Maximum Forage Yield Research Articles

Adjusting spatial use to establish productive and stable Elymus nutans monocultures and mixed sowing systems

Community arrangement plays a critical role in maintaining forage community production and stability. To explore reasonable management for efficient community production in alpine regions, three monoculture communities composed of Elymus nutans, Cross row (S_C), Double row (S_D), and Single Row (S_R), and three mixed communities consisting of Elymus nutans and Onobrychis viciifolia, Broadcast(M_B), Dependent row (M_D) and Independent row (M_I) were established in Tianzhu County on the Qinghai Tibetan Plateau during 2018–2019. The results showed S_C was the most productive monoculture community, with less intraspecific competitiveness and higher population density after establishment, which could reduce the influence of lodging on yield loss. The maximum forage yield was attained at the end of 2018 (5187.6 kg·ha−1) and August 2019 (26190.9 kg·ha−1). In mixed communities, the relationship of natural height between E. nutans and O. viciifolia was relatively stable, but growth rate displayed asynchronous traits. Besides, mixed communities had higher lodging resistance compared with monoculture communities; E. nutans showed higher competitiveness than O. viciifolia, but O. viciifolia competivity when the community natural height decreased. M_B (3015.3 kg·ha−1 in 2018; 4804.6 kg·ha−1 at the flowering of 2019), and M_D (7686.2 kg·ha−1 in 2019) had better performance in forage yield. Our study has demonstrated the feasibility of adjusting plant spatial arrangements as a means to enhance forage production in alpine regions. It is crucial to consider the interaction of growth rates, as this factor determines the optimal utilization time for monocultural and mixed communities. Additionally, this study highlights the influence of changes in sowing patterns on forage growth and yield, while enriching the grassland establishment mode, thus supporting the development of sustainable livestock systems in the Qinghai Tibet Plateau.

Impact of Seeding Techniques and Planting Density on Productivity and Profitability of Oat Cultivar (Supergreen Oat)

Less fodder availability in the Rabi season causes a dramatic reduction in Pakistan's livestock sector's production capacity. In this regard, a field investigation was carried out for two years (2016-17 to 2017-18) at the Research Area of Fodder Research Sargodha to assess the most suitable seeding techniques and planting density for the new oat cultivar “Supergreen Oat”. Three seeding techniques were tested, i.e., 15 cm, 30 cm, and 45 cm apart rows, and three planting densities of 67.5 kg ha-1, 80 kg ha-1, and 92.5 kg ha-1. The experiment was sown during the first week of November each year by using seed rate according to treatments of new oat cultivars “Supergreen Oat”. Data regarding average forage yield, agronomic yield attributes, and economics of both variable factors, row spacing, and seeding rate were recorded. Perspective indicated statistically significant differences among the treatments. Row spacing of 15 cm apart lines produced the maximum forage yield (116.53 t ha-1) as compared to other sowing techniques, and the seeding rate (80 kg ha-1) performed better (118.58 t ha-1) as compared to both seeding rates. The interactive effect of both variable factors revealed that the seeding rate 80 kg ha-1 (SR2) performed better when sown at 15 cm (RS1) apart line to line (127.26 t ha-1) and also showed a maximum benefit cost ratio (2.85).

Irrigation and nitrogen fertilization influence on alfalfa yield, nutritive value, and resource use efficiency in an arid environment

