Spatial differences influence nitrogen uptake, grain yield, and land-use advantage of wheat/soybean relay intercropping systems

Cereal/legume intercropping is becoming a popular production strategy for higher crop yields and net profits with reduced inputs and environmental impact. However, the effects of different spatial arrangements on the growth, grain yield, nitrogen uptake, and land-use advantage of wheat/soybean relay intercropping are still unclear, particularly under arid irrigated conditions. Therefore, in a three-year field study from 2018 to 2021, soybean was relay intercropped with wheat in different crop configurations (0.9 m, narrow strips; 1.8 m, medium strips; and 2.7 m, wide strips), and the results of intercropping systems were compared with their sole systems. Results revealed that intercrops with wide strips outperformed the narrow and medium strips, when the objective was to obtain higher total leaf area, dry matter, nitrogen uptake, and grain yield on a given land area due to reduced interspecific competition between intercrops. Specifically, at maturity, wide strips increased the dry matter accumulation (37% and 58%) and its distribution in roots (37% and 55%), straw (40% and 61%), and grains (30% and 46%) of wheat and soybean, respectively, compared to narrow strips. This enhanced dry matter in wide strips improved the soybean’s competitive ability (by 17%) but reduced the wheat’s competitive ability (by 12%) compared with narrow strips. Noticeably, all intercropping systems accumulated a significantly higher amount of nitrogen than sole systems, revealing that wheat/soybean relay intercropping requires fewer anthropogenic inputs (nitrogen) and exerts less pressure on the ecosystem than sole systems. Overall, in wide strips, intercropped wheat and soybean achieved 62% and 71% of sole wheat and soybean yield, respectively, which increased the greater total system yield (by 19%), total land equivalent ratio (by 24%), and net profit (by 34%) of wide strips compared to narrow strips. Our study, therefore, implies that the growth parameters, grain yields, nutrient accumulation, and land-use advantage of intercrop species could be improved with the proper spatial arrangement in cereal/legume intercropping systems.

(Fig. 1d-f).At 45, 75, and 105 DAS, the mean maximum LAI of both crops was observed in sole systems, while the mean minimum LAI of both crops was noticed in narrow strips.In WSI, at 105 DAS, the average highest LAI of wheat (3.2) and soybean (4.5) was recorded in wide strips, whereas the average lowest LAI of wheat (2.1) and soybean (3.7) was noted in narrow strips.However, the total LAI of intercropping systems was significantly higher than the LAI of sole wheat and sole soybean (Fig. 1g-i).For instance, at 105 DAS, the total LAI in narrow strips, medium strips, and wide strips, respectively, was increased by 81%, 100%, and 120% compared to sole wheat and by 29%, 43%, and 57% compared to sole soybean, indicating that the WSI as a whole developed better canopy to capture solar radiations.

Dry matter accumulation and distribution in wheat and soybean
The different planting systems significantly affected the dry matter of wheat (Fig. 2a-c) and soybean (Fig. 2d-f).The dry matter of both crops in all systems increased rapidly from 45 to 105 DAS and achieved the highest values at maturity.Average over the years, at maturity, the maximum (1562.4g m −2 ) dry matter of wheat in sole wheat was 77%, 57%, and 29% higher than the dry matter of wheat in narrow strips, medium strips, and wide strips, respectively; whereas, the maximum (677.6 g m −2 ) soybean dry matter in sole soybean was 90%, 40%, and 20%, higher than the dry matter of soybean in narrow strips, medium strips, and wide strips, respectively.In contrast, at all sampling times, the total dry matter of WSI was significantly higher than the dry matter of sole systems (Fig. 2g-i), and the total dry matter of different planting systems exhibited the trend as wide strips > sole wheat > medium strips > narrow strips > sole soybean.Overall, among WSI, at maturity, the total dry matter in wide strips was increased by 43% and 21% compared to narrow and medium strips, respectively.Besides, the different planting systems significantly changed the dry matter distribution in plant organs of wheat (Table 1) and soybean (Table 2) at 45, 75, and 105 DAS and maturity, except at the first sampling stage (45 DAS) of wheat.Across the years, at maturity, wheat distributed the highest dry matter in the roots (189.9 g m −2 ), straw (962.9 g m -2 ), and grains (409.6 g m −2 ) in sole wheat, while the highest dry matter in the roots (101.5 g m −2 ), straw (476.9 g m −2 ), and grains (99.2 g m −2 ) of soybean were noticed in sole soybean.However, in WSI, compared to narrow strips, wide strips increased the distribution of dry matter in the grains of wheat and soybean by 30% and 46%, respectively.Additionally, in all years of this study, the dynamics of dry matter accumulation and its

