Ground Biomass Yield Research Articles

Response of Sulphur Fertilizer Application to Bread Wheat (<i>Triticum aestivum</i>) Growth and Yield in Kulumsa, Arsi, Ethiopia

A field study was conducted during 2013/14 cropping season with the objectives of to study the response of bread wheat to different rates of sulfur fertilizer, to study the effect of sulphur fertilization on growth and yield of bread wheat and to suggest some recommendations about the optimal rates of sulfur fertilizer application for bread wheat as well as for further sulfur research works. The treatments applied as one factor of six levels of sulphur (0, 20, 40, 60, 80 and 100 kg S ha-1. The treatments were replicated three times in a Randomized Complete Block Design. The experiment was carried out at the Kulumsa Agricultural Research Center on clay textured soil. Data were collected and statistical analysis was done on various characters of the crop. Soil Samples were also taken before and after the implementation of the experiment and chemically analyzed. The analysis of variance for the results of the study revealed among the agronomic and yield parameters of wheat; Number of Seedling, Number of Tillers per Plant, 50% of flowering date, Plant Height, spike length, Number of Spikes, Number of Seeds per spike, Total Above Ground Biomass Yield and Harvest Index were non-significant (p> 0.05) influenced by rate of S whereas Thousand Grains Weight, and grain yield were significantly (p≤0.05) affected by rates of S. Application of 60 kg S/ha increased the grain yield of wheat by 12.64%, 11.39%, 6.44% and 2.52% respectively when compared with the no S application. 60 kg/ha is recommended for vertisol at kulmsa.

Review on Plant Population Density and Row Spacing Effects on Yield of Maize (Zea mays) in Ethiopia

In this review maize is highly sensitive cereal crop to most agronomic practices such as plant population density and plant spacing. Plant population density and row spacing is one of the best agronomic practice to increase maize crop productivities. Depending on the environmental yield potential of the land, improvements of intera and inter row spacing practices are important for land productivity to each maize varieties. The optimum plant population density that increases the yield and yield components of a single plant. As the review indicates most yield components of maize varieties are affected by plant population density and row spacing due to resource competition results yield reduction. As the plant population increase per cultivated land area, economic yield and above ground biomass yield was decreased. Similarly the narrowest intera and inter row plant spacing decreases economic yield and above ground biomass yield of maize crop. Keywords : population, maize, density, spacing, cob DOI: 10.7176/JBAH/10-21-02 Publication date: November 30 th 2020

Monitoring Forage Mass with Low-Cost UAV Data: Case Study at the Rengen Grassland Experiment

Monitoring and predicting above ground biomass yield of grasslands are of key importance for grassland management. Established manual methods such as clipping or rising plate meter measurements provide accurate estimates of forage yield, but are time consuming and labor intensive, and do not provide spatially continuous data as required for precision agriculture applications. Therefore, the main objective of this study is to investigate the potential of sward height metrics derived from low-cost unmanned aerial vehicle-based image data to predict forage yield. The study was conducted over a period of 3 consecutive years (2014–2016) at the Rengen Grassland Experiment (RGE) in Germany. The RGE was established in 1941 and is since then under the same management regime of five treatments in a random block design and two harvest cuts per year. For UAV-based image acquisition, a DJI Phantom 2 with a mounted Canon Powershot S110 was used as a low-cost aerial imaging system. The data were investigated at different levels (e.g., harvest date-specific, year-specific, and plant community-specific). A pooled data model resulted in an R2 of 0.65 with a RMSE of 956.57 kg ha−1, although cut-specific or date-specific models yielded better results. In general, the UAV-based metrics outperformed the traditional rising plate meter measurements, but was affected by the timing of the harvest cut and plant community.

Performance of Wheat in Five Soils of Different Textures under Freshwater and Wastewater Irrigation