In arid regions, water and nitrogen are the two most limiting factors for sustainable pastoral production systems. In this study, we determined the potential effects of irrigation and nitrogen application on forage yield, nutritive values, and resource use efficiency of alfalfa in arid agro-climatic conditions. Field experiments were carried out using three irrigation regimes (W1, 300; W2, 450; and W3, 600 mm) and three nitrogen application rates (N1, 150; N2, 225; and N3, 300 Kg N ha−1). Alfalfa seeds were sown in fall 2014, uniformly managed for crop establishment, and subjected to different treatments in spring 2015–2016. Results indicated that irrigation, nitrogen, and their interaction (W × N) significantly (P ≤ 0.05) affected alfalfa forage yield, quality, irrigation water use efficiency (IWUE), and nitrogen use efficiency (NUE). Forage yield followed an increasing trend with increasing the irrigation amount at each harvest in both growing seasons. However, crude protein (CP), relative feed values (RFV), and IWUE were significantly decreased while neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents were increased at the high irrigation level (W3). The maximum forage yield was achieved with W3 treatment (25.9 and 23.1 t ha−1), followed by W2 (25.8 and 21.7 t ha−1) in 2015 and 2016. In both years, the highest IWUE (57.3 and 48.2 kg mm−1), CP (16.1 % and 17.7 %), and RFV (197.1 % and 186.2 %) values were achieved with W2 treatment. Moreover, increasing N application resulted in a linear decline in alfalfa forage yield, nutritive quality, and resource use efficiency. The maximum forage yield (24.4 and 21.2 t ha−1), CP (15.5 % and 16.4 %), RFV (210.3 % and 198.8 %), IWUE (54.3 and 47.0 kg mm−1), and NUE (169.9 and 141.2 kg kg−1), and lower ADF (25.7 % and 24.9 %) and NDF (31.0 % and 33.1 %) was obtained with application of 150 kg N ha−1 in 2015 and 2016. The regression equations of irrigation and nitrogen application indicated a quadratic relationship between yield and forage nutritive values. Overall, 450 mm irrigation coupled with 150 kg N ha−1 (W2N1) showed the most promising effects in terms of achieving optimal forage yield consistent with enhanced forage nutritive values, and greater resource use efficiency of alfalfa in the arid region of North China.

Influence of preceding crop and tillage system on forage yield and quality of selected summer grass and legume forage crops under arid conditions

Among the crop production factors, preceding crop and tillage management affect the sustainable use of soil resources and ultimately crop growth and productivity. This study aimed at investigating the impact of preceding winter crops (grass or legume) and different tillage systems on forage yield, quality and nutritive values of three summer grass (Sudan grass, pearl millet and teosinte) and two legume forage crops (cowpea and guar) under arid conditions. The results exhibited that growing forage crops after legumes (as berseem clover) produced the highest fresh and dry forage yields and quality attributes compared with grasses (as wheat) with the exception of crude fiber content, which was decreased. Moreover, tillage practices showed positive impact on forage yields and quality attributes. The maximum forage yields and quality parameters were recorded under conventional tillage (CT) practice compared with reduced tillage (RT) and no-tillage (NT) systems. Among the evaluated crops, the highest yields of fresh forage, dry forage, crude fiber, crude protein and total digestible nutrient were exhibited by grass forage crops (Sudan grass, pearl millet and teosinte), whereas the highest crude protein content and the digestible energy values were produced by legume forage crops (cowpea and guar). The maximum fresh forage, dry forage, crude fiber, crude protein, total digestible nutrient and digestible crude protein yields were produced by pearl millet followed by Sudan grass under CT and RT after berseem clover. The highest net return was recorded by sowing pearl millet after berseem clover and applying CT followed by RT practices, which could be recommended for the commercial production. Moreover, it could be assumed that the combination of growing grass forage crops after legume crops under CT or RT systems could enhance forage crop yield and quality with an improvement in soil properties for sustainable agriculture with low cost and the highest net income.

