Prior Crop Research Articles

Farmers’ Toolkit: Deep Learning in Weed Detection and Precision Crop & Fertilizer Recommendations

Agriculture is widely recognized as a significant and indispensable occupation on a global scale. The current imperative is to optimize agricultural practices and progressively transition towards smart agriculture. The Internet of Things (IoT) technology has dramatically enhanced people’s daily lives via diverse applications across several domains. Previous studies have yet to effectively incorporate Artificial Intelligence (AI) with sensor technology to provide comprehensive guidance to agricultural practitioners, hindering their ability to achieve good outcomes. This research offers Farmers’ Toolkit with four layers: sensor, network, service, and application. This toolkit aims to facilitate the implementation of a smart farming system while effectively managing energy resources. With a specific emphasis on the application layer, the toolkit uses a deep learning methodology to construct a fertilizer recommendation system that aligns with the expert’s perspective. This study utilizes IoT devices and Wireless Sensor Network (WSN) methods to enhance the efficiency and speed of recommending appropriate crops to farmers. The recommendation process considers several criteria: temperature, yearly precipitation, land area, prior crop history, and available resources. The identification of undesirable vegetation on agricultural fields, namely the detection of weeds, is carried out using drone technology equipped with frame-capturing capabilities and advanced deep-learning algorithms. The findings demonstrate an accuracy rate of 94%, precision rate of 92%, recall rate of 96%, and F1 score of 94%. The toolkit for farmers alleviates physical labor and time expended on various agricultural tasks while enhancing overall land productivity, mitigating potential crop failures in specific soil conditions, and minimizing crop damage inflicted by weeds.

Maize residue input rather than cover cropping influenced N2O emissions and soil–crop N dynamics during the intercrop and cash crop periods

The well-known benefits of cover cropping for mitigating climate change and improving soil quality could be threatened by increased greenhouse gas emissions. Therefore, such practices could have negative consequences in the context of global climate change. The present year-long field experiment, carried out under irrigated semiarid conditions, evaluated the effect of returning maize crop residues at two topsoil input levels in combination with bare fallow, a cereal (barley, Hordeum vulgare L.) and a legume (vetch, Vicia sativa L.) as cover crops as part of an annual cover crop–cash crop (maize, Zea mays L.) rotation. In addition, control plots, without the addition of nitrogen fertilizer (either in the previous cropping season or during the experiment), were established following the same experimental design in order to assess the carry-over impact of residual nitrogen from prior crops. Nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) fluxes were measured together with soil mineral nitrogen and crop yields and nitrogen use efficiency. The significant effect of maize residue input on N2O emissions during the cover crop phase (this was 43% greater for the lower maize residue input than for the higher) was offset after subsequent maize fertilization (there was a 170% increase following the higher maize residue input compared to the lower). Although no differences in soil mineral nitrogen content were reported between treatments before maize fertilization, N2O emissions were 72% higher on the fertilized plots than on the control plots. Before maize fertilization, N2O emissions were increased by the incorporation of cover crop residues and soil rewetting after irrigation, with the highest N2O fluxes being reported for the cereal crop. Cumulative CO2 fluxes were higher in the plots with cover crops (cereal and legume) than in bare fallow plots, while CH4 sink was not affected by cover cropping or maize residue input. The grain yield penalty for maize production (a 7% decrease) with the legume cover crop on the nitrogen fertilized plots (the opposite of what was observed in the control area) highlights the need for an accurate estimation of the nitrogen supply from the mineralization of legume residues. Overall, cover crop and maize residue input did not have any significant effect on annual cumulative N2O emissions, so the positive effects of these practices should be considered to recommend them under semiarid conditions for climate change mitigation and adaptation.

