1. Four varieties of marrow stem kale, three of thousand headed kales, Hungry Gap Kale and Rape-Kale were grown at three centres in mid-Wales. They were sampled in the early winter period and separate leaf and stem samples analysed for the proximate constituents and minerals.2. Leaf to stem ratios were measured on both a green and dry matter basis and the latter values used to calculate whole plant values for the chemical constituents.3. The leaves of the marrow stem kales were higher in dry matter than the stems, except in the case of the Purple Stem Kale. This variety resembled the thousand headed and rape-type kales in having a higher dry matter in the stems. On a dry matter basis, the leaves of all the varieties were richer than the stems in ether extract, crude protein, total ash and all the minerals except potassium and sodium. These elements occurred to a greater extent in the stems of the fleshy stemmed marrow stem kales than in the leaves. The stems were higher in crude fibre and nitrogen-free extractives.4. The leaves of the rape-type kales were higher than those of the other varieties in silica, phosphorus and potassium. They were the best source of phosphorus on a whole plant basis. The marrow stem kales had considerably higher leaf and stem values for sodium and were markedly superior to the other varieties as a source of the element.

The DE values of corn grain for pigs will differ among corn sources. More accurate prediction of DE may improve diet formulation and reduce diet cost. Corn grain sources ( = 83) were assayed with growing swine (20 kg) in DE experiments with total collection of feces, with 3-wk-old broiler chick in nitrogen-corrected apparent ME (AME) trials and with cecectomized adult roosters in nitrogen-corrected true ME (TME) studies. Additional AME data for the corn grain source set was generated based on an existing near-infrared transmittance prediction model (near-infrared transmittance-predicted AME [NIT-AME]). Corn source nutrient composition was determined by wet chemistry methods. These data were then used to 1) test the accuracy of predicting swine DE of individual corn sources based on available literature equations and nutrient composition and 2) develop models for predicting DE of sources from nutrient composition and the cross-species information gathered above (AME, NIT-AME, and TME). The overall measured DE, AME, NIT-AME, and TME values were 4,105 ± 11, 4,006 ± 10, 4,004 ± 10, and 4,086 ± 12 kcal/kg DM, respectively. Prediction models were developed using 80% of the corn grain sources; the remaining 20% was reserved for validation of the developed prediction equation. Literature equations based on nutrient composition proved imprecise for predicting corn DE; the root mean square error of prediction ranged from 105 to 331 kcal/kg, an equivalent of 2.6 to 8.8% error. Yet among the corn composition traits, 4-variable models developed in the current study provided adequate prediction of DE (model ranging from 0.76 to 0.79 and root mean square error [RMSE] of 50 kcal/kg). When prediction equations were tested using the validation set, these models had a 1 to 1.2% error of prediction. Simple linear equations from AME, NIT-AME, or TME provided an accurate prediction of DE for individual sources ( ranged from 0.65 to 0.73 and RMSE ranged from 50 to 61 kcal/kg). Percentage error of prediction based on the validation data set was greater (1.4%) for the TME model than for the NIT-AME or AME models (1 and 1.2%, respectively), indicating that swine DE values could be accurately predicted by using AME or NIT-AME. In conclusion, regression equations developed from broiler measurements or from analyzed nutrient composition proved adequate to reliably predict the DE of commercially available corn hybrids for growing pigs.

The possibility of combining the early rapid growth of extreme spring (express) wheat cultivars with the high grain-producing ability of long-season types as a dual-purpose crop (fodder and grain) for the high-rainfall zone of E. Australia was investigated in an experiment at Canberra in 1985. Mixtures of cv. Sunset, an express wheat, and Isis, a winter wheat, in the proportions of 1:3, 1:1 and 3:1, were compared with 4 long-season and 2 short season wheat cultivars, oats and pastures (Lolium rigidum/Trifolium subterraneum with and without N fertilizer), all sown at the end of summer. Cereals and pastures were cut monthly from 3 different starting dates. Cereals were cut until their developing ears were above ground, and pastures were cut until the trial ended in Nov. In a 4th treatment, cereals were left uncut. An early start to cutting allowed all long-season wheats to be harvested several times for fodder, but in general the total amount harvested was greatest from the latest initial cutting date treatment. The greatest amount of DM harvested (9 t/ha) came from the express wheat Sunset and from Sunset/Isis mixtures, 2 t/ha more than from Isis alone. As well as producing considerably greater amounts of DM during winter, the Sunset/Isis mixtures yielded as much grain (3.4 t/ha from the latest initial cutting date treatment) as Isis alone. DM and grain yields of mixtures were stable across the range of ratios used. It was concluded that grazing of crops sown for winter feed in cool environments should be delayed as long as possible without endangering ears, thereby providing max. amounts of fodder and effectively smothering weeds. Under this regime, mixtures of express and winter wheats should provide at least as much feed as a pasture treated similarly. If cutting started early, both would be less productive, and the crop could be inferior to the pasture.

No abstract

This study evaluated the relative performance of spring wheat under direct drill in comparison with more conventional tillage methods, under a wide range of nutrition treatments and in the presence of an aggressive weed component, Phalaris aguatica (syn. tuberosa). Four tillages were applied: conventional fallow; direct drilled plus pre-emergence grazing; direct drilled plus the pre-sowing herbicide glyphosate; and reduced tillage. There were five levels of phosphorus and two of nitrogen, and a post-emergent herbicide 2,4-D was applied to half of the plots. Growth of crop and weeds was measured at six stages of development, together with final yields. Nitrogen and phosphorus uptake and concentration were measured throughout development. Plant nutrients were not released as efficiently with direct drilling as cultivation. Crop plants in direct drilled were not only deficient in nitrogen but also in phosphorus during early development, whereas cultivation ensured that high nutrient levels were attained in fallow plots. Direct drilled plots did not appear to recover completely from this initial deficiency unless fertilized and freed from weed competition. When weeds were controlled, yields of direct drilled plots were comparable with yields of fallow at higher levels of phosphorus and nitrogen, because at these high nutrient levels yields in fallow were suppressed. However, weed competition and/or poorer nutrition lowered direct drill yields. It was concluded that direct drilling requires a new approach, sensitive to the changed agronomic conditions that it engenders. Competition with weeds may be avoided by choosing a vigorous cultivar, avoiding dominant weed species and using herbicides strategically and economically. A high plane of nutrition proniotes the success of direct drilling.