The effect of stocking rate and fertilizer usage on income variability for dairy farms in England and Wales

A mathematical model of grass production and utilization on a dairy farm is described. Using the model an assessment has been made of the extent to which financial uncertainty arising from year-to-year variability in grass yields, coupled with a preference among farmers for minimizing risks, may explain the relatively low stocking rates and observed nitrogen usages on many dairy farms in England and Wales. The degree of risk has been equated with the probability of profits in a particular year being less than those required to cover the consumption needs and short-term borrowing requirements of the farmer. The results of the analysis indicate that a strategy of minimizing risks may lead to a significantly lower stocking rate than one of maximizing profits. Thus, considerations of risk may lead to stocking rates which are suboptimal from the viewpoint of economic and biological efficiency. However, there is no evidence to suggest that the comparatively low average usage of nitrogen on dairy farms in the UK is determined by risk considerations. On the contrary, increasing nitrogen usage lowers the apparent financial risk at a given stocking rate.     

FACTORS LIMITING ANIMAL PRODUCTION FROM GRAZED PASTURE*

Animal production from intensively managed pasture (240 units N/ac or 300 kg N/ha applied annually) should in theory reach 11,000 Ib/ac (12,500 kg/ha) of milk or 1550 lb/ac (1750 kg/ha) of liveweight gain per year. The figure for theoretical milk production is achieved in experiments, although rarely approached in commercial practice; the figure for liveweight gain is never approached, either experimentally or commercially. On commereial farms in Britain, the average stocking rate for grazed lowland pasture in 1971 was about 0·74 cow equivalents/ac (l±82/ha), compared with a theoretical target of 1·9/ac; in 1969 fertilizer N application was about 48 units/ae (60 kg/ha). The main purpose of this paper is to suggest reasons for the differences between practical, experimental and theoretical levels of production. Economic factors may deter farmers from intensifying their grassland management, but the deterrent to high stocking rates may be the fear of running out of grass. In practice, ungrazed herbage is used as a buffer, but other feeds might be used for this purpose. Concentrates, pelleted roughages and even long dried grass and silage are too attractive to grazing beef cattle to be offered to appetite; but silage might be used as a long-term buffer. Fouling of pasture reduces efficiency of harvesting, but attempts to overcome this effect, by conditioning of grazing animals, spreading excreta or by alternation of grazing and cutting, have largely been unsuccessful. High production per unit area cannot be achieved without high production per animal. Legumes have often been found to increase production per animal, and a technique has been developed for growing red-clover and grass in adjoining areas and grazing them together. The clover was grazed satisfactorily by dairy cows (and caused no bloat) but failed to increase milk yield per animal. Recent calorimetric studies of grass have shown that the net energy value of digestible organic matter is variable, and in particular is low for late-season herbage.     

The effect of stocking rate and calving date on grass production,utilization and nutritive value of the sward during the grazing season

A 2‐year whole‐farm system study compared the accumulation, utilization and nutritive value of grass in spring‐calving grass‐based systems differing in stocking rate (SR) and calving date (CD). Six treatments (systems) were compared over two complete grazing seasons. Stocking rates used in the study were low (2·5 cows ha^?1), medium (2·9 cows ha^?1) and high (3·3 cows ha^?1), respectively, and mean CDs were 12 February (early) and 25 February (late). Each system had its own farmlet of eighteen paddocks and one herd that remained on the same farmlet area for the duration of the study. Stocking rate had a small effect on total herbage accumulation (11 860 kg DM ha^?1 year^?1), but had no effect on total herbage utilization (11 700 kg DM ha^?1 year^?1). Milk and milk solids (MS; fat + protein) production per ha increased by 2580 and 196 kg ha^?1 as SR increased from 2·5 to 3·3 cows ha^?1. Milk production per ha and net herbage accumulation and utilization were unaffected by CD. Winter feed production was reduced as SR increased. Increased SR, associated with increased grazing severity, resulted in swards of increased leaf content and nutritive value. The results indicate that, although associated with increased milk production per ha, grazed grass utilization and improved sward nutritive value, the potential benefits of increased SR on Irish dairy farms can only be realized if the average level of herbage production and utilization is increased.     