This study investigated the effects of five soils of different textures on wheat cultivation under irrigation with freshwater (FW) and municipal wastewater (WW). The experimental design was a split-plot with irrigation water quality as main factor and soil texture as sub-factor in three replications. These factors respectively comprised 2 and 5 treatments. Soil texture significantly (p£0.05) influenced plant height, leaf area index (LAI), spike length, number of grains per spike, above ground dry matter (ADM), grain yield, straw yield and biomass yield of wheat in most cases both under FW and WW irrigation. The harvest index (HI) of wheat responded significantly under FW irrigation only. Under FW, treatment T5 (silt loam) produced the highest grain yield (4.2 t ha–1) followed by T3 (loam-1) (3.1 t ha–1); the lowest yield (2.0 t ha–1) was in the control treatment, T1 (loamy sand). Under WW, treatment T2 (sandy loam) produced the highest grain yield (5.0 t ha–1) followed by T4 (loam-2) (4.5 t ha–1) both of which are statistically similar; the lowest yield (3.4 t ha–1) was in the control treatment. Treatments T2 and T4 provided the highest straw yield (5.6 t ha–1) and treatment T2 provided the highest biomass yield (10.6 t ha–1), both under WW; both T2 and T4 produced invariant biomass yields. Compared to other treatments, T2 and T4 gave statistically similar but significantly higher water productivity with respect to straw and grain yields. The lowest water productivity was in treatment T1 under both water qualities. The results of this study provided sound criteria in selecting suitable lands for wheat cultivation based on irrigation water quality, specifically in alluvial plains where soil texture is prone to high variations. Also, the observed facts of improved productivity of lower quality coarse-textured soils due to addition of easily available and inexpensive clay would provide guidance to bring unproductive sandy soils under production by clay amendments.

Effect of Planting Date and Nitrogen Application Level on Production Yield and Oil Content in Dill Plant

A complete randomized block design with three replications was conducted at two consecutive growing seasons (2014-2015 and 2015-2016) to evaluate the influence of planting date and nitrogen application level on growth parameters and oil yield production of dill plant. Experimental factors included three planting dates (15th of October, 15th of November and 15th of December) and five levels of nitrogen fertilizer (i.e urea) application (0, 30, 60, 90 and 120 kg/hectare). Both studied factors significantly influenced growth parameters (plant height, number of branches per plant, number of umbrellas per plant, 1000 seed weight, above ground biomass yield, seed yield and harvest index) and oil yield and oil percentage The results indicated that early planting date (1st of October) has a positive influence on all studied parameters in this study. Furthermore, this study showed that addition of nitrogen fertilizers significantly improved all studied parameters. Comparing the influence of the two studied factors, it seems that planting date when compared to nitrogen fertilizer application has more pronounced influence on all studied production parameters of dill plant.

Performance Evaluation and Response of Yield Components and Yield of Bread Wheat to NPK Fertilizers at Hidebu Abote District of North Shewa Zone, Oromia

A field experiment was carried out on nitisols of Hidebu Abote district, North Shewa Zone, Oromia where wheat production is severely constrained by lack of an appropriate rate and types of fertilizer recommendation to evaluate wheat crop response to NPK fertilizer application. Fifteen NPK nutrients levels were considered and applied as treatments along with control (no fertilizer) at yaya Deka Bora peasant association were arranged in randomized complete block design (RCBD) with three replications at two farmers field. The ANOVA result indicated that plant height (PH), above ground biomass yield (AGBMY), straw yield (SY), Thousand grain weight (TGW), grain yield (GY) and harvest index (HI) of bread wheat showed significant (P ≤ 0.05) response to the NPK fertilizer application at both sites. The highest AGBMY (13.61 and 12.46 tons ha-1), SY (8.13 and 7.33 tons ha-1) and GY (5475.00 and 5414.33 kg ha-1) were recorded with the application of 69:30:20 NPK fertilizer combination at (site 1 and site 2) respectively and the lowest were recorded on control treatments. However the highest PH (103.8 and 97.27 cm) at site 1 and site 2 was recorded respectively with the application of 92:10:20 NPK nutrients combinations. Both the statically and economical analysis showed that 69:30:20 NPK kg ha-1 of fertilizer application results in higher yield and economically profitable for bread wheat production in the study area. However further research experiment with multi locations, cropping seasons and different bread wheat cultivar have to be required in order to give best conclusive recommendation for the farmers.

Effect of Bacillus subtilis and Bacillus amyloliquefaciens culture on the growth and yield of off-season potato (Solanum tuberosum L.)

A study was carried out in order to investigate the effect of microbial fertilizer application on off-season potato (Solanum tuberosum L. cv. Universia) under field conditions in early spring and late autumn in 2016. The experiment included Control (C, no application), Standard Fertilizer Application (SFA), Microbial Fertilizer Application (MFA) and SFA+MFA treatments. An equal mixture of three strains of Bacillus subtilis VKPM B-10641(DSM 24613), Bacillus amyloliquefaciens VKPM B-10642 (DSM 24614) and Bacillus amyloliquefaciens В-10643 (DSM 24615) was applied at 1x109 cfu/ml to tubers before planting and to plants at flowering stage in MFA and SFA+MFA plots. Treatments affected the plant growth parameters. SFA plots produced the highest tuber yields in both seasons. MFA plots had earlier emergence time (40 days), higher number of stems per plant (3), higher number of leaves per plant (37.2), thicker stem diameter (10.15 mm), higher above ground biomass yields (5.42 t/ha), higher single tuber weight (104.21 g) and higher tuber yields (22.06 t/ha) compared with control plots (42 days, 2.2, 31.2, 9.15 mm, 4.40 t/ha, 90.88 g and 20.14 t/ha respectively). Tuber yield in MFA plots (26.56 t/ha) was equal to SFA plots (26.81 t/ha) in warmer autumn planting. Combination of SFA and MFA produced lower tuber yields (21.72 t/ha) than SFA treatment (26.81 t/ha). In conclusion, Bacillus subtilis and Bacillus amyloliquefaciens gave comparable tuber yields to chemical fertilizer application in warmer autumn plantings, but lower tuber yields in colder spring conditions warranting further experiments with cold tolerant psychrophilic bacterial strains for off-season potato production.

