Identification of relevant environmental descriptors

Based on previous experiences and a literature review the most relevant environmental descriptors were selected and tested by means of field experiments. These included: (i) the temperature-humidity index (THI), (ii) the cattle stocking system (rotational stocking, continuous stocking or strip-grazing), (iii) the botanical composition of the grasslands, (iv) the net grassland productivity in terms of Net Energy (NE) and/or energy-corrected milk (ECM) per unit grassland area, and (v) the behaviour of dairy cows within grazing herds as recorded with SensOor® technology

The contribution of mineralization to grassland N uptake on peatland soils with anthropogenic A horizons

Peatland soils contain large amounts of nitrogen (N) in the soil and mineralization can contribute substantially to the annual mineral N supply of grasslands. We investigated the contribution of N mineralization from peat with respect to the total annual N uptake on grasslands with anthropogenic A horizons and submerged tile drains. The study included i) a pot experiment to determine potential N mineralization from the topsoil and the subsoil, ii) a 1-year field experiment to study herbage yields and N uptake under fertilized and non-fertilized conditions and iii) a 3-year field study where herbage yield and N uptake from the top 30 cm and the entire soil profile were monitored. The 3-year field study yielded an average N uptake of 342 kgha(-1) under non-fertilized conditions but the contribution of subsoil peat N mineralization to the total N uptake was found to be negligible. Our calculations demonstrate that peat N mineralization contributed only 10% to 30% to the total N-uptake, mainly coming from the top 30 cm. Most of the N uptake under unfertilized conditions appears to be largely the result of mineralization from long-term inputs of dung, ditch sludge, farmyard manure, cow slurry and non-harvested herbage

The influence of feeding strategy on growth and rejection of herbage around dung pats and their decomposition

Fresh cattle dung from four farms with different feeding strategies was used to create artificial dung pats in a continuously grazed pasture in order to compare the rejection of herbage growing around the pats, the effect on undisturbed herbage growth under cages and pat decomposition. The first farm was an extensive organic farm (ORGE) with young steers grazing on a biodiverse sward. The second was an intensive organic farm (ORGI) with dairy cattle grazing on a grass/clover sward during the day and fed low-protein forages indoors. The third dung used was from an integrated farm (TNT), where the feeding strategy was aiming for high dung quality by including straw in the diet. The fourth examined dung was from a conventional farm (CONV) aiming for a high milk production per cow, where fertilized grazed grass was the main component of the diet. A human smell test was performed to rank the odour of the four dungs. After 6 weeks of continuous grazing with dairy cattle, herbage yield around TNT pats tended to be lowest, whilst undisturbed herbage yield in and around caged TNT pats was highest (

Laboratory and greenhouse assessment of plant availability of organic N in animal manure

Laboratory data (thermal fractionation, pepsin extraction, C:No ratio) of dung and manure were mutually compared and contrasted with plant-availability of organic N (No) as found in a greenhouse experiment according to the double-pot technique. Two types of fresh cow dung (one with a relatively wide and the other with a relatively narrow C:No ratio) and four types of manure (from poultry, sheep, pigs and cow) were compared with ammonium nitrate as chemical reference fertilizer. Relative effectiveness of organic N (REo) was used as characteristic; it was calculated as the fraction of organic N that has the same availability to plants as inorganic N. REo for poultry and sheep manure could not be assessed, probably because of NH3 volatilization causing direct damage to plants and N losses. REo values decreased in the order: dung with narrow C:No > dung with wide C:No > pig manure > cow manure. Thermal fractionation did not provide a suitable index of plant-availability of organic N. Pepsin extracted organic N gave a positive, and C:No ratio a negative relationship with REo. Also between pepsin extracted organic N and C:No ratio a negative relationship was found. As C:No ratio is relatively easy to determine, it is considered the most practical laboratory index for plant availability of organic N in animal manures low in ammonia. When using the double-pot technique, application rates of manure types high in ammonia should be restricte

Evaluation of the performance of dual-purpose cows in European pasture-based systems