Yield and yield components of wheat and soybean
Yield and yield components of wheat differed significantly in all planting systems, as presented in (Table 3; Fig. 4a-c).Sole wheat always had a significantly higher grain yield than in intercropping systems.However, in WSI, the wide strips had a higher grain yield than the narrow and medium strips.For instance, the wide strips increased the wheat grain yield by 14% and 9% compared to narrow strips and medium strips, respectively.Moreover, in yield components, the ear density m 2 and seeds spike -1 of sole wheat were significantly higher than those in intercropping systems.In contrast, the hundred-seed weight of intercropped wheat was significantly higher in intercropping than sole wheat.On average, in WSI, the wide strips had higher ear density (214.2 m 2 ) and seeds (38.2 spike −1 ) of wheat than narrow and medium strips, and the maximum hundred seed weight (4.4 g) of wheat was observed in medium strips than wide and narrow strips, suggesting that wheat in wide and medium strips invested their photosynthates more efficiently for yield and yield components than in narrow strips, especially at the time of the formation of yield components.An increase in strip width significantly increased the soybean yield in all intercropping systems, but the sole soybean always had a significantly higher yield than intercropped soybean yield in narrow, medium, and wide strips (Table 3; Fig. 4d-f).Over the years, the intercropped soybean had 53%, 58%, and 71% of sole soybean yield in narrow strips, medium strips, and wide strips, respectively.Furthermore, in all years, the pods plant −1 , seeds plant −1 , and hundred seed weight of soybean were significantly lower under intercropping systems than the corresponding values in sole soybean.Compared to narrow strips, the wide strips increased the pods plant −1 (by 32%), seeds plant −1 (by 24%), and hundred seed weight (by 20%), indicating that the improvement in yield and yield components of intercropped soybean in wide strips were due to the relaxed competitive interactions www.nature.com/scientificreports/ between wheat and soybean.Additionally, in WSI, the total grain yield of wide strips (3835.2kg ha −1 ) was significantly higher than medium strips (by 13%; 3407.5 kg ha −1 ) and narrow strips (by 19%; 3215.8 kg ha −1 ), demonstrating that the use of wide strips was more effective and efficient in utilizing the available resources (land and nitrogen) than medium and narrow strips in WSI (Table 3; Fig. 4).

Land equivalent ratio and competition ratio
Different strip widths in WSI significantly affected the pLERw, pLERs, and total LER values (Table 3).On average, among WSI, wheat and soybean had the highest and lowest pLERw and pLERs values in wide strips and narrow strips, respectively.The values of total LER in narrow strips, medium strips, and wide strips ranged from 1.04 to 1.35, exhibiting a land use advantage over sole systems.Generally, across the years and WSI, the mean values of total LER were higher in wide strips than in narrow and medium strips.Wide strips increased the total LER by 24% and 16% compared to narrow and medium strips, respectively, demonstrating that wide strips were more advantageous in achieving the intercropping benefits.Moreover, the changes in strip width significantly impacted the competitive abilities of wheat and soybean in WSI (Table 3).The mean maximum (1.02) and minimum (0.87) values of CRw were noted in narrow strips and wide strips, while the opposite trends were noticed for the values of CRs, and the average highest (1.15) and lowest (0.98) values of CRs were noticed in wide strips and narrow strips, respectively.Overall, the wide strips increased the CRs by 17% and reduced the CRw by 12% compared to narrow strips, exhibiting that the competitive ability of intercrops in the WSI was closely associated with changes in strip width.

