W.B. Hoogmoed

Sensing Soil Properties in the Laboratory, In Situ, and On-Line: A Review

Abstract Since both the spatial and vertical heterogeneities in soil properties have an impact on crop growth and yield, accurate characterization of soil properties at high sampling resolution is a preliminary step in successful management of soil-water-plant system. Conventional soil sampling and analyses have shown mixed economical returns due to the high costs associated with labor-intensive sampling and analysis procedures, which might be accompanied with map uncertainties. Therefore, the conventional laboratory methods are being replaced or complemented with the analytical soil sensing techniques. The objective of this chapter is to review different soil sensing methods used to characterize key soil properties for management of soil-water-plant system. This will cover laboratory, in situ in the field, and on-line measurement methods. This review chapter is furnished with an overview of background information about a sensing concept, basic principle and brief theory, various factors affecting the output of the sensor, and justification of why specific soil properties can be related with its output. The literature review is succeeded with an integration and analysis of findings in view of application in the precision agriculture domain. Potentials and limitations of current sensor technologies are discussed and compared with commonly used state-of-the-art laboratory techniques. As sensing is commonly addressed as a very technical discipline, the match between the information currently collected with sensors and those required for site-specific application of different inputs, and crop growth and development is discussed, highlighting the most accurate method to measure a soil property for a given application.

Sensing Soil Properties in the Laboratory, In Situ, and On-Line

Abstract Since both the spatial and vertical heterogeneities in soil properties have an impact on crop growth and yield, accurate characterization of soil properties at high sampling resolution is a preliminary step in successful management of soil-water-plant system. Conventional soil sampling and analyses have shown mixed economical returns due to the high costs associated with labor-intensive sampling and analysis procedures, which might be accompanied with map uncertainties. Therefore, the conventional laboratory methods are being replaced or complemented with the analytical soil sensing techniques. The objective of this chapter is to review different soil sensing methods used to characterize key soil properties for management of soil-water-plant system. This will cover laboratory, in situ in the field, and on-line measurement methods. This review chapter is furnished with an overview of background information about a sensing concept, basic principle and brief theory, various factors affecting the output of the sensor, and justification of why specific soil properties can be related with its output. The literature review is succeeded with an integration and analysis of findings in view of application in the precision agriculture domain. Potentials and limitations of current sensor technologies are discussed and compared with commonly used state-of-the-art laboratory techniques. As sensing is commonly addressed as a very technical discipline, the match between the information currently collected with sensors and those required for site-specific application of different inputs, and crop growth and development is discussed, highlighting the most accurate method to measure a soil property for a given application.

Potential Effect of Conservation Tillage on Sustainable Land Use： A Review of Global Long-Term Studies

Although understood differently in different parts of the world, conservation tillage usually includes leaving crop residues on the soil surface to reduce tillage. Through a global review of long-term conservation tillage research, this paper discusses the long-term effect of conservation tillage on sustainable land use, nutrient availability and crop yield response. Research has shown several potential benefits associated with conservation tillage, such as potential carbon sequestration, nutrient availability, and yield response. This research would provide a better perspective of the role of soil conservation tillage and hold promise in promoting application of practical technologies for dryland farming systems in China.

Burning crop residues under no-till in semi-arid land, Northern Spain—effects on soil organic matter, aggregation, and earthworm populations

Stubble burning has traditionally been used in semi-arid land for pest and weed control, and to remove the excess of crop residues before seeding in no-tillage systems. We compared differences in soil properties in a long-term (10 years) tillage trial on a carbonated soil in semi-arid north-east Spain under no-tillage with stubble returned and stubble burnt, with the conventional tillage system (mouldboard plough, stubble returned) as a reference. Differences in total soil organic C and C in particulate organic matter, mineralisation potential, soil physical properties (bulk density, penetration resistance, and aggregate size distribution and stability), and earthworm populations were quantified. The effect of stubble burning was absent or insignificant compared with that of tillage in most of the parameters studied. The most significant effect of stubble burning was the change in soil organic matter quality in the topsoil and penetration resistance. No-till plus stubble burning stocked an amount of organic C in the soil similar to no-till without burning, but the particulate organic matter content and mineralisation potential were smaller. Earthworm activity was similar under the 2 no-till systems, although a trend towards bigger earthworms with increasing penetration resistance was observed under the system with burning. Our results indicate that the role of burnt plant residues and earthworms in organic matter accumulation and soil aggregation in Mediterranean carbonated soils under no tillage is of major importance, meriting further attention and research.

Soil tillage and water infiltration in semi-arid Morocco: the role of surface and sub-surface soil conditions

Production of cereals in a dryland farming system forms an important part of agricultural production in Morocco. Yield levels on the Sais Plateau between Meknes and Fez in the semi-arid zone, however, remain low possibly because of sub-optimum water use due to inefficient tillage systems. A study was carried out to investigate the effect of soil tillage operations on water infiltration. Two systems of seedbed preparation on a silty clay soil were compared: traditional disc harrow (‘cover crop’) versus reduced tillage using a spring tined cultivator (‘vibrocultor’). Infiltration processes were studied using a rainfall simulator applying rainfall typical for aggressive events in the region. The effect of tillage and rainfall on the structure of the soil was assessed by both quantitative and descriptive methods. It was found that the disc harrow caused excessive pulverisation and seal formation under rainfall. Water infiltration, on the other hand, was not hindered by plough sole formation or subsoil compaction. It is suggested that reduced tillage by the spring tine cultivator is less costly and results in lower losses of water by runoff, thus leaving more water available for the crop.