PSVI-20 Trends in Mycotoxin Contamination of the 2022 United States Corn Crop

Abstract Mycotoxins are harmful secondary fungal metabolites detrimental to animal health, even at reduced quantities. Focus on clinical signs such as decreased feed intake and vomiting overlook impacts of mycotoxicosis, including increased disease incidence and severity, immune modulation, inflammation, and gastrointestinal disorders. This study was conducted to compare mycotoxin contamination of initial samples of the 2022 corn crop with previous year trends. Samples were analyzed utilizing the liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for six major mycotoxin groups: aflatoxins (Afla), type A trichothecenes (A-Trich), type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN), and ochratoxin A (OTA). The 2022 crop year data were compared with the prior four harvest years using GLIMMIX procedure of SAS with harvest year as fixed effect and sample as the experimental unit. A limited number of samples is available thus far (n = 44) as harvest is still progressing, therefore the risk profile of this crop year is likely to change as the sample pool expands. Contamination levels in corn for the tested toxin groups have remained consistent over the survey period. To date, 97% of the samples evaluated contained at least one mycotoxin, compared with 90% that was observed in 2021. The percentage of Afla contaminated samples increased (P < 0.05) in 2022 corn compared with the 2020 and 2021 harvest years (42 vs. 5 and 7%). The percentage of FUM contaminated samples in 2022 corn is greater (P < 0.05) compared with 2020 and 2021 (88 vs. 64 and 64%). The preliminary results of the 2022 US corn crop survey indicate mycotoxin occurrence and contamination levels are similar or greater (Afla and FUM) to the prior crop year and will continue to challenge animal health and performance as these ingredients are fed out.

Yield and Nutrient Uptake of T. Aman Rice as Influenced by Fertilizer Management and Preceding Crop Combinations in Vegetable-Vegetable-Rice Cropping Sequence

In recent years awareness of fertility status of soil and the nutrients requirement for crops according to cropping arrangement has increased. In this context, the study was carried out over 2 years (2018 and 2019) at the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) research farm to assess the influence of fertilizer management and preceding crop combinations on yield and yield contributing attributes of subsequent T. Aman rice; to determine the amount of nutrient concentration and taken up by the subsequent T. Aman rice regarding the preceding crops combinations and fertilizer treatments in vegetable–vegetable–rice cropping sequence. Treatments consisted of three prior crop combinations, i.e., before planting T. Aman rice (Potato-Stem Amaranth, Garlic-Stem Amaranth and Cauliflower-Stem Amaranth) including for each, four replications of two fertilizer treatments: commercial organic fertilizer (N based organic compost) and inorganic fertilizer (Soil test based inorganic fertilizer without cow dung). The subsequent T. Aman rice (BRRI dhan75) yields and yield contributing characters were not significantly affected by the interaction effect of preceding crop combinations and fertilizer application. Furthermore, fertilizer treatments had no significant effect on yields and yield components of T. Aman rice (BRRI dhan75) excluding plant height. Preceding crop combination had significant effect on grain panicle-1 of T. Aman rice (BRRI dhan75). At the end of two years, results clearly indicated that yield contributing parameters of BRRI dhan75 performed better under both preceding crop combinations as P2 (Garlic-Stem Amaranth) and P3 (Cauliflower-Stem Amaranth) with F2 (soil test based inorganic fertilizer management). Whereas yield was found greater under both preceding crop combination, P1 (Potato - Stem Amaranth) with F1 (N based organic compost alone) and P2 (Garlic-Stem Amaranth) using F2 (soil test based inorganic fertilizer). The interaction of preceding crop combination and fertilizer application demonstrated significant effect on nutrient concentration (Nitrogen, Phosphorus and Potassium) in grain and straw of T. Aman. The application of inorganic fertilizer using the soil test-based method significantly increased N uptake by grain under both preceding crop combination as P2 (Garlic-Stem Amaranth) and P3 (Cauliflower-Stem Amaranth) compared with a sole application of N based organic compost. Yet, it is too quick to create a decisive remark based on only these very few numbers of preceding crops combinations and fertilizer treatments in vegetable-vegetable-rice cropping sequence. Therefore, a detailed study with a huge number of organic and inorganic fertilizer treatments applied under large number of vegetable-vegetable-rice cropping sequence is obviously needed to reach a precise conclusion.