Economic viability
Grain yields of both crops impacted the gross income, benefit-to-cost ratio, and net profit of all systems (Table 4).The mean maximum gross income (1813 US$ ha −1 ) and net profit (1081 US$ ha −1 ) were recorded in wide strips, while the mean minimum gross income (1075 US$ ha −1 ) and net profit (320 US$ ha −1 ) were observed in sole soybean.Average across the years and planting systems, the wide strips increased the net profit by 34% and 42% compared to narrow strips and sole wheat, respectively, suggesting that the strip intercropping of wheat and www.nature.com/scientificreports/soybean was economically advantageous over narrow strips in WSI and sole wheat.Moreover, the benefit-to-cost ratio differed considerably among various planting systems; the average highest (2.6) benefit-to-cost ratio was noticed in wide strips, whereas the average lowest (1.5) benefit-to-cost ratio was noted in sole soybean.
Table 3. Grain yield, land equivalent ratio, and the competitive ratio of wheat and soybean under different planting systems.Means are averages over three replicates ± standard error of the mean.NS: Non-significant differences were detected between means using the LSD test.

Discussion
Intercropping contains multifaceted research interests from a broad range of researchers, including agronomists, agroecologists, and environmentalists.Despite the wide range of agronomic advantages and ecological services offered by intercropping, large-scale farmers still prefer mechanized monocultures, where crops mature evenly with improved methods of plant protection and crop varieties over un-mechanized intercropping systems, where intercrops mature unevenly and do not have proper plant protection measures and intercropping-specific crop varieties [45][46][47] .Thus, resource-exhaustive monocultures requiring higher anthropogenic inputs exert extra pressure on the ecosystem compared to intercropping systems that have a lower environmental impact.This situation demands us to investigate such spatio-temporal attributes of intercropping systems that could compete with monocropping systems in terms of mechanization and food security to extend their ecological advantages.Subsequently, with an objective to explore the potential spatio-temporal arrangements for possible mechanization of intercropping systems with higher agro-economic and ecological returns, we conducted this study to verify our three hypotheses.The first hypothesis was confirmed by our data; compared to narrow strips, both intercrops had a higher dry matter and grain yield with wide strips.The data strongly confirmed the second hypothesis: intercropping systems accumulated higher total nitrogen than sole systems.The third hypothesis was also strongly confirmed; both intercrops were planted, harvested, and threshed easily with the existing farm machinery in wide strips.This ultimately increased the net profit by saving considerable labour expenses on sowing, harvesting, and threshing, reducing the yield losses with manual management of crops.Eventually, our findings revealed that wide strips for intercrops are (a) more appropriate and favourable for obtaining the maximum benefits of WSI, (b) critical for land productivity and large-scale adoption of intercropping systems, and (c) intercropping systems could play an important role in decreasing the environmental impact of agriculture as legume-based intercropping systems require fewer anthropogenic inputs (nitrogen and phosphorus) than sole cereal systems.
Our results demonstrated that changing the strip widths in WSI affected the growth of intercropped species, which might be linked with competition between intercrops for available resources 12,48 ; as the competitive ability of intercrops positively or negatively influenced by the changes in the spatial arrangement of crops in intercropping 10,20 .Similar to our results, a recent review reported a close association between strip widths and interspecific interactions of intercrops in intercropping 40 .The increase in width in the present study shifted the impact of spatial arrangement in favour of soybean and increased the overall yield and mechanization potential of the WSI.Besides mechanization, competition for sunlight is another important constraint, especially in narrow strips, that limits the production of cereal/legume intercropping systems because cereals often provide shade to legumes 41,42 , as observed in this study that early-planted wheat (47 ± 06 Days) intercepted more sunlight due to its greater leaf area and plant height, which affected the initial growth and competitive ability of soybean for water and nutrient uptake, particularly in narrow strips.However, widening the strip width from 0.9 to 2.7 m increased the leaf area and dry matter of soybean, indicating that the wider strips helped to establish an ecological niche that relaxed the competition for sunlight, water, and nutrients between intercrops.These results are consistent with past research in which scientists had confirmed that the intercrops attained the highest values of leaf area index, dry matter, and grain yield in wide strips than in narrow strips 10,31,35,38,49 .
Data from this study further revealed that intercropping with wide strips was more advantageous than with narrow strips.The higher dry matter of intercrops in wide strips demonstrates the efficient utilization of available resources 5 .This could be associated with a high light interception by intercrops because it is directly proportional to the leaf area 39,41 .Although the values of the partial leaf area of intercrops in wide strips were lower than the corresponding values in pure stands, however, the total LAI in wide strips was consistently higher than the LAI of sole wheat or soybean, which could enhance the radiation use efficiency of WSI.This is consistent with past reports 50,51 , in which they obtained higher grain yield with wide strips than narrow strips in cereal/ legume strip intercropping systems and linked it with an increased radiation use efficiency of intercrops 20,52 .The diversity in intercropping leads to better ecological complementarity due to less niche overlap and variable competitive ability 53 .The cereals usually have a competitive advantage over legumes, and incompatible strip width may intensify this competition.On the other hand, provided the suitable spatio-temporal arrangements, the cereal-legume intercropping may also complement each other.For instance, in the present study, the reduced competition in wider strips helped to complement the temporal difference and nitrogen uptake and utilization in wheat and soybeans.Firstly, without interspecific competition, the early-sown wheat showed vigorous initial growth and nitrogen uptake to invest in its reproductive parts at later growth stages.Secondly, the wide strips reduced the competitive pressure of wheat over soybean and facilitated interspecific complementarity during Table 4.Total expense, gross income, net profit, and the benefit-to-cost ratio of wheat and soybean under strip intercropping and sole cropping systems.The local market price for wheat was US$ 233 t -1 in 2019, 258 t -1 in 2020, and 345 t -1 in 2021, and for soybean was US$ 697 t -1 in 2019, 650 t -1 in 2020, and 615 t -1 in 2021.