Improving the productivity of degraded pasture land through demonstration of legume forage over sowing: The case of Ayba pasture land, South Tigray, Ethiopia

The study was undertaken in Northern Ethiopia, at Emba Alaje District, to assess forage yield of the natural pasture over sown with adapted legume forage. The design was a single plot design and the treatments were farmers’ practice and Vicia sativa over sown. A total of 60 quadrats of 1 by 1 m2 size were used for herbaceous species composition, above ground biomass and dry matter yield and analyzed by t-test equal variances using R-software. Over sowing legume forage increased dry matter yield significantly as compared with the farmers’ practice pasture land. The higher dry matter yield was recorded for pasture land over sown with Vicia sativa (3.43 ton/ha). Vicia sativa over sown also increased the basal cover of herbaceous (2.28) compared to farmers’ practice (1.47). Similarly, the Vicia sativa over sown pasture land had significantly (p < 0.001) higher forage biomass than the farmers’ practice area. Results from the comparative analysis also indicated that Vicia sativa over sown on the degraded grazing land had a higher cost effective than the existing farmers’ practice as the calculated net return was found to be positive. It is, therefore, concluded that over sowing degraded grazing land with Vicia sativa improves biomass yield, and it is also cost-effective as compared with farmers’ practice. Therefore, based on the finding of the study it is highly recommended that the concerned governmental and nongovernmental organization should give emphasis to promote Vicia sativa over sown for the rehabilitation of degraded pasture land.

English

The use of right amount of fertilizer based on crop requirement has a significant importance for sustainable crop production. Study was undertaken to investigate the effects of NPSZnB blended fertilizer for maize yield production at Laelay Adiyabo and Medebay Zana districts. Seven treatments were used for the field experiment. Treatments were without fertilizer, blanket recommended NP (64 kg N ha-1+69 kg P2O5 ha-1) and five treatments of blended fertilizer rates (150, 200, 250, 300, and 350 kg NPSZnB ha-1). Treatments were laid out in RCBD design with three replications. The results revealed that among fertilizers rates significantly (P ≤ 0.05) affected almost all the maize traits tested except tasseling, silking and maturity in Laelay Adiyabo district. However, in Medebay Zana district except tasseling, silking and maturity, plant height and thousand seeds weight, the rest parameters of above ground biomass yield, stover yield grain yield and harvest index were found significantly (P<0.05) affected by the fertilizer treatments. Highest stover yields (11.12 and 11.76 t ha-1) were obtained from application of 150 and 250 kg NPSZnB ha-1for Laelay Adiyabo and Medebay Zana districts, respectively. At both districts of Laelay Adiyabo and Medebay Zana areas the highest grain yields (3.20 and 2.97 t ha-1) were obtained, respectively from application of NPSZnB fertilizer at the rate of 300 kg ha-1, while the minimum grain yields of both districts were obtained from the control checks. The highest marginal rate of returns of 242 and 255% were obtained from application of 150 kg NPSZnB ha-1in both Laelay Adiyabo and Medebay Zana districts, respectively. Therefore, based on the result obtained from this study 150 kg NPSZnB ha-1 can be recommended as profitable for the production of maize at both districts of the study areas. Key words: Blended fertilizer, maize yield, profitability.

