration, the desorption rates in NPKC1 treatment was the lowest, which indicated that low organic fertilizer was more conducive to the soil P retention capacity. Therefore, organic fertilizer application could increase soil P availability and retention capacity, and lower organic fertilizer addition (NPKC1) was better to improve soil P availability and retention capacity in saline-alkaline soils.

Soil chemical attributes under combinations of organic fertilizing and water salinity

“…This can be attributed to the supply of nutrients afforded by organic fertilizers, which increases the soil P content (Table 3), particularly at lower salinity levels, and to the fact that the nutrient is also extracted from the soil solution by the plant during its cycle, what can also reduce its levels in the soil. Contrary to the present study, Mengmeng et al (2021) found an increase in the levels of available phosphorus in soil affected by salts, when using organic fertilizer.…”

Biomass composite with exogenous organic acid addition supports the growth of sweet sorghum (Sorghum bicolor ‘Dochna’) by reducing salinity and increasing nutrient levels in coastal saline–alkaline soil

“…As leaf residues of plants, pine needles have more soluble nutrients than the other materials; their nitrogen and phosphorus elements exhibit a trend of first enrichment, then release, and gradually increasing, allowing them to permanently assist organic acid fertilization and directly increase soil nutrient content ( Gao et al., 2019 ; Manral et al., 2020 ). The colloidal properties of cow manure can enhance the bonding of organic and inorganic complexes, promote the formation of soil aggregates and the accumulation of organic matter, and effectively enhance the availability and retention of nutrients ( Chen et al., 2021a ). However, its own nutrient content is relatively low, and the overall effect of combining the activation function of an organic acid with cow manure is slightly lower than that compared with pine needles.…”

Analysis on Air Pollutants in COVID-19 Lockdown Using Satellite Imagery: A Study on Pakistan

“…On preprocessed satellite imagery, applied the basic binary operation of digital image processing to measure the multitemporal change of reduction in the pollutants of air at the level of surface [22].…”