The influence of soil wetness on utilized output from grassland on commercial farms

Records of grassland productivity have been used for 93 farms in 1975–76 (a dry year) and 117 farms in 1977–78 (a wetter year). The samples were selected to contrast well-drained and poorly/ badly drained farms and were further subdivided into dairy and beef. The number of farms in each of the four subsamples for each year was between 19 and 32. In addition the number of days on which the soil was at meteorological field capacity (field capacity days) on each farm was calculated.
The mean utilized metabolizable energy (UME) output within the dairy sample was 45 GJ ha⁻¹ on both well-drained and poorly/badly drained farms. Within the beef sample the output was 41 GJ ha⁻¹ on well-drained farms and 37 GJ ha⁻¹ on the poorly/badly drained farms.
The correlation between fertilizer N and UME output was stronger on well-drained farms than on the poorly/badly drained farms in the wetter year (r = 0.69 v. 0.16 on dairy farms; r = 0.56 v. − 0.12 on beef farms). In the drier year the converse was found (r=0.15 v . 0.49 on dairy farms; 0.13 v. 0.44 on beef farms). The effect of field capacity days on output was inconsistent; only within the dairy sample in the wetter year did increased wetness appear to reduce output.
It is suggested that soil wetness may have only a small effect on utilized output from grassland on a whole-farm basis because (i) most farms have at least some well-drained land, (ii) much of the utilization damage occurs in relatively short periods in spring and autumn and (iii) despite having utilization problems, badly drained land is capable of growing large quantities of grass.     

农垦国有资产盈利能力的综合评价

通过文献分析，建立起农垦国有资产盈利能力的财务评价指标，根据“十五”期间各垦区的财务数据，利用主成分分析法，确定各指标的权重并对垦区盈利状况进行深入分析，发现：2002年，税费改革极大的刺激了农垦经济的发展，部分垦区的盈利能力显著增强；“十五”期间，农垦国有资产的平均盈利能力逐渐上升，垦区间差异先缩小后扩大。     

Sward composition and output on grassland farms

Records of grassland productivity were kept for 2 years on 136 lowland dairy farms and 131 lowland beef farms. The grassland on each farm was classified according to the proportion of sown (preferred) species. The farms were then ranked on this basis and divided into quarters:
On dairy farms the lowest quarter had 31% sown species and utilized metabolizable energy (UME) output from grass of 40.8 GJ ha⁻¹, whereas the highest quarter had 70% sown species and UME output of 45.6 GJ ha⁻¹. Dairy farmers in the lowest quarter used least fertilizer N and differences in output were no greater than would be expected from differences in N input. On beef farms the lowest quarter had 28% sown species and UME output of 32.3 GJ ha⁻¹, and the highest quarter had 63% sown species and UME output of 45.9 GJ ha⁻¹On these farms differences in fertilizer N could not completely account for differences in output.
It is concluded that on beef farms botanical composition of grassland is a good indicator of its productivity but is not necessarily a prime cause of differences in output. On dairy farms there is little evidence of a direct benefit resulting from a high proportion of sown species. On such farms the need for deliberate manipulation of the botanical composition of grassland by reseeding or chemical means is questioned.     

Effects of grazing and precipitation on herbage production,herbage nutritive value and performance of sheep in continental steppe

The present study highlights the effects of sheep grazing and precipitation on herbage and animal performance in a grazed steppe of Inner Mongolia. Experimental data were collected during grazing periods of four consecutive years (2005–2008), and effects were analysed across a gradient of seven grazing intensities. Variation in annual precipitation, reflected by the effect of ‘year’, was the major factor affecting herbage; i.e., the production and nutritive value of herbage increased with increasing precipitation. Herbage parameters were also affected by grazing intensity, as herbage production (HP) and herbage nutritive yields decreased, while herbage nutritive values increased with increasing grazing intensity. The grazing‐induced decrease in herbage nutritive yields suggests that decreases in HP offset the positive effect of grazing on the nutritive value. Liveweight gain (LWG) was predominantly affected by grazing intensity, as LWG per sheep and per ha decreased and increased, respectively, with increasing grazing intensity. However, responses varied among years: LWG per sheep was maximized by light grazing in the drought year and by moderate grazing the wet year. Our results showed that herbage shortage at high grazing intensities reduces LWG per sheep and thus diminishes responses in LWG per ha. Nevertheless, the highest grazing intensity provides highest animal production per ha in the short term; however, this is not sustainable in the mid‐ and long term because decreasing HP induces degradation processes. Based on our results, a reduction in grazing intensity that still provides 78% of the maximum LWG per ha meets the requirements of a sustainable grazing management.     

