Experiments were carried out during 1978–81 in which lagoon-matured digested sludge (LMDS) was applied in November and in February to four soils which were cropped with ryegrass and the effects compared with ammonium nitrate fertilizer.

Over the whole experimental series the nitrogen in spring-applied LMDS was 47·6% as effective in producing dry matter as nitrogen in ammonium nitrate fertilizer, and was 40·2% as effective in nitrogen uptake. Overall, 20·3% of the N available from the LMDS was derived from mineralization of sludge organic nitrogen, equivalent to a 1st-year release from the organic-N in sludge of about 9%. This compares with reported values of 15–16% for 1st-year release of organic-N liquid digested sludge. Overall, autumn-applied LMDS sludge gave poorer results than when applied in spring. This did not apply to a silty loam with a pH of about 5, but poorer results with autumn-applied LMDS were associated with soils with pH values of 7·5 or more. On average an application of 140 m3 LMDS/ha provided 178 kg available-N/ha and 36 kg potassium/ha; this is an N:K ratio of 4·9:1.

There were increases of Cd, Cu and Zn in herbage as a result of applications of both fertilizer and of sludge; the effects were additive. Sludge increased herbage Ni concentrations but fertilizer-N reduced them. Three years' applications hardly raised Cu and Zn herbage concentrations to the threshold level for deficiency for ruminant animals, and were not near toxic levels for plant growth or animal nutrition.

Two sets of experiments were carried out during 1978–82 in order to compare the value of nitrogen in liquid undigested sludge (LUDS) with that in ‘Nitro-Chalk’. One set took place in the area of north Hertfordshire-south Bedfordshire, and the other at the University of Leeds. In the first growing season after application the relative effectiveness of LUDS-N was about 20%. In subsequent years it was about 40% though it was less on a soil initially very deficient in soil-N. At Leeds the 2nd-year value was 60–75%.

In the growing season immediately following treatment, N mineralized from LUDS became available too late to increase D.M. yields greatly; much of this appeared to be retained in the turf mat and increased the yield of D.M. the following year. When the lower 1st-year responses were taken into account there did not appear to be any yield penalty in making autumn (November) applications, compared with spring (February). This overall result concealed differences between soils.

In a year when it was dry during the main growing period yields were reduced by about 25%. It seems that LUDS-N is most valuable when it is applied regularly to the same area, and in the wetter parts of the country. Much LUDS comes from smaller rural sewage treatment works which are much less likely to carry contamination from potentially toxic elements.

Field experiments on efficiency of fertilizer N applied as calcium ammonium nitrate (CAN) and urea to no-tillage maize (Zea mays) were conducted under humid (Onne) and subhumid (Mokwa) conditions. At both the locations the rate of N was 150 kg/ha.

A comparison of apparent crop recovery of applied N indicated that CAN was a more effective N source than urea under subhumid conditions (Mokwa) but that urea was more effective under humid conditions (Onne). In 1981, percentages of applied N recovered by the maize crop at Onne were 28 and 50% from CAN and urea, respectively, whereas the recovery at Mokwa was 46 and 34%, respectively. Total recovery by crop and soil (0–120cm) of CAN at Onne with divided application was equivalent to that at Mokwa with single application at planting (54%). However, the total recovery of urea was much lower at Mokwa (40%) than at Onne (60%). The results in 1982 followed similar trends. Excessive N leaching loss from CAN under humid conditions and volatilization loss from urea under subhumid conditions are considered to be the reasons for poor efficiency of fertilizer N.

The results on the influence of growing various crops in five fixed annual sequences on the changes in available and total phosphorus and potassium content of a Tolewal sandy loam (Typic Ustipsamment) are reported. The available phosphorus content showed an increase in each of the five crop rotations after completion of two cycles. The maximum increase was observed in groundnut-based cropping sequences whereas the increase under the other three rotations was more or less of the same order. A slight decrease in the available P content during the 3rd year was observed after the harvest of bajra in a bajra fodder–potato–wheat sequence which was replenished after the harvest of potato and wheat. Total P content of the soil also showed an increase in all five rotations after completion of two cycles. A decrease in total P content of the soil was also observed after the bajra harvest. Balance sheet of P indicated net gain of P in all five crop rotations and the maximum gain of 62 kg P/ha was observed in the maize–wheat–moong rotation. Theavailable K status of the soil showed an increase in each of the five cropping sequences after completion of two cycles. The available K status after harvest of various crops in the rotation could not fully explain the dynamics of K availability. The total soil K content indicated a negative K balance in each of the five crop rotations after completion of three cycles and the maximum negative balance occurred in a maize–wheat–moong sequence. The negative K balance was related to the amount of fertilizer K added and that removed by the crops. The results suggested the need for modifying the existing K fertilizer recommendations to compensate gradual loss of native K soil fertility.

