R.J. Haynes

Bio: R.J. Haynes is an academic researcher from New Zealand Institute for Crop and Food Research. The author has contributed to research in topics: Soil organic matter & Soil structure. The author has an hindex of 2, co-authored 2 publications receiving 1219 citations.

Influence of lime, fertilizer and manure applications on soil organic matter content and soil physical conditions: A review

Abstract: The effects of lime, fertilizer and manure applications on soil organic matter status and soil physical properties are of importance to agricultural sustainability. Their effects are complex and many interactions can occur. In the short-term, liming can result in dispersion of clay colloids and formation of surface crusts. As pH is increased the surface negative charge on clay colloids increases and repulsive forces between particles dominate. However, at higher lime rates, Ca2+ concentrations and ionic strength in soil solution increase causing compression of the electrical double layer and renewed flocculation. When present in sufficient quantities, both lime and hydroxy-Al polymers formed by precipitation of exchangeable Al, can act as cementing agents bonding soil particles together and improving soil structure. Liming often causes a temporary flush of soil microbial activity but the effect of this on soil aggregation is unclear. It is suggested that, in the long-term, liming will increase crop yields, organic matter returns, soil organic matter content and thus soil aggregation. There is a need to study these relationships on existing long-term liming trials. Fertilizers are applied to soils in order to maintain or improve crop yields. In the long-term, increased crop yields and organic matter returns with regular fertilizer applications result in a higher soil organic matter content and biological activity being attained than where no fertilizers are applied. As a result, long-term fertilizer applications have been reported, in a number of cases, to cause increases in water stable aggregation, porosity, infiltration capacity and hydraulic conductivity and decreases in bulk density. Fertilizer additions can also have physico-chemical effects which influence soil aggregation. Phosphatic fertilizers and phosphoric acid can favour aggregation by the formation of Al or Ca phosphate binding agents whilst where fertilizer NH4 + accumulates in the soil at high concentrations, dispersion of clay colloids can be favoured. Additions of organic manures result in increased soil organic matter content. Many reports have shown that this results in increased water holding capacity, porosity, infiltration capacity, hydraulic conductivity and water stable aggregation and decreased bulk density and surface crusting. Problems associated with large applications of manure include dispersion caused by accumulated K+, Na+ and NH4 + in the soil and production of water-repellant substances by decomposer fungi.

Transformations and plant uptake of urine N and S in long and short-term pastures

Abstract: A field trial was carried out to compare the transformations and plant uptake of urine N and S in a short-term pasture from within an arable/pasture ley rotation and a long-term pasture. Animal urine labelled with 15N and 35S was applied to microplots at both sites. These microplots were destructively sampled at various time intervals over 12 months and analysed for 15N and 35S. It is known that soil organic matter accumulates under short-term pastures compared with a long-term pasture in which accumulation and degradation are in balance. Consequently, it was hypothesised that immobilization of urine N and S is more intense in the short-term. However, in this study there was considerably less immobilization of 15N and 35S into soil organic forms under short-term pasture than long-term pasture. This was attributable to a greater pasture dry matter response to urine application under the short-term pasture (due to its inherently low N fertility) resulting in a greater plant uptake of 15N and 35S with less 15N and 35S consequently being available for immobilization. At both sites, all of the applied 35S was accounted for through plant uptake and recovery in the soil, but 21–48% of the 15N was unaccounted for and presumed to have been lost through gaseous emissions. It was concluded that accumulation of soil organic N and S under short-term pastures is likely to be attributable to turnover of plant residues (particularly root material) and does not appear to be related to immobilization in urine patches.

Enhancing crop yields in the developing countries through restoration of the soil organic carbon pool in agricultural lands.

