Gnotobiotic pigs were fed control and soya-bean protein containing diets in an attempt to identify direct effects of this protein on intestinal structure and function.

Feeding diets containing soya-bean protein for 4 days to 21-day-old gnotobiotic pigs increased crypt depth in the lower half of the small intestine. This increase was accompanied by a corresponding reduction in lactase activity, brought about mainly by a decrease in the apparent rate at which this enzyme appeared in the luminal membrane of developing enterocytes. Sucrase and maltase II and III activities increased slightly in tissue taken from pigs fed soya-bean protein. Alanine transport measured in the presence and absence of Na remained unaffected by change of diet.

The structure and function of control gnotobiotic pig intestine differed from that found in normal unweaned piglets. The possible source of these differences and the probable role played by enteric microflora in amplifying initial effects of soya-bean protein on intestinal function is discussed.

Field studies on leaching a highly saline sandy loam soil having a shallow groundwater table showed that application of 150 mm water in two equal parts at 10 days interval had no distinct advantage over a single application of the whole amount. On the contrary, the surface-accumulated salts were displaced to a lesser extent and the salt peak remained at a shallower depth under split application, particularly during periods of high atmospheric evaporativity when the leached salts tended to move upward between successive water applications. A soil mulch created by shallow tillage reduced evaporation losses and curtailed upward movement of salts, resulting in nearly 10% increase in leaching efficiency. Significantly a small quantity of water (0·41 cm leaching water per unit soil depth) sufficed for 70% chloride removal, indicating that under the prevailing conditions a larger fraction of the pores contributed to the leaching process. A compact layer, having a bulk density of 1·69 g/cm3, at the soil surface, also appeared to be related to the higher leaching efficiency by maintaining a preponderance of unsaturated flow.

The ability of two chemicals, Benlate and BAS352-04F, to control chocolate spot (Botrytis fabae) disease of field beans (Vicia faba) was examined in five small-plot or field experiments. The incidence of the fungus was never such as to reach the aggressive stage naturally, although severe infection was induced temporarily in certain experiments by enclosing the plots in plastic-covered boxes after inoculation with fungus. Increasing the recommended dose of BAS352-04F but not Benlate resulted in improved control and applying either chemical twice was preferable to a single application. Control by BAS352-04F was sometimes better than Benlate in the early days after infection whereas the reverse was true later. These results are in keeping with their roles as contact, and systemic and contact fungicides respectively. In these small experiments, with low levels of infection, the use of fungicides did not result in significant increases in yield or yield components.

In the present study, the effect of weather on maize yields in northern China was examined using data from 10 districts in Inner Mongolia and two in Shaanxi province. A regression model with a flexible functional form was specified on the basis of agronomic considerations. Explanatory variables included in the model were seasonal growing degree days, precipitation, technological change (e.g. adoption of new crop varieties, improved equipment, better management, etc.) and dummy variables to account for regional fixed effects. Results indicated that a fractional polynomial model in growing degree days could explain variability in maize yields better than a linear or quadratic model. Growing degree days, precipitation in July, August and September, and technological changes were important determinants of maize yields. The results could be used to predict potential maize yields under future climate change scenarios, to construct financial weather products and for policy makers to incentivize technological changes and construction of infrastructure (e.g. irrigation works) that facilitate adaptation to climate change in the agricultural sector.

Nine different capacitance probe methods were used to estimate the herbage yields of 32 small pasture plots; ten meter readings were used in conjunction with the yield data from a variable number (n) of quadrats in each plot. Expected yields were determined by cutting ten quadrats per plot. Estimated yields were compared with expected yields for both the differing methods and the differing values of n. At each level of n the yield estimates from the different probe methods were compared with those obtained simply by cutting n quadrats.

Using calibration data from only one quadrat per plot (n = 1), all probe methods except one gave greater accuracy than that obtained from the single quadrat yields only. For n = 2, the advantage of the probe methods was less pronounced and where n = 3 only one probe method (one which involved no regression computations) gave superior accuracy to that obtained merely by using the yield data from the three cut quadrats. At n > 3, only the one probe method gave increased precision; all other probe methods were markedly less accurate than the equivalent raw quadrat results.

Only one probe technique (which combined data from markedly dissimilar swards) gave yield estimates which were noticeably biased.

Results from an earlier study are presented to demonstrate the influence of season, species and irrigation on probe calibration.

Recommendations are made on the various probe methods which may prove effective in some experimental situations.