新疆生产建设兵团第四师71团玉米密植高产全程机械化生产技术模式发展调研

从种植品种、种植密度与种植方式、机械化作业和收储烘干等环节对新疆生产建设兵团第四师71团场玉米生产技术的发展进行调研。分析表明,71团场位于西北灌溉玉米区,通过规模化、标准化生产和统一作业管理,以密植增产为基础、子粒收获为核心、绿色防控与秸秆还田为保障构建的玉米密植高产全程机械化绿色生产技术,实现了高产和高效的协同提高与绿色可持续生产。经农业农村部专家指导组田间测产验收,2012年、2014年和2017年连续创造16701 kg/hm^2、18414 kg/hm^2和18447 kg/hm^2的全国玉米大面积(700 hm^2)高产纪录,净利润在15000元/hm^2以上,为现代玉米生产树立了成功的模式和样板。     

The contribution of perennial ryegrass (Lolium perenne L.) breeding to whole pasture productivity under dairy cattle grazing in New Zealand. 2. Rates of gain in production traits and economic value

Perennial ryegrass (Lolium perenne) plant breeding has delivered several high performing and broadly adapted cultivar-endophyte (Epichloë) combinations for the New Zealand pasture-based livestock industries. However, the trends in key traits and the potential economic value being added to farm systems have not previously been addressed systematically. Rates of gain in yield, nutritive value, phenological and morphological traits, and the economic value of those traits, were estimated among and within ryegrass functional groups (heading date, ploidy) traded commercially between 1973 and 2012. Whole pasture dry matter yield improvements of c. 80 and 60 kg DM/ha per year were identified in in late-season heading diploids and tetraploids respectively. Trends in metabolisable energy were negative within functional groups, but positive when all cultivar-endophyte combinations were included in the analysis due to the addition of tetraploids and late-season heading diploids from the mid-1990s. The estimated trend in overall economic value (all cultivar-endophyte combinations included) was $7/ha per year based on DM yield only, about half the rate of gain previously estimated using small-plot merit testing data. The trend increased to $15/ha per year when ME was included due to the emergence of commercial tetraploids from the early 2000s onwards. Estimated economic gains were high within late-season heading diploids and tetraploids but not mid-season diploids. These trends suggest that, if high performing cultivar-endophyte combinations had been adopted in New Zealand dairy systems, then pasture utilization should have increased by ~1 t DM/ha above the current industry average. Reasons for this apparent discrepancy are discussed.     

An economically based evaluation index for perennial and short‐term ryegrasses in New Zealand dairy farm systems

Grazed pastures based on ryegrass species provide most of the feed for dairy cattle in New Zealand. There are many cultivars of perennial (Lolium perenne), annual and Italian (L. multiflorum), and hybrid (L. boucheanum) ryegrasses available for dairy farmers to use in pasture renewal. This study describes an index which ranks ryegrass cultivars relative to a genetic base according to the estimated economic value (EV) of seasonal dry matter (DM) traits. A farm system model was used to derive EVs (Grazed pastures based on ryegrass species provide most of the feed for dairy cattle in New Zealand. There are many cultivars of perennial (Lolium perenne), annual and Italian (L. multiflorum), and hybrid (L. boucheanum) ryegrasses available for dairy farmers to use in pasture renewal. This study describes an index which ranks ryegrass cultivars relative to a genetic base according to the estimated economic value (EV) of seasonal dry matter (DM) traits. A farm system model was used to derive EVs ($ ha^?1 calculated as change in operating profit divided by unit change of the trait) for additional DM produced in different seasons of the year in four regions. The EV of early spring DM was consistently high across all regions, whereas EV for late spring DM was moderate to low. Genotype × environment analysis revealed significant reranking of DM yield among ryegrass cultivars across regions. Hence, separate performance values (PVs) were calculated for two mega‐environments and then combined with the corresponding season and region EV to calculate the overall EV for twenty‐three perennial ryegrass and fifteen short‐term ryegrass cultivars. The difference in operating profit between the highest ranked and lowest ranked perennial ryegrass cultivar ranged from $556 ha^?1 to $863 ha^?1 year^?1 depending on region. For short‐term ryegrasses used for winter feed, the corresponding range was $394 to $478 ha^?1 year^?1. Using PV for DM yield, it was estimated that plant improvement in perennial ryegrass has added $12–$18 ha^?1 year^?1 (depending on region) operating profit on dairy farms since the mid‐1960s.     