FORAGE YEILD AND COMPITITION INDICES OF CEREALS MIXED INTERCROPPING WITH FORAGE LEGUMES IN SULAIMANI REGION

The present study was conducted in Sulaimani region at two different locations, Kanipanka and Qlyasan during winter season of 2019-2020 to estimate the response of forage yield and some competition indices to the effect of crop pure stands and their mixtures of barley and triticale intercropped with narbon vetch and grass pea with some different patterns. The experiment was designed according to Completely Randomized Block Design with three replications. As the average of both location the maximum green forage yield was produced by pure narbon vetch 32.610 ton ha-1, while pure barley produce maximum dry forage yield and dry matter % reached 5.506 ton ha-1 and 8.55% at booting stage respectively, but the crop mixture barley/grass pea at a rate 2:1 produce maximum green and dry forage yield 32.083 and 5.616 ton ha-1 respectively at booting stage. The crop mixture barley/vetch 1:1 gave maximum dry matter% 17.88% at the same stage. The highest value for total LER was 1.401recorded by the mixture of triticale/grass pea at elongation stage, while the highest relative crowding coefficient was 1.285 recorded by the same mixture at a rate 1:1 at the same cutting stage. Maximum competitive ratio for cereals was 3.652 recorded by barley in the mixture barley/grass pea 1:2 at elongation stage, while for legume it was 2.292 for narbon vetch in the mixture triticale/vetch 2:1 at booting stage.

Rendimiento de la planta de frijol caupí [Vigna unguiculata (L.) Walp] y calidad nutricional en los sistemas de cultivo intercalado de frijol caupí y sorgo

In traditional row and strip cowpea-sorghum intercropping systems, cowpea forage yield reduces significantly due to intense competition and dominance of sorghum in acquiring growth resources. This field study evaluated novel mixed strip intercropping systems of forage cowpea and sorghum having different number of crops rows arranged under different spatial arrangements. Cowpea was intercropped with sorghum in 8, 12 and 16 rows strips with row-row spacing of 30, 45 and 60 cm. In each strip, equal number of rows of cowpea and sorghum were maintained. Factorial arrangement of randomized complete block design with three replicates was used to execute the field trials during summer seasons of 2013 and 2014. Strips having 12 rows and 60 cm row-row spacing positively affected all agronomic variables of cowpea which led to maximum forage yield (22.2 and 23.7 t ha-1 during 2013 and 2014 respectively) and dry matter biomass (6.63 and 6.94 t ha-1 during 2013 and 2014 respectively). In contrast, 8-rows strips having line spacing of 30 cm outperformed other intercropping systems by yielding the maximum herbage yield and dry matter biomass of sorghum. The intercropping system comprising of 12-rows strips with 60 cm row-row spacing remained superior in recording the maximum crude protein, fats and total ash along with the minimum fiber content of cowpea. In addition, this intercropping system under rest of spatial arrangements also remained unmatched, while 16-rows strips under all planting geometries remained inferior to other intercropping systems. Thus, cowpea intercropping with sorghum in 12-rows strips having 60 cm spacing offers biologically viable solution to improve biomass and forage quality of cowpea in intercropping with sorghum.

Integrated nutrient management in cowpea with the application of microbial inoculants

Indian livestock sector is one of the largest in the world and fodder is vital component of profitable animal production. Legumes are one of the predominant crops of mixed crop-livestock systems providing highly nutritious fodder as well as contributing soil fertility. Nevertheless, the fodder production and quality in the country is not adequate to meet out the prerequisite of growing livestock population. Optimum nutrition is thus required for getting the maximum forage yield and quality. Nutrient Management is propounded as a promising strategy for addressing such challenges. Microbial inoculants being an important component of integrated nutrient management are eco-friendly and economical sources of nutrient. The benefit of combining organic and inorganic sources of nutrients in integrated nutrient management has proved superior to the use of each component individually. Thus, the present review will feature the need of integrated nutrient management, plant growth promoting rhizobacteria as microbial inoculants, role of microbial inoculants in integrated nutrient management of various leguminous crops and emerging examples of integrated nutrient management in cowpea. The realization attained from literature assessed herein will further help to understand the role of microbial inoculants in integrated nutrient management.