Long-term in situ moisture conservation in horti-pasture system improves biological health of degraded land

In situ moisture conservation practices can conserve fertile topsoil and enhance available water in soil profile. We hypothesised that reclaiming degraded land ecologically through tree + pasture + in situ moisture conservation practices would significantly improve soil organic carbon (SOC) and health. Hence, the objectives were a) to identify changes in nutrient cycling enzymes and SOC status due to different in situ soil moisture conservation options in surface and subsurface soil layers, and b) to test the potentiality of soil enzymes to determine long-term nutrient availability. We conducted a long-term experiment involving aonla (Emblica officinalis) trees + pasture (Cenchrus ciliaris + Stylosanthes seabrana) + in situ soil moisture conservation measures viz. staggered contour trenches (T1), continuous contour trenches (T2), stone mulch (T3), vegetative barriers (T4), control (T5) and fallow land (T6) since 2007. Recommended dose of nitrogen (N), phosphorus (P) and potassium (K) were added to all treatments, except T6. SOC concentration increased by ~51 and 31% in T1 and T2, respectively, over T5 in surface (0–15 cm) soil. Culturable bacterial and fungal populations increased by ~20 and 95% in T1 over T5 in surface soil. Activities of all soil enzymes increased in T1 and T2 (ranging from 42 to 289%) over T5 and T6 in both surface and sub-surface (15–30 cm) layers. However, specific activity of phenol oxidase was ~25% lower for T1 than T6, suggesting more efficient SOC sequestration in T1. Moreover, geometric mean enzyme activity of T1 was ~65 and 33% higher than T5 and T3, respectively, in surface soil. Treated soil quality index (T-SQI) of T1 was ~184% higher than T5. Soil functional diversity was also ~1.24 and 1.22 times higher in T1 and T2 than T5, respectively. Peroxidase was the major C degrading enzyme in this ecosystem. Protease, urease and phosphatase significantly influenced N and P availability along with fruit and pasture yields. Importantly, ~96, 62 and 82% variability of SOC, N and P concentrations, respectively, could be attributed to their corresponding enzyme activities. Principal components analysis (PCA) revealed one-way operational role of soil enzymes. Thus, enzymes are potentially important for recycling nutrients from litters, root biomass of fruit trees and grasses to boost their availability in the long run. Adoption of horti-pasture system combined with moisture conservation practices and staggered contour trenches or continuous contour trenches ensured higher above ground biomass yield, SOC, nutrient availability and soil quality. Thus, long-term use of these practices could be recommended for reclamation and improving soil health and crop productivity of degraded lands of central India.

ASSESSMENT OF AQUACROP MODEL IN PREDICTION MAIZE HYBIRDS YILD BY SIMULATION PRODUCTION UNDER DEFICIT IRRIGATION

The study was carried out at the field of Agriculture College, Duhok University, ‎during spring season 2015, using drip irrigation system., the irrigation ‎levels (100%, 75% and 50% of field capacity) arranged in main plots and maize hybrids namely Symiami, IK58*HS and Ddhi9445*HS in the sub plots within split plot design in Randomize Complete Block Design.The data were recorded on, grain yield, above ground biomass, and harvest index. The results showed that the Actual evapotranspiration (ETa) was linear relationship with water applied and water ‎use. The production parameters were significantly affected by increasing irrigation levels. The level 100% of field capacity showed higher amounts of grain yield, &nbsp;above ground biomass and grain yield plant-1 compared with 75% and 50% of field capacity. The maize hybrids exhibited a significant effect on grain yield and above ground biomass and the hybrid IK58*HS was superior in grain yield plant-1 and above ground biomass.AquaCrop model was found to be accurate and fit to simulate grain yield, &nbsp;above ground biomass.According to this study, which was revealed that the productivity parameters of maize hybrids were more affected by deficit irrigation. The 100% of field capacity and the hybrid IK58*HS gave a significant increase in most of&nbsp; production parameters. AquaCrop ‎model can be used as a helpful tool in the evaluation and comparison of crops productivity and irrigation strategies.

Synergy and/or Antagonism in a Cover Crop Sequence: Rotational Effects on Rye in the Midwest

Cover cropping reduces soil erosion mainly by providing cover when the soil is left barren after a short season crop. It also improves nutrient cycling and prevents the loss of NO3-N by leaching especially during late fall and early spring season. When CCs are grown in a sequence, they are able to harvest both the benefits mentioned above and provide ecological services. However, there may be synergistic or antagonistic effects in action between CCs just as is the case of CC allelopathy in weed control. Field experiments were conducted over two cropping seasons (2016-16 and 2016-17) at Michael Fields Agricultural Institute, Wisconsin on a forest derived Fox silt loam (Fine-loamy, mixed, mesic Typic Hapludalfs) under organic certification to determine the effect of sequential planting of CCs on Above Ground Biomass (AGB) yield, N and C addition and to determine the synergistic or antagonistic effect of the species grown in a sequence on each other. Ten different species of CCs were planted immediately after crop harvest in early August followed by winter rye in a sequence, after roll-crimping of the first cover. The cropping sequences significantly affected the cover crop yield and related parameters. Radish &amp;ndash; winter rye sequence was the best performing one in both years of study with regard to the AGB yield (13.96 and 14.87 Mg ha-1 respectively), and large amounts of N and C added to the soil. Phacelia &amp;ndash; winter rye followed close, with the sequence recording on par yields in 2015-16 (13.28 Mg ha-1). Winter rye performed better following a dicot compared to monocot; non-legume compared to a legume. The CC sequences also exhibited synergism and antagonism. The yield of winter rye was boosted when the biomass yield of the forage radish it followed increased, which we consider as synergy: while the yield of winter rye reduced whenever the yield of oat, barley or beseem clover it followed increased, which we consider as an antagonistic effect. The other CCs performed moderately and were greatly a reflection of the prevailing weather conditions. More research along this line is recommended to generate research based information on synergy and antagonism in CC sequence.

