Seasonal Changes of Soil Quality Indicators in Selected Arid Cropping Systems

Abstract

Abstract:Improving the soil quality in arid agro-ecosystems requires a greater understanding of how the time-of-sampling and management affect the soil measurements. We evaluated the selected soil quality indicators on samples collected at a 0-0.15 m depth, and at various sampling dates of the year, corresponding to the fall of 2015, winter of 2015/2016, spring of 2016, and the summer of 2016. The three crop management systems sampled included alfalfa (Medicago sativa), upland cotton (Gossypium hirsutum), and pecan (Carya illinoinensis). The soil properties measured included the wet aggregate stability (WAS), mean weight diameter of dry aggregates (MWD), dry aggregates greater than 2 mm (AGG >2 mm), dry aggregates less than 0.25 mm (AGG <0.25 mm), available water capacity (AWC), soil organic matter (SOM), permanganate oxidizable carbon (POXC), soil bulk density (BD), soil electrical conductivity (EC), pH, nitrate-nitrogen (NO3-N), extractable potassium (K), extractable phosphorus (P), calcium (Ca), magnesium (Mg), sodium adsorption ratio (SAR), and micronutrients (zinc, iron, copper, and manganese). Out of the 21 soil measurements, 15 varied significantly with the time-of-sampling within a year, although there were no consistent trends in variability. However, only a few measurements differed significantly with the crop management practices tested. Wet aggregate stability, MWD, AWC, and BD were significantly higher in the summer, while POXC and SOM were significantly higher in the fall and winter, respectively. Soil quality indicators such as NO3-N, K, and P decreased significantly during the spring. This study shows that the seasonal variability of the soil measurements can be significant in the arid agro-ecosystems, with the magnitude of variation depending on the measurement type. The soil managers in the region need to account for this variability, in order to be able to assess the changes in the soil quality. Also, because of the variability that can occur across the different sampling dates within a year, it is advisable to sample during the same period every year, for a consistent interpretation of the directional changes of the soil quality indicators.

Cover crop and crop residue removal effects on temporal dynamics of soil carbon and nitrogen in a temperate, humid climate

“…Greater microbial activity results in an increase in the potential of residue decomposition. Our result of high MBC and MBN in early spring, perhaps due to low soil temperature and high soil moisture, was consistent with several studies [ 22 – 24 ]. Additionally, June 2015 had higher total precipitation than June 2016, which might have impacted the microbial mediated soil functions and processes between both site-years.…”

“…Soil OC and total N change slowly over the long-term and are considered as the indicators of stable fraction of soil C and N, whereas SLAN (Solvita labile amino N), Solvita CO 2 -burst, microbial biomass C and N (MBC and MBN), water extractable organic C and N (WEOC and WEON), wet aggregate stability (WAS), total inorganic N, and cumulative 2d C mineralization (Cmin 2d ), are known to vary over short (seasonal) term, and thus, are the indicators of labile fraction of C and N. Seasonal variability (across the growing season) in labile fractions of C and N [20][21][22][23][24] is primarily dependent on the quantity of crop residue produced, rhizodeposition during crop growth, and soil temperature and precipitation, which influence the soil microbial activity and residue decomposition [25]. Microbial activity is a key factor affecting the cycling of labile pools of C [26] and N. For instance, MBC and MBN respond quickly to the addition/incorporation of crop residue in the soil.…”

Winter cover crops effects on soil properties and sweet corn yield in semi‐arid irrigated systems

“…Higher MWD is an indicator of more large‐aggregate fractions in the soil that will resist particle detachment and transport through wind erosion, while lower MWD is an indicator of more small‐size fractions that can easily be transported by the wind. Wet aggregate stability (WAS) was measured using the Cornell Sprinkle Infiltrometer (Ogden, van Es, & Schindelbeck, ; Omer, Idowu, Ulery, Vanleeuwen, & Guldan, ). For WAS measurement, 50 g of air‐dried aggregates (2–4 mm) were carefully spread on a 2‐mm sieve and subjected to a simulated rainfall of 2.5 J of energy under the Cornell Sprinkle Infiltrometer for 300 s. After the rainfall application, the remaining soil on top of the 2‐mm sieve was collected and oven‐dried.…”

Diversified Crop Rotation: An Approach for Sustainable Agriculture Production

“…Alfalfa, chile, and cotton are three plants that correspond to a variety of crops. ese three plants-alfalfa, chile, and cotton-belong to different crop families, so they can help break the disease cycle and boost productivity [38,39]. By breaking the pest cycle, lowering weeds and illnesses, improving soil quality, and safeguarding the ecosystem, the DCR aids in pest management [40].…”