Planting systems
Total expense (US$ ha -1 ) Gross income (US$ ha -1 ) Net profit (US$ ha - www.nature.com/scientificreports/ the co-growth period.For example, the anthesis of wheat synchronized with the flowering stage of soybean and higher competitive advantage of border-row wheat plants induced higher nitrogen fixation in soybean due to exhaustive uptake of nitrogen from border rows (supported by better light availability).Previous literature has verified the strong recovery growth of soybeans after the harvesting of cereal crops 17 .Similarly, our results also showed the growth improvement in soybeans after the harvesting of wheat; in addition, the extra growing space for soybeans in wide strips than narrow strips led to better resource use and the formation of yield components and yield.Altogether, the higher total nitrogen uptake in intercropping systems with the same nitrogen inputs verified the better niche complementarity and less environmental impact of the wheat/soybean relay intercropping systems over their sole systems 54,55 .Furthermore, the highest total nitrogen uptake in wide strips of wheat/ soybean relay intercropping systems verified that wider strips complement the temporal differences between wheat and soybean in obtaining yield and ecological advantages.The higher yield advantage in wide strips verified the ecological benefits of increased strip width and confirmed that the changing planting configuration, manipulated by strip widths, had a direct impact on the yield and yield components of intercrops in WSI.For instance, the grain yield of intercropped wheat and soybean considerably increased from 54 and 53% (planted in narrow strips, where both intercrops were sown in narrow strips of 0.9 m) to 62% and 71% (grown in wide strips, where both intercrops were planted in wide strips of 2.7 m), respectively.The higher grain yield of intercrops in wide strips was mainly gained from increased dry matter accumulation and its investment in yield formation components of wheat (spike m −2 , by 34%; seeds spike −1 , by 33%; and hundred seed weight, by 5%) and soybean (pod plant −1 , by 32%; seed plant −1 , by 24%; and hundred seed weight, by 20%) than narrow strips, whereas a decrease in spike m −2 , seeds spike −1 , and hundred seed weight of wheat, and pod plant −1 , seed plant −1 , and hundred seed weight of soybean largely caused the yield loss of intercrops narrow strips compared to wide strips.This was the implication of the functional complementary and facilitative effects between intercrops 8 , as the negative effects of wheat shade on soybean were reduced because the soybean border rows were farthest from wheat border rows in wide strips than narrow strips 39 , which substantially increased the soybean yield while maintaining wheat yield.Additionally, in wide strips, the intraspecific competition for growing space and resources was also lessened due to a temporal niche differentiation; for instance, the wheat attained the anthesis and grain filling stages earlier than the flowering and pod formation stages of soybean, this temporal difference allowed both crops to use land and other resources more efficiently than sole systems, resulting in a relative yield advantage for soybean and wheat.All in all, for land use in WSI, we can conclude that intercrops in wide strips produced more grain per unit area of land than in narrow strips, which confirmed the benefits of intercropping over sole systems.
Overall, the positive impacts of wide strips on LER were significant in all years of this study.Compared to narrow strips, the increased LER with wide strips was mainly attributed to ecological niche optimization provided by the edge row and spatial light distribution advantage.Our findings and previous studies on cereal/ legume intercropping 31,36 indicate the positive impact of wide strips on LER 56,57 .Importantly, wide strips in intercropping can be operated and managed using the existing small farm equipment, especially in developing countries (Pakistan and India), where farmers do not have large sowing and harvesting machines as farmers have in Europe or the USA.Consequently, with small farm machinery and wide strips in WSI, it is easy for farmers to achieve the economic, yield and environmental benefits of intercropping.These results highlight the previously mentioned concerns that if researchers do not design new wide-strip intercropping systems or develop small farm machinery, traditional intercropping will become less profitable for farmers.In conclusion, the wide strips are easier to manage, require less labor work, and produce higher grain yields than narrow strip designs in intercropping, as we observed in this study; therefore, we have to replace the narrow strip intercropping designs with wide strip intercropping systems.
Previously, many researchers have confirmed that intercropping with 2 m strips produced higher net profit than 3 or 4 m 1,12,20,40 .However, in this study, the wide strips of 2.7 m gave higher net profit than the narrow strips of 0.9 m; results are similar to those of previous studies 4,31,[35][36][37][38] .A higher net profit of wide strips indicated that wheat and soybean could be planted and harvested using the existing small farm machinery.The significant improvement in the net profit of wide strips was largely attributed to a greater relative grain yield of soybean with a maintained wheat relative grain yield, which greatly contributed to increasing the net profit of wide strips over narrow strips because soybean was valued at four times more expensive than the value of wheat.Importantly, in all years of this study, compared to narrow strips, farm machinery saved 212 US$ per season in 2019, 240 US$ per season in 2020, and 300 US$ per season in 2021 in wide strips, which is a huge net profit for the farmers of developing countries, e.g., Pakistan, where the average monthly income is just around 100 ± 10 US$ per season 58 .The practical implications of our study are clear; intercropping with wide strips is the better planting strategy for producing legumes and cereals in a sustainable and environmental-friendly way with limited land and fewer anthropogenic inputs.However, future research is needed to fully understand the water, light, and nutrient utilization mechanism of intercrops in wide strips under intercropping systems.