Twenty-four years of contrasting cropping systems on a brown chernozem in Southern Alberta: crop yields, soil carbon, and subsoil salinity

Cropping systems with perennial forages and reduced fallow frequency generally increase soil organic carbon and thus subsequent soil health and crop yield. We evaluated the impact of prior cropping systems on subsequent yields and soil properties in a semiarid region by using crop yields as a bioassay of soil health following the termination of a 24-year crop rotation study in the Brown soil zone in Alberta. During 24 growing seasons from 1992 to 2015, the study included three fallow-containing rotations, two annual crop rotations that were cropped continuously, and perennial grass hay, each with two to six fertilizer treatments. During the bioassay period from 2016 through 2020, all plots in the study were uniformly cropped. Compared to unfertilized fallow wheat, soil organic C in the fall of 2015 was 54% higher after 24 years of fertilized grass and up to 14% higher following annual crops in rotations without fallow. The most notable impact of the previous cropping system on yield during the bioassay years was low yield following perennial grass in 2016 and 2018. Soil electrical conductivity measurements showed that subsoil salinity was elevated following perennial grass, demonstrating the importance of subsoil characteristics for healthy soils. Crop yields in the fifth year of the crop bioassay were 10%–20% greater due to reduced fallow frequency or increased crop diversity. The long-term impact of the cropping system on crop yield in this study depended on drought intensity due to counteracting changes in soil organic matter and subsoil salinity.

Soybean Crops Penalize Subsequent Wheat Yield During Drought in the North China Plain.

Contemporary wisdom suggests that inclusion of legumes into crop rotations benefit subsequent cereal crop yields. To investigate whether this maxim was generically scalable, we contrast summer soybean–winter wheat (SW) with summer maize–winter wheat (MW) rotation systems in an extensive field campaign in the North China Plain (NCP). We identify heretofore unseen interactions between crop rotation, synthetic N fertilizer application, and stored soil water. In the year with typical rainfall, inclusion of soybean within rotation had no effect on wheat ear number and yield, while N fertilization penalized wheat yields by 6–8%, mainly due to lower dry matter accumulation after anthesis. In contrast, in dry years prior crops of soybean reduced the rate and number of effective ears in wheat by 5–27 and 14–17%, respectively, leading to 7–23% reduction in wheat yield. Although N fertilization increased the stem number before anthesis in dry years, there was no corresponding increase in ear number and yield of wheat in such years, indicating compensating reduction in yield components. We also showed that N fertilization increased wheat yield in MW rather than SW as the former better facilitated higher dry matter accumulation after flowering in dry years. Taken together, our results suggest that soybean inclusion reduced soil available water for subsequent wheat growth, causing yield penalty of subsequent wheat under drought conditions. We call for more research into factors influencing crop soil water, including initial state, crop water requirement, and seasonal climate forecasts, when considering legumes into rotation systems. Graphical Response of wheat population and yield to soybean inclusion under limited-irrigation.

Quantifying the Impact of Reduced Nitrogen Rates on Grain Yield and Nitrogen Use Efficiency in the Wheat and Rice Rotation System of the Yangtze River Region

Nitrogen (N) plays a vital role in plant growth; however, the yield response to N fertilizer is regularly declining in the major cropping systems due to overuse and the upper limit of yields. Heavy losses of N are also documented due to its excessive use in the rice-wheat rotation system, resulting in low nitrogen-use efficiencies (NUE) and environmental problems. Therefore, a three-year field experiment was performed with different N managements to investigate the impact of reduced N input rates in this exhaustive cropping system. Reducing the N application rates did not affect the wheat and rice yields significantly, only during the second wheat season was the yield slightly reduced as compared to higher N input treatments. Decreasing the N input rates in the prior crop and present crop, and the interactions of both rice and wheat seasons (R × W) did not influence the yields of either crop. A reduction in N fertilizer had a considerable impact on dry matter production during the wheat seasons but demonstrated no effect during the rice season. The accumulation of N was significantly reduced during both crop seasons by lowering the rate of N application. In addition, the NUE indices were significantly influenced by N fertilizer application rates. In conclusion, N fertilizer input rates for both rice and wheat crops can be lowered as compared to present fertilization rates without any risk of yield decline. Lowering the N input increases the NUE and effectively reduces N losses, and soil N status can also be maintained.