Flowers were present over a period of approximately 6 weeks in 12 varieties of oil-seed rape. A linear relationship was found between flower cover (maximum 74%) and photon reflectivity (400–700 nm) which increased from around 0·047 during vegetative growth to 0·195 for a canopy in full flower. Reflexion and absorption of photons by flowers reduced light available to the leaf canopy and immature pods. Spectral measurements indicate that flowering canopies reflect substantially more radiation and absorb less than vegetative canopies between 500 and 700 nm but reflect less and absorb slightly more between 400 and 500 nm.

Seed yield was not strongly correlated with estimates of the radiation absorbed by the leaf canopy under the flower layer. It appears that whilst increased flower density in a canopy might be expected to contribute to increased seed yield, increased reflectivity by petals may have a negative effect on yield. Breeding for reduced petal size or for apetalous lines may result in improved yields by producing more efficient light distribution within the canopy.

Sheep were exercised on a treadmill to study the effect of increased energy demand on roughage intake and ruminal characteristics.

The experiment consisted of a pre-exercise period during which exercise sheep walked for 30 min/day at 2 km/h against a gradient of 0° followed by a full exercise period during which they walked a total of 9 km/day at 3 km/h against a 10°gradient during six daily sessions of 30 min each. Control sheep received no exercise but were treated similarly to exercise sheep in all other respects.

The mean values obtained during the pre-exercise period for the exercise and control groups and during the full exercise period for the exercise and control groups respectively were 1347, 1125; 1177 and 1114 g/day for organic matter (OM) intake; 956, 921; 803 and 848 g for rumen OM contents; 11·8, 13·6; 12·2 and 12·3 h for rumen retention time of water; 17·5, 20·2; 16·8 and 17·6 h for rumen retention time of fermentable OM; 27·3, 28·2; 26·4 and 26·7 h for rumen retention time of unfermentable OM and 46·9, 48·1, 44·4 and 45·9 kg for empty body weight. Only the decline in OM intake from pre-exercise to full exercise period differed significantly between exercise and control groups.

It is concluded from these results that an increase in the difference between energy demand and supply per se is not responsible for the apparent increase in the upper limit to OM accumulation in the rumen and concomitant increase in roughage intake observed during other situations of increased energy output such as lactation and severe cold.

Screen house and field experiments at the Sugar Research Institute, University of Ilorin, Nigeria were carried out to evaluate the effects of various amounts of nitrogen and potassium fertilizers singly and in combinations on growth, yield and crop quality of sugarcane cultivar Co 957. Growth rate, number of green leaves per mother shoot, leaf area, plant height, stalk length and tiller density were significantly affected by nitrogen application but were not significantly affected by potassium. Similarly, cane tonnage was significantly affected by nitrogen but not by potassium. In the screen house trial, responses to N were linear from 0 to 160 kg N/ha. However, in the field, while the measured variables also increased linearly with N application from 0 to 160 kg N/ha, they decreased at 200 kg N/ha.

Cane quality decreased with increased nitrogen and potassium. However, these reductions were significant only at the highest level of nitrogen and potassium. There were no significant nitrogen and potassium interactions on any of the variables studied.

Urea with molasses and starch, casein, and fish meal with maize gluten meal were compared with a urea control as different nitrogen and energy sources in straw diets fed ad libitum to four mature non-lactating Swedish Red and White cows in a 4 × 4 latinsquare design. Cows fed fish meal with maize gluten meal had increased neutral detergent (ND) fibre intake, digestibility, and total digestion compared with those fed the urea control. When fed casein, cows tended to have higher ND fibre intake, lower ND fibre digestibility, and higher total ND fibre digestion than the urea control. Cows fed urea with molasses and starch had the same ND fibre intake, lower ND fibre digestibility, and lower total ND fibre digestion than the control. Treatments had no influence on rumen pH, rumen in sacco ND fibre kinetics, rumen residence times and median faecal particle size. Rumen ammonia concentrations were lower for the urea with molasses and starch as well as for the fish meal with maize gluten meal treatments when compared with the urea control. Rumen volatile fatty acid concentrations for supplemented diets were either unchanged or higher than for the control diet.