Conclusion
The study data confirmed that the wide strips produced higher relative grain yields and saved 20%-30% of the land than narrow strips in WSI or sole systems.Notably, the net profit of wide strips was greatly higher than the net profits of medium strips and narrow strips in WSI; it was also higher than the net profits of sole wheat and sole soybean.Moreover, the intercropping systems accumulated more nitrogen from the soil profile than sole systems, which showed the advantage of intercropping systems over sole cropping systems for saving fertilizers (nitrogen) and the environment.Besides, narrow strips in intercropping systems are difficult to manage because most of the farm machinery has been developed for homogeneous and large cultivated areas.Therefore, the narrow strips need to be transformed into wide strips that could be mechanized and tailored using the existing farm www.nature.com/scientificreports/machinery without losing the crop diversification advantage of intercropping.All in all, these results support the great potential of wide strip intercropping systems for diversifying and restoring the exhaustive sole systems, which could contribute to the sustainable intensification of agriculture.However, without addressing the labor challenge, i.e., through mechanization or spatial management of intercrops, it is difficult for researchers and policymakers to promote the adoption of cereal legume intercropping systems.

Ethics statement
No specific permissions were required to conduct these field experiments.All experiments were performed according to institutional guidelines of the Islamia University of Bahawalpur, Pakistan.Besides, it is confirmed that all methods were performed following the relevant guidelines/regulations/legislation.

Experimental design and crop management
These experiments were carried out using a randomized complete block design with three replications.In total, there were five systems: three strip intercropping systems differing with strip widths (narrow strips, 0.9 m strip for each intercrop; medium strips, 1.8 m strip for each intercrop; and wide strips, 2.7 m strip for each intercrop)  , and 2020, respectively, while the determinate soybean variety 'NARC-2' was sown on December 21, 23, and 25 in 2018, 2019, and 2020, respectively.Wheat was harvested on April 12, 09, and 02 in 2019, 2020, and 2021, respectively, while soybean was harvested on May 07, 05, and 02 in 2019, 2020, and 2021, respectively.Overall, on average, across the years, the total crop growth period of the WSI was 172 ± 06 days, the total days of wheat and soybean growing period were 145 ± 08 days and 136 ± 02 days, respectively, and the total co-growth period was 106 ± 08 days (Fig. 6).At the time of wheat and soybean sowing, phosphorus was applied @ 60 kg ha −1 .The first dose of nitrogen was applied @ 60 kg ha −1 to wheat strips, and 30 kg ha −1 to soybean strips when wheat was at the tillering stage 59 and soybean was at the fifth trifoliate stage 60 .The second nitrogen dose was applied @ 60 kg ha −1 to wheat strips, and 30 kg ha −1 to soybean strips when wheat was at the booting stage 59 and soybean was at the R 2 stage 60 .Urea and diammonium phosphate were used as a source of nitrogen and phosphorus, respectively.