GRAIN YIELD, FORAGE YIELD AND FORAGE QUALITY OF DUAL PURPOSE WHEAT AS AFFECTED BY CUTTING HEIGHTS AND SOWING DATE

Dual purpose wheat production can help to produce the forage needed for livestock feeding, without reducing the sowing area of reserved for grain production. To determine the proper management techniques that reduce the loss of grain yield crops in dual purpose systems is very important. The objectives of this study were to investigate the effects of sowing date and cutting heights on grain yield, forage yield and nutritive value of dual-purpose wheat. The experimental design was split-plot under randomized complete block design, sowing dates (early, normal and late) as the main plot treatments and cutting heights (5, 7.5 and 10 cm) as the subplot treatments with three replications. Forage yield and forage protein yield were significantly affected by sowing date. Maximum forage yield and forage protein yield were obtained at normal sowing date (20 November) in both years, while maximum grain yield was obtained at early sowing date (20 October). The effect of sowing date on forage quality characters varied between years. Deeper cutting increased forage yield, while decreased grain yield. The effects of cutting heights on forage quality were different between years. The cutting treatments caused the decrease yield of the grain, but dual-purpose system for winter wheat was an advantageous crop system when evaluated in terms of the total amount of production. The height of 7.5 cm can be recommended as a suitable cutting height in term of the total crop quantity.

Effects of nitrogen fertilizer and corn cultivars on corn silage yield

A split plot experiment using the randomized complete block design with three replications was carried out at the Gharakheil Agronomic Research Station of Iran in the crop year 2014 to evaluate the effects of nitrogen fertilizer and cultivar on forage corn yield and yield components. The main-plot factor included three corn cultivars (SC704, SC677 and SC400) and the sub-plot factor, four application rates of urea (100, 200, 300 and 400 kg/ha). Analysis of the data showed that the effects of cultivar and rate of urea application and their mutual effects on most of the studied traits were significant (α=5%). The mean comparison, using the Least Significant Range (LSR) test indicated the maximum forage and dry matter yields (40.95 and 12.90 t/ha, respectively) were obtained in the treatment of SC704 and urea at 200 kg/ha.

<b>Forage yield and quality of marandugrass fertigated with treated sewage wastewater and mineral fertilizer

The high consumption of water in irrigated agriculture and lack of alternative water sources make reusing sewage water a highly promising option for irrigation. This paper is aimed at evaluating Brachiaria brizantha cv. Marandu forage quality and yield when fertigated with treated sewage wastewater (TSW) and mineral fertilizer, in the 2013 and 2014 crop years in Jaboticabal, Sao Paulo State, Brazil. A homogeneous water depth was applied using a triple-line sprinkling irrigation system under a gradual TSW application, using the following TSW and water ratios: E5 = 1.0; E4 = 0.87; E3 = 0.6; E2 = 0.31, E1 = 0.11, and E0 = 0.0. Annual biomass yield increased with the TSW application, ranging from 31.3 to 47.4 Mg ha -1 in 2013 and from 25.7 to 56.9Mg ha -1 in 2014, for E1 and E5, respectively. Forage yield had marked seasonality, with the highest values in summer (35.9 to 44.7%) and spring (35.7 to 38.4%) and the lowest ones during the fall-winter seasons (19.6 to 25.7%). Despite the high nitrogen rates (1,132 kg ha -1 ), maximum forage yield was not achieved, hence further nitrogen increments would still enhance yield. Forage improved quality has counterbalanced the low fall-winter yields in terms of crude protein (CP) and neutral detergent fibre (NDF).

DINÂMICA DE CRESCIMENTO E PRODUTIVIDADE DE FORRAGEM DE Trachypogonplumosus SOB NÍVEIS DE CORREÇÃO DA FERTILIDADE DO SOLO E IDADES DE REBROTA