Experiments are described in which the decomposition of various plant materials and of purified preparations of plant constituents, during rotting under neutral aerobic conditions in the presence of soil organisms, has been studied in relation to the formation of humic matter.

The formation of humic matter was more closely related to the change in the lignin content than to the change in content of the other groups of plant constituents estimated.

Amendment of recalcitrant organic materials with high carbon/nitrogen (C/N)-ratio may improve and maintain soil labile C for a longer period, thus enhancing the productivity of soils with low fertility; however, immobilization of N may affect the plant growth negatively. To reduce the negative impacts, recalcitrant organic materials can be pre-incubated with N-rich sources or applied in combination with fertilizers. The current study evaluated sawdust biochar (BC) and pre-incubated cattle manure–sawdust mixture (CS) amendments with synthetic fertilizers in improving soil carbon pool, soil fertility and maize (Zea mays L.) yield on a tropical Alfisol. Four treatments: control, site-specific fertilizer (SSF), site-specific fertilizer with sawdust biochar (BC + SSF) or pre-incubated cattle manure-sawdust mixture (CS + SSF), were evaluated for two seasons with maize. The residual effect was evaluated in the third season. During the year of active C application, lability index, C management index and potentially mineralizable N were significantly greater in CS + SSF than BC + SSF treatment. However, the same indices measured in the third season with no further application of amendments were significantly greater in BC + SSF than in CS + SSF treatment, indicating an increase in more recalcitrant C pool with BC amendment. Application of organic amendments improved soil fertility parameters compared with the application of fertilizer alone. Maize yield was significantly increased by fertilizer, with or without organic amendments; with significantly greater yield in BC + SSF than other treatments. Results suggest that soil amendment with BC had greater potential to improve the soil carbon pool and maintain labile carbon for a longer period than a pre-incubated CS.

Heat stress during the reproductive and grain-filling stages leads to severe yield losses in rice, especially in irrigated areas during the dry season in Thailand. Thus, breeding for heat-tolerant rice is one of the strategies for developing rice crops adapted to the effects of high temperature in major growing regions. M9962, a fast neutron-induced mutant, was identified as a heat-tolerant line that was then used as a donor parent and crossed with the Phisanulok 2 (PSL2) cultivar (the recurrent parent) in a backcross breeding programme. Heat tolerance scoring under controlled greenhouse and field conditions was based on the percentage of spikelet fertility. Yield trials for the BC2F7 and BC3F6 lines were subsequently conducted under field conditions at three locations and under controlled greenhouse conditions during the dry season of 2019 (DS2019). In the early generation, 210 plants of the BC1F1 population and 440 plants of BC2F1 population were evaluated for their heat tolerance, and the spikelet fertility distribution within the BC1F1, BC2F1 and BC3F1 populations showed a skewed-right pattern. In addition, most rice plants in every generation were heat sensitive. Finally, compared with PSL2, the four-candidate heat-tolerant lines exhibited a high percentage of spikelet fertility and high yield. In addition, the one candidate line, BC2F7-6-5-4-1-1-21 was most similar to PSL2 in terms of genetic background, plant type and grain quality. Thus, backcross breeding programmes via the spikelet fertility can be used as an indirect trait to select for heat tolerance.

The objective was to elucidate the effects of dietary supplementation with guanidinoacetic acid (GAA) on performance, egg quality and the liver antioxidant activity of laying hens. A total of 128, 72-week-old ISA Brown laying hens were randomly divided into four equal groups (32 birds), and each subgroup had eight replicates (four birds/cage). The control group (GAA0) fed the basal diet with no supplements, while the other experimental groups fed the basal diets supplemented with 0.5 (GAA1), 1.0 (GAA2) and 1.5 (GAA3) g of GAA/kg diet. The experiment lasted for 6 weeks. The addition of GAA at a rate of 1.5 g kg−1 significantly increased the hen-day egg production and egg mass as compared to the control group (P = 0.016 and 0.003, respectively). Although the egg weight was not affected (P = 0.521) by the dietary supplements, the shell ratio, shell thickness, yolk index and Haugh units increased linearly with the increase in the dietary supplements of the GAA (P = 0.036, 0.001, 0.012 and 0.004, respectively). The liver MDA levels decreased linearly with the increment in the dietary levels of the GAA (P = 0.012). Birds in the GAA2 and GAA3 showed a significantly higher liver nitric oxide level (52.50 and 54.21 mg/g, respectively) when compared with GAA0 and GAA1 groups (P = 0.029). Compared to the GAA0 group, all GAA-supplemented groups showed significantly higher liver ATP levels (P = 0.047). In conclusion, the dietary GA supplements at doses of 1.0 or 1.5 g kg−1 may improve the laying performance, antioxidant activity and the status of cellular energy metabolism in laying hens.