English

Thirty bread wheat genotypes were tested to assess the genetic variability, among studied genotypes using alpha-lattice design at Tongo sub-center of Assosa Agricultural Research Center and Kulumsa Agricultural Research Center in 2015. Analysis of variance revealed that there were statistically significant differences among the genotypes for most of the traits at individual and across locations. From the combined analysis of variance, significant (p&le;0.05) effect due to location, varieties and G&times;E was observed for most of the traits. The varieties showed wider variability in mean grain yield of 1284.4-3788.7 kg ha-1, 2588.3-4683.3 kg ha-1 and 1936.4 - 4095.6 at Tongo, Kulumsa and across location, respectively. Moderate PCV values (&gt;10%) were obtained for grain yield, 1000 kernel weight, harvest index, tillers per plant and spikes per plant at individual location and across location including days to heading, above ground biomass yield, spike length and kernels per spike at Tongo and above ground biomass yield at Kulumsa. Similarly, moderate GCV values (&gt;10%) were obtained for grain yield, 1000 kernel weight, tillers per plant and spikes per plant&nbsp; at individual location including days to heading, harvest index and kernels per spike at Tongo and above ground biomass yield at Kulumsa. Lower (&lt;10%) was obtained for all traits across location. High heritability estimates (&gt;80%) were obtained for days to heading (86.0%) and days to maturity (85.1%) at Tongo and days to heading (86.2 and 82.69%) and spikes length (80.1 and 82.85%) at Kulumsa and across location. But relatively high genetic advance (&gt;20%) was obtained for grain yield (28.5%) and harvest index (24.3%) at Tongo. Moderate genetic advance (10-20%) was observed for 1000 kernel weight, spikes length and days to heading at individual location and across location including spikelets per spike, tillers per plant, above ground biomass, spikes per plant and plant height at individual location. Generally, it has been observed the presence of variability among the genotypes, heritability in the tested traits of the genotypes studied. Hence, Selection and hybridization on those genotypes based on the trait with high GCV, heritability and genetic advance can be recommended for farther yield improvement of bread wheat at respective location. Key words: Heritability, genetic advance, traits, phenotypic, genotypic coefficient of variation. &nbsp

Impact of no-till and mulching on soil carbon sequestration under rice (Oryza sativa L.)-rapeseed (Brassica campestris L. var. rapeseed) cropping system in hilly agro-ecosystem of the Eastern Himalayas, India

Decline in soil organic carbon (SOC) and low biomass production in sloping uplands are of growing concern for sustainable agriculture worldwide. This concern is in general in the Eastern Himalayan regions (EHR) of India in particular. A field experiment was conducted with the objectives to generate additional biomass and sequester more C in coarse-textured sloping lands. This experiment is done for four consecutive years in the EHR, India. The rice (Oryza sativa L.)–rapeseed (Brassica campestris L. var. rapeseed) cropping system was practiced during the first two years (2012-13 to 2013-14) and rice–rapeseed–cowpea (Vigna unguiculata L.) system during the two following years (2014-15 to 2015-16) of the study under different tillage and mulch systems. The tillage system included: 1) CT-RI: conventional tillage (CT) with 100% residue incorporation (RI) and 2) NT-RR: no-till (NT) with 100% residue retention (RR). The mulches included 1) rice straw mulch (SM), 2) Gliricidia sp. mulch (GM), 3) brown manuring mulch (BM)–cowpea grown as intercrop with rice up to 40 days after sowing (DAS), killed with 2,4-D and 4) no mulch (NM). The cowpea, as a cover crop was introduced during 2014 and 2015 as pre-rainy season crop before the sowing of rice to generate additional biomass in the system. The four year total above ground biomass yield of rice and rapeseed didn’t vary significantly between CT-RI (31.93 and 17.40 Mg ha−1) and NT-RR (31.86 and 17.46 Mg ha−1), respectively. However, the total above ground biomass yield of cowpea was more under NT-RR (10.75 Mg ha−1) when compared to that under CT-RI (9.79 Mg ha−1). The amount of total biomass (above + below ground) and C added into the soil was more under NT-RR than that under the CT-RI. After 4 cropping cycles, the NT-RR had higher SOC concentration, pool (29.9 vs. 29.1 Mg ha−1), sequestration rate (450 vs. 265 kg ha-1 yr−1) and C retention efficiency (7.7 vs. 4.6%) than those under the CT-RI at 0–30 cm depth. The mulched plots produced more crop biomass (both above and below ground), recycled more C in soils with a trend of relatively more SOC pool (29.7–29.8 vs. 29.0 Mg ha−1), sequestration rate (391–428 vs. 221 kg ha-1 yr−1) and C retention efficiency (6.64–6.94% vs. 4.66%) than those of NM treatment. These results were seen despite difference among the mulch treatments (SM, GM and BM) which were statistically non-significant after 4 cropping cycles. Inclusion of cowpea as cover crop during pre-rainy season in the system doubled the rate of C sequestration (478 kg C ha-1 yr−1). Therefore, the data supports the recommendation of cultivation of the rice–rapeseed system under NT-RR along with cowpea intercropping up to 40 DAS (BM) in rice. Besides this, the inclusion of pre-rainy season cowpea before rice could generate additional biomass and enhance SOC sequestration on upland and sloping hills in the EHR of India and in similar conditions elsewhere.