Resumo Avaliaram-se os efeitos de níveis de correção da fertilidade do solo (testemunha, calagem, adubação e calagem + adubação) e da idade de rebrota (21, 28, 35, 42, 49, 56, 63, 70, 77 e 84 dias) sobre a dinâmica de crescimento e rendimento de forragem de Trachypogon plumosus em Roraima. O aumento da idade de rebrota resultou em maiores rendimentos de matéria seca (MS), taxa absoluta de crescimento (TAC), taxa de assimilação líquida (TAL), razão de área foliar (RAF) e índice de área foliar (IAF), ocorrendo o inverso quanto à taxa média de crescimento (TMC). A gramínea mostrou-se responsiva à melhoria da fertilidade do solo. A calagem + adubação ou a adubação proporcionaram maiores rendimentos de MS (1.934 e 1.661 kg ha-1), TAC (36,6 e 31,5 kg ha-1 dia-1), TMC (32,5 e 27,9 kg ha-1 dia-1), TAL (4,993 e 4,152 g/m2), RAF (152,9 e 140,9 cm2/g) e IAF (2,42 e 2,14). Para otimizar a eficiência de utilização da forragem produzida e reduzir perdas por senescência da gramínea, o período mais adequado de sua utilização, durante o período chuvoso, situa-se entre 56 e 63 dias com o uso de adubação e calagem + adubação e entre 63 a 70 dias para a testemunha e a calagem.

Study on leaf area index and leaf area duration of growth analytical parameters in Wheat, Barley, and Oat

An experiment were conducted in rabi season during 2012–2013 and 2013–2014 to find out the effect of cereal crops (Wheat, Oat, Barley) and cutting schedule on forage and grain yield. The study revealed the maximum chlorophyll accumulation in Barley and wheat during the initial stage at 95 DAS and wheat and barley during the reproductive stage at 30 DAS. Cutting at 50 DAS is proved beneficial on chlorophyll accumulation. Photosynthetic rate was maximum in wheat at 90 DAS. However cutting did not affect photosynthesis rate stomatal conductance and transpiration rate. Barley gave maximum fodder yield (fresh/day). Cutting at 50 DAS was beneficial in producing maximum forage yield without sacrificing grain yield of cereal crops.

Growth, Yield and Quality Performance of Pearl Millet (<i>Pennisetum americanum</i> L.)

Livestock industry of Pakistan is expanding day by day. To meet its growing demand high fodder yielding and nutritious varieties of fodder crops are needed. Pearl millet (Pennisetum americanum L.) is an excellent choice for this purpose. In order to explore the possibility of the better yield potential varieties of pearl millet performed in a good manner under agro ecological conditions of Faisalabad during the year 2012. A field experiment was conducted at Agronomic Research Area, University of Agriculture, Faisalabad, Pakistan. Randomized complete block design was used with three replications; the net plot size was 1.8 m × 6 m. The experiment was comprised of nine millet varieties named Cholistani Bajra, Barani Bajra, MB-87, Sargodha Bajra 2011, 18-BY, Super Bajra-1, PARC-MS-2, 86-M-52 and FB-822. All other agronomic practices were kept normal and constant. Data on yield and yield components were recorded by standard procedure. Significant results were recorded among the varieties for forage growth and yield. The variety 86-M-52 produced maximum forage and dry matter yield because of more number of leaves (14), leaf area (3540.1 cm2) followed by Sargodha Bajra-2011. All cultivars have statistically significant differences in respect of quality characteristics. However, non-significant differences were observed among cultivars regarding ash contents. The cultivar Sargodha Bajra-2011 has the highest crude protein (10.347%) and the cultivar FB-822 has the minimum crude protein percentage (6.733%). While PARC-MS-2 has the highest crude fiber percentage (34.667%) but variety MB-87 has the minimum crude fiber (24.333%). Variety 86-M-52 proved better for getting higher forage yield followed by Sargodha Bajra-2011 than all other varieties. Sargodha Bajra-2011 is the best cultivar that performed well in respect of quality parameters under irrigated conditions of Faisalabad.