PSV-16 Recent Mycotoxin Contamination Trends in 2021 United States Corn

Abstract Mycotoxins are harmful secondary fungal metabolites detrimental to animal health even at low levels. The study was conducted to compare mycotoxin contamination of initial samples of the 2021 corn crop with previous year trends. Samples were analyzed utilizing the liquid chromatography and tandem mass spectrometry (LC-MS/MS) method for 6 major mycotoxin groups: aflatoxins (Afla), type A trichothecenes (A-Trich), type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN), and ochratoxin A (OTA). The 2021 corn crop year data were compared with the prior harvest years using GLIMMIX procedure of SAS with harvest year as fixed effect and sample as the experimental unit. A limited number of samples is available thus far (n = 44) as harvest is still progressing, therefore the risk profile of this crop year is likely to change as the sample pool expands. To date, 100% of the samples evaluated contained at least one mycotoxin, compared with 87% that was observed in 2020. The FUM is the most prevalent mycotoxin group (80% positive in 2021 vs. 49% in 2020) with average contamination level 5,883 ppb, which is significantly (P < 0.05) greater than the 2019 and 2020 harvested corn (3,348 ppb and 2,783 ppb, respectively). Contamination levels in corn for Afla, A-Trich, B-Trich, ZEN, and OTA have remained consistent over the survey period. The percentage of B-Trich and ZEN contaminated samples are numerically decreased in 2021 compared with 2020 (B-Trich: 59% vs. 50%; ZEN: 20% vs. 11%), whereas Alfa contaminated corn has increased numerically (5% vs. 23%). The preliminary results of the 2021 corn crop survey indicate mycotoxin occurrence and contamination levels are similar or greater (FUM) to the prior crop year and will continue to challenge animal health and performance as these ingredients are fed out.

Prior crop season management constrains farmer adaptation to warming temperatures: Evidence from the Indo-Gangetic Plains

Climate change induced heat stress is predicted to negatively impact wheat yields across the Indo-Gangetic Plains (IGP) of India. Research suggests that early sowing of wheat can substantially reduce this impact. However, a large proportion of farmers sow wheat late across this region, likely resulting in large-scale yield loss. We examined the extent of late wheat sowing across the IGP and which perceptional, management, biophysical, and socio-economic factors are associated with delayed sowing using household survey data from 2429 farmers and the cumulative logit model. Our results indicate that despite understanding that early sowing can be helpful to avoid terminal heat stress, over 50% of farmers sow wheat later than their perceived ideal wheat sowing date. We find that variables related to how wheat fields are prepared prior to sowing are associated with wheat sowing date. Specifically, farmers who had shorter fallow periods prior to sowing wheat and those who used zero tillage were 95% and 65% more likely to sow wheat earlier, respectively. In addition, we found that how farmers managed their rice crop in the preceding cropping season impacted wheat sowing date – farmers who transplanted and harvested rice later and/or planted longer duration rice varieties sowed their wheat later. Our results suggest that policies that promote earlier sowing of rice, such as improved access to irrigation and direct seeding machinery, and reduced field preparation time, such as wider adoption of zero tillage technologies, can help farmers across the IGP sow wheat earlier. This is critical given that warming temperatures will only increase the negative impacts of terminal heat stress on wheat yields across this region over the coming decades.

