Miaomiao Cheng

R. Bowichean, R. W. Bell, M. Cheng, S. Thanachit, and S. Anusontpornperm, “Release Kinetics of Boron in Acidic Soils as Affected by Calcium Form Different Sources,” Applied and Environmental Soil Science 2024 (2024): 6418954, https://doi.org/10.1155/aess/6418954.

The article was originally published incorrectly as a Review article. The correct article type is ‘Research Article’, and the article has been updated to reflect this.

We apologize for this error.

Understanding soil potassium (K) availability is critical for developing K fertilizer recommendations, especially in regions with low soil K reserves. The quantity/intensity isotherm and K release were used to evaluate the dynamics of K in loam-and clay-textured soil types developed from highly weathered parent materials in Western Australia (WA). Twenty-one soil types with a wide range of properties were collected from 0–10, 10–20 and 20–30 cm depths on farmland in WA. The equilibrium activity ratio of K+ varied from 0.1 × 10-3 to 45.6 × 10-3 (mol L-1)1/2 and was significantly higher in surface soils than subsurface soils. The labile K (KL) ranged from 0.03 to 2.18 cmolc kg−1, and the contributions of non-specifically adsorbed K towards KL were >50 % in surface soils but lesser in subsoils. The potential buffering capacity (PBCK) ranged from 5.4 to 185 cmolc kg−1 (mol L-1)-1/2 and was significantly correlated with soil effective cation exchange capacity (ECEC), pH and clay content. The ECEC alone explained 94.5 % of the variation in PBCK. The cumulative amounts of K released after 213 h ranged from 27 to 833 mg kg−1, with a rapid release of K up to 22 h followed by a gradual release until the end. In conclusion, most soils, especially surface soils, had adequate K availability for crop production but it is vulnerable to losses and depletion. Given the overall low ECEC and PBCK, split or delayed K applications are recommended, alongside practices that enhance K buffering capacity in WA soils.

Aims
Production of high yielding forage grasses on the extensive areas of tropical sandy soils in the Lower Mekong Basin is constrained by acidity, low soil nutrient concentrations, and potassium and sulfur depletion, limiting the ability of rural households in the region to meet the economic opportunities arising from the growing demand for livestock products in Asia. This research aimed to measure the response of forages grown in sandy soils that were provided with additional potassium sulfur, and lime inputs. It was hypothesized that additional potassium, sulfur and lime above local recommendations would increase biomass production and soil organic carbon concentrations.

Methods
An experiment was conducted over two years in the Lao PDR to compare the response and soil organic carbon accumulation of forage grasses grown in sandy soils that were either managed according to recommended fertilizer and manure additions, or provided with additional potassium and sulfur at four different rates, and lime.

Results
Yield increases of 25% were achieved with additional K and S but benefits were conditional on season and variety. Soil organic carbon concentration in the top 5 cm increased by up to 1.38 t ha−1 with forage production.

Conclusions
High yielding forages are likely to become limited by soil potassium. The imbalance of supplied nitrogen relative to potassium highlights inefficiencies in the recommended rates relative to forage production requirements, demonstrating potential to improve productivity and reduce nitrogenous waste. Increases in organic carbon stocks indicate the potential for improved forages to provide environment benefits.

Conservation Agriculture (CA) practices are being adopted in rice‐based intensive cropping systems in the Eastern Gangetic Plain (EGP) to improve soil fertility and system productivity, but very limited study was done regarding its effect on phosphorus (P) availability and balance. This study examined the effect of tillage practice, residue retention, and P fertiliser doses on P balance, P use efficiency (PUE), and system productivity in a rice‐based intensive cropping system. The experiment was initiated in 2015 with two factors, namely: tillage (strip planting = SP and conventional tillage = CT) and two levels of crop residue retention (high residue, HR = 50% rice + 100% lentil/40 cm mustard + 100% mungbean residues; and low residue, LR = 15% rice + no lentil/15 cm mustard + no mungbean residues). From 2018, it was converted to three factors with the splitting of plots for doses of P (lower dose = LD, 50% P of recommended dose (RD); 100% P of RD; and higher dose = HD, 150% P of RD). The yields of mustard and mungbean and the system yield were 13%–14%, 8%–13%, and 4%–5% higher in SP than CT, respectively, while rice yield was 6%–8% lower. Likewise, the yield of individual crops and the system yield were about 7%–10% higher in HR compared to LR. There was no response to increasing P fertiliser above the RD, but the LD depressed the yield of mustard, mungbean, and rice. The P balance (surplus) was positive (19 kg ha −1 year −1 ) under the current LR practice, while the HR retention reduced the positive P balance by 7% due to higher P removal by crops. The LD of P left a negative P balance, while the HD increased the positive P balance and decreased PUE. Therefore, we conclude that while HR coupled with SP increased crop yield, the current RD of P application remained optimal because of increased recycling of P in crop residues and P use efficiency.