Performance evaluation of AquaCrop in simulating soil water storage, yield, and water productivity of rainfed soybeans (Glycine max L. merr) in Ile-Ife, Nigeria

In this study, experiments were carried out for two seasons at the teaching and research farms, Obafemi Awolowo, Nigeria to evaluate the performance of FAO AquaCrop version 5.0 in simulating canopy cover, soil water storage, above ground biomass, evapotranspiration, grain yield and water productivity of soybeans (TGX 1448 2E) under rainfed conditions. The Experimental treatments consisted of conventional and six water conservation practices: Tied ridges; Mulching; Bund; Tied ridges plus mulch; Tied ridges plus bund and Bund plus mulch. The experimental treatments were arranged in randomised complete block design with four replicates. The 2012 and 2011 data sets were used for calibration and validation respectively. The performance of AquaCrop was tested using the regression coefficient (b), coefficient of determination (R2), Root mean square error (RMSE), Normalised root mean square error (NRMSE), Nash and Sutcliffe efficiency coefficient (EF), Willmott’s index of agreement (d-index) and percentage bias (PBIAS). AquaCrop simulated canopy cover adequately for the two seasons, 0.95 ≤ b ≤ 0.99; R2 ≥ 0.95 and RMSE ≤ 11.6%. The model captured well the variability in soil water storage with 0.95 ≤ b ≤ 1.01; R2 ≥ 0.74 and RMSE ≤ 10.2 mm. AquaCrop simulated evapotranspiration with R2 = 0.66 and RMSE = 64.6 mm. The model simulated dry above ground biomass with RMSE ≤ 0.25 t ha−1 and d-index ≥ 0.98. Grain yield was simulated with b = 1.01; R2 = 0.99; RMSE of 0.03 t ha−1d-index = 1.00 and the maximum deviation between the simulated and predicted grain yields is 3%. The water productivity was simulated with R2 = 0.78 and RMSE = 0.08 kg m-3. Considering the overall performance, the AquaCrop model is adequate in simulating canopy cover, dry above ground biomass and grain yield. However, it has low aptitude in simulating evapotranspiration and water productivity of rainfed soybeans under soil surfaces management practices.

Responses of Soybean (&amp;lt;i&amp;gt;Glycine max&amp;lt;/i&amp;gt; L.) Varieties to NPS Fertilizer Rates at Bako, Western Ethiopia