Predicting soil organic matter nitrogen mineralization

AbstractThe objectives of this study were to develop a model for soil organic matter (SOM) N mineralization that required minimal inputs, to test the model using independent datasets, and to determine if the results could be used in adjusting commercial N fertilizer recommendations. A first‐order model was adjusted monthly for differences in soil temperature and moisture. A daily time step was used to allow N mineralization estimates from one date to another. Simulations began in the month where temperature exceeded 10 °C. Model predictions were compared with those in published studies in northern California and Illinois. In the first California study, model predictions were near observed values in four of five locations. In the second California study, model predictions were within the 95% confidence interval of those based on laboratory incubation corrected for field temperature and moisture regimes. In a third study, unfertilized corn (Zea mays L.) yields were compared with seasonal N mineralization predictions plus N from the prior crop for 15 Illinois soils. The result was 32.0 kg corn kg−1 seasonal available N as compared with the typical value of 67.5 kg corn kg−1 commercial N fertilizer. Nitrogen mineralization predictions for Illinois soils were related to total N, suggesting that an equation could replace simulation modeling for a given soil–location combination. It is proposed that the N mineralization model, which has readily obtainable inputs (total N, bulk density, monthly weather), could be used in conjunction with field studies to refine commercial N fertilizer recommendations.

植株密度和氮素互作对垂穗披碱草生物量分配的影响

垂穗披碱草（Elymus nutans）是高寒地区建植和改良栽培草地的首选草种。虽然合理植株密度和氮素添加量是垂穗披碱草栽培草地稳产的关键因子，但两者之间是否存在最佳互作组合仍不清楚。采用盆栽试验，通过分析不同植株密度（58、102、146株/m²）和氮素添加量（0、200、400 mg/kg）组合状态下垂穗披碱草株高、单株分蘖数、地上生物量、地下生物量、根系体积和地上地下生物量比，以确定理论上是否存在植株密度和氮素添加量的最佳组合。结果表明：随植株密度增加，垂穗披碱草株高、地上生物量和地上地下生物量比值均先增加后降低，而单株分蘖数逐渐减小，根系体积和地下生物量先增加后保持相对稳定；随氮素添加量增加，垂穗披碱草单株分蘖数、地上生物量和地上地下生物量比值均表现为先增加后降低，地下生物量逐渐降低。植株密度与氮素添加量互作虽然对垂穗披碱草的根系体积和单株分蘖数没有显著影响，但两者互作显著影响了垂穗披碱草株高、地上生物量、地下生物量、地上地下生物量比（P<0.01），这些指标与植株密度和氮素添加量的关系均表现为一个开口向下的抛物面。当植株密度为102株/m²和氮素添加量为200 mg/kg时，垂穗披碱草栽培草地产量最大，生物量分配最优。垂穗披碱草植株密度和氮素添加互作时理论上存在最佳组合，这为垂穗披碱草栽培草地的田间管理提供了理论依据。;Elymus nutans is the prior crop to establish the pasture or improve the pasture in the alpine regions because it is cold-resistant tolerance with good quality. Although proper plant density and nitrogen application rate are conserved as the key factors to affect the yield stability of Elymus nutans pasture, whether there is an optimally theoretical combination of plant density and nitrogen application rate for maintaining the relative yield of Elymus nutans is not well documented. A pot experiment was conducted in a greenhouse to investigate the effect of different combination of plant densities and nitrogen application rates on the plant height, tiller per plant, aboveground biomass, underground biomass, root volume and aboveground to underground biomass ratio, which can be used to identify an optimally theoretical combination between plant density and nitrogen application rate. In this study, the plant densities consisted of 58, 102, 146 plants per square meter and nitrogen application rate was 0, 200, 400 mg/kg. This study showed that with the increase of plant density, the plant height, aboveground biomass and aboveground to underground biomass ratio of Elymus nutans increased first and then decreased, while the tiller per plant decreased gradually, the root volume and underground biomass increased first and then remained relatively stable. The tiller per plant, aboveground biomass and aboveground to underground biomass ratio of Elymus nutans increased first and then decreased with the increase of nitrogen application rates, and the underground biomass decreased gradually. Interaction between plant densities and nitrogen application rates was found to had no effect on root volume and tiller per plant, whereas it was observed to have significant effects on the plant height, aboveground biomass, underground biomass, and the aboveground to underground biomass ratio. The relationships between above-mentioned parameters (plant height, aboveground biomass, underground biomass, and the aboveground to underground biomass ratio) and nitrogen application rate and plant density showed the downward 3D response surfaces, and this demonstrated that there was an optimally theoretical combination between proper plant density and nitrogen application rate, under which plant height, aboveground biomass, underground biomass, and the aboveground to underground biomass ratio were the best. In this study, the optimal combination of plant density and nitrogen application rate were 102 plants per square meter and the nitrogen application rate was 200 mg/kg. The findings of this study suggest that there is an optimally theoretical combination of plant density and nitrogen application rate for maintaining the relative yield of Elymus nutans pasture, which can provide a scientific basis for high persistence yield and optimal allocation of above/underground biomass of Elymus nutans pasture in the field management.