Bangladesh publishes fertilizer recommendations but most farmers do not use these recommendations. In this study, we tested the performance of the Fertilizer Recommendation Guide (FRG), Rice Crop Manager (RCM) and Soil Testing Kit (STK) for determining fertilizer requirements of monsoon rice (Oryza sativa L) against Farmers’ Fertilizer Practice (FFP). Rates of nitrogen, phosphorus, potassium, sulfur and zinc were determined by four methods and used on 72 farmer’s fields in five agro-ecological zones (AEZ) over two years. All methods produced significantly higher grain yield than FFP (4.12 t ha-1): they were 13.8%, 9.6% and 8.3% higher for STK, RCM and FRG, respectively. RCM didn’t perform consistently across the locations. Overall, the STK performed the best followed by FRG. The superiority of STK is attributed to its assessment of current soil status while the FRG recommendation is grounded on an older data set of soil analysis for each AEZ. The N dose was comparable among the methods while P dose was much higher for FFP, and RCM underestimated the K requirement of rice. Farmers declined to adopt the STK.  By contrast, the supply of FRG information to the farmers by providing a simplified card with training is a simple and accessible technology.

Sustenance of soil fertility is a key challenge in intensive rice farming in subtropical agro-ecosystems due to unbalanced fertilization. Recommended fertilizer rates are assumed to optimize crop productivity but their effects on the maintenance of long-term soil fertility are not well studied. A long-term field experiment was evaluated for crop yield and soil properties after crop 54 and crop 60 of continuous practice with six treatments that varied the supply of N, P and K relative to current recommended rates (RFD - specified N, P, K, S, Zn and B fertilizer doses) and a zero-added fertilizer for an annual mustard-mungbean-rice rotation. Soil nutrient contents, organic carbon (SOC) and bulk density (BD) were determined at different soil depths. Long-term RFD maintained the annual N balance (0.7 kg ha− 1), produced positive P (17.2 kg ha− 1) and S (22.9 kg ha− 1) balances but negative K balance (-140 kg ha− 1) in soils with the highest system rice equivalent yield (13.3 t ha− 1) and marginal benefit cost ratio (9.6). The SOC, TN and extractable nutrients were higher in RFD than with higher doses except extractable P which was increased by higher P. While long-term RFD was the most profitable for crop production and achieved a neutral N balance between inputs and outputs, it caused soil K depletion and P and S accumulation. Our results give insights into the modifications to the RFD that better maintain not only yield and crop profitability but also long-term soil fertility.

Low-cadmium (Cd)-accumulating rice (Oryza sativa L.) cultivated by OsNRAMP5 mutation is a promising approach for ensuring food safety and human health. However, the impacts of reduced manganese (Mn) uptake caused by OsNRAMP5 mutation on rice growth and Cd accumulation under varying Mn levels remains unknown. Here, hydroponics and pot experiments were used to investigate the growth and Cd accumulation of an OsNRAMP5 mutant rice, Zhong’an 7 (ZA7), and the wild type, Zhongzao 35 (ZZ35), under different Mn supply conditions, and the Mn thresholds for ZA7 were determined. There was lower biomass of ZA7 than ZZ35 under hydroponic conditions with 0–0.05 μM Mn supply, and this was alleviated at Mn concentrations ranging from 1 to 200 μM. In pot Experiment I the grain yields of ZA7 in five soils increased from 5.92 to 15.0 g pot−1 as the inherent soil available Mn ranged from 3.17 to 400 mg kg−1. In pot Experiment II the exogenous MnSO4 significantly increased ZA7 grain yields by 135–173 % and reduced grain Cd concentrations by 50.3–72.9 % (p < 0.05). Furthermore, both hydroponic and pot experiments show that Cd concentrations in ZA7 were significantly lower than those in ZZ35, and decreased further with increasing Mn supply. Finally, the relationship between soil available-Mn (diethylene-triamine-pentaacetic acid-extractable, DTPA-Mn), which is directly related to plant Mn uptake, and ZA7 grain yields fitted well. The optimum DTPA-Mn content for maximum yield of ZA7 occurred at 263 mg kg−1 and the minimum DTPA-Mn threshold ensuring 90 % of the optimum grain yield was 165 mg kg−1. Thus, the results demonstrated the greater Mn-deficiency sensitivity and higher Mn requirement of ZA7 compared to ZZ35, shedding new light on the wider application of OsNRAMP5 mutant rice under different Mn conditions.