Soybean (<i>Glycine max. L</i>) is among the most important legume crops produced in western Ethiopia. However, declining soil fertility and poor soil fertility management practices decrease yields. A field experiment was conducted in Bako Agricultural Research center during 2018 main cropping season to investigate the effect of NPS rates on yield and yield components of soybean varieties and to identify economically feasible rates of blended NPS rate that increase the productivity. Dhidhessa, Ethio-yugoslavia and Wello of soybean varieties and five rates of NPS (0, 50,100,150 and 200 kg ha^-1). The experiment was laid out in arrangement in RCBD with three replications. The highest hundred seed weight (16.9g) was recorded from Ethio-yugoslavia and the lowest (15g) from Wello. Significant effect was exhibited on days to 50% flower, above ground biomass yield and seed yield due to main effects of NPS rate. The highest (55.78) and the lowest (53.78) numbers of days to flowering were recorded due to application of 200 kg NPS ha^-1 and 0 kg NPS ha^-1, respectively. The tallest (81.63cm) and the shortest (65.60 cm) plants were recorded under 200 kg NPS ha^-1 and 0 kg NPS ha^-1, respectively. The highest (8718 kg ha^-1) above ground dry mass was obtained at the highest rate of 200 kg NPS ha^-1 and the lowest (6910 kg ha^-1) was due to 0 kg NPS ha^-1. The highest (2763 kgha^-1) seed yield was recorded from the application of 100 kgha^-1 NPS rate and the lowest (1935kgha^-1) seed yield was recorded from nil application of NPS fertilizer rate. The best combination with high grain yield and economic benefit is 100kgha^-1 NPS fertilizer rate with Didhessa Variety. The major measured parameters contributing for grain yield were above ground biomass, number of pod per plant and no of primary branch per plant. This experiment generally confirmed as 100kgha^-1 NPS for soybean was appropriate. This trial was conducted at strong acid soil, these it is expected as the plants might not have access to use the applied fertilizer and if it was conducted with lime application the responses might be changed. Thus, it can be concluded that combined application of 100 kg ha^-1 of blended NPS with Dhidhessa variety could be used at similar agro ecology. However, since the study was conducted for one season at one location, it has to be repeated over seasons and locations to make a conclusive recommendation.

Radiation interception, extinction coefficient and use efficiency of wheat crop at various irrigation and nitrogen levels in a semi-arid location

Field experiments were conducted to study the effect of irrigation and nitrogen levels on radiation use efficiency (RUE), radiation extinction coefficient (κ) and temporal variation of leaf area index (LAI) and fraction intercepted photosynthetically active radiation (fIPAR). The LAI of wheat increased with increase in irrigation and nitrogen levels. The fIPAR also followed trend similar to LAI. The LAI and fIPAR showed logarithmic relationship with R2 value of 0.92 and 0.93 for the years 2013–2014 and 2014–2015, respectively. The κ value varied between 0.41 and 0.78 and was significantly affected by nitrogen levels but was not influenced by irrigation levels. The grain and above ground biomass (AGB) yields of wheat were not affected significantly by irrigation levels. However, application of 160 kg N ha−1 (N160) registered higher grain (12–33%) and AGB (22–25%) yeilds as compared to that with application of 40 kg N ha−1 (N40). Similar to AGB, the total intercepted photosynthetically active radiation (TIPAR) was not affected by irrigation levels but N160 treatment registered 9–20% higher TIPAR compared to N40 treatment. The linear relationship between TIPAR and AGB revealed that 83–86% variation in AGB yield of wheat can be explained by TIfIPAR. The RUE of wheat under three irrigations (I3) was 6 and 18% higher (P < 0.05) than the five (I5) and two (I2) irrigation treatments, respectively for the year 2013–2014. However, there was no significant effect of irrigation on RUE of wheat in the year 2014–2015. N160 treatment registered 5–13% higher RUE than the N40 treatment. Thus wheat may be grown with three irrigations (CRI, flowering and grain filling) and 160 kg N ha−1 for higher RUE without significant reduction in AGB of wheat compared to five irrigation levels in semi-arid location of Delhi region.

Calibration and Validation of CSM‐CROPGRO‐Cotton Model Using Lysimeter Data in the Texas High Plains

AbstractTexas High Plains (THP), one of the most important food and fiber producing regions in the Ogallala Aquifer Region, currently faces rapid decline of groundwater levels. Predicted climate extremes and high temporal variability in growing season precipitation may require growers to pump more groundwater from the Ogallala Aquifer to meet higher crop water demand. The Decision Support System for Agrotechnology Transfer (DSSAT) Cropping System Model (CSM) is a widely used crop simulation tool for evaluating impacts of different water and crop management practices, including irrigation on crop yield and water use efficiency. In this study, CROPGRO‐Cotton module of the DSSAT was calibrated and validated using 2000, 2001, 2002, and 2010 irrigated lysimeter field data managed by the USDA‐ARS (United States Department of Agriculture ‐ Agricultural Research Service) Conservation and Production Research Laboratory at Bushland, TX. The lysimeter field consisted of four equal plots designated as NE, SE, NW, and SW. Crop growth characteristics including leaf area index (LAI), above ground biomass (AGB), evapotranspiration (ET), soil moisture, and lint yield of 2000‐NE, 2000‐SE, and 2001‐NE, were used for calibration and 2002‐NE, 2010‐NE, and 2010‐SE were used for validation. The calibrated and validated model was used to simulate the long term (1924–2012) crop yield and seasonal crop ET. During the calibration process, some of the cultivar and ecotype parameters that influence LAI, AGB, and lint yield were adjusted for better statistical results. Measured and simulated LAI, AGB, ET, soil moisture, and lint yield showed good agreement during calibration and validation as indicated by performance statistics such as r2 from 0.70 to 0.82, and percent error (PE) = −0.85 to 17.3% for LAI; r2 = 0.89 to 0.95, and PE = −7.36 to −13.66% for AGB; and r2= 0.90 to 0.94, and PE = 3.20 to 3.44% for ET during calibration and validation, respectively. The model underestimated ET during peak vegetative growth and development stage except in some circumstances. The calibrated and validated model was able to simulate lint yield and seasonal ET during a long term (1924–2012) historic period for Bushland, TX, under irrigated conditions. The calibrated model could be used to schedule ET based irrigation management practices in the THP and to estimate future ET for other modeling experiments.