Changes in the wheat phosphatases (phytase-Phy and acid phosphatase-AcPh) and the degradation of their substrates (inositol phosphates esters) during seed germination have been examined in two studies. Germinated grains with high phytate degrading enzymes are of potential interest in the improvement of phosphorus availability in monogastric animals. In the first study, the seeds were soaked for 1 and 14 h and germinated for 3 and 5 days with and without the addition of gibberellic acid (GA3). In the second study, the seeds were soaked for 1 h and germinated for 1, 3 and 5 days with GA3. Phytase (up to 1800 and 1573 U/kg) and acid phosphatase (up to 13 115 and 10 154 U/g) activities and IP6 (6·96 and 7·67 mg/g), IP5 (0·40 and 0·60 mg/g) and IP4 (0·04 and 0·04 mg/g) were detected in ungerminated spring and winter wheat, respectively. The germination process caused a significant increase of Phy and AcPh activities in spring (up to 275 and 235%) and winter wheat (up to 250 and 329%) and a reduction in the phytate phosphorus content (up to 35 and 64%, respectively). Phytate phosphorus content was affected in both spring and winter wheat by the soaking time. Finally, during the course of germination, IP6 and IP5 were more rapidly degraded in winter wheat (62 and 62%) than in spring wheat (32 and 29%), and IP4 was only a short-living intermediate, which was increased during hydrolysis and degraded to IP3. In conclusion, the germination process caused a significant increase of Phy and AcPh in spring and winter wheat, which was accompanied with a significant reduction of phytate phosphorus content and an increase in the content of lower inositol phosphates.

The present paper records some investigations on the growth of the clover- and pea-nodule organisms (Rhizobium trifolii Dangeard and Rh. leguminosarum Frank), and the nitrogen fixation of the pea, at low temperatures. Growth of the bacteria was studied with pure culture experiments in large flasks, in which the bacteria were grown on a solid gelatine medium. The amount of nitrogen in the bacterial mass thus obtained was used as the basis of comparison. The fixation of nitrogen by peas was studied with a pot-culture experiment in a relatively cold greenhouse. Inoculated plants were grown in quartz sand, and were supplied at an early stage with mineral nitrogen either as Ca(NO3)2 or (NH4)2SO4. The plants were harvested after flowering and analysed. The main results of these experiments were the following:

(1) Pure-culture experiments with five strains of clover-nodule bacteria and four strains of pea-nodule bacteria showed that at 6–13° C. the strains imported from more temperate climates grew distinctly less well than did the northern European strains. Even between the Swedish and Finnish strains there were clear differences: the latter formed the more bacterial matter in the cold. It may be appropriate to consider such differences when selecting cultures for inoculating leguminous crops.

(2) In the pot-culture experiment, the application of mineral nitrogen (30 mg. N per plant) to inoculated peas kept at relatively low temperatures had very little effect on the amount of dry matter produced. The slightness of this effect was similar to what has been previously observed in experiments at more favourable temperatures. Nitrogenous fertilization slightly lowered the amounts and percentages of total N present as protein and amino nitrogen, in the crop; but nitrate application somewhat increased the nitrate content of the crop. Hence, it may be concluded that, even under these low-temperature conditions, the application of artificial nitrogen has not had a favourable effect on the size or quality of the crop.

The foregoing experiments give definite evidence, corroborative of the work of Koch, Remy and others, that the nitrogen content of sand or soil may be appreciably increased by the activity of Azotobacter when some suitable source of energy is supplied. For this purpose sugars such as dextrose and saccharose are suitable, but distinct gains have also been obtained by the use of plant residues. In laboratory experiments an increment of upwards of 6 mgrm. of nitrogen per gram of plant residues occurred, but in pot experiments gains of 9 mgrm. per gram of substance were obtained.

