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A study was conducted to understand the role of different soybean production systems and soil chemical and physical attributes on phytonematode population density in a physical model of production systems. In an area of 28 hectares, the following production systems were established 26 years ago: a) conventional system (CS) - succession of soybeans in summer and oats in winter, and continuous soil preparation with disc harrow; b) no-till system (NTS) - with rotation of summer crops (soybeans and corn) and winter crops (wheat, oats, and fodder radish); c) integrated crop-livestock system (ICLS) - conducted in no-till system and using Urochloa brizantha (cultivar Piatã) pasture, in crop-livestock rotation every two years; d) permanent pasture system (PP) - U. brizantha (cultivar Piatã) with beef cattle. Twenty six years after the systems were installed, soil samples were taken for nematological analysis and analysis of the soil's chemical and physical attributes. The results showed an almost absolute prevalence of the reniform nematode (Rotylenchulus reniformis, Rr) in the area. The PP system had the lowest population (average of 2 Rr/200cc), followed by the ICLS systems (average of 12 to 25 Rr/200cc). The highest population densities were observed in the CS system (1068 Rr/200cc) and the NTS system when soybeans were grown in the last two years before sampling (1361 Rr/200cc). The highest population densities of R. reniformis were associated with higher soil density in the arable layer, higher K and P levels in the soil, and lower organic matter contents.

In building a sustainable food system, the management of livestock production should avoid nitrogen (N) surplus and ensure animal-sourced food self-sufficiency. Reducing livestock quantities in regions producing excess of animal-sourced food and livestock manure is an effective approach for mitigating manure N surplus. In this study, we considered the eastern regions of China as a case study to quantitatively analyze whether meat self-sufficiency could be met when reducing the livestock quantity to avoid manure N surplus. In addition to considering the baseline scenario, considering the current livestock quantity (scenario C), we defined three strategies corresponding to livestock reduction scenarios: taking meat self-sufficiency as a priority regardless of the manure balance (scenario TB); taking manure N surplus avoidance as a priority regardless of the meat balance (scenario MNB); and considering the most limiting conditions between satisfying meat self-sufficiency and avoiding manure N surplus (scenario LF). A balance index was used to describe the excess (i.e., positive value) or deficiency (i.e., negative value) of meat and manure N. Concerning the whole of eastern China, in scenario LF, the meat balance index (TBI) and manure N balance index (MNBI) were 0.25 and −0.39, respectively, which could satisfy meat demand while avoid manure N surplus (for scenarios C, TB, and MNB, the TBIs were 1.95, 0, and 1.09, and the MNBIs were 0.56, −0.48, and 0, respectively). At the regional level, the regions with meat self-sufficiency accounted for more than 70% in the LF scenario, and manure N surplus could be avoided in all regions. However, southwestern China should adopt further measures, such as trading among adjacent regions and increasing manure fertilizer application, to satisfy the meat demand while avoiding surplus manure N.

ABSTRACT The objective of this study was to monitor the temporal variation in penetration resistance (PR) after soil saturation under different management systems in three areas of the Cerrado biome: two in no-till systems (NT with 3 and 10 years of implementation) and one of crop-livestock integration (CL with 9 years of implementation) with soybean/forage succession. Four transects were delimited in each area. The delimited area was saturated and the PR measurements were performed daily for 11 days at 10 transect points, up to 0.40 m of depth. Soil moisture was determined with PR measurements, soil hydraulic conductivity, and organic carbon. PR values were more significant in the 0.10 - 0.20 m layer than in the 0.0 - 0.10 and 0.20 - 0.40 m layers. The NT-3 area showed a lower PR value (1.65 MPa) than the area under NT-10 and CL-9, with 2.48 and 2.69 MPa, respectively. Thus, critical soil moisture values, that is, soil moisture values most susceptible to soil compaction were determined. Thus, in the NT-3 area, the critical moisture was 0.20 kg kg-1, in the NT-10, ranged from 0.19 - 0.20 kg kg-1, and in the CL-9, between 0.23 and 0.20 kg kg-1. Monitoring soil moisture can prevent management operations from restricting root growth.

The objective of this study was to monitor the temporal variation in penetration resistance (PR) after soil saturation under different management systems in three areas of the Cerrado biome: two in no-till systems (NT with 3 and 10 years of implementation) and one of crop-livestock integration (CL with 9 years of implementation) with soybean/forage succession. Four transects were delimited in each area. The delimited area was saturated and the PR measurements were performed daily for 11 days at 10 transect points, up to 0.40 m of depth. Soil moisture was determined with PR measurements, soil hydraulic conductivity, and organic carbon. PR values were more significant in the 0.10-0.20 m layer than in the 0.0-0.10 and 0.20-0.40 m layers. The NT-3 area showed a lower PR value (1.65 MPa) than the area under NT-10 and CL-9, with 2.48 and 2.69 MPa, respectively. Thus, critical soil moisture values, that is, soil moisture values most susceptible to soil compaction were determined. Thus, in the NT-3 area, the critical moisture was 0.20 kg kg-1, in the NT-10, ranged from 0.19-0.20 kg kg-1, and in the CL-9, between 0.23 and 0.20 kg kg-1. Monitoring soil moisture can prevent management operations from restricting root growth. [ABSTRACT FROM AUTHOR]