Abstract: Food production in developing countries, estimated at 1223 million metric tons (Mg), must be increased by 778 million Mg or 2·5 per cent y−1 between 2000 and 2025 to meet the needs of an increased population and projected change in diet. Among numerous options, the one based on enhancing soil quality and agronomic productivity per unit area through improvement in soil organic carbon pool has numerous ancillary benefits. The available data show that crop yields can be increased by 20–70 kg ha−1 for wheat, 10–50 kg ha−1 for rice, and 30–300 kg ha−1 for maize with every 1 Mg ha−1 increase in soil organic carbon pool in the root zone. Adoption of recommended management practices on agricultural lands and degraded soils would enhance soil quality including the available water holding capacity, cation exchange capacity, soil aggregation, and susceptibility to crusting and erosion. Increase in soil organic carbon pool by 1 Mg ha−1 y−1 can increase food grain production by 32 million Mg y−1 in developing countries. While advancing food security, this strategy would also off-set fossil fuel emissions at the rate of 0·5 Pg C y−1 through carbons sequestration in agricultural soils of developing countries. Copyright © 2005 John Wiley & Sons, Ltd.

Is there a critical level of organic matter in the agricultural soils of temperate regions: a review

Abstract: Soil organic matter (SOM) is a complex mixture, which influences a number of soil properties and nutrient cycling, and is itself influenced in kind and amount by land-use, soil type, climate and vegetation. There is considerable concern that, if SOM concentrations in soils are allowed to decrease too much, then the productive capacity of agriculture will be compromised by deterioration in soil physical properties and by impairment of soil nutrient cycling mechanisms. This has clear implications for the sustainable use of soil. We have focussed our discussion from the standpoint of the sustainability of UK agriculture, because we know that best, but similar concerns are equally valid elsewhere in the world. Although soil scientists would expect to find different behaviour in different soils at different ‘critical’ concentrations of SOM, it seems widely believed that a major threshold is 2% soil organic carbon (SOC) (ca. 3.4% SOM), below which potentially serious decline in soil quality will occur. This review summarises what is known about critical thresholds of SOC or SOM, mainly in soils of temperate regions. It examines critically the quantitative, rather than anecdotal or descriptive, evidence for such thresholds and their potential effects on soil quality, soil physical properties and crop nutrition, and the links between these. We conclude that the quantitative evidence for such thresholds is slight, although there is some evidence that there might be an desirable range of SOC covering a wide spectrum of soils, but again the quantitative evidence for this needs considerable development. There is also little quantitative evidence that reduction in SOC concentrations in the soils of England and Wales will have marked effects on other soil properties or crop yields. The data do suggest, however, that more research is required on the nature of SOC, particularly of the so-called ‘active’ or ‘fresh’ fraction and its influence on the properties of a range of soil types under different land uses. This is particularly relevant to the ongoing debate about soil quality, its definition, and the identification of appropriate indicators that relate soil quality to soil functions.

Effects of compost, mycorrhiza, manure and fertilizer on some physical properties of a Chromoxerert soil

Abstract: Addition of organic materials of various origins to soil has been one of the most common rehabilitation practices to improve soil physical properties. Mycorrhiza has been known to play a significant role in forming stable soil aggregates. In this study, a 5-year field experiment was conducted to explore the role of mycorrhizal inoculation and organic fertilizers on the alteration of physical properties of a semi-arid Mediterranean soil (Entic Chromoxerert, Arik clay-loam soil). From 1995 to 1999, wheat ( Triticum aestivum L.), pepper ( Capsicum annuum L.), maize ( Zea mays L.) and wheat were sequentially planted with one of five fertilizers: (1) control, (2) inorganic (160–26–83 kg N–P–K ha −1 ), (3) compost at 25 t ha −1 , (4) farm manure at 25 t ha −1 and (5) mycorrhiza-inoculated compost at 10 t ha −1 . Soil physical properties were significantly affected by organic fertilizers. For soil depths of 0–15 and 15–30 cm, mean weight diameter (MWD) was highest under the manure treatment while total porosity and saturated hydraulic conductivity were highest under the compost treatment. For a soil depth of 0–15 cm, the compost and manure-treated plots significantly decreased soil bulk density and increased soil organic matter concentration compared with other treatments. Compost and manure treatments increased available water content (AWC) of soils by 86 and 56%, respectively. The effect of inorganic fertilizer treatment on most soil physical properties was insignificant ( P >0.05) compared with the control. Mycorrhizal inoculation+compost was more effective in improving soil physical properties than the inorganic treatment. Organic fertilizer sources were shown to have major positive effects on soil physical properties.