Soil mineral nitrogen and microbial parameters as influenced by catch crops and straw management

Abstract

Agricultural management can affect soil chemistry, nutrient cycling and microbial properties, but the relationship among them is not well explored. Catch crops play an important role in decreasing nitrogen (N) leaching in the autumn, and thereby reduce undesirable environmental effects, improve soil physical and microbiological properties. We investigated the effect of catch crops and straw management on soil mineral nitrogen (N min ) and microbial activity on a clay loam Gleyic Cambisol (CMg). A two-factor experiment was set up: 1) catch crops (narrow-leafed lupin, mixture of narrow-leafed lupin and oats, white mustard and without catch crops), and 2) straw management methods (with and without). The total amount of bacteria and fungi, dehydrogenase and urease activity, and potential nitrification rate were assayed during two successive spring barley growing seasons. Also we determined N in the soil and soil leachate. Our experimental findings indicated that the N min dynamics in the soil and nitrate nitrogen (N-NO 3 ) leaching depended on the catch crops, the amount of decomposers and the weather conditions. Cultivation of post-harvest catch crops in a clay loam Cambisol reduced N min content by 50-62% at the 0-40 cm soil layer, stubble breaking in the autumn by 23-41%, compared with the soil where the stubble had not been broken and no catch crops had been grown. Also, cultivation of catch crops reduced nitrate (N-NO 3 ) concentration in the soil leachate by 32-62%. The biological variables differed among all treatments, especially among years. Higher counts of heterotrophic bacteria and fungi and greater enzymatic activity were recorded in the plots with catch crops. Higher nitrification activity was established in the plots without catch crops. The amount of cellulose degrading bacteria did not differ significantly between the treatments. Further research is needed to get a better insight into the processes of mineralization and immobilization of catch crops' residues and soil N min and N-NO 3 leaching in agricultural ecosystems.

Nitrogen cycle bacteria in soils of organically and conventionally managed crop rotations

“…Soil microflora influences the availability of nutrients for crop production via a range of activities such as the decomposition of crop residues, immobilization of nutrients and mineralization (Bünemann et al, 2006). Enzymes produced by soil microorganisms catalyze biochemical processes involved in nutrient cycling in soil (Scherer et al, 2011;Janušauskaitė et al, 2013).…”

Content of Magnesium in Soil and Plants as Affected by Green Manure

“…Poorer yield of pea in the better soil conditions could have resulted from the later sowing time in Szadłowice, caused by the later harvest of the previous crop. The pea biomass yields obtained in the study may be regarded as average for legumes grown as catch crops in Central Europe [11,15,16]. The total weight of Mg accumulated in the catch crop biomass was only 4.8-7.8 kg·ha -1 (Table 3).…”

The introduction of soybean in an organic crop rotation in the Nemoral zone: the impact on subsequent spring wheat productivity

“…Increasing the proportion of legume crops in a rotation, increases the proportion of N in the global nutrient cycles and also decreases the quantity of N lost from it (Seufert et al, 2012). At the ecosystem level, the net N gain due to N 2 fixation benefits the subsequent crops and contributes to increased soil N fertility (Kumar, Goh, 2000;Janušauskaitė et al, 2013). Legume diversification increases the quantity, quality and chemical diversity of residues, in such a way that high diversity rotations can sustain soil biological communities and positively affect the soil organic matter (Tiemann et al, 2015).…”