The vertical migration of N. carpocapsae infective juveniles applied to the soil surface or introduced 14 cm below the soil surface was studied in four different soil types (pure silica sand, coarse sandy loam, silty clay loam, and clay). The percentage of juveniles able to migrate and infect wax moth pupae placed in the soil decreased as the percentage of clay and silt increased. Most nematode...

The interactive effects of soil texture and type of N fertility (i.e., manure vs. commercial N fertilizer) on N(2)O and CH(4) emissions have not been well established. This study was conducted to assess the impact of soil type and N fertility on greenhouse gas fluxes (N(2)O, CH(4), and CO(2)) from the soil surface. The soils used were a sandy loam (789 g kg(-1) sand and 138 g kg(-1) clay) and a...

Incubation experiment was conducted on four soil types in Nigeria using cattle dung (CD) at the rate of 2.5g/kg soil ( 5 t ha), Urea fertilizer at the rate of 0.1g/kg soil ( 200 kg ha ) and cattle dung (2.5g/kg soil) combined with Urea 0.05g/kg soil (100 kg ha) as treatments. The objective of the experiment was to compare the rate of OC, NH4 – N, NO3 – N and available P release on soils selecte...

The extraction of nematodes from clay soil is difficult using flotation-sieving methods of soil-water suspensions. Aggregated soil particles trap nematodes and prevent them from passing through the top coarse sieves during decanting. Also, the soil aggregates clog the sieves which slows the decanting operation. In addition, clay particles are difficult to clean from centrifuge tubes that are us...

I N T R O D U C T I O N T h e s t u d y o f c lay f o r m a t i o n i n soils m a y b e d i v i d e d i n t o t h r e e p a r t s : (1) a q u a n t i t a t i v e e v a l u a t i o n o f t h e a m o u n t o f c lay f o r m e d f r o m a g i v e n a m o u n t o f p a r e n t m a t e r i a l , (2) a q u a l i t a t i v e e v a l u a t i o n of t h e k i n d o f m i n e r a l s a n d o t h e r s u ...

Management of soils to reduce the amount of PM10 emitted during agricultural tillage operations is important for attainment of air quality standards in California's San Joaquin Valley (SJV). The purpose of this study was to improve and expand upon earlier work of predicting tillage-generated dust emissions based on soil properties. We focus on gravimetric soil water content (GWC) and soil textu...

An 18 4R38 radial-ply tractor drive tyre was operated at 10% travel reduction, at three correctly inflated combinations of dynamic load and inflation pressures on a structured clay soil and at another combination of load and inflation pressure on a loose sandy loam and a loose clay loam soil. Soil–tyre interface pressures on the face of one lug and on an undertread region between two lugs were ...

Significantly more occlusion bodies (OB) of DuPont viral construct HzSNPV-LqhIT2, expressing a scorpion toxin, were transported by artificial rainfall to cotton plants from sandy soil (70:15:15 sand-silt-clay) than from silt (15:70:15) and significantly more from silt than from clay (15:15:70). The amounts transported by 5 versus 50 mm of precipitation were the same, and transport was zero when...

Expansive soils owe their characteristics to the presence of swelling clay minerals. As they get wet, the clay minerals absorb water molecules and expand; conversely, as they dry they shrink, leaving large voids in the soil. Swelling clays can control the behavior of virtually any type of soil if the percentage of clay is more than about 5 percent by weight. Soils with smectite clay minerals, s...

Recent studies of soil–landscape relationships in northeastern Patagonia identified fibrous-clay minerals in calcic and petrocalcic horizons developed on old fluvio-glacial plains called “Rodados Patagónicos” (RP). The objectives of this study were: i) to evaluate the occurrence of fibrous-clay minerals in the arid soil environment, and ii) to establish the relationship between the soil propert...