A 2-year field study indicated that pearl millet yielded more when sown after fallow, cow pea and green gram than after maize. Preceding fallow, cow pea and green gram reduced the nitrogen requirement of pearl millet by 40 kg/ha compared with maize. Pearl millet responded linearly up to the highest rate of nitrogen (80 kg/ha). N applied to millet had no residual effect on the subsequent crop of chickpea. The chickpea yield followed the order fallow > green gram ≥ cow pea > maize. Chickpea responded to phosphorus up to 40 kg/ha. Green gram-pearl millet-chickpea proved the most profitable cropping sequence. Continuous cropping and application of nitrogen and phosphorus improved the organic carbon and available phosphorus but decreased the available potassium status of the soil.

The effects of pasture height and of a cereal-based concentrate or a sugar-beet pulp supplement were studied with 30 spring-calving cows on continuously stocked, perennial ryegrass dominant pasture in a 3 × 3 latin-square design with periods of 4 weeks. Pastures were maintained at heights of about 5·0 cm (short) or 6·5 cm (control). On the short pasture, the two supplements had similar effects and were additive but on the control pasture, compared with sugar-beet pulp, the cereal concentrate depressed herbage intake. Average fat-corrected milk yields were 26·3 and 28·1 kg/day on short and control areas respectively. Both supplements increased milk yields by about 0·7 kg per kg OM supplied. Cows on the short pasture tended to lose weight. Supplements slightly increased live weight and sugar-beet pulp tended to increase body condition score. In observations continued after the conclusion of the main experiment the short pasture was more productive and of slightly higher nutritive value. Cows receiving the concentrate supplements increased total intake but this was reflected only in live weight. The total utilized metabolizable energy for the whole season was about 130 GJ/ha.

In a 2-year field study, all the maize cultivars tried (Partap-1 Ageti-76, Ganga-5 and DHM-103) produced similar length of ears and equivalent grain yields. However, Partap-1 and Ganga-5 produced greater 100-kernel weight and greater grain yield per ear but fewer ears per hectare than Ageti-76 and DHM-103. The yield attributes and grain yields of maize sown on 19 December, 29 December and 8 January were identical and were superior to those of the 19 January sowing. Maize sown on 19 December, 29 December and 8 January exhibited longer ears, more ears and fully developed kernels and thereby produced greater grain yields than the 18 January sowing.

During 1983–4, in the 19 December and 29 December sowings all the cultivars gave identical grain yields. In the 8 January sowing Partap-1 and Ageti-76 produced similar yields and proved better than Ganga-5 and DHM-103. In the 18 January sowing Ageti-76, Ganga-5 and DHM-103 yielded more than Partap-1.

Thirty Ossimi lambs were used in an experiment to compare those whose tail was docked shortly after birth with controls. After weaning at 4 months of age the groups were further subdivided and two of the four groups closely shorn according to a 2 × 2 factorial design.

Male lambs at 20 kg were subjected to intensive finishing until the age of 50 weeks and nine were then slaughtered to determine carcass characteristics.

There was a trend for increased live-weight gain in the docked lambs in the preweaning stage (up to 16 weeks).

This trend was also present, although not statistically significant, in the final phase of intensive feeding from 20 kg weight to 50 weeks. Shearing significantly improved daily gain in this final period (P < 0·05). These increases in gain were also apparently associated with improvements in efficiency, as judged on a group basis.

Docking and shearing also tended to cause increases in body measurements: height, chest girth and abdomen girth in the case of docking (P < 0·05) and chest girth, chest depth and abdomen girth in the case of shearing (P < 0–05).

Carcass characteristics, measured on a relatively small sample, indicated several effects of docking and shearing on carcass traits although most of these were consistent with the expected differences stemming from the higher carcass weights acheived at 50 weeks of age by docked and sheared lambs.

The genetic parameters controlling the expression of seed yield and the yield components have been studied using both generation mean and triple test cross (TTC) analyses in two crosses of field pea. From generation mean analysis, it is obvious that in addition to significant estimates of additive and dominance components, epistatic components of mean [(i) and (I) types] were also important and duplicate type of epistasis was predominant for all the traits in both sets of crosses. In the TTC analysis, the major genetic component of variance was the additive component, though the dominance component was also found to be significant. There was evidence of epistasis for most of the characters studied. In fact, the overall epistasis (i type) was the major component of epistasis, but the parameter F was found in the non-significant range. The mean performance of the characters studied was higher in randomly-mated biparental progenies (BIPs) but there were more desirable transgressive segregants in the TTC population. Thus the genetic information obtained from both analyses seems to be complementary rather than alternative modes of inheritance in governing the expression of these useful economic traits.