The effect of organic and chemical fertilizers on oilseed rape productivity and weed competition in short rotation

A two-year field experiment was conducted to investigate the impact of short crop rotation and organic amendments on rapeseed yield under weed competition conditions. The primary experimental plots consisted of either triticale or pea as a prior crop, consisting of four subplots with either 25 tons of composted cattle manure (CCM), 150 kg urea N ha−1 (N), 25 tons composted cattle manure + 75 kg urea N ha−1 (CCM + N), or no urea N or manure added as the control (C0). Rapeseed seed yield was not significantly affected by previous crops, except for rapeseed grown after pea which had slightly higher seed yield (2058 kg ha−1) than those grown after triticale (1942 kg ha−1). Plants that received CCM + N produced the highest amount of seed yield (2447 kg ha−1), but were not significantly different from plants that received just urea N (2218 kg ha−1). Weeds gained more biomass when the previous crop was pea compared to those whose previous crop was triticale. Weeds in plots that received CCM + N produced the greatest biomass, followed by N, and CCM plots, respectively.

Root mass may affect soil water infiltration more strongly than the incorporated residue

This Brief Report includes a single-finding that is reported with descriptions of an unexpected observation. Crop residue incorporation increases stable soil pores and soil water infiltration, consequently, reduces surface water runoff and soil erosion. However, to our knowledge, quantitative studies for the relation between incorporated residue and infiltration rate has not been conducted. To know the relation is important for avoiding soil erosion under crop rotation in practically. We continuously grew corn (cleaning crop), rhodes grass, and okra under greenhouses. The water infiltration rate was measured on the ridge at similar soil moisture conditions, on the day incorporating the prior crop residue. The simple linear regression analysis was conducted. The coefficient of determination R2 was 0.91; however, that for aboveground dry matter of prior crop was 0.93, unexpectedly. Though, our experiment not designed for distinguish those effect; previous studies have revealed the positive relation between plant root mass and soil erosion resistance. Our data also show a positive relationship between resistance to erosion and root mass when assuming that the aboveground biomass is proportional to the root mass. The result also showed that the effect of the prior crop root mass disappears within the next crop period. This suggests that maintaining a large root mass is crucial for reducing soil erosion.

Root mass may affect soil water infiltration more strongly than the incorporated residue

This Brief Report includes a single-finding that is reported with descriptions of an unexpected observation. Crop residue incorporation increases stable soil pores and soil water infiltration, consequently, reduces surface water runoff and soil erosion. However, to our knowledge, quantitative studies for the relation between incorporated residue and infiltration rate has not been conducted. We examined the relationship between the quantity of crop residue of the prior crop and the water infiltration rate. We continuously grew corn (cleaning crop), rhodes grass, and okra under greenhouses. The water infiltration rate was measured on the ridge at similar soil moisture conditions, on the day incorporating the prior crop residue. A correlation between the quantity of incorporated residue and the soil water infiltration rate was not constant; because, the infiltration rate per incorporated residue was irregularly low when it had no prior crop. By contrast, aboveground biomass of the prior crop showed a stronger correlation with water infiltration rate ( r = 0.965), without outliers. Furthermore, the correlation was weakened ( r = 0.872) by the treatment affected the soil moisture that affects the root mass. Previous studies have revealed the positive relation between plant root mass and soil erosion resistance. Our data also show a positive relationship between resistance to erosion and root mass when assuming that the aboveground biomass is proportional to the underground biomass. The result also showed that the effect of the prior crop root mass disappears within the next crop period. This suggests that maintaining a large root mass is crucial for reducing soil erosion.

