Impact of Amendments on the Physical Properties of Soil under Tropical Long-Term No Till Conditions

Abstract

Tropical regions have been considered the world’s primary agricultural frontier; however, some physico-chemical deficiencies, such as low soil organic matter content, poor soil structure, high erodibility, soil acidity, and aluminum toxicity, have affected their productive capacity. Lime and gypsum are commonly used to improve soil chemical fertility, but no information exists about the long-term effects of these products on the physical attributes and C protection mechanisms of highly weathered Oxisols. A field trial was conducted in a sandy clay loam (kaolinitic, thermic Typic Haplorthox) under a no-tillage system for 12 years. The trial consisted of four treatments: a control with no soil amendment application, the application of 2.1 Mg ha-1 phosphogypsum, the application of 2.0 Mg ha-1 lime, and the application of lime + phosphogypsum (2.0 + 2.1 Mg ha-1, respectively). Since the experiment was established in 2002, the rates have been applied three times (2002, 2004, and 2010). Surface liming effectively increased water-stable aggregates > 2.0 mm at a depth of up to 0.2 m; however, the association with phosphogypsum was considered a good strategy to improve the macroaggregate stability in subsoil layers (0.20 to 0.40 m). Consequently, both soil amendments applied together increased the mean weight diameter (MWD) and geometric mean diameter (GMD) in all soil layers, with increases of up to 118 and 89%, respectively, according to the soil layer. The formation and stabilization of larger aggregates contributed to a higher accumulation of total organic carbon (TOC) on these structures. In addition to TOC, the MWD and aggregate stability index were positively correlated with Ca2+ and Mg2+ levels and base saturation. Consequently, the increase observed in the aggregate size class resulted in a better organization of soil particles, increasing the macroporosity and reducing the soil bulk density and penetration resistance. Therefore, adequate soil chemical management plays a fundamental role in improving the soil’s physical attributes in tropical areas under conservative management and highly affected by compaction caused by intensive farming.

Rate and Timing of Meat and Bone Meal Applications Influence Growth, Yield, and Soil Water Nitrate Concentrations in Sweet Corn Production

“…Similar to the results of Ahmad et al [38], we found that soil water NO 3 -N concentrations were higher in Poamoho than in Waimānalo for depths of 30 and 60 cm. The increased leaching at Poamoho could be due to the differences in soil physical and mineral properties between the two locations [39]. Nitrate-nitrogen losses were reduced by 20% at Waimānalo and 40% at Poamoho when MBM was applied in split applications compared to a single preplant application.…”

Identification of Quantitative Trait Loci Associated with Nutrient Use Efficiency Traits, Using SNP Markers in an Early Backcross Population of Rice (Oryza sativa L.)

“…Rice breeding programs need to incorporate NuUE traits as this helps resource-poor farmers to save on fertilizer, and allows maximization of valuable resources to increase profitability. To date, several morphological and agronomic traits have been identified, and they can be used as indicators of nitrogen (N) [ 52 , 64 , 65 , 66 ], phosphorus (P) [ 7 , 38 , 67 , 68 , 69 , 70 ], and potassium (K) [ 16 , 39 , 40 , 71 , 72 , 73 ] deficiency tolerance under both field and hydroponic conditions. Using different genetic backgrounds of mapping populations, such as RILs, NILs, BILs, ILs, CSSLs, DHs, and BC 2 F 4 , there are several reports on QTL identification with independent studies of low-N, -P, and -K conditions.…”

Soil Physical Properties as Influence by Poultry and Cow Dung from Different Housing and Stacking Types Following Telfairia occidentalis (Hook F.) Production

“…The post planting soil physical properties were observed to be improved by the application of amendments [7]. Soil physical properties contribute to water and nutrient activities, soil temperature, aeration, nutrient cycling, and root growth which affect yield of crops [8,9].…”