THE EFFECT OF HIGH NITROGEN LEVELS AND STOCKING RATES ON MILK OUTPUT FROM PASTURE

An experiment using 40 lactating dairy cows was conducted for 3 successive years to examine the effects of fertilizer N applied at 400 and 700 kg/ha (358 and 627 lb/ac) at stocking rates of 4.94 and 7.41 cows/ba (2 and 3 cows/ac). The animals were grazed in groups of 10 per treatment, using a fixed rotational grazing system, for 22 weeks in each year. Milk ontput/cow and/ha was significantly affected by stocking rate, the mean milk outputs being 2499 and 2218 kg/cow (5498 and 4880 lb/ cow) and 12313 and 16396 kg/ha (11032 and 14691 lb/ac) at the lower and higher stocking rates, respectively. Milk yield/cow at the lower stocking rate was not affected by N level. At tbe higher stocking rate, increasing the amount of N resulted in a 7.4% increase in milk output/cow and/ha. This response to N declined from 1.7% in the first year of the trial to 2.4% in the third year. The response in milk yield to N appeared to he greatest during the first part of the grazing season. Milk composition, liveweight change, and herbage availahilities and intakes were also recorded.     

Effects of different plant density and nitrogen application rate on nitrogen use efficiency of potato tuber

In order to investigate the plant density and nitrogen level on nitrogen use efficiency components (agronomical, physiological, apparent recovery and nitrogen use efficiency), the amount of nitrogen uptake by plant, yield and yield components of potato (Solanum tuberosum L.) Agria cultivars' tuber, a factorial experiment based on randomized complete block design was conducted in Ardabil, Iran, in 2006 with three replications. Factors were adjusted for the nitrogen level (0, 80, 160 and 200 kg ha(-1) net nitrogen) and plant density (5.5, 7.5 and 11 plant m(-2)). Results showed that with increasing the nitrogen levels and plant densities agronomical nitrogen use efficiency, physiological nitrogen efficiency and nitrogen use efficiency were decreased and apparent recovery nitrogen efficiency was increased. The most nitrogen uptake in plant was observed at the 200 kg ha(-1) net nitrogen. The most yield and number of tuber per unit area were gained at the 80 and 160 kg ha(-1) net nitrogen. Increasing the plant density resulted in increasing in the tuber yield per unit area and the rate of nitrogen up to the 160 kg ha(-1) net nitrogen. So, application of the 80 kg ha(-1) net nitrogen and plant density of 11 plant m(-2) is recommended to get highest yield with the most nitrogen use efficiency.     

黑龙江省粮食生产效率及玉米生产主体效率实证分析

以黑龙江省干旱半干旱区、半湿润区、湿润区具有代表性的13个市县为研究区域，利用2010～2019年黑龙江省农业生产面板数据及2019年实地调研数据，选择DEA方法的投入导向BCC模型，测算黑龙江省近10年农业生产效率及农业生产主体效率。结果表明，黑龙江省半湿润区粮食生产综合效率最高、干旱半干旱区最差。2010～2019年黑龙江粮食生产整体实现了1%的全要素生产率平均增长，玉米生产者综合效率以规模66.7～667 hm²最高；组织形式以合作社为种植主体的综合效率均值最高，其次为农户。     