Growth and productive responses of tropical grass Panicum maximum to nitrate and ammonium supply

This study was conducted to investigate growth response parameters and forage yield of Panicum maximum Jacq. plants supplied with nitrate (NO3-) and ammonium (NH4+) as N source in a nutrient solution. Six NO3- and NH4+ combinations were tested at the following proportions: 100-0, 85-15, 70-30, 55-45, 40-60 and 25-75%. Grass shoot (number of tillers and leaves and leaf surface area) and root (length and surface area) growth parameters and dry matter production exhibited highest values in P. maximum plants growing in the nutrient solution supplied with NO3-:NH4+ at the proportions ranging between approximately 70-30 and 55-45%. The use of NO3-:NH4+ mixture at the ratio of 55-45% instead of the NO3- solely as N source in the nutrient solution enhanced the production of tillers and leaves and the leaf area surface of P. maximum by about 30, 20 and 30%, respectively. Plants supplied with NO3- and NH4+ mixture (55-45%) showed an increased root length and root surface area by approximately two and six-fold, respectively, compared with P. maximum fertilized with NO3- exclusively in the growth medium. Supplying N in the nutrient solution as NO3- or NH4+ exceeding approximately 70 or 50%, respectively, caused a diminished P. maximum forage yield. Enhanced N-use efficiency associated with P. maximum plants supplied with a NO3- and NH4+ mixture in the growth medium supports the assumption that it is possible to increase plant production by managing N fertilization based on quality (N forms) of N fertilizers applied in pasture systems.

Irrigation, Phosphorus Fertilizer and Phosphorus Solubilizing Microorganism Effects on Yield and Forage Quality of Turnip (Brassica rapa L.) in an Arid Region of Iran

Turnip has a high potential to produce abundant nutritious and valuable forage when availability of perennial warm and cool-season species is limited. Water deficit and fertility affect not only growth and yield of crops but also their quality and nutritional value. To evaluate the effect of different phosphorous fertilizers on forage yield and quality of turnip under deficit irrigation regimes, a field experiment was conducted during 2009. The experimental treatments arranged as split plots were five levels of irrigation, no irrigation (IR0), irrigation at sowing time (IR1), irrigation at sowing time + commencement of tuber formation (IR2), (irrigation at sowing time + commencement of tuber formation + commencement of stem elongation (IR3) and normal irrigation (IRN), assigned to main plots and four levels of fertilizers, no fertilizer (FCo), 100 % FCh (100 % chemical fertilizer), seed inoculation by Pseudomonas putida (FBi), 50 % FCh + FBi, assigned to subplots. The maximum forage yield was obtained at IRN, which followed a decreasing trend as the number of irrigations decreased. The best phosphorous fertilizer treatments affecting forage yield were 100 % FCh and 50 % FCh + FBi in sequence. As the water stress increased, in vitro dry matter digestibility (IVDMD), metabolizable energy, and protein yield followed a decreasing trend while in the same situation the crude protein, water soluble carbohydrates, acid detergent fiber, and ash content followed an increasing trend.

Plant and soil responses to nitrogen and phosphorus fertilization of bromegrass‐dominated haylands in Saskatchewan, Canada

AbstractField experiments were conducted at three different sites in Saskatchewan, Canada (Colonsay, Vanscoy and Rosthern) over two years (2005 and 2006) to determine the effects of dribble‐banded and coulter‐injected liquid fertilizer applied in the spring of 2005 at 56, 112 and 224 kg N ha−1 with and without P at 28 kg P2O5 ha−1. The three sites were unfertilized, 7‐ to 8‐year old stands of mainly meadow bromegrass (Bromus riparius)‐dominated haylands. All fertilization treatments produced significantly (P ≤ 0·05) higher dry matter yield than the control in the year of application at the three Saskatchewan sites. There was no significant difference between the two application methods (surface dribble band vs. coulter injected) for any fertilizer treatments. The addition of 28 kg P2O5 ha−1 P fertilizer along with the N fertilizer did not have a significant effect on yield in most cases. In the year of application, increasing N rates above 56 kg N ha−1 did not significantly increase yield over the 56 kg N ha−1 rate in most cases, but did increase N concentration, N uptake and protein concentration. A significant residual effect was found in the high N‐rate treatments in 2006, with significantly higher yield and N uptake. In 2005, the forage N and P uptake in the fertilized treatments were significantly higher than the control in all cases. The N uptake at the three Saskatchewan sites increased with increasing N rate up to the high rate of 224 kg N ha−1, although the percent recovery of applied N decreased with increasing rate. The P fertilization with 28 kg P2O5 ha−1 also increased P uptake. Overall, rates of fertilizer of approximately 56 kg N ha−1 appear to be sufficient to produce nearly maximum forage yield and protein concentration of the grass in the year of application.