Two potato genotypes, Kufri Sindhuri (KS) and Kufri Chandramukhi (KC), were grown in association with sugarcane (cv. Co 1148) at 1:1 (SP) and 1:2 (SPP) sugarcane (S): potato (P)row arrangements. Growth behaviour and yield of both crops in companionship were compared with those of their sole cropping. Initially, KC accumulated more dry matter in tubers than KS. At harvest, the contribution of tubers to total dry matter was the same in both genotypes. However, KS produced significantly higher absolute tuber yields than KC. Potato row arrangements in sugarcane did not significantly affect the proportion of dry matter in different plant components. However, SPP gave significantly higher tuber yields than SP and was the same as with sole potatoes. Drymatter accumulation, canopy development and yield of sugarcane were not affected significantly by potato row arrangements in the companion cropping system. Sugarcane was unaffected by KC in companion cropping but KS exerted an adverse effect on all the growth characters and yield of sugarcane. Similarly, in sequential cropping, sugarcane yielded significantly less when planted after KS than after KC.

An experiment on the use of wheat straw (ploughed in or composted at the rate of 53⅓ cwt./acre every second year) and NPK fertilizers in the maintenance of fertility was carried out at Rothamsted between 1933 and 1958. The effects of these treatments on the yields of the crops of the rotation used in the experiment—barley, sugar beet, potatoes—are discussed in the present paper.

The treatments appear to have had no effect on crop yields through improvements to the soil caused by better structure or increased organic matter content. All the effects obtained can be attributed to changes in the supplies of available nutrients. The most important of these changes appear to have been: (1) nitrogen deficiencies due to the immobilization of soil nitrogen or nitrogen fertilizer by the straw: there is some evidence that this added to the store of slowly available nitrogen; (2) additions to potassium supplies from potassium in the straw. Factor (1) affected all three crops. Factor (2) affected potatoes, the only crop of the three to give good responses to potassium.

It was found that when the straw was ploughed in directly about 0·08 ewt. N fertilizer applied to the crops for each ton of straw was sufficient to overcome losses in yield due to nitrogen deficiencies. The straw improved the yields of potatoes in the first and second years after application. Provided that allowance was made for losses of available nitrogen the yields of potatoes from ploughed-in straw were about the same as the yields obtained by adding K fertilizer to the crop, equal in amount to the potassium in the straw. When part of the fertilizers was ploughed in with the straw instead of being given directly to the crop the yields of potatoes were reduced.

Compost made with NT fertilizers and straw and ploughed in with K fertilizer gave much poorer yields than were obtained by ploughing the straw in directly and applying the fertilizers to the crops. Losses of available nitrogen were severe, all the N fertilizer used in making the compost (0·15 cwt. N for each ton of straw) being either lost through drainage or immobilized by the straw. In addition, more than one half of the potassium in the straw was lost in composting.

There was no evidence that any of the nitrogen immobilized in the decomposition of the straw became available in the first or second years after application. Residues from repeated applications of straw every second year over 18 years increased the yields of potatoes and sugar beet in the last 6 years of the experiment. The increases may have been due to the release of previously immobilized nitrogen.

Blood samples were taken from 172 Friesian bulls during 1973–5 on three or four occasions. The bulls were in Milk Marketing Board cattle breeding centres in England and Wales and were from 1 to 14 years of age.

The blood samples were analysed for packed cell volume, haemoglobin, erythrocytes, mean corpuscular volume and glucose, and samples of serum for the concentrations of albumin, total protein, urea-nitrogen, inorganic phosphate, Ca, Mg, K, Na and Cu.

Packed cell volumes and haemoglobin and K concentrations were higher in bulls than those previously recorded in dairy cows. There were significant age relationships for packed cell volume, haemoglobin, albumin and globulin (P < 0·001), inorganic phosphate and erythrocytes (P < 0·01) and Ca and Mg (P < 0·05).

Repeatability estimates were calculated and compared with estimates previously obtained for dairy cows.

On the basis of improved contemporary comparisons of the bulls, there was a significant relationship between the average milk yield of a bulls daughters and the concentrations of urea, inorganic phosphate and K (P < 0·05) in the blood serum of the bull.

Setts of water yam (Dioscorea alata) weighing 350, 100, or 20 g were grown in the field. Tuber formation occurred in 50% of the plants at 8, 9·2, and 11 weeks after planting respectively, thus showing delayed tuber formation as sett weight decreased. Leaf area per plant and tuber yield per plant decreased with decreasing sett weight, but the tuber multiplication ratio increased with decreasing sett weight. There was a high coefficient of variation for tuber yield per plant and for leaf area per plant. It is suggested that the delayed tuber formation for small setts may be partly responsible for the low tuber yield per plant observed.