河西走廊灌溉玉米施肥现状评价与减肥对策

选取河西走廊灌溉玉米典型种植区张掖,连续2年进行农户调查玉米施肥现状及存在问题。结果表明,玉米产量两年平均为12 589 kg/hm~2,两年均是中产等级的样本数占总样本数的比例最高。氮肥投入处于偏高(438～584 kg/hm~2)和很高(584 kg/hm~2)等级以上的占比为47%(2018年)和76%(2019年),磷肥投入处于偏高(187～250 kg/hm~2)和很高(250 kg/hm~2)等级以上的占比为88%(2018年)和38%(2019年),钾肥投入处于偏低(104～208 kg/hm~2)和很低(104 kg/hm~2)等级的占比为26%和68%(2019年);两年平均N 525.3 kg/hm~2、P_2O_5 236.3 kg/hm~2、K_2O 87.1 kg/hm~2,平均N、P_2O_5、K_2O的肥料偏生产力(PFP)分别为25.0、53.5、102.6 kg/kg,远低于全国平均。调研结果表明,河西灌溉玉米氮磷肥施用严重过量,钾肥投入盲目,有机肥不受重视。应通过优化田间管理、选用新型肥料、配施有机肥等措施,有效减少化肥投入,实现玉米绿色可持续生产。     

京科968的灌浆特征与产量性能分析

以京科968为材料, 采用春播、夏播2种播期, 设置45 000、60 000、75 000株/hm²共3种密度处理, 对其灌浆特征与产量性能进行分析。结果表明, 粒重与灌浆速率最大时的生长量(W_max)、最大灌浆速率(G_max)、活跃灌浆天数(P)呈极显著正相关, 与达到最大灌浆速率的天数(T_max)、灌浆起始势(R₀)呈显著或极显著负相关。平均叶面积指数、穗数、产量与密度呈正相关;平均净同化率、穗粒数、千粒重与密度呈负相关;平均叶面积指数与穗数与产量都呈极显著正相关。     

Yearly variation in maize silage fermentation and nutritive quality

A significant effect of year on maize nutritive value has been reported in many studies; however, the direct effect of year on both nutritive values and fermentation traits of maize silage has not been directly investigated. During a 7‐year period (2006–2012), we investigated the following variables of 597 maize silages commercially produced in bunker silos on farms in the Czech Republic: dry‐matter content (DM), crude protein (CP), starch, amylase‐treated neutral detergent fibre (aNDF), acid detergent fibre (ADF) and net energy lactation (NEL), as well as fermentation traits such as pH, contents of lactic acid (LA), acetic acid (AA), butyric acid (BA) and the ratio between LA and volatile fatty acids. The effect of year and DM explained 16 and 30% of the variability in nutritive and fermentation traits respectively. Although a common silage DM content was used for each year, the climatic effect of year significantly changed almost all tested variables, but particularly aNDF, ADF, starch, AA and BA. The year contribution to trait variability effect was as much as two times higher for fermentation traits (12·6%) as for nutritive value (6·1%). Temperature–precipitation relationships associated with achieved maize yield were considered as factors explaining the year effect. Temperature and precipitation averaged over the full vegetation period had low relevance to nutritive and fermentation traits. This study reveals the importance of year‐to‐year variation in silage nutritive value and fermentation, which could be useful for understanding the contribution of year to these changes in both field experiments and national assessments.     

The productivity of grassland farms in seven climatic zones of England and Wales

Records of grassland productivity were kept for 2 years on 152 dairy and 179 beef farms. Results were collated for six lowland zones, delineated primarily on the basis of average rainfall, and an upland zone. Contemporary and long-term average meteorological records were also collected.
In most of the lowland zones stocking rates and use of fertilizer N were similar, but utilized metabolizable energy (UME) output from grass varied; it was 25% higher in the wet, cool zone of north-west England and east Wales than in the dry zone of eastern England. The ranking of zones for utilized output corresponded closely with the ranking for summer rainfall.
On upland farms stocking rate was 25% lower and UME output 15% lower than on lowland farms, but this was achieved from little more than half the N input.
The differences between zones were similar to those shown in other published farm data. They also showed a similar trend to that demonstrated in grass cutting experiments. This suggests that farmers were, on average, able to exploit the extra grass grown in wetter climates. The incidence of difficult topography and impeded drainage was similar in dry and wet zones, but did have a more serious effect in the wet zones. The much higher level of concentrate feeding in the driest zone may have reduced the utilization of grass.     

