Incorporation Of Legume Residues Research Articles

Temporal variation in mineral nitrogen in soil as influenced by incorporation of legume or cereal residues under submergence or well drained conditions

A laboratory study was conducted at the Indian Agricultural Research Institute, New Delhi on a sandy clay loam soil of pH 7.9 and organic C content of 0.34% to study the effect of incorporating Sesbania or Vigna legume residues or wheat straw at 15 and 30t ha−1 on temporal variation in ammoniacal and nitrate‐N in soil under submergence and well drained conditions. Under submergence most mineral N was present as ammoniacal‐N, while under well drained conditions it was present as Nitrate‐N. The content of ammoniacal N in soil was the highest after 30 days of incubation and declined thereafter under submergence. On the other hand under well drained conditions the mineral‐N (mostly nitrate) content in soil at 30 DAI was very little and showed increases only later, reaching the highest level at 90 DAI. Application of wheat straw specially at 301 ha−1 level resulted in immobilization of native soil‐N. These results show that rice which is grown under submergence can be transplanted soon after incorporation of legume residues, but for wheat or other crops which are grown under well drained condition a time interval of 30 days or more needs to be provided before sowing the crop.

Fallow residue management effects on upland rice in three agroecological zones of West Africa

Improving fallow quality in upland rice-fallow rotations in West Africa through the site-specific use of leguminous cover crops has been shown to sustain the productivity of such systems. We studied the effects of a range of residue management practices (removal, burning, mulching and incorporation) on fallow biomass and N accumulation, on weed biomass and yield response of upland rice and on changes in soil physical and chemical characteristics in 2-year field trials conducted in three agroecological zones of Cote d'Ivoire. Across fallow management treatments and agroecological zones, rice yields were on average 20–30% higher in legume than in natural fallow plots. Weed biomass was highest in the savanna zone and lowest in the bimodal forest and tended to be less following a legume fallow. Regardless of the type of fallow vegetation and agroecological zone, biomass removal resulted in the lowest rice yields that varied from 0.5 t ha–1 in the derived savanna zone to 1.5 t ha–1 in the Guinea savanna zone. Burning of the fallow vegetation significantly increased yield over residue removal in the derived savanna (0.27 t ha–1, P<0.05) and bimodal forest zones (0.27 t ha–1, P<0.01), but not in the Guinea savanna. In both savanna environments, residue incorporation was superior to the farmers' practice of residue removal and rice yield increases were related to amounts of fallow N returned to the soil (r 2=0.803, P<0.01). In the forest zone, the farmers' practice of residue burning produced the highest yield (1.43 t ha-1 in the case of legumes) and resulted in the lowest weed biomass (0.02 t ha–1). Regardless of the site, improving the quality of the fallow or of its management had no significant effects on either soil physical or soil chemical characteristics after two fallow cycles. We conclude that incorporation of legume residues is a desirable practice for rice-based fallow rotation systems in savanna environments. No promising residue management alternatives to slash-and-burn were apparent for the forest zone. Determining the possible effects on soil productivity will require longer-term experiments.

Legume Residue Incorporation and Wetland Rice Yield

Legume Residue Incorporation and Wetland Rice Yield

Economics of fertilizer use in the Maize-Mungbean/Dhaincha-T.aman rice cropping pattern

Field experiments were conducted over three years during 2001-2004 and 2002-2005 at BAU farm, Mymensingh and OFRD farm, Rangpur, respectively, using farm yard manure (FYM), dhaincha (Sesbania) and mungbean residue along with inorganic fertilizers. For the first crop (maize), there were five treatments i.e. T1: Control, T2: Moderate Yield Goal (MYG), T3: High Yield Goal (HYG), T4: FYM 5t/ha + Inorganic fertilizer for MYG as IPNS basis, T5: FYM 5t/ha + Inorganic fertilizer for HYG as IPNS basis. Each year, FYM was applied to maize crop and GM/MBR was applied before transplanting of aman rice. Integrated use of manure and inorganic fertilizers (IPNS basis) produced comparable seed yield of maize with the chemical fertilizers alone irrespective of moderate or high, yield goal basis (MYG or HYG) in both locations. After harvest of maize, mungbean and dhaincha (Sesbania) seeds were sown as per treatments. For T. aman rice (third crop), each of the plots of T2 and T3 treatments were subdivided into six, so there were altogether 15 treatments. At both locations, the incorporation of Sesbania biomass and mungbean residue along with inorganic fertilizers for MYG gave identical grain yields of T. aman rice with the fertilizers alone applied for HYG. There was an inverse relationship between the higher dose of fertilizer application and marginal benefit cost ratio (MBCR) at both the locations. Considering gross margin and marginal benefit-cost ratio (MBCR), legume residue incorporation along with inorganic fertilizers (IPNS basis) was found to be the best treatment (T3.3.3). Keywords: Economics; Fertilizer use; Cropping pattern; Organic manure; IPNS DOI: http://dx.doi.org/10.3329/jbau.v9i1.8741 JBAU 2011; 9(1): 37-42