Amid the current environmental crises that exert enormous pressure on the arable lands, there is a need to adopt environment-friendly effective but highly productive conservation agriculture practices to feed the growing world population. Thus, a study was conducted to test the hypothesis that the inclusion of cowpea (Vigna unguiculata L. Walp) live mulch under no-till and reduced tillage in the summer maize (Zea mays L.) – rainy season maize-mustard (Brassica juncea (L.) czern) sequence would enhance agronomic productivity, energy use efficiency, and water productivity while reducing greenhouse gases emissions. Five tillage treatments viz., no-till, no-till-live mulch, reduce tillage, reduce tillage-live mulch, and conventional tillage were evaluated in three times replicated randomized complete block design. Land productivity for maize–maize–mustard system was the highest under reduced tillage-live mulch. No-till-live mulch had 36.4% lesser energy requirement, 2.4 times more energy productivity than that under conventional tillage. Reduced tillage-live mulch and no-till-live mulch had higher water productivity compared to all other treatments. The conventional tillage had the highest net CO2-eq emission while no-till-live mulch had the lowest. Inclusion of cowpea as live mulch enhanced C sequestration which has the potential to offset approximately half of the total CO2 emission, enhance energy use efficiency, land and water productivity. The findings of this study might be useful to develop a policy for sustainable high productivity through efficient resource use in the Eastern Himalayan Ecosystems that have the potential to become the corn belts of India.

The food-energy-water-carbon nexus in a maize-maize-mustard cropping sequence of the Indian Himalayas: An impact of tillage-cum-live mulching

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Energy-saving tillage with a combined unit with universal working bodies

Geophysical surveys are now commonly used in agriculture for mapping applications. High-throughput collection of geophysical properties such as electrical conductivity (inverse of resistivity) can be used as a proxy for soil properties of interest (e.g., moisture, texture, salinity). Most applications only rely on a single geophysical survey at a given time. However, time-lapse geophysical surveys have greater capabilities to characterize the dynamics of the system, which is the focus of this work. Assessing the impact of agricultural practices through the growth season can reveal important information for the crop production. In this work, we demonstrate the use of time-lapse electrical resistivity tomography (ERT) and electromagnetic induction (EMI) surveys through a series of three case studies illustrating common agricultural practices (cover crops, compaction with irrigation, and tillage with N fertilization). In the first case study, time-lapse EMI reveals the initial effect of cover crops on soil drying and the absence of effect on the subsequent main crop. In the second case study, compaction leading to a shallower drying depth for potatoes (Solanum tuberosum L.) was imaged by timelapse ERT. In the third case study, larger changes in electrical conductivity over time were observed in conventional tillage compared with direct drill using timelapse EMI. In addition, different N application rates had a significant effect on the yield and leaf area index but only ephemeral effects on the dynamics of electrical conductivity, mainly after the first application. Overall, time-lapse geophysical surveys show great potential for monitoring the impact of different agricultural practices that can influence crop yield.

Time-lapse geophysical assessment of agricultural practices on soil moisture dynamics

The corn biomass and nutrient dynamics may be altered when it is intercropped with Brachiaria (syn. Urochloa spp.). The present study aimed to investigate the dynamics of biomass, nitrogen (N), phosphorus (P) and potassium (K) for farming systems that produce corn intercropped with Brachiaria species. Field experiments were performed during the season and off-season, in a split-plot design. The main plots were composed of Brachiaria species (B. brizantha, B. ruziziensis and B. Convert) intercropped with corn, in addition to corn monocropping. The subplots consisted of three forage sampling periods, ranging from 0 to 60 days after the corn harvest. The intercropping arrangements did not affect the corn grain yield, nutrient accumulation and partitioning, relatively to the corn monocropping. After the grain harvest, B. brizantha achieved the greater biomass accumulation rate in both the season (69 kg ha-1 day-1) and off-season (17 kg ha-1 day-1). The nutrient accumulation ranged widely between the Brachiaria species and planting seasons: 0.2-1.2 kg ha-1 day-1 for N; 0.01-0.07 kg ha-1 day-1 for P; and 0.13-0.8 kg ha-1 day-1 for K. However, the greatest nutrient accumulation was found for B. brizantha, followed by B. ruziziensis and then B. Convert. In the short-term, corn intercropped with Brachiaria in the season showed the largest effect on the nutrient cycling and biomass yield. The intercropping between corn and B. brizantha in the season was the best way to enhance the biomass yield and the N, P and K cycling.
KEYWORDS: Zea mays L., Urochloa spp., nutrient balance, forage plants.