The effects of silage additives on performance of dairy bulls were determined in a feeding trial using 45 Nordic Red and 45 Holstein bulls. Both breeds were allotted randomly to three treatments: (1) timothy silage (TS) without additives + barley (CON); (2) TS with sodium benzoate, potassium sorbate and sodium nitrate-based additive + barley (SALT); and (3) TS with a mixture of mostly formic acid and propionic acid-based additive + barley (ACID). The bulls were fed total mixed rations ad libitum. During the experimental period of 259 days, the average dry matter intake was 10·1 kg/d and there was no difference among the treatments. The average live-weight gain (LWG) and carcass gain was 1363 and 741 g/d, respectively. There were no treatment differences in the carcass gain but LWG of the CON bulls was 5% higher compared with the SALT and ACID bulls. Carcass conformation score of the SALT and ACID bulls was 6% higher compared with the CON bulls. The experiment demonstrated that there was only a slight benefit from silage additives in animal performance when silage dry matter was 350–400 g/kg and silage was ensiled in round bales.

Feeding fodder beet (FB) to dairy cows in early lactation has recently been adopted by New Zealand dairy producers despite limited definition of feeding and grazing management practices that may prevent acute and sub-acute ruminal acidosis (SARA). This modelling study aimed to characterize changes of rumen pH, milk production and total discomfort from FB and define practical feeding strategies of a mixed herbage and FB diet. The deterministic, dynamic and mechanistic model MINDY was used to compare a factorial arrangement of FB allowance (FBA), herbage allowance (HA) and time of allocation. The FBA were 0, 2, 4 or 7 kg dry matter (DM)/cow/day (0FB, 2FB, 4FB and 7FB, respectively) and HA were 18, 24 or 48 kg DM/cow/day above ground. All combinations were offered either in the morning or afternoon or split across two equal meals. Milk production from 2FB diets was similar to 0FB but declined by 4 and 16% when FB increased to 4 and 7 kg DM, respectively. MINDY predicted that 7FB would result in SARA and that rumen conditions were sub-optimal even at moderate FBA (pH < 5.6 for 160 and 90 min/day, 7FB and 4FB respectively). Pareto front analysis identified the best compromise between high milk production and low total discomfort was achieved by splitting the 2FB diet into two equal meals fed each day with 48 kg DM herbage. However, due to low milk response and high risk of acidosis, it is concluded that FB is a poor supplement for lactating dairy cows.

The effects of the sowing date of cotton and application of nitrogenous fertilizer to it on the incidence of insect pests were investigated over a 5-year period. Response to frequent insecticide spraying was also determined and the results were related to previously reported interactions between nitrogen, sowing date and insecticide application in their effects on yield and its year-to-year variation. Numbers of jassids (Empoasca lybica de Berg) and whiteflies (Bemisia tabaci Genn) were considerably greater on the fertilized plots. The pattern of pest population change over the season varied with sowing date and also from year to year as did the relative numbers of jassids and whiteflies. Effects of spraying on the yield obtained under different agronomic treatments and in different years were clearly related to effects on numbers of insect pests.

Genetic gains (ΔG) are determined by the breeders' equation ΔG = [(ck σ2G)/(y σP)], where c, k and y are the parental control, a function of the selection intensity and number of years to complete one selection cycle, respectively, while σ2G and are σP the genetic variance and the square root of the phenotypic variance. Plant breeding programs should deliver above 1% of annual genetic gains after testing and selection. The aim of this research was to estimate genetic gains in potato breeding after testing of cultivars released in western Europe in the last 200 years under high yield potential, and stress-prone environments affected by a pest (late blight) or daylength. The annual genetic gains for tuber yield and flesh's starch content for potato breeding in Europe were about 0.3 and −0.1%, respectively, thus telling that the realized genetic gains of foreign cultivars for both traits are small or negative, respectively, in the Nordic testing sites. The national annual productivity gains in potato grown in Sweden were on average 0.7% in the last 60 years while the genetic gains for tuber yield considering only the table cultivars released after the 2nd World War were about 0.36%, thus showing that breeding contributed just above ½ of it. Furthermore, genetic gains for breeding low reducing sugars in the tuber flesh, and high host plant resistance to late blight were small (<0.2% per year). These results highlight that genetic gains are small when testing bred germplasm outside their target population of environments.