Measurements
In all years of this study, the leaf area index (LAI) of both crops was determined three times at 45, 75, and 105 days after seed emergence (DAS) of each crop.For this purpose, a sample area of one square meter was manually harvested, and the leaf length and maximum width were measured.Then, the leaf area was estimated by multiplying the leaf length and width with the crop-specific co-efficient factor of 0.83 for wheat 61 and 0.75 for soybean 62 .
Table 5.The planting configuration of wheat and soybean under different planting systems.*Distance between the strips of wheat and soybean in intercropping systems.**Sole wheat and soybean were sown according to the local planting densities: 2,200,000 plants ha -1 for wheat and 167,000 plants ha −1 for soybean.However, in strip intercropping systems, we used 50% of sole wheat density for intercropped wheat and 100% of sole soybean density for intercropped soybean, rendering the relative density of intercropped wheat and soybean equal to 0.5 and 1, respectively.*** The total planting density in strip intercropping systems was equal to 1.5; therefore, the design of strip intercropping systems was additive.

Figure 1 . 3 Figure 2 .
Figure 1.Leaf area index of wheat (a-c) and soybean (d-f), and total leaf area index (g-i) at 45, 75, and 105 days after seed emergence under different planting systems: SW (sole wheat), SS (sole soybean), NS (narrow strips; 0.9 m), MS (medium strips; 1.8 m), and WS (wide strips; 2.7 m). Means are averages over three replicates ± standard error of the mean.

Figure 3 .
Figure 3. Nitrogen uptake of wheat (a-c) and soybean (d-f), and total nitrogen uptake (g-i) at 45, 75, and 105 days after seed emergence and maturity under different planting systems: SW (sole wheat), SS (sole soybean), NS (narrow strips; 0.9 m), MS (medium strips; 1.8 m), and WS (wide strips; 2.7 m). Means are averages over three replicates ± standard error of the mean.
13:16916 | https://doi.org/10.1038/s41598-023-43288-3 These experiments were carried out during the winter and spring seasons of 2018-19, 2019-20, and 2020-21 at Khairpur Tamewali under arid irrigated conditions, the experimental field of the National Research Center of Intercropping (29.57°N, 72.25°E; altitude of 130 m), the Islamia University of Bahawalpur, Pakistan.The study area is located in the south of Pakistan, 60 km southeast of Bahawalpur Division, South Punjab.The research region has an annual rainfall of 145 mm (typically, most rain occurs during the monsoon season from end-June to end-August) with a mean temperature of 25.7 °C.The soil type is sandy loam with organic matter of 5.3 g kg −1 , pH of 7.9, total nitrogen of 0.4 g kg −1 , total available phosphorus of 5.3 mg kg −1 , total available potassium of 78.9 mg kg −1 , and bulk density of 1.47 Mg m −3 .The daily PAR, average temperature, and total precipitation during the three growing seasons are presented in Fig. 5.In addition, the total rainfall from sowing to harvesting (November to April) of crops was 53 mm, 232 mm, and 34 mm in 2018-19, 2019-20, and 2020-21, respectively.

Figure 6 .
Figure6.The growth period of wheat and soybean under strip intercropping systems.The upper bar represents the wheat growing period (first sown intercrop species), and the lower bar represents the soybean growing period (second planted intercrop species).The co-growth period is the number of days when both crops grow together.

Table 1 .
Dry matter distribution in wheat at 45, 75, and 105 days after seed emergence (DAS) and maturity under different planting systems.Means are averages over three replicates ± standard error of the mean.NS: Non-significant differences were detected between means using the LSD test.

Table 2 .
Dry matter distribution in soybean at 45, 75, and 105 days after seed emergence (DAS) and maturity under different planting systems.Means are averages over three replicates ± standard error of the mean.