Boron (B) release mechanism is vital in supplying available B, particularly in acidic soils, because a temporary B deficiency can be triggered when liming the soil. This research was conducted with the aim at elucidating the role of Ca on B release kinetics in three acidic soils of Thailand to ascertain the kinetic release of B as affected by added calcium (Ca) from two sources: ground limestone (GL) and calcium chloride (CaCl2). Topsoil samples were incubated with either GL or CaCl2 at 0, 0.5, 1.0, or 1.5 times of the lime requirement for 7 days; thereafter, the soil pH and the kinetics of B release were analyzed based on successive extractions with 0.01 M CaCl2 solution for 72 h, which was comparatively described using four kinetic models: Elovich, parabolic diffusion, power function, and first-order of which each model would differently provide unique insights into the kinetic release of plant nutrient from soil. The added Ca significantly affected B release into the soil with the release kinetics of B in the two-time segments only conforming to the power function model in which approximately 70% of B was released rapidly during the initial phase and the rest was in a slow-release phase later on. Compared at the same rates of Ca applied, CaCl2 accelerated more B release than GL with no statistical difference in some soils. This was directly impacted by a decrease in soil pH as significantly caused by the addition of CaCl2. In addition, the B release rate significantly correlated with soil organic matter (r = 0.699(& lowast;& lowast;), p < 0.01). Our findings suggested that increasing soil organic matter should be recommended to provide more B availability but liming or using GL as a Ca source should be cautious as it can lead to B deficiency for plants grown in these acidic soils.

The adoption of conservation agriculture (CA) practices is likely to alter soil phosphorus (P) pools and availability leading to changes in P fertilizer use and management. However, the impacts of CA practices on soil P fractions and their distribution in the soil profile under rice-based systems is not well-understood. This study examined the effect of two crop establishment practices (strip planting, SP and conventional tillage, CT) and two crop residue levels (high residue, HR- 40% of above ground biomass and low residue, LR- 15%) on P fractions in the soil profile under a lentil–mungbean–rice sequence. After three consecutive years of CA practice, covering nine crops, composite soil samples were collected at 0–5, 5–15, 15–30, 30–45 and 45–60 cm depths and analysed for solution P, NaHCO3-extracted inorganic (NaHCO3 Pi) and organic (NaHCO3Po) P, NaOH-extracted inorganic (NaOH Pi) and organic (NaOH Po) P, stable P, residue P, total P, soil organic carbon (SOC) and total nitrogen (N). The inorganic P (solution P, NaHCO3 Pi, NaOH Pi and stable P) comprised 53–59% while the organic P (NaHCO3 Po and NaOH Po) comprised only 6%–13% of total P. However, CA practices increased SOC with the corresponding increase in soil organic P fractions. HR increased solution P, NaOH Po, stable P, residue P, total P, as well as SOC contents along with the stocks of total carbon (C), N, and P at up to 15 cm while increasing NaHCO3 Pi, NaOH Pi and TN at up to 30 cm depth compared with the LR. Likewise, SP increased the inorganic P fractions (NaHCO3 Pi and NaOH Pi) at 0–30 cm depth over the CT while P fractions in the deeper soil layers were similar to each other. In conclusion, the increase in soil P pools at up to 15–30 cm depths especially because of increased crop residue retention should allow for a decrease in P fertilizer inputs in intensive rice-based systems.

Globally, zinc (Zn) deficiency in soils, and subsequently crops, has emerged as one of the most prevalent among micronutrients, resulting in a severe decline in crop yields and nutritional quality and in adversely affecting animal and human health. Worldwide, more than half of the agricultural soils are inherently deficient in Zn, and the health of about one-third of the global human population is impacted by Zn deficiency. Zinc is an essential micronutrient for animal and human health, and, in the developing world, Zn deficiency has been identified as the fifth cause of disease and death for humans. The World Health Organization (WHO) reports that annually more than 800,000 people, including around 450,000 children under the age of 5, die due to Zn deficiency. Zinc supplementation was frequently associated with boosting immunity against COVID-19 in recent years. Because most of the Zn in animals and humans is derived from soil-grown crops, their source of Zn is highly dependent on plant Zn, especially in crops or fodder; in turn, crop Zn is dependent on available soil Zn levels. This integrated review describes Zn distribution, behavior, and fate in soils and its uptake and role in plants and crop production, as well as in the well-being of animals and humans. It discusses recent findings concerning Zn deficiency in all steps of the human food chain (from soil, to crop, animal, and human), and how it can be addressed through novel Zn fertilizers, soil amendments, and biofortification of Zn.