Root mass may affect soil water infiltration more strongly than the incorporated residue

This Brief Report includes a single-finding that is reported with descriptions of an unexpected observation. Crop residue incorporation increases stable soil pores and soil water infiltration, consequently, reduces surface water runoff and soil erosion. However, to our knowledge, quantitative studies for the relation between incorporated residue and infiltration rate has not been conducted. We examined the relationship between the quantity of crop residue of the prior crop and the water infiltration rate. We continuously grew corn (cleaning crop), rhodes grass, and okra under greenhouses. The water infiltration rate was measured on the ridge at similar soil moisture conditions, on the day incorporating the prior crop residue. A strong correlation was found between the quantity of inputted residue and the soil water infiltration rate ( r = 0.953); however, that of corn, had no prior crop, is the outlier. The outliner is nonnegligible because the infiltration rate per input residue is two fifth of other crops. By contrast, aboveground biomass of the prior crop showed a stronger correlation with water infiltration rate ( r = 0.965), without outliers. Previous studies have revealed the logarithmic relation between plant root mass and soil erosion resistance. Our data also show a positive relationship between resistance to erosion and root mass when assuming that the aboveground biomass is proportional to the underground biomass. The result also showed that the effect of the prior crop root mass disappears within the next crop period. This suggests that maintaining a large root mass is crucial for reducing soil erosion.

Root mass may affect soil water infiltration more strongly than the incorporated residue

This Brief Report includes a single-finding that is reported with descriptions of an unexpected observation. Crop residue incorporation increases stable soil pores and soil water infiltration, consequently, reduces surface water runoff and soil erosion. However, to our knowledge, quantitative study for the relation between incorporated residue and infiltration rate has not been conducted. In this study, we examined the relationship between the quantity of crop residue of the prior crop and the water infiltration rate. We grew corn, rose grass, and okra in crop rotation under greenhouses and measured the water infiltration rate at the time of ridge making. A strong correlation was found between the quantity of applied residue and the soil water infiltration rate ( r = 0.953), although there were outliers in the case of no prior crop. By contrast, aboveground biomass of the prior crop showed a stronger correlation with water infiltration rate (r = 0.965), without outliers. Previous studies have revealed the logistical relation between plant root mass and soil erosion. Our data also show a positive relationship between resistance to erosion and root mass when assuming that aboveground biomass is proportional to the underground biomass. The result also showed that the effect of the prior crop root mass disappears within the next crop period. This suggests that maintaining a large root mass is crucial for reducing soil erosion.

Root mass may affect soil water infiltration more strongly than the incorporated residue

Crop residue incorporation increases stable soil pores and soil water infiltration, consequently, reduces surface water runoff and soil erosion. However, few studies have examined the relationship between crop residue incorporation and water infiltration. A previous study showed that water infiltration increases depending on the quantity of applied wheat straw. In this study, we examined whether the relationship is applicable to different crop residues in a crop rotation. We grew corn, rose grass, and okra in crop rotation under greenhouses and measured the water infiltration rate at the time of ridge making. A strong correlation was found between the quantity of applied residue and the soil water infiltration rate ( r = 0.953), although there were outliers in the case of no prior crop. By contrast, aboveground biomass of the prior crop showed a stronger correlation with water infiltration rate ( r = 0.965), without outliers. Previous studies have revealed the exponential relation between plant root mass and soil erosion. Our data also show a positive relationship between resistance to erosion and root mass when assuming that aboveground biomass is proportional to the underground biomass. The result also showed that the effect of the prior crop root mass disappears within the next crop period. This suggests that maintaining a large root mass is crucial for reducing soil erosion.