The demand for organic products in Europe is growing, especially organic products of animal origin. Organic dairy milk production requires grazing of cows, which results in a feed ration that is pasture-based. The breed that is kept by far the most for dairy production in Europe is the Holstein Friesian cow, a high-yielding dairy cow. This cattle breed has been developed in North America and was selected for its high milk yield. The disadvantages of this one-sided selection for production manifest in the health, fertility and longevity of the cow. More important, the high milk yield of the Holstein Friesian is only achieved when the cows are fed a diet of high quality and especially concentrates, which is not always possible in a pasture-based system. In this study the alternative for the Holstein Friesian breed is considered, namely the dual-purpose cow. Most countries feature indigenous cow breeds which were traditionally kept for both milk and meat. Because of the popularity of the Holstein Friesian breed these local breeds are less used in dairy production systems. An extensive literature study was carried out to compare the popular Holstein Friesian breed to the local dual-purpose cattle breeds. This showed that local dual-purpose breeds display in many traits such as health, fertility, meat quality and longevity an advantage over the Holstein Friesian. Additionally, dual-purpose cows are better able to cope with a harsh environment and a diet of low quality. Furthermore, the grazing behaviour of one of the Dutch dual-purpose breeds, the Dutch Friesian, was compared in the current study to the Holstein Friesian. For this purpose the monitoring system SensOor (AGIS) was used. SensOor registers the four main conducts of the cows, namely eating, ruminating, resting and other activity (such as walking, standing, etc.). The system expresses the time the cows spend on these conducts in percentages per hour or per day. In this study the SensOor system was validated under grazing conditions for the first time. Before, the SensOor system was only validated indoors or in a dirt pen. The validation under grazing conditions was done by observing the behaviour of the cows on the pasture, and comparing these observations with the SensOor output. The observation of the activity ‘grazing’ corresponded very well with the detection of the activity ‘eating’ (R² = 0.97). As the validation of SensOor under grazing conditions was successful, the output of the system was used to compare the behaviour of the two cattle breeds. In the current study no significant differences in behaviour were found, which can be explained by the differences in size of the cows (HF: 650 kg, DF: 575 kg) which have therefore different energy requirements. Another explanation could be that the high quality of the grassland on the studied farm concealed the ability of dual-purpose cows to cope with low-quality roughages. Besides the study of the behaviour of the cows, the herbage production on two farms was estimated. This was done by the placement of grass cages on the pastures. The herbage growth under the cages was mown, weighed and analysed. In conclusion, the monitoring system SensOor is very suitable to monitor the grazing time of cows. The literature study showed that dual-purpose cows have advantages over the Holstein Friesian (especially in milk composition, meat quality, health and longevity). Concerning their grazing behaviour, dual-purpose cows might spend more time on grazing and constitute more grass in their diet. This difference in behaviour was not shown by the output of SensOor. The absence of this difference might be explained by the excellent environment of the Friesian pastures. It is expected that the advantage concerning grass and feed intake of dual-purpose cows are better demonstrated in a harsh environment with pastures of low quality

Diagnosis for ecological intensification of maize-based smallholder farming systems in the Costa Chica, Mexico

Enhanced utilization of ecological processes for food and feed production as part of the notion of ecological intensification starts from location-specific knowledge of production constraints. A diagnostic systems approach which combined social-economic and production ecological methods at farm and field level was developed and applied to diagnose extent and causes of the perceived low productivity of maize-based smallholder systems in two communities of the Costa Chica in South West Mexico. Social-economic and production ecological surveys were applied and complemented with model-based calculations. The results demonstrated that current nutrient management of crops has promoted nutrition imbalances, resulting in K- and, less surprisingly N-limited production conditions, reflected in low yields of the major crops maize and roselle and low resource use efficiencies. Production on moderate to steep slopes was estimated to result in considerable losses of soil and organic matter. Poor crop production, lack of specific animal fodder production systems and strong dependence on animal grazing within communal areas limited recycling of nutrients through manure. In combination with low prices for the roselle cash crop, farmers are caught in a vicious cycle of cash shortage and resource decline. The production ecological findings complemented farmers opinions by providing more insight in background and extent of livelihood constraints. Changing fertilizer subsidies and rethinking animal fodder production as well as use of communal lands requires targeting both formal and informal governance structures. The methodology has broader applicability in smallholder systems in view of its low demand on capital intensive resource

Charles Glenn: A Response

This paper was given in response to Dr. Glenn’s presentation

Adam\u27s Navel: A Natural and Cultural History of the Human Form (Book Review)

Reviewed Title: Adam’s navel: A natural and cultural history of the human form, by Michael Sims. New York: Viking, 2003. 342 pp

Great with Child: Reflections on Faith, Fullness, and Becoming a Mother (Book Review)

Reviewed Title: Great with Child: Reflections on Faith, Fullness, and Becoming a Mother, Debra Rienstra (Tarcher Putnam, 2002), 295 pp