Maximizing Timothy Forage Yield and Quality by Balanced Nitrogen, Phosphorus, and Sulfur Fertilization

A 3‐yr (2005–2007) field experiment was conducted on a Gray Luvisol (Typic Cryoboralf) loam near Star City, SK, Canada, to determine the influence of single and combined annual applications of N, P, and S fertilizers on timothy (Phleum pratense L.) forage dry matter yield (DMY), quality [concentration of crude protein (CP), nitrate N, acid detergent fiber (ADF), neutral detergent fiber (NDF), total P, and total S] and N, P, and S uptake, and residual nitrate N, extractable P, and sulfate‐S in soil. The highest DMY and nutrient uptake were obtained when N and S were applied together. Concentration of CP and total P in forage increased with application of N alone, but decreased with the addition of S along with N. Concentrations of nitrate N in forage (< 0.011 g nitrate N kg−1) were much lower than those considered potentially toxic (>2.26 g nitrate N kg−1) to livestock. Concentration of ADF and NDF in forage increased with N application. Concentration of total S in forage increased with S application, but decreased with N application. Residual soil nitrate N in 0 to 60 cm depth increased with N application, but decreased when S was applied in combination with N. Residual soil extractable P in 0 to 15 cm depth increased with P fertilizer, but decreased when N and/or S were applied in combination with P. Residual soil sulfate‐S increased with S fertilization, but usually decreased when S was applied in combination with N. In conclusion, combined applications of N and S fertilizers produced maximum forage yield and nutrient uptake of timothy, and reduced accumulation of nitrate N in this soil lacking in these nutrients.

Productivity and water use of alfalfa and subsequent crops in the semiarid Loess Plateau with different stand ages of alfalfa and crop sequences

Alfalfa ( Medicago sativa L.) plays an important role in crop–livestock mixed farming on marginal land in the semiarid Loess Plateau. However, the duration, yield performance and water use of long-term alfalfa stands and choice of appropriate subsequent crops are not clear. A 5-year field experiment was conducted at Zhonglianchuan, Gansu Province, China from 2001 to 2005. Productivity and water use were determined and compared between (1) three alfalfa stands that were 1–5 (A1–5), 6–10 (A6–10) and 11–15 (A11–15) years old during the trial; (2) alfalfa using conventional cultivation and a water-harvesting technique (RA1–5); and (3) conventional crop rotation (CK) and four 5-year crop sequence rotations sown after 10-year-old alfalfa had been ploughed, being millet–wheat–potato–pea–potato (MWLPL); millet–corn–corn–wheat–wheat (MCCWW); millet–potato–wheat–corn–corn (MLWCC) and millet–fallow–pea–potato–pea (MFPLP). Forage yield peaked in 7-year-old alfalfa (5740 kg ha −1), but 9-year-old alfalfa had the maximum forage yield profit (4477 kg ha −1 y −1) in terms of whole growing years. Soil water use efficiency (WUE S in terms of forage yield and soil water use) of alfalfa increased dramatically up to the 11th year, and then leveled off from year 12 to 15. Forage yield and WUE B/ET (WUE in terms of aboveground biomass and evapotranspiration) of alfalfa were significantly higher using water harvesting compared with conventional cultivation, but were significantly lower than CK. Soil water content did not change in CK as stand age increased, but it decreased in conventional alfalfa stands. After 10 years of alfalfa, a fallow year was not necessary before planting annual crops as soil water was greatly restored after sowing subsequent annual crops. Yield of some crops in the four crop sequence rotations did not differ significantly from CK. MWLPL and MLWCC had more aboveground biomass than MCCWW and MFPLP but the choice of crop sequence needs to be further considered.