Root mass may affect soil water infiltration more strongly than the incorporated residue

Crop residue incorporation increases stable soil pores and soil water infiltration and reduces surface water runoff and soil erosion. However, few studies have examined the relationship between crop residue incorporation and water infiltration. A previous study showed that water infiltration increases depending on the quantity of applied wheat straw. In this study, we examined whether the relationship is applicable to different crop residues in a crop rotation. We grew corn, rose grass, and okra in crop rotation under plastic film houses and measured the water infiltration rate at the time of ridge making. A strong correlation was found between the quantity of applied residue and the soil water infiltration rate (r = 0.953), although there are outliers in the case of no prior crop. However, aboveground biomass of the prior crop showed a stronger correlation with water infiltration rate (r = 0.965), without outliers. Previous studies have revealed the exponential relation between plant root mass and soil erosion. Our data also show a positive relationship between resistance to erosion and root mass when assuming that aboveground biomass is proportional to the underground biomass. The result also showed that the effect of the prior crop root mass disappears within the next crop period. Our results indicate that maintaining a large root biomass is crucial for reducing soil erosion.

Root mass may affect soil water infiltration more strongly than the incorporated residue

Crop residue incorporation increases stable soil pores and soil water infiltration and reduces surface water runoff and soil erosion. However, few studies have examined the relationship between crop residue incorporation and water infiltration. A previous study showed that water infiltration increases depending on the quantity of applied wheat straw. In this study, we examined whether the relationship is applicable to different crop residues in a crop rotation. We grew corn, rose grass, and okra in crop rotation under plastic film houses and measured the water infiltration rate at the time of ridge making. A strong correlation was found between the quantity of applied residue and the soil water infiltration rate (r = 0.953), although there are outliers in the case of no prior crop. However, aboveground biomass of the prior crop showed a stronger correlation with water infiltration rate (r = 0.965), without outliers. Previous studies have revealed the exponential relation between plant root mass and soil erosion. Our data also show a positive relationship between resistance to erosion and root mass when assuming that aboveground biomass is proportional to the underground biomass. The result also showed that the effect of the prior crop root mass disappears within the next crop period. Our results indicate that maintaining a large root biomass is crucial for reducing soil erosion.

EFECTO DE PRE-CULTIVOS HOSPEDEROS Y NO HOSPEDEROS EN EL CRECIMIENTO Y PROPÁGULOS MICORRÍCICOS DE TRIGO EN ANDISOL E INCEPTISOL DE CHILE

Arbuscular mycorrhizal (AM) fungi are obligate symbionts that improve nutrient absorption of plants. Including non-mycorrhizal plants in crop rotations as previous-crops can affect the symbiosis. The objective of this work was to study the influence of prior crop with an AM host or a non-host plant on the mycorrhizal propagule number, growth and nutrient uptake in wheat grown in the second year under greenhouse conditions. Oats, lupin and rapeseed were seeded the first year in an Andisol and an Inceptisol of La Araucania Region, Chile, followed by wheat in the second year. The treatments were: oats-wheat (A-T), lupin-wheat (L-T) and rapeseed-wheat (R-T). The highest above ground biomass, number of inflorescences of plants, and P and Fe contents in leaves were obtained in L-T (cropping with a non-host followed by a host plant) in an Andisol. A significant increase in the content of Mg and K in wheat was observed in the A-T treatment in an Inceptisol. Regarding mycorrhizal parameters, the highest root colonization (35%) in wheat was observed in L-T in the Andisol, while the A-T treatment recorded the highest spore number but the lowest root colonization (19%). The highest phosphatase activity of wheat roots was observed in R-T in both types of soils, while the lowest value recorded in L-T in the Andisol. It is was concluded that growing wheat after a non-mycorrhizal host plant, like rapeseed, decreases the number of mycorrhizal propagules (spores) in both Andisol and Inceptisol, while pre-cropping with host plants increases the propagule number in wheat.