Microstructural and associated chemical changes during the composting of a high temperature biochar: Mechanisms for nitrate, phosphate and other nutrient retention and release

Recent studies have demonstrated the importance of the nutrient status of biochar and soils prior to its inclusion in particular agricultural systems. Pre-treatment of nutrient-reactive biochar, where nutrients are loaded into pores and onto surfaces, gives improved yield outcomes compared to untreated biochar. In this study we have used a wide selection of spectroscopic and microscopic techniques to investigate the mechanisms of nutrient retention in a high temperature wood biochar, which had negative effects on Chenopodium quinoa above ground biomass yield when applied to the system without prior nutrient loading, but positive effects when applied after composting. We have compared non-composted biochar (BC) with composted biochar (BCC) to elucidate the differences which may have led to these results. The results of our investigation provide evidence for a complex series of reactions during composting, where dissolved nutrients are first taken up into biochar pores along a concentration gradient and through capillary action, followed by surface sorption and retention processes which block biochar pores and result in deposition of a nutrient-rich organomineral (plaque) layer. The lack of such pretreatment in the BC samples would render it reactive towards nutrients in a soil-fertilizer system, making it a competitor for, rather than provider of, nutrients for plant growth.

Barley undersown with red clover in organic and conventional systems: nitrogen aftereffect on legume growth

Nitrogen (N) deficiency is a major problem in organic and low-input farming systems. Growing spring cereals with undersown legumes has a positive effect on soil fertility, enriching it with nitrogen, through symbiosis of legumes with nodule bacteria. Two hypotheses were tested: 1) undersowing of red clover increases the protein content of barley grains and 2) mineral N has negative aftereffect on growth of legume plants. The aim of this study was to investigate the effect of organic (cattle manure, off-season cover crop) and mineral N in organic and conventional farming systems on (i) barley (Hordeum vulgare L.) grain yield and quality, (ii) biomass yield formation of undersown red clover (Trifolium pratense L.) and (iii) the aftereffect of mineral and organic N fertilisers on the red clover crop biomass yield in the following year. The experiment was established in 2008 at the Estonian University of Life Sciences (58°22ʹ N, 26°40ʹ E) on the soil described as Stagnic Albic Luvisol (LV ab-st) (WRB, 2014) with sandy loam surface texture, 1.38% C, 0.13% N, 133 mg kg-1 P, 210 mg kg-1 K and pHKCl 6.0. The crops were treated using different farming systems: three organic (Org0, OrgI and OrgII) and four conventional (N0, N40, N80 and N120); nitrogen sources during crop cycle period: N0 and Org0 = symbiotically fixed atmospheric N2, N40 = N2 + mineral N 40 kg ha-1 N, N80 = N2 + mineral N 80 kg ha-1 N, N120 = N2 + mineral N 120 kg ha-1 N, OrgI = N2 + N taken up by cover crops (NCC) and OrgII = N2 + NCC + N applied with manure (Nm). Our study revealed that grain yield of barley was strongly affected by undersown red clover; because of competition for nutrients in cereallegume mixture the grain yield of barley in organic system was 11‒61% lower than that in conventional system. The seed rate of undersown red clover (2.84 million viable seed per ha) was too high. The content of proteiin depended on the availability of mineralised nitrogen. The mean protein content of barley grains over the trial years and treatments was 99 ± 1.6 g kg-1 in the conventional system, which was 17% higher than that in the organic system. Undersowing of red clover had no significantly positive effect on the grain yield and protein content of barley. Mineral N fertiliser had no negative aftereffect on growth of the red clover crop the following year. Mean above ground biomass yield over the trial years for the red clover crop 2nd cut was 17% higher in the conventional system than in the organic system.