Single Irrigation Can Achieve Relatively High Production and Water Use Efficiency of Siberian Wildrye Grass in the Semiarid Agropastoral Ecotone of North China

Siberian wildrye grass (Elymus sibiricus L.) is widely planted in the agropastoral ecotone of North China (APENC). Scheduled irrigation is an important approach to increase the forage yield in this semiarid region. Based on field experiments conducted in Bashang Plateau in APENC during 2002 to 2004, we studied the feasibility of applying single irrigation (SI) to increase forage yield by bringing the soil water storage in the root zone (0–60 cm) to field capacity at the elongating stage. The results showed that Siberian wildrye grass consumed water most rapidly during the elongating stage. With 48 to 62 mm of water applied during elongating stage, forage yields reached 6000 kg ha−1, a 110% increase compared with no irrigation (NI). With full irrigation (FI) in the growing season, forage yield was only increased by 10% compared with that under SI. The average water use efficiency (WUE) under SI was 1.9 kg m−3, a 76% increase compared with NI or a 10% increase compared with FI. The average irrigation water use efficiency (IWUE) under SI was 10.8 kg m−3 which was almost three times that under FI. Therefore, a single irrigation can be a simple agricultural practice for local farmers, and has great potential to contribute to sustainability of semiarid APENC. In addition, forage yield and WUE showed a quadratic trend with total evapotranspiration (ET). The maximum forage yield in this semiarid area was about 6900 kg ha−1 at 390 mm ET, whereas the maximum WUE was 1.9 kg m−3 at 360 mm ET.

Micronutrients in Soils, Crops, and Livestock

Micronutrient concentrations are generally higher in the surface soil and decrease with soil depth. In spite of the high concentration of most micronutrients in soils, only a small fraction is available to plants. Micronutrients, also known as trace elements, are required in microquantities but their lack can cause serious crop production and animal health problems. Crops vary considerably in their response to various micronutrients. Brassicas and legumes are highly responsive to molybdenum (Mo) and boron (B), whereas corn and other cereals are more responsive to zinc (Zn) and copper (Cu). Micronutrient deficiencies are more common in humid temperate regions, as well as in humid tropical regions, because of intense leaching associated with high precipitation. Soil pH is one of the most important factors affecting the availability of micronutrients to plants. With increasing pH, the availability of these nutrients is reduced with the exception of Mo whose availability increases as soil pH increases. In most plant species, leaves contain higher amounts of nutrients than other plant parts. Therefore, whenever possible, leaves should be sampled to characterize the micronutrient status of crops. Deficiency symptoms for most micronutrients appear on the younger leaves at the top of the plant, whereas toxicity symptoms generally appear on the older leaves of plants. As summarized by Deckers and Steinnes, micronutrient deficiencies are widespread in developing countries, which have much poorer soil resources than the fertile soils of Europe and North America. Many of these areas lie in the humid tropics with extremely infertile, highly weathered, and/or highly leached soils, which are intensely deficient in nutrients. The rest of such soils are in the semiarid and areas adjacent to the latter, where alkaline and calcareous soil conditions severely limit the availability of micronutrients to plants. Frequently, the Cu, iron (Fe), manganese (Mn), Zn, and selenium (Se) levels in forages, which are sufficient for optimum crop yields, are not adequate to meet the needs of livestock. Selenium is a trace mineral, which is not required by plants, and maximum forage yields can be obtained on soils with very low amounts of soil Se. However, if animals are fed feed crops and forages with low Se, they could suffer from serious muscular disorders and other diseases. White muscle disease caused by Se deficiency is the most common disorder and is found in calves and lambs. Sufficiency levels of micronutrients for crops have been discussed in relation to the animal requirement.