The phenology of the emergence of brassica pod midge from overwintering sites previously sown with spring oil-seed rape and its subsequent infestation of spring rape crops was studied over 3 years. Adults emerged from the overwintering sites from mid-May until early July, but infestation of spring rape did not begin until late June. Two generations occurred on spring rape. Mature larvae dropped from the pods almost daily from early to mid-July until mid-August to early September to form cocoons in the soil. A small proportion of these larvae developed into pupae and emerged as a second generation of adults to lay further eggs in the crops. Larvae from these eggs dropped to the soil to diapause within cocoons.

Environmental and cultural factors that may limit the yield of short-duration pigeonpea were investigated over three seasons. Plants in the peninsular Indian environment at Patancheru grew less and produced less dry matter by first-flush maturity than at Hisar, a location in northern India where the environment is considered favourable for the growth of short-duration pigeonpea. However, with a similar sowing date in June, the mean seed yields of three genotypes, ICPL 4, ICPL 81 and ICPL 87, were very similar, at about 2·3 t/ha, in both environments. This was mainly due to the higher ratio of grain to above-ground dry matter at Patancheru. In addition to the first harvest, all genotypes showed a potential for two more harvests owing to the warm winters at Patancheru. The potential for multiple harvests was particularly high in ICPL 87, which yielded 5·2 t/ha from three harvests in 1982–3, 3·6 t/ha from two harvests in 1983–4, and 4·l t/ha from three harvests in 1984–5. The optimum plant population density at Patancheru was 25–35 plants/m2 for ICPL 87, but was higher for the other two genotypes.

At Patancheru, the total dry-matter and seed yield of first and subsequent harvests were significantly reduced by delaying sowing beyond June. Generally, the second- and the third-harvest yields were lower on vertisol than on alfisol under both irrigated and unirrigated conditions.

The total yield of ICPL 87 from two harvests was far higher than that of a well-adapted medium-duration genotype BDN 1, grown over a similar period. The yield advantage was greater on the alfisol because of the better multiple harvest potential of this soil. The results of this study demonstrate that properly managed short-duration genotypes of pigeonpea may have considerable potential for increased yield from multiple harvests in environments where winters are warm enough to permit continued growth.

A microplot experiment was conducted for two consecutive years, 1978–9 and 1979–80, on alkaline calcareous soils of Chittor, Kapasan, Nimbaheda and Chhotisadari blocks at the Department of Agronomy, College of Agriculture, Udaipur (India). It was found that soil application of 250 kg S/ha both of elemental sulphur and gypsum significantly increased chlorophyll a and b and concentrations of N, K and S of plants. Leaf sap pH and P and Fe concentrations were, however, significantly reduced by sulphur treatments. Foliar application of 0·2% Fe-EDDHA increased chlorophyll a and b and caused marginal increase in N concentration of plants. K and S concentrations remained unaffected but P and Fe concentrations underwent significant reduction. Leaf sap pH was not at all affected by this treatment.

Failure of metabolic translocation of iron and hence its inactivation inside the plant is suggested to be the most probable cause for the incidence of chlorosis despite high tissue Fe concentration. Sulphur application created a balanced nutritional environment and thus kept iron physiologically active for chlorophyll synthesis. Reduced efficacy of Fe-EDDHA might be due to high P concentration in the plant.

Twenty-five male Shugor, 25 female Shugor, 25 male Watish and 25 female Watish lambs, individually fed for 57 days, were used to study post-weaning growth performance and carcass composition of these breed types when subjected to a period of intensive feeding.

Means and standard error of means of daily gain on experiment were 191·0±5·81, 166·0±5·81, 150·0±5·81 and 134·0±5·81 g for Shugor males, Watish males, Shugor females and Watish females, respectively. The means and S.E. for feed conversion ratio (FCR) were 5·79±0·190, 7·30±0·190, 7·47±0·190 and 8·00±0·190 in the same order. Shugor and male lambs had better gain (P < 0·001) and FCR (P < 0·01)than Watish and female lambs respectively.