Field studies to assess the workable range of soils in the tropical zone of Veracruz, Mexico

In the tropical area of Veracruz (Mexico) the decision of when and how to carry out tillage operations is based on qualitative criteria. It often results in excessive and unnecessary work, energy waste, operational delay, soil exposure to water erosion and soil structural damage. Objective criteria are needed in this area for selecting when and how to do cultivation in order to meet crop and conservation requirements. The workable range of typical soils of the area (Haplic Pheaozems) was quantified by assessing in-field implement effects on the soil structure and measuring the specific energy applied by the tractor–implement combination. This was done over a range of soil moisture contents inside and outside the theoretical friable consistency state of the soils, determined by the shrinkage and plastic limits. Empirical relationships between initial moisture content and the technological result of tillage showed that these results for moist loam and clay soils shifted from optimum to poor at soil water potentials that coincides quite well with the plastic limit. However, as soil was drying out, the implement effect changed from optimum to sub-optimum at soil moisture contents well above the shrinkage limit, so the actual field workable range was smaller than the theoretical friable status of the soils. The minimum input of specific energy to obtain optimum results, was close to the soil water potential where results changed to sub-optimum as soils were drying out. To support decisions for tillage planning and operation, valuable information on workable periods can be obtained by making use of quantified workability thresholds.

Regional distribution of nitrogen fertilizer use and N-saving potential for improvement of food production and nitrogen use efficiency in China

BACKGROUND An apparently large disparity still exists between developed and developing countries in historical trends of the amounts of nitrogen (N) fertilizers consumed, and the same situation holds true in China. The situation of either N overuse or underuse has become one of the major limiting factors in agricultural production and economic development in China. The issue of food security in N-poor regions has been given the greatest attention internationally. Balanced and appropriate use of N fertilizer for enriching soil fertility is an effective step in preventing soil degradation, ensuring food security, and further contributing to poverty alleviation and rural economic development in the N-poor regions. RESULTS Based on the China Statistical Yearbook (2007), there could be scope for improvement of N use efficiency (NUE) in N-rich regions by reducing N fertilizer input to an optimal level (≤180 kg N ha(-1)), and also potential for increasing yield in the N-poor regions by further increasing N fertilizer supply (up to 116 kg N ha(-1)). For the N-rich regions, the average estimated potential of N saving and NUE increase could be about 15% and 23%, respectively, while for the N-poor regions the average estimated potential for yield increase could be 21% on a regional scale, when N input is increased by 13%. CONCLUSION The study suggests that to achieve the goals of regional yield improvement, it is necessary to readjust and optimize regional distribution of N fertilizer use between the N-poor and N-rich regions in China, in combination with other nutrient management practices.

Proximal Gamma-Ray Spectroscopy to Predict Soil Properties Using Windows and Full-Spectrum Analysis Methods

Fine-scale spatial information on soil properties is needed to successfully implement precision agriculture. Proximal gamma-ray spectroscopy has recently emerged as a promising tool to collect fine-scale soil information. The objective of this study was to evaluate a proximal gamma-ray spectrometer to predict several soil properties using energy-windows and full-spectrum analysis methods in two differently managed sandy loam fields: conventional and organic. In the conventional field, both methods predicted clay, pH and total nitrogen with a good accuracy (R2 ≥ 0.56) in the top 0–15 cm soil depth, whereas in the organic field, only clay content was predicted with such accuracy. The highest prediction accuracy was found for total nitrogen (R2 = 0.75) in the conventional field in the energy-windows method. Predictions were better in the top 0–15 cm soil depths than in the 15–30 cm soil depths for individual and combined fields. This implies that gamma-ray spectroscopy can generally benefit soil characterisation for annual crops where the condition of the seedbed is important. Small differences in soil structure (conventional vs. organic) cannot be determined. As for the methodology, we conclude that the energy-windows method can establish relations between radionuclide data and soil properties as accurate as the full-spectrum analysis method.

Research on A Special Scarifier Mechanism With Finite Element Analysis Method

A scarifier mechanism with rotary tillage and anti-rotary grubbing is proposed for inducing the power of tillage in hardens soil. MAT147 material modal is amended by experimental method and soil high-speed cutting finite element modal is build through SPH method, further, the tools parameter of proposed mechanism and soil cutting speed are studied by FEA numerical simulation through orthogonal experiments method. Finally, the result shows that the proposed mechanism with proper structural parameters and work speeds can reduce the requirement of power of tillage and increase the working efficiency of small agricultural machinery.

Balanced N and C input recommendations for rain‐fed maize production in northern China based on N balances and grain yields

BACKGROUND This study aimed to assess longer-term (1993-2009) effects of combined applications of fertiliser, maize stover, and cattle manure on maize yields, partial nitrogen (N) and carbon (C) balances, and water and N-use efficiencies, to guide N and C input recommendations for rain-fed maize production in northern China. RESULTS The field trial, with three factors at five levels and 12 treatments, was conducted at Shouyang Dryland-Farming Experimental Station, Shanxi, China. Data analysis revealed higher N balances but lower C balances significantly occurred in a dry year than in a wet year. Positive N balances related to higher N inputs resulted in higher soil available N, even downward to deep layers with increasing N inputs, while positive C balances due to higher C inputs could be benefit to increase soil organic C. Based on partial N balances and grain yields, N and C inputs at ranges of 100 kg N ha-1 and 1.9-2.9 Mg C ha-1 could be recommended for target yields of 6.7-7.2 Mg ha-1 in rain-fed maize production. CONCLUSION The study suggests that N balances close to neutral be given priority to improving N-use efficiency, and more positive C balances also be important for sustaining target yields and soil fertility levels.