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Contribution of corn intercropped with Brachiaria species to nutrient cycling.

Cover crops (CCs) are herbaceous plants established in the inter-rows of woody crops. CCs have multiple purposes, including improving soil organic matter and soil nutrients. In the present research, a permanent grass, Brachypodium distachyon (BRA); two annual crucifers, Eruca vesicaria (ERU) and Sinapis alba (SIN); and the natural flora of the area (SPV) were studied during four seasons in a Mediterranean olive orchard. C, N, P and K released from residue were measured. Likewise, soil organic matter (SOM), soil N, P and K were assessed up to a depth of 40 cm. C was released in higher amounts from the residue. The final percentages of remaining K in the plant residues from the mowing were the lowest, indicating the fastest release of this nutrient. The different precipitation recorded between seasons influenced both the dynamics of the CCs in the developing and decomposition stages as well as of the SOM and soil nutrients at the surface. Overall, SOM and soil K were higher at the surface (0−5 cm) after each decomposition period. BRA increased the SOM at the surface to the greatest extent. No significant differences between CCs were observed in SOM in the whole profile. In the global balance, SIN increased soil N over 1.5 Mg ha−1 in the first 40 cm. SIN also improved soil K by 2.7 Mg ha−1 and ERU by 2.5 Mg ha−1, with significantly higher amounts in both crucifers than in BRA. Soil P was only enhanced in the first 10 cm by CCs, as it decreased over the whole profile (0−40 cm). From the soil fertility perspective, BRA improved the SOM and soil N at surface (0−5 cm) to a greater extent than SVP, which is currently the most used CC by farmers.

Soil organic matter and nutrient improvement through cover crops in a Mediterranean olive orchard

Soil compaction is a serious threat to agricultural production because of an expanding agricultural mechanization. Conservation tillage and use of pioneer plants can be an environmentally solution to alleviate the adverse effects of soil compaction. Root penetration into compacted soil of two winter cover crops with different rooting patterns, i.e. tap-rooted white mustard (Sinapis alba L.), and fibrous-rooted winter rye (Secale cereal L.), and of maize (Zea mays L.) in the consecutive growing season was assessed. Additionally, the effects of two spring tillage methods were evaluated, i.e. strip tillage and intensive tillage (by mouldboard ploughing). Winter rye showed significantly higher root penetration than white mustard in the top 15 cm, while an opposite trend was observed at 20–45 cm depth. After one season, maize root penetration was significantly greater following white mustard than winter rye at 30–40 cm depth. Strip tillage, like intensive tillage, could sufficiently loosen soil for adequate maize growth even though maize root distribution was restricted to tilled rows in contrast with intensive tillage. In conclusion, white mustard already showed positive short-term effects on maize growth, whereas strip tillage did not negatively affect it. Combining both is a viable option to reduce the negative impact of soil compaction on maize growth.

Short-term effects of cover crops and tillage methods on soil physical properties and maize growth in a sandy loam soil

Impact of potential bio-subsoilers on pore network of a severely compacted subsoil

Slurry spreaders are among the heaviest machines used for farming operations. The effects of soil wetness and tyre pressure on physical soil properties were evaluated by using a ˜5 Mg wheel load slurry spreader mounted on a tractor. The impacts were also compared with Terranimo® model predictions and X-ray micro-computed tomography (X-ray micro-CT) parameters. In the consecutive maize growing season, soil physical properties, total mineral nitrogen content and maize above biomass were evaluated additionally between in and out track positions. Immediately after traffic, penetration resistance (PR) was significantly higher (P  30 μm) of soil trafficked under moist conditions was different (P ≤ 0.10) from those under dry conditions. Macro-porosity showed a clear response (P   0.05) between in- and out-track positions while above ground dry biomass of maize reduced with ˜7% at in-track positions.

Lidong Ren

Papers

Short-term effects of cover crops and tillage methods on soil physical properties and maize growth in a sandy loam soil

Impact of potential bio-subsoilers on pore network of a severely compacted subsoil

Effects of soil wetness and tyre pressure on soil physical quality and maize growth by a slurry spreader system

Effects of traffic-induced soil compaction on crop growth and soil properties