Shugor had heavier slaughter weight and cold carcass weight than Watish (P < 0·01). Males were superior to females in slaughter weight, carcass weight and dressing percentage (P < 0·01). No difference was detected in lean, fat or bone percentage between breed type or sex (P < 0·05). Males had larger muscle area (P < 0·001) than females. On the other hand, females had more percentage kidney knob and channel fat (P < 0·001) and thicker fat depth (P <0·01) than males. Shugor were superior (P < 0·01) in fat depth to Watish.

Percentage non-carcass components showed that females had more percentage omental and mesenteric fat (P < 0·001) and percentage full stomach (P < 0·01). Breed type and sex showed significant effect (P < 0·001) on percentage liver.

In linear measurements, Shugor had greater carcass length and femur length (P < 0·01). Males had bigger circumference of buttocks and chest depth (P < 0·001).

For carcass joints as a percentage of side weight, the only clear effect of breed type was on percentage loin (P < 0·05). Males had bigger percentage middle neck (P < 0·001) and shoulder and percentage scrag (P < 0·01) than females, whereas females had higher percentage loin and chump.

Heritability estimates of some carcass traits, admittedly based on limited numbers, ranged from 0·32 (S.E. 0·183) for leg to 0·18 (S.E. 0·180) for loin weights. Linear carcass measurements showed low heritability of around 0·10 (S.E. 0·160).

The effect of a slant-legged subsoiler (Trade name, ‘Paraplow’) on the growth of two crops of winter wheat following an intensively grazed grass-clover ley was investigated in 1981–2 and 1982–3. The treatments for the first crop were direct drilling, loosening the soil by shallow cultivation before drilling, loosening by ‘Paraplow’, and a combination of ‘Paraplow’ and shallow cultivation. For the second crop these treatments were repeated and a fifth added, loosening by ‘Paraplow’ after drilling. Seed was sown with a triple disk direct drill and all treatments received the same quantity of fertilizer.

Soil compaction was measured with a cone penetrometer in the autumn of 1982 and spring 1983; root axes were counted and dry-matter weights of shoot, grain yield and components of yield obtained.

Loosening soil by ‘Paraplow’ did not increase significantly the number of roots nor was the uptake of water by the crop in dry periods affected, even though soil strength, measured as cone resistance, was considerably reduced.

Shallow cultivation increased grain yield in the first wheat by 0·34 t/ha (P< 0·05) but had no effect on the second wheat. The ‘Paraplow’ did not increase yield of the first crop but the mean response of 0·65 t/ha in the second crop was significant (P < 0·05). Using the ‘Paraplow’ before or after drilling gave similar yields. Increases in yield were produced by more grains per unit area, not increased 1000-grain weights.

It is concluded that the apparently compacted soil did not restrict the growth of wheat and that the beneficial effect of the ‘Paraplow’ in the second crop was probably due to better drainage in the wet spring.

The effects of supplementation of a barley-barley straw diet containing 4 mg copper (Cu)/kg dry matter (D.M.) either with 5 mg molybdenum (Mo)/kg D.M. or with 500 mg iron (Fe)/kg D.M. on the Cu status, growth and clinical condition of calves are described. Liver and plasma Cu concentrations declined rapidly within 12–16 weeks to levels indicating severe Cu deficiency in both the Mo- and Fe-supplemented groups. The changes in Cu status were similar for both supplements and did not differ significantly from each other. Clinical signs of Cu deficiency, as indicated by reduced growth rate and changes in hair texture and colour, were evident after 16–20 weeks only in animals on the Mosupplemented diet. The reduced growth rate was accompanied by a decreased food intake and reduced efficiency of food utilization. The Mo-supplemented animals also exhibited an altered Fe metabolism, particularly when the growth rate was affected. The results confirm earlier reports that the effects of Mo on growth and clinical condition are independent of its effect on Cu status and suggest that the altered production might be due to effects on the control of food intake, food utilization, or Fe metabolism.

A comparative study of sorption maxima (simple and double Langmuir equations) and buffer capacity of acid soils was made in order to select the most useful P-sorption parameter. Data were obtained from 20 acid soils from Galicia (north-west Spain) and selection was made by linear and multiple regressions among sorption parameters, and between these and some soil characteristics related to phosphate sorption (clay and organicmatter content, pH in NaF, and 0·5 M-CuCl2-extracted Al).

The phosphate buffer capacity, determined by the slope of the regression ‘sorbed-P v. logc’, was the best parameter to represent soil phosphate sorption behaviour. 0·5 M-CuCl2- extracted Al was the edaphic characteristic which best related to sorption properties.