Closing the cassava yield gap: An analysis from smallholder farms in East Africa

Cassava yields in Africa are small and it remains unclear which factors most limit yields. Using a series of farm surveys and on-farm and on-station trials in Uganda and western Kenya, we evaluated the importance of abiotic, biotic and associated crop management constraints for cassava production in a range of socio-economic settings as found in smallholder farms in the region. Average yields under farmer management were 8.6 t ha⁻¹, but these were more than doubled to 20.8 t ha⁻¹ by using improved crop establishment, improved genotypes and 100–22–83 kg ha⁻¹ of single-nutrient N–P–K fertilizers. A farm survey revealed large yield differences between farms. Less endowed farmers harvested less cassava per unit area than better endowed farmers (difference of 5.9 and 9.7 t ha⁻¹ in Kenya and Uganda, respectively); differences were associated with less access to labour, poorer soils, and premature harvesting by less endowed farmers. Analysis of 99 on-farm and 6 on-station trials showed that constraints for cassava production varied strongly between sites and years. Poor soil fertility, early water stress and sub-optimal weed management limited cassava production by 6.7, 5.4 and 5.0 t ha⁻¹, respectively, when improved crop establishment and genotypes were used. Pests and diseases were relatively unimportant, while weed management was particularly important in farmer fields during a dry year in Kenya (yield gap of 11.6 t ha⁻¹). The use of complementary analytical tools such as multiple regression and boundary line analysis revealed that many fields were affected by multiple and interacting production constraints. These should be addressed simultaneously if significant productivity improvements are to be achieved. This will be more difficult for less endowed than for better endowed farm households, since the former lack social and financial capital to improve management.     

The future of lucerne in British agriculture: an economic assessment

With its potential for high yields and high animal output, lucerne appears to be an underexploited crop in British agriculture. In this paper an attempt is made to assess the prospects for expansion of the area of lucerne in Britain from an economic viewpoint, concentrating on lucerne as a conservation crop. Under good management lucerne is shown to have lower production costs than grass and its inclusion in the diet of dairy cows, but not beef cattle, could significantly lower winter feed costs. However, under apparently similar growing conditions, lucerne yields on different farms vary significantly, ranging from 9 to 13 t dry matter ha⁻¹ a⁻¹. At the lower yields, the economic attraction of growing and feeding lucerne in place of grass is small. Moreover, since potential lucerne production is concentrated in the south and east of Britain, lucerne competes with other arable crops. For lucerne to offer a gross margin per unit area comparable with these, the price for conserved lucerne would have to be set at a level at which dairy farmers would derive little economic advantage from feeding it. Thus, although lucerne is a forage crop with some potential, at present it is likely to offer economic possibilities only where producers can combine high yields with on-farm utilization of the crop.     

Investigating external effects of shrimp farming on rice farming in southern Thailand: a technical efficiency approach

Rice and shrimp farming are two important economic activities in rural southern Thailand that compete each other in land allocation leading to land use conflicts. Moreover, it can be observed that the conversion of rice fields to shrimp farms is already extended from coastal areas to the inlands. These conversions are making more area be saline which is essential condition for shrimp cultivation but deleterious for rice farming. We are looking at the unidirectional externalities originating from the conversion which brings the productivity of adjacent rice fields further down. This study attempts to quantify the external effects on rice yield and efficiency of rice farming by constructing three models. Model I, we assess the rice yield function by using the multiple linear regression while in Model II, we attempt to delineate the technical efficient frontier of rice farms by using an input oriented non-parametric approach, so called data envelopment analysis. Model III, we probe into the factors influencing technical efficiency scores using the Tobit regression. Database of the study is constituted by primary survey data from 120 rice farms in Songkhla province for the crop year 2004/2005. The 30 out of 120 sample farms have been affected by externality of shrimp farming. The empirical results of all three models show that shrimp farming externalities caused a production drop of 467–515 kg paddy rice per ha and significantly affect the technical efficiency of rice farms. The